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Eusterhues K, Thieme J, Narvekar S, Araki T, Kazemian M, Kaulich B, Regier T, Wang J, Lugmeier J, Höschen C, Mansfeldt T, Totsche KU. Importance of inner-sphere P-O-Fe bonds in natural and synthetic mineral-organic associations. Sci Total Environ 2023; 905:167232. [PMID: 37734608 DOI: 10.1016/j.scitotenv.2023.167232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 09/23/2023]
Abstract
Sorption of organic molecules on mineral surfaces can occur through several binding mechanisms of varying strength. Here, we investigated the importance of inner-sphere P-O-Fe bonds in synthetic and natural mineral-organic associations. Natural organic matter such as water extracted soil organic matter (WESOM) and extracellular polymeric substances (EPS) from liquid bacterial cultures were adsorbed to goethite and examined by FTIR spectroscopy and P K-edge NEXAFS spectroscopy. Natural particles from a Bg soil horizon (Gleysol) were subjected to X-ray fluorescence (XRF) mapping, NanoSIMS imaging, and NEXAFS spectro-microscopy at the P K-edge. Inner-sphere P-O-Fe bonds were identified for both, adsorbed EPS extracts and adsorbed WESOMs. Characteristic infrared peaks for P-O-Fe stretching vibrations are present but cannot unambiguously be interpreted due to possible interferences with mono- and polysaccharides. For the Bg horizon, P was only found on Fe oxides, covering the entire surface at different concentrations, but not on clay minerals. Linear combination fitting of NEXAFS spectra indicates that this adsorbed P is mainly a mixture of orthophosphate and organic P compounds. By combining atomic force microscopy (AFM) images with STXM-generated C and Fe distribution maps, we show that the Fe oxide surfaces were fully coated with organic matter. In contrast, clay minerals revealed a much lower C signal. The C NEXAFS spectra taken on the Fe oxides had a substantial contribution of carboxylic C, aliphatic C, and O-alkyl C, which is a composition clearly different from pure adsorbed EPS or aromatic-rich lignin-derived compounds. Our data show that inner-sphere P-O-Fe bonds are important for the association of Fe oxides with soil organic matter. In the Bg horizon, carboxyl groups and orthophosphate compete with the organic P compounds for adsorption sites.
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Affiliation(s)
- Karin Eusterhues
- Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany.
| | - Jürgen Thieme
- NSLS II, Brookhaven National Laboratory, Upton, NY-11973, USA
| | - Sneha Narvekar
- Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany
| | - Tohru Araki
- Diamond Light Source, Didcot, OX11 0DE, United Kingdom
| | | | | | - Tom Regier
- Canadian Light Source Inc., Saskatoon, Saskatchewan S7N 5A8, Canada
| | - Jian Wang
- Canadian Light Source Inc., Saskatoon, Saskatchewan S7N 5A8, Canada
| | - Johann Lugmeier
- Technical University of Munich, TUM School of Life Sciences, Department of Life Science Systems, Soil Science, Emil-Ramann-Str. 2, 85354 Freising, Germany
| | - Carmen Höschen
- Technical University of Munich, TUM School of Life Sciences, Department of Life Science Systems, Soil Science, Emil-Ramann-Str. 2, 85354 Freising, Germany
| | - Tim Mansfeldt
- Department of Geosciences, Institute of Geography, University of Cologne, Germany
| | - Kai Uwe Totsche
- Institut für Geowissenschaften, Friedrich-Schiller-Universität Jena, Burgweg 11, 07749 Jena, Germany
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Zhao B, Shakouri M, Feng R, Regier T, Zeng Y, Zhang Y, Zhang J, Wang L, Luo JL, Fu XZ. Crystallization Engineering of CuNi 2 S 4 Ultra-Fine Nanocrystals with Optimized Band Structures for Efficient Photocatalytic Pollutant Degradation and Hydrogen Production. Small Methods 2023; 7:e2201612. [PMID: 37452235 DOI: 10.1002/smtd.202201612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/26/2023] [Indexed: 07/18/2023]
Abstract
The mono-dispersed cubic siegenite CuNi2 S4 ultra-fine (≈5 nm) nanocrystals are fabricated through crystallization engineering under hot injection. The strong hydroxylation on mostly exposed CuNi2 S4 (220) surface leads to the formation of multi-valence (Cu+ , Cu2+ , Ni2+ , Ni3+ ) species with unsaturated hybridization and coordination micro-environments, which can induce rich redox reactions to optimize interfacial kinetics for the adsorbed reaction intermediates. The as-synthesized CuNi2 S4 nanocrystals with ultra-small particle size and the characteristics of being highly dispersed can increase specific surface area and hydroxylated active sites, which considerably contribute to the improvement of photocatalytic activities. Experimental and theoretical studies indicate that the CuNi2 S4 with unique surface condition can properly modulate the charge density distribution and the electronic band structure, thus achieving an optimal band gap for enhancing visible light absorption. Additionally, the strong hydroxylation on CuNi2 S4 (220) surface can not only make the photocatalytic process stable in alkaline environment but also bring about an impurity level between conduction and valence band, which facilitates the separation of photo-induced charge carriers by suppressing the rapid re-combination of exited electrons and holes. The optimization of band structure should be the intrinsic reason for the efficient photocatalytic pollutant degradation and hydrogen production under visible light illumination.
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Affiliation(s)
- Bin Zhao
- Shenzhen Key Laboratory of Energy Electrocatalytic Materials, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Mohsen Shakouri
- Canadian Light Source Inc., Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - Renfei Feng
- Canadian Light Source Inc., Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - Tom Regier
- Canadian Light Source Inc., Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - Yuxiang Zeng
- Shenzhen Key Laboratory of Energy Electrocatalytic Materials, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Yu Zhang
- Instrumental Analysis Center of Shenzhen University (Lihu Campus), Shenzhen University, Shenzhen, Guangdong, 518055, China
| | - Jiujun Zhang
- College of Materials Science and Engineering, Fuzhou University, Fuzhou, 350108, China
- Institute for Sustainable Energy, College of Sciences, Shanghai University, Shanghai, 200444, China
| | - Lei Wang
- Shenzhen Key Laboratory of Energy Electrocatalytic Materials, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Jing-Li Luo
- Shenzhen Key Laboratory of Energy Electrocatalytic Materials, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Xian-Zhu Fu
- Shenzhen Key Laboratory of Energy Electrocatalytic Materials, Shenzhen Key Laboratory of Polymer Science and Technology, Guangdong Research Center for Interfacial Engineering of Functional Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China
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Schmidt MP, Mamet SD, Senger C, Schebel A, Ota M, Tian TW, Aziz U, Stein LY, Regier T, Stanley K, Peak D, Siciliano SD. Positron-emitting radiotracers spatially resolve unexpected biogeochemical relationships linked with methane oxidation in Arctic soils. Glob Chang Biol 2022; 28:4211-4224. [PMID: 35377512 DOI: 10.1111/gcb.16188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/21/2022] [Accepted: 03/26/2022] [Indexed: 06/14/2023]
Abstract
Arctic soils are marked by cryoturbic features, which impact soil-atmosphere methane (CH4 ) dynamics vital to global climate regulation. Cryoturbic diapirism alters C/N chemistry within frost boils by introducing soluble organic carbon and nutrients, potentially influencing microbial CH4 oxidation. CH4 oxidation in soils, however, requires a spatio-temporal convergence of ecological factors to occur. Spatial delineation of microbial activity with respect to these key microbial and biogeochemical factors at relevant scales is experimentally challenging in inherently complex and heterogeneous natural soil matrices. This work aims to overcome this barrier by spatially linking microbial CH4 oxidation with C/N chemistry and metagenomic characteristics. This is achieved by using positron-emitting radiotracers to visualize millimeter-scale active CH4 uptake areas in Arctic soils with and without diapirism. X-ray absorption spectroscopic speciation of active and inactive areas shows CH4 uptake spatially associates with greater proportions of inorganic N in diapiric frost boils. Metagenomic analyses reveal Ralstonia pickettii associates with CH4 uptake across soils along with pertinent CH4 and inorganic N metabolism associated genes. This study highlights the critical relationship between CH4 and N cycles in Arctic soils, with potential implications for better understanding future climate. Furthermore, our experimental framework presents a novel, widely applicable strategy for unraveling ecological relationships underlying greenhouse gas dynamics under global change.
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Affiliation(s)
- Michael P Schmidt
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- USDA-ARS United States Salinity Laboratory, Riverside, California, USA
| | - Steven D Mamet
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Curtis Senger
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Alixandra Schebel
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Mitsuaki Ota
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Tony W Tian
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Umair Aziz
- Department of Computer Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Lisa Y Stein
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Tom Regier
- Canadian Light Source, Inc., Saskatoon, Saskatchewan, Canada
| | - Kevin Stanley
- Department of Computer Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Derek Peak
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Steven D Siciliano
- Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Chen Z, Zhang G, Wen Y, Chen N, Chen W, Regier T, Dynes J, Zheng Y, Sun S. Atomically Dispersed Fe-Co Bimetallic Catalysts for the Promoted Electroreduction of Carbon Dioxide. Nanomicro Lett 2021; 14:25. [PMID: 34889998 PMCID: PMC8664923 DOI: 10.1007/s40820-021-00746-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/08/2021] [Indexed: 05/05/2023]
Abstract
The electroreduction reaction of CO2 (ECO2RR) requires high-performance catalysts to convert CO2 into useful chemicals. Transition metal-based atomically dispersed catalysts are promising for the high selectivity and activity in ECO2RR. This work presents a series of atomically dispersed Co, Fe bimetallic catalysts by carbonizing the Fe-introduced Co-zeolitic-imidazolate-framework (C-Fe-Co-ZIF) for the syngas generation from ECO2RR. The synergistic effect of the bimetallic catalyst promotes CO production. Compared to the pure C-Co-ZIF, C-Fe-Co-ZIF facilitates CO production with a CO Faradaic efficiency (FE) boost of 10%, with optimal FECO of 51.9%, FEH2 of 42.4% at - 0.55 V, and CO current density of 8.0 mA cm-2 at - 0.7 V versus reversible hydrogen electrode (RHE). The H2/CO ratio is tunable from 0.8 to 4.2 in a wide potential window of - 0.35 to - 0.8 V versus RHE. The total FECO+H2 maintains as high as 93% over 10 h. The proper adding amount of Fe could increase the number of active sites and create mild distortions for the nanoscopic environments of Co and Fe, which is essential for the enhancement of the CO production in ECO2RR. The positive impacts of Cu-Co and Ni-Co bimetallic catalysts demonstrate the versatility and potential application of the bimetallic strategy for ECO2RR.
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Affiliation(s)
- Zhangsen Chen
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC, J3X 1P7, Canada
| | - Gaixia Zhang
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC, J3X 1P7, Canada.
| | - Yuren Wen
- School of Materials Science and Engineering, University of Science and Technology, 100083, Beijing, People's Republic of China
| | - Ning Chen
- Canadian Light Source, University of Saskatchewan, Saskatoon, SK, S7N 2V3, Canada
| | - Weifeng Chen
- Canadian Light Source, University of Saskatchewan, Saskatoon, SK, S7N 2V3, Canada
| | - Tom Regier
- Canadian Light Source, University of Saskatchewan, Saskatoon, SK, S7N 2V3, Canada
| | - James Dynes
- Canadian Light Source, University of Saskatchewan, Saskatoon, SK, S7N 2V3, Canada
| | - Yi Zheng
- Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, 350116, People's Republic of China.
| | - Shuhui Sun
- Institut National de la Recherche Scientifique-Énergie Matériaux et Télécommunications, Varennes, QC, J3X 1P7, Canada.
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5
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Negassa W, Eckhardt KU, Regier T, Leinweber P. Dissolved organic matter concentration, molecular composition, and functional groups in contrasting management practices of peatlands. J Environ Qual 2021; 50:1364-1380. [PMID: 34403153 DOI: 10.1002/jeq2.20284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
About 91,300 ha of peatlands has been rewetted in western Europe since the mid-1990s. Still, it is unknown how long-term rewetting alters the dissolved organic matter (DOM) concentration, molecular composition, and functional groups. We examined these DOM characteristics in three peatland types subjected to 47- to 231-yr drainage and 18- to 24-yr rewetting to address this knowledge gap. Cold water-extractable DOM was characterized by pyrolysis field ionization mass spectrometry (Py-FIMS) and X-ray absorption near-edge structure (XANES) spectroscopy. The dissolved organic carbon (DOC) concentration in the rewetted forest peatland was 2.7 times higher than in the drained forest peatland. However, rewetting decreased the DOC concentrations by 1.5 and 4 times in the coastal peatland and percolation mire, respectively, compared with their respective drained peatlands at the topsoil horizons. The Py-FIMS analysis revealed that all nine DOM compound classes' relative abundances differed between the rewetted and drained forest peatland with the lower relative abundances of the labile DOM compound classes in the rewetted forest peatlands. However, most DOM compound classes' relative abundances were similar between the rewetted and drained coastal peatlands and percolation mires. The XANES also revealed nine carbon and seven nitrogen functional groups with no apparent differences between the two contrasting management practices. The influence of drainage and rewetting on DOC concentration and molecular composition depends on peatland type, drainage period, rewetting intensity, and peat degradation status that should be considered in future research for understanding DOM transformation and transportation from degraded and restored peatland ecosystems.
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Affiliation(s)
- Wakene Negassa
- Soil Science, Univ. of Rostock, Justus-von-Liebig-Weg 6, 18051, Rostock, Germany
| | - Kai-Uwe Eckhardt
- Soil Science, Univ. of Rostock, Justus-von-Liebig-Weg 6, 18051, Rostock, Germany
| | - Tom Regier
- Canadian Light Source Inc., Saskatoon, Saskatchewan, S7N 5A8, Canada
| | - Peter Leinweber
- Soil Science, Univ. of Rostock, Justus-von-Liebig-Weg 6, 18051, Rostock, Germany
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6
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Zhang B, Wang L, Cao Z, Kozlov SM, García de Arquer FP, Dinh CT, Li J, Wang Z, Zheng X, Zhang L, Wen Y, Voznyy O, Comin R, De Luna P, Regier T, Bi W, Alp EE, Pao CW, Zheng L, Hu Y, Ji Y, Li Y, Zhang Y, Cavallo L, Peng H, Sargent EH. High-valence metals improve oxygen evolution reaction performance by modulating 3d metal oxidation cycle energetics. Nat Catal 2020. [DOI: 10.1038/s41929-020-00525-6] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jones ME, Nico PS, Ying S, Regier T, Thieme J, Keiluweit M. Manganese-Driven Carbon Oxidation at Oxic-Anoxic Interfaces. Environ Sci Technol 2018; 52:12349-12357. [PMID: 30260632 DOI: 10.1021/acs.est.8b03791] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The formation of reactive manganese (Mn) species is emerging as a key regulator of carbon oxidation rates, and thus CO2 emissions, in soils and sediments. Many subsurface environments are characterized by steep oxygen gradients, forming oxic-anoxic interfaces that enable rapid redox cycling of Mn. Here, we examined the impact of Mn(II)aq oxidation along oxic-anoxic interfaces on carbon oxidation in soils using laboratory-based diffusion reactors. A combination of cyclic voltammetry, X-ray absorption spectroscopy, and X-ray microprobe imaging revealed a tight coupling between Mn(II)aq oxidation and carbon oxidation at the oxic-anoxic interface. Specifically, zones of Mn(II)aq oxidation across the oxic-anoxic transition also exhibited the greatest lignin oxidation potential, carbon solubilization, and oxidation. Microprobe imaging further revealed that the generation of Mn(III)-dominated precipitates coincided with carbon oxidation. Combined, our findings demonstrate that biotic Mn(II)aq oxidation, specifically the formation of Mn(III) species, contributes to carbon oxidation along oxic-anoxic interfaces in soils and sediments. Our results suggest that we should regard carbon oxidation not merely as a function of molecular composition, which insufficiently predicts rates, but in relation to microenvironments favoring the formation of critically important oxidants such as Mn(III).
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Affiliation(s)
- Morris E Jones
- School of Earth & Sustainability and Stockbridge School of Agriculture , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Peter S Nico
- Earth and Environmental Sciences Area , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Samantha Ying
- Department of Environmental Sciences , University of California Riverside , Riverside , California 92521 , United States
| | - Tom Regier
- Canadian Synchrotron Lightsource , Saskatoon , Canada
| | - Jürgen Thieme
- NSLS-II, Brookhaven National Laboratory , Brookhaven , New York 11973 , United States
| | - Marco Keiluweit
- School of Earth & Sustainability and Stockbridge School of Agriculture , University of Massachusetts , Amherst , Massachusetts 01003 , United States
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Duchesne PN, Li ZY, Deming CP, Fung V, Zhao X, Yuan J, Regier T, Aldalbahi A, Almarhoon Z, Chen S, Jiang DE, Zheng N, Zhang P. Golden single-atomic-site platinum electrocatalysts. Nat Mater 2018; 17:1033-1039. [PMID: 30250176 DOI: 10.1038/s41563-018-0167-5] [Citation(s) in RCA: 152] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 08/13/2018] [Indexed: 05/24/2023]
Abstract
Bimetallic nanoparticles with tailored structures constitute a desirable model system for catalysts, as crucial factors such as geometric and electronic effects can be readily controlled by tailoring the structure and alloy bonding of the catalytic site. Here we report a facile colloidal method to prepare a series of platinum-gold (PtAu) nanoparticles with tailored surface structures and particle diameters on the order of 7 nm. Samples with low Pt content, particularly Pt4Au96, exhibited unprecedented electrocatalytic activity for the oxidation of formic acid. A high forward current density of 3.77 A mgPt-1 was observed for Pt4Au96, a value two orders of magnitude greater than those observed for core-shell structured Pt78Au22 and a commercial Pt nanocatalyst. Extensive structural characterization and theoretical density functional theory simulations of the best-performing catalysts revealed densely packed single-atom Pt surface sites surrounded by Au atoms, which suggests that their superior catalytic activity and selectivity could be attributed to the unique structural and alloy-bonding properties of these single-atomic-site catalysts.
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Affiliation(s)
- Paul N Duchesne
- Department of Chemistry, Dalhousie University, Halifax, NS, Canada
| | - Z Y Li
- Nanoscale Physics Research Laboratory, School of Physics & Astronomy, University of Birmingham, Birmingham, UK
| | - Christopher P Deming
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Victor Fung
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Xiaojing Zhao
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and National & Local Joint Engineering Research Center for Preparation Technology of Nanomaterial, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Jun Yuan
- Department of Physics, University of York, York, UK
| | - Tom Regier
- Canadian Light Source, Saskatoon, SK, Canada
| | - Ali Aldalbahi
- Department of Chemistry, College of Science, King Saud University , Riyadh, Saudi Arabia
| | - Zainab Almarhoon
- Department of Chemistry, College of Science, King Saud University , Riyadh, Saudi Arabia
| | - Shaowei Chen
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - De-En Jiang
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Nanfeng Zheng
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and National & Local Joint Engineering Research Center for Preparation Technology of Nanomaterial, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Peng Zhang
- Department of Chemistry, Dalhousie University, Halifax, NS, Canada.
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Zheng X, Zhang B, De Luna P, Liang Y, Comin R, Voznyy O, Han L, García de Arquer FP, Liu M, Dinh CT, Regier T, Dynes JJ, He S, Xin HL, Peng H, Prendergast D, Du X, Sargent EH. Theory-driven design of high-valence metal sites for water oxidation confirmed using in situ soft X-ray absorption. Nat Chem 2017; 10:149-154. [DOI: 10.1038/nchem.2886] [Citation(s) in RCA: 364] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 09/29/2017] [Indexed: 12/23/2022]
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10
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Yang J, Wang J, Pan W, Regier T, Hu Y, Rumpel C, Bolan N, Sparks D. Retention Mechanisms of Citric Acid in Ternary Kaolinite-Fe(III)-Citrate Acid Systems Using Fe K-edge EXAFS and L3,2-edge XANES Spectroscopy. Sci Rep 2016; 6:26127. [PMID: 27212680 PMCID: PMC4876610 DOI: 10.1038/srep26127] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/27/2016] [Indexed: 12/01/2022] Open
Abstract
Organic carbon (OC) stability in tropical soils is strongly interlinked with multivalent cation interaction and mineral association. Low molecular weight organic acids (LMWOAs) represent the readily biodegradable OC. Therefore, investigating retention mechanisms of LMWOAs in mineral-cation-LMWOAs systems is critical to understanding soil C cycling. Given the general acidic conditions and dominance of kaolinite in tropical soils, we investigated the retention mechanisms of citric acid (CA) in kaolinite-Fe(III)-CA systems with various Fe/CA molar ratios at pH ~3.5 using Fe K-edge EXAFS and L3,2-edge XANES techniques. With Fe/CA molar ratios >2, the formed ferrihydrite mainly contributed to CA retention through adsorption and/or coprecipitation. With Fe/CA molar ratios from 2 to 0.5, ternary complexation of CA to kaolinite via a five-coordinated Fe(III) bridge retained higher CA than ferrihydrite-induced adsorption and/or coprecipitation. With Fe/CA molar ratios ≤0.5, kaolinite-Fe(III)-citrate complexation preferentially occurred, but less CA was retained than via outer-sphere kaolinite-CA complexation. This study highlighted the significant impact of varied Fe/CA molar ratios on CA retention mechanisms in kaolinite-Fe(III)-CA systems under acidic conditions, and clearly showed the important contribution of Fe-bridged ternary complexation on CA retention. These findings will enhance our understanding of the dynamics of CA and other LMWOAs in tropical soils.
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Affiliation(s)
- Jianjun Yang
- Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, Newark, USA, 19716
| | - Jian Wang
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Canada, S7N 2V3
| | - Weinan Pan
- Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, Newark, USA, 19716
| | - Tom Regier
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Canada, S7N 2V3
| | - Yongfeng Hu
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Canada, S7N 2V3
| | - Cornelia Rumpel
- CNRS, Institute of Ecology and Environment Paris, IEES, UMR (CNRS-INRA-UPMC-UPEC-IRD), Thiverval-Grignon, France, 78850
| | - Nanthi Bolan
- Global Centre for Environmental Remediation (GCER), University of Newcastle, NSW, 2308, Australia.,Centre for Environmental Risk Assessment and Remediation (CERAR),University of South Australia, Mawson Lakes, Australia, SA 5095
| | - Donald Sparks
- Department of Plant and Soil Sciences, Delaware Environmental Institute, University of Delaware, Newark, USA, 19716
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Zhang B, Zheng X, Voznyy O, Comin R, Bajdich M, García-Melchor M, Han L, Xu J, Liu M, Zheng L, García de Arquer FP, Dinh CT, Fan F, Yuan M, Yassitepe E, Chen N, Regier T, Liu P, Li Y, De Luna P, Janmohamed A, Xin HL, Yang H, Vojvodic A, Sargent EH. Homogeneously dispersed multimetal oxygen-evolving catalysts. Science 2016; 352:333-7. [PMID: 27013427 DOI: 10.1126/science.aaf1525] [Citation(s) in RCA: 924] [Impact Index Per Article: 115.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/09/2016] [Indexed: 12/19/2022]
Abstract
Earth-abundant first-row (3d) transition metal-based catalysts have been developed for the oxygen-evolution reaction (OER); however, they operate at overpotentials substantially above thermodynamic requirements. Density functional theory suggested that non-3d high-valency metals such as tungsten can modulate 3d metal oxides, providing near-optimal adsorption energies for OER intermediates. We developed a room-temperature synthesis to produce gelled oxyhydroxides materials with an atomically homogeneous metal distribution. These gelled FeCoW oxyhydroxides exhibit the lowest overpotential (191 millivolts) reported at 10 milliamperes per square centimeter in alkaline electrolyte. The catalyst shows no evidence of degradation after more than 500 hours of operation. X-ray absorption and computational studies reveal a synergistic interplay between tungsten, iron, and cobalt in producing a favorable local coordination environment and electronic structure that enhance the energetics for OER.
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Affiliation(s)
- Bo Zhang
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. Department of Physics, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Xueli Zheng
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Oleksandr Voznyy
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Riccardo Comin
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Michal Bajdich
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA. SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Max García-Melchor
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA. SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA
| | - Lili Han
- Tianjin Key Laboratory of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China. Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Jixian Xu
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Min Liu
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Lirong Zheng
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - F Pelayo García de Arquer
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Cao Thang Dinh
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Fengjia Fan
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Mingjian Yuan
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Emre Yassitepe
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Ning Chen
- Canadian Light Source (CLS), 44 Innovation Boulevard, Saskatoon, SK, S7N 2V3, Canada
| | - Tom Regier
- Canadian Light Source (CLS), 44 Innovation Boulevard, Saskatoon, SK, S7N 2V3, Canada
| | - Pengfei Liu
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Yuhang Li
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Phil De Luna
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Alyf Janmohamed
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada
| | - Huolin L Xin
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Huagui Yang
- Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Aleksandra Vojvodic
- SUNCAT Center for Interface Science and Catalysis, Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA. SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.
| | - Edward H Sargent
- Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada.
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12
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Singh SB, Wang YF, Shao YC, Lai HY, Hsieh SH, Limaye MV, Chuang CH, Hsueh HC, Wang H, Chiou JW, Tsai HM, Pao CW, Chen CH, Lin HJ, Lee JF, Wu CT, Wu JJ, Pong WF, Ohigashi T, Kosugi N, Wang J, Zhou J, Regier T, Sham TK. Observation of the origin of d0 magnetism in ZnO nanostructures using X-ray-based microscopic and spectroscopic techniques. Nanoscale 2014; 6:9166-9176. [PMID: 24978624 DOI: 10.1039/c4nr01961j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Efforts have been made to elucidate the origin of d(0) magnetism in ZnO nanocactuses (NCs) and nanowires (NWs) using X-ray-based microscopic and spectroscopic techniques. The photoluminescence and O K-edge and Zn L3,2-edge X-ray-excited optical luminescence spectra showed that ZnO NCs contain more defects than NWs do and that in ZnO NCs, more defects are present at the O sites than at the Zn sites. Specifically, the results of O K-edge scanning transmission X-ray microscopy (STXM) and the corresponding X-ray-absorption near-edge structure (XANES) spectroscopy demonstrated that the impurity (non-stoichiometric) region in ZnO NCs contains a greater defect population than the thick region. The intensity of O K-edge STXM-XANES in the impurity region is more predominant in ZnO NCs than in NWs. The increase in the unoccupied (occupied) density of states at/above (at/below) the conduction-band minimum (valence-band maximum) or the Fermi level is related to the population of defects at the O sites, as revealed by comparing the ZnO NCs to the NWs. The results of O K-edge and Zn L3,2-edge X-ray magnetic circular dichroism demonstrated that the origin of magnetization is attributable to the O 2p orbitals rather than the Zn d orbitals. Further, the local density approximation (LDA) + U verified that vacancies in the form of dangling or unpaired 2p states (due to Zn vacancies) induced a significant local spin moment in the nearest-neighboring O atoms to the defect center, which was determined from the uneven local spin density by analyzing the partial density of states of O 2p in ZnO.
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Affiliation(s)
- Shashi B Singh
- Department of Physics, Tamkang University, Tamsui 251, Taiwan.
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13
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Zhou J, Duchesne PN, Hu Y, Wang J, Zhang P, Li Y, Regier T, Dai H. Fe–N bonding in a carbon nanotube–graphene complex for oxygen reduction: an XAS study. Phys Chem Chem Phys 2014; 16:15787-91. [DOI: 10.1039/c4cp01455c] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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14
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Yang J, Liu J, Dynes JJ, Peak D, Regier T, Wang J, Zhu S, Shi J, Tse JS. Speciation and distribution of copper in a mining soil using multiple synchrotron-based bulk and microscopic techniques. Environ Sci Pollut Res Int 2014; 21:2943-2954. [PMID: 24170498 DOI: 10.1007/s11356-013-2214-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 10/02/2013] [Indexed: 06/02/2023]
Abstract
Molecular-level understanding of soil Cu speciation and distribution assists in management of Cu contamination in mining sites. In this study, one soil sample, collected from a mining site contaminated since 1950s, was characterized complementarily by multiple synchrotron-based bulk and spatially resolved techniques for the speciation and distribution of Cu as well as other related elements (Fe, Ca, Mn, K, Al, and Si). Bulk X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that soil Cu was predominantly associated with Fe oxides instead of soil organic matter. This agreed with the closest association of Cu to Fe by microscopic X-ray fluorescence (U-XRF) and scanning transmission X-ray microscopy (STXM) nanoanalysis, along with the non-occurrence of photoreduction of soil Cu(II) by quick Cu L3,2-edge XANES spectroscopy (Q-XANES) which often occurs when Cu organic complexes are present. Furthermore, bulk-EXAFS and STXM-coupled Fe L3,2-edge nano-XANES analysis revealed soil Cu adsorbed primarily to Fe(III) oxides by inner-sphere complexation. Additionally, Cu K-edge μ-XANES, L3,2-edge bulk-XANES, and successive Q-XANES results identified the presence of Cu2S rather than radiation-damage artifacts dominant in certain microsites of the mining soil. This study demonstrates the great benefits in use of multiple combined synchrotron-based techniques for comprehensive understanding of Cu speciation in heterogeneous soil matrix, which facilitates our prediction of Cu reactivity and environmental fate in the mining site.
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Affiliation(s)
- Jianjun Yang
- Department of Environmental Engineering, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, People's Republic of China
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15
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Gong M, Li Y, Wang H, Liang Y, Wu JZ, Zhou J, Wang J, Regier T, Wei F, Dai H. An Advanced Ni–Fe Layered Double Hydroxide Electrocatalyst for Water Oxidation. J Am Chem Soc 2013; 135:8452-5. [DOI: 10.1021/ja4027715] [Citation(s) in RCA: 2171] [Impact Index Per Article: 197.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ming Gong
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Yanguang Li
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Hailiang Wang
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Yongye Liang
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Justin Z. Wu
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
| | - Jigang Zhou
- Canadian Light Source Inc., Saskatoon, Saskatchewan S7N 0X4, Canada
| | - Jian Wang
- Canadian Light Source Inc., Saskatoon, Saskatchewan S7N 0X4, Canada
| | - Tom Regier
- Canadian Light Source Inc., Saskatoon, Saskatchewan S7N 0X4, Canada
| | - Fei Wei
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Hongjie Dai
- Department of Chemistry, Stanford University, Stanford, California 94305, United
States
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16
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Zhou J, Wang J, Hu Y, Regier T, Wang H, Yang Y, Cui Y, Dai H. Imaging state of charge and its correlation to interaction variation in an LiMn0.75Fe0.25PO4 nanorods–graphene hybrid. Chem Commun (Camb) 2013; 49:1765-7. [DOI: 10.1039/c3cc39015b] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Levy G, Sutarto R, Chevrier D, Regier T, Blyth R, Geck J, Wurmehl S, Harnagea L, Wadati H, Mizokawa T, Elfimov IS, Damascelli A, Sawatzky GA. Probing the role of co substitution in the electronic structure of iron pnictides. Phys Rev Lett 2012; 109:077001. [PMID: 23006394 DOI: 10.1103/physrevlett.109.077001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Indexed: 06/01/2023]
Abstract
The role of Co substitution in the low-energy electronic structure of Ca(Fe(0.944)Co(0.056))(2)As(2) is investigated by resonant photoemission spectroscopy and density-functional theory. The Co 3d state center of mass is observed at 250 meV higher binding energy than that of Fe, indicating that Co possesses one extra valence electron and that Fe and Co are in the same oxidation state. Yet, significant Co character is detected for the Bloch wave functions at the chemical potential, revealing that the Co 3d electrons are part of the Fermi sea determining the Fermi surface. This establishes the complex role of Co substitution in CaFe(2)As(2) and the inadequacy of a rigid-band shift description.
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Affiliation(s)
- G Levy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
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18
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Wang H, Liang Y, Gong M, Li Y, Chang W, Mefford T, Zhou J, Wang J, Regier T, Wei F, Dai H. An ultrafast nickel–iron battery from strongly coupled inorganic nanoparticle/nanocarbon hybrid materials. Nat Commun 2012; 3:917. [DOI: 10.1038/ncomms1921] [Citation(s) in RCA: 309] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 05/21/2012] [Indexed: 12/23/2022] Open
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20
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Abstract
Ferrihydrite is a common iron hydroxide nanomineral commonly found in soils, sediments, and surface waters. Reactivity with this important environmental surface often controls the fate and mobility of both essential nutrients and inorganic contaminants. Despite the critical role of ferrihydrite in environmental geochemistry, its structure is still debated. In this work, we apply bulk sensitive Fe L edge X-ray absorption spectroscopy to study the crystal field environment of the Fe in ferrihydrite and other Fe oxides of known structure. This direct probe of the local electronic structure provides verification of the presence of tetrahedrally coordinated Fe(III) in the structure of ferrihydrite and puts to rest the controversy on this issue.
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Affiliation(s)
- Derek Peak
- Department of Soil Science, College of Agriculture and Bioresources, University of Saskatchewan, 51 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5A8.
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21
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Liang Y, Wang H, Zhou J, Li Y, Wang J, Regier T, Dai H. Covalent hybrid of spinel manganese-cobalt oxide and graphene as advanced oxygen reduction electrocatalysts. J Am Chem Soc 2012; 134:3517-23. [PMID: 22280461 DOI: 10.1021/ja210924t] [Citation(s) in RCA: 637] [Impact Index Per Article: 53.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Through direct nanoparticle nucleation and growth on nitrogen doped, reduced graphene oxide sheets and cation substitution of spinel Co(3)O(4) nanoparticles, a manganese-cobalt spinel MnCo(2)O(4)/graphene hybrid was developed as a highly efficient electrocatalyst for oxygen reduction reaction (ORR) in alkaline conditions. Electrochemical and X-ray near-edge structure (XANES) investigations revealed that the nucleation and growth method for forming inorganic-nanocarbon hybrids results in covalent coupling between spinel oxide nanoparticles and N-doped reduced graphene oxide (N-rmGO) sheets. Carbon K-edge and nitrogen K-edge XANES showed strongly perturbed C-O and C-N bonding in the N-rmGO sheet, suggesting the formation of C-O-metal and C-N-metal bonds between N-doped graphene oxide and spinel oxide nanoparticles. Co L-edge and Mn L-edge XANES suggested substitution of Co(3+) sites by Mn(3+), which increased the activity of the catalytic sites in the hybrid materials, further boosting the ORR activity compared with the pure cobalt oxide hybrid. The covalently bonded hybrid afforded much greater activity and durability than the physical mixture of nanoparticles and carbon materials including N-rmGO. At the same mass loading, the MnCo(2)O(4)/N-graphene hybrid can outperform Pt/C in ORR current density at medium overpotentials with stability superior to Pt/C in alkaline solutions.
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Affiliation(s)
- Yongye Liang
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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22
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Zhou J, Wang J, Zuin L, Regier T, Hu Y, Wang H, Liang Y, Maley J, Sammynaiken R, Dai H. Spectroscopic understanding of ultra-high rate performance for LiMn0.75Fe0.25PO4 nanorods–graphene hybrid in lithium ion battery. Phys Chem Chem Phys 2012; 14:9578-81. [DOI: 10.1039/c2cp41012e] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Liang Y, Li Y, Wang H, Zhou J, Wang J, Regier T, Dai H. Co₃O₄ nanocrystals on graphene as a synergistic catalyst for oxygen reduction reaction. Nat Mater 2011; 10:780-6. [PMID: 21822263 DOI: 10.1038/nmat3087] [Citation(s) in RCA: 2607] [Impact Index Per Article: 200.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 06/30/2011] [Indexed: 05/21/2023]
Abstract
Catalysts for oxygen reduction and evolution reactions are at the heart of key renewable-energy technologies including fuel cells and water splitting. Despite tremendous efforts, developing oxygen electrode catalysts with high activity at low cost remains a great challenge. Here, we report a hybrid material consisting of Co₃O₄ nanocrystals grown on reduced graphene oxide as a high-performance bi-functional catalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Although Co₃O₄ or graphene oxide alone has little catalytic activity, their hybrid exhibits an unexpected, surprisingly high ORR activity that is further enhanced by nitrogen doping of graphene. The Co₃O₄/N-doped graphene hybrid exhibits similar catalytic activity but superior stability to Pt in alkaline solutions. The same hybrid is also highly active for OER, making it a high-performance non-precious metal-based bi-catalyst for both ORR and OER. The unusual catalytic activity arises from synergetic chemical coupling effects between Co₃O₄ and graphene.
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Affiliation(s)
- Yongye Liang
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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24
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Dong C, Pichaandi J, Regier T, van Veggel FCJM. The unexpected structures of "core-shell" and "alloy" LnF3 nanoparticles as examined by variable energy X-ray photo-electron spectroscopy. Nanoscale 2011; 3:3376-84. [PMID: 21761041 DOI: 10.1039/c1nr10317b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Lanthanide fluoride nanoparticles were synthesized in aqueous media using procedures intended for a core-shell structure of Ln((1))F(3)-Ln((2))F(3), its reverse architecture, and an alloy structure. Their structures were examined by variable photon energy photo-electron spectroscopy using synchrotron radiation, along with X-ray powder diffractometry, transmission electron microscopy, energy dispersive X-ray spectroscopy, and luminescence spectroscopy. The results show that the nanoparticles intended for a core-shell structure do not have a core-shell structure, and that nanoparticles intended for an alloy structure do not always have an alloy structure. A possible explanation for this is cation exchange, a phenomenon that occurs when LnF(3) nanoparticles are exposed to another Ln(3+) ion in aqueous media, resulting in Ln(3+) ions in nanoparticles being quickly replaced by Ln(3+) ions in solution. This cation exchange effectively competes with the precipitation of LnF(3), which leads to a concentration gradient in the case of the combination of LaF(3) and GdF(3), and to nearly an alloy structure (isotropic mixture of all the ions) in the case of the combination of LaF(3) and NdF(3), regardless of the procedure used. Finally, the intended "core-shell" nanoparticles were doped with Eu(3+) to show that a non-core-shell structure can also give rise to the improvement of optical properties as compared with the corresponding core nanoparticles. These results suggest that conclusions in the literature that a core-shell structure was obtained as inferred by TEM or enhanced luminescence may not be correct.
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Affiliation(s)
- Cunhai Dong
- Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia, Canada V8W 3V6
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25
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Yang J, Regier T, Dynes JJ, Wang J, Shi J, Peak D, Zhao Y, Hu T, Chen Y, Tse JS. Soft X-ray Induced Photoreduction of Organic Cu(II) Compounds Probed by X-ray Absorption Near-Edge (XANES) Spectroscopy. Anal Chem 2011; 83:7856-62. [DOI: 10.1021/ac201622g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jianjun Yang
- Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029, P.R. China
- Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Canada S7N 5E2
| | - Tom Regier
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Canada S7N 0X4
| | - James J. Dynes
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Canada S7N 0X4
| | - Jian Wang
- Canadian Light Source Inc., University of Saskatchewan, Saskatoon, Canada S7N 0X4
| | - Jiyan Shi
- Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029, P.R. China
| | - Derek Peak
- Department of Soil Science, University of Saskatchewan, Saskatoon, Canada S7N 5A8
| | - Yidong Zhao
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Science, Beijing 100049, P.R. China
| | - Tiandou Hu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Science, Beijing 100049, P.R. China
| | - Yingxu Chen
- Institute of Environmental Science and Technology, Zhejiang University, Hangzhou 310029, P.R. China
| | - John S Tse
- Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Canada S7N 5E2
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26
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Armelao L, Heigl F, Brunet S, Sammynaiken R, Regier T, Blyth RIR, Zuin L, Sankari R, Vogt J, Sham T. The Origin and Dynamics of Soft X‐Ray‐Excited Optical Luminescence of ZnO. Chemphyschem 2010; 11:3625-31. [DOI: 10.1002/cphc.201000730] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Lidia Armelao
- Department of Chemistry, ISTM‐CNR and INSTM, University of Padova, Via Marzolo 1, 35131 Padova (Italy), Fax: (+39) 049 827 5227
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London N6 A 5B7 (Canada), Fax: (+1) 519 661 3022
| | - Franziskus Heigl
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London N6 A 5B7 (Canada), Fax: (+1) 519 661 3022
| | - Sophie Brunet
- Saskatchewan Structural Science Center, University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada)
| | - Ramaswami Sammynaiken
- Saskatchewan Structural Science Center, University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada)
| | - Tom Regier
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Robert I. R. Blyth
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Lucia Zuin
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Rami Sankari
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Johannes Vogt
- Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon S7N 0X4 (Canada)
| | - Tsun‐Kong Sham
- Department of Chemistry, University of Western Ontario, 1151 Richmond Street, London N6 A 5B7 (Canada), Fax: (+1) 519 661 3022
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27
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Kruse J, Schlichting A, Siemens J, Regier T, Leinweber P. Pyrolysis-field ionization mass spectrometry and nitrogen K-edge XANES spectroscopy applied to bulk soil leachates--a case study. Sci Total Environ 2010; 408:4910-4915. [PMID: 20656327 DOI: 10.1016/j.scitotenv.2010.07.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Revised: 06/29/2010] [Accepted: 07/02/2010] [Indexed: 05/29/2023]
Abstract
Although dissolved organic matter (DOM) is an important component of C- and N-fluxes in the environment, its structural composition is still poorly understood due to methodological challenges. We explored the potential of combining pyrolysis-field ionization mass spectrometry (Py-FIMS) and N X-ray absorption near edge structure (N-XANES) spectroscopy to study the molecular-chemical composition of lyophilized bulk soil solution samples that were not subjected to pretreatment like dialysis. Soil leachates were collected at 90 cm and 220 cm depth from an arable and a fallow site. Py-FIMS spectra reflected differences in DOM composition related to land use and sampling depth. Land use effects were expressed in higher abundances of carbohydrates and peptides at the arable than at the fallow site. The relative proportions of carbohydrates decreased and the proportions of lignin-derived compounds increased with depth, indicating a relative enrichment to more stabilized DOM along the flow path. Nitrogen XANES spectra were dominated by the signal of NO(3)-salts but also indicated the presence of organic, non-amidic N as found in imidazoles, pyrazoles, purines and/or nitrile-N, whereas N-compounds like pyridines, pyrroles, quinoline and indole were detected by Py-FIMS. Thus, the combined application of Py-FIMS and N-XANES yielded complementary information regarding the molecular-chemical composition of DOM. Future applications of these techniques may benefit from selectively analyzing soil solution samples with lower nitrate concentrations collected in early spring.
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Affiliation(s)
- Jens Kruse
- University of Rostock, Institute for Land Use, 1851 Rostock, Germany.
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28
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Li YS, Tang Y, Yang Q, Maley J, Sammynaiken R, Regier T, Xiao C, Hirose A. Ultrathin W-Al dual interlayer approach to depositing smooth and adherent nanocrystalline diamond films on stainless steel. ACS Appl Mater Interfaces 2010; 2:335-338. [PMID: 20356176 DOI: 10.1021/am9007159] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The adherence of diamond coated on steel is commonly low and needs to be strengthened with thick intermediate layers. In this paper, a nanoscale W-Al dual metal interlayer has been applied on SS304 substrates to facilitate deposition of continuous, adherent and smooth diamond thin films. During the microwave plasma-enhanced chemical vapor deposition process, the Al inner layer 30 nm thick diffuses into steel surface inhibiting carbon diffusion and graphitization. The W outer layer 20 nm thick is transformed into W carbides, both preventing carbon diffusion and enhancing diamond nucleation. The diamond films synthesized are of high purity and have smooth surfaces and dense structures. Indentation and shear deformation tests indicate high delaminating tolerance of the diamond films.
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29
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Heigl F, Armelao L, Sun XHJ, Didychuk C, Zhou XT, Regier T, Blyth RIR, Kim PSG, Rosenberg RA, Sham TK. XANES and photoluminescence studies of crystalline GeO2(Tb) nanowires. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/190/1/012130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Wilks RG, MacNaughton JB, Kraatz HB, Regier T, Blyth RIR, Moewes A. Comparative Theoretical and Experimental Study of the Radiation-Induced Decomposition of Glycine. J Phys Chem A 2009; 113:5360-6. [DOI: 10.1021/jp900794v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. G. Wilks
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - J. B. MacNaughton
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - H.-B. Kraatz
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - T. Regier
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - R. I. R. Blyth
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - A. Moewes
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
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Zhou XT, Zhou JG, Murphy MW, Ko JYP, Heigl F, Regier T, Blyth RIR, Sham TK. The effect of the surface of SnO2 nanoribbons on their luminescence using x-ray absorption and luminescence spectroscopy. J Chem Phys 2008; 128:144703. [DOI: 10.1063/1.2841419] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arima V, Blyth RIR, Matino F, Chiodo L, Della Sala F, Thompson J, Regier T, Del Sole R, Mele G, Vasapollo G, Cingolani R, Rinaldi R. Zinc porphyrin-driven assembly of gold nanofingers. Small 2008; 4:497-506. [PMID: 18348225 DOI: 10.1002/smll.200700276] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nanofingers of gold covered by porphyrins are prepared by a combination of atomic manipulation and surface self-organization. A submonolayer of zinc(II) 5,10,15,20-tetrakis(4-tert-butylphenyl)-porphyrin (ZnTBPP) axially ligated to a self-assembled monolayer of 4-aminothiophenol (4-ATP) on Au(111) is prepared and studied using a combination of ultrahigh vacuum techniques. Under the electric field produced by the STM tip, the relatively weakly bound Au surface atoms along the discommensuration lines become mobile due to the strong bond to 4-ATP, while the tendency of the porphyrins towards self-assembly result in a collective motion of gold clusters. The clusters diffuse onto the surface following well-defined pathways along the [112] direction and then reach the step edges where they assembled, thus forming nanofingers. First-principles density functional theory calculations demonstrate the reduction of the binding energies between the surface gold clusters and the substrate induced by adsorption of thiols. Scanning tunneling microscopy images show assemblies across three adjacent discommensuration lines of the Au(111)-(22 x square root 3) reconstruction, which collectively diffuse along these lines to form islands nucleated at step edges.
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Affiliation(s)
- Valentina Arima
- National Nanotechnology Laboratory (CNR-INFM), Distretto Tecnologico ISUFI, Università degli studi di Lecce ,via Arnesano, 73100 Lecce, Italy.
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Otero E, Wilks RG, Regier T, Blyth RIR, Moewes A, Urquhart SG. Substituent Effects in the Iron 2p and Carbon 1s Edge Near-Edge X-ray Absorption Fine Structure (NEXAFS) Spectroscopy of Ferrocene Compounds. J Phys Chem A 2008; 112:624-34. [DOI: 10.1021/jp074625w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- E. Otero
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - R. G. Wilks
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - T. Regier
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - R. I. R. Blyth
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - A. Moewes
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - S. G. Urquhart
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
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Leinweber P, Kruse J, Walley FL, Gillespie A, Eckhardt KU, Blyth RIR, Regier T. Nitrogen K-edge XANES - an overview of reference compounds used to identify unknown organic nitrogen in environmental samples. J Synchrotron Radiat 2007; 14:500-511. [PMID: 17960033 DOI: 10.1107/s0909049507042513] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 08/30/2007] [Indexed: 05/25/2023]
Abstract
The chemical nature of soil organic nitrogen (N) is still poorly understood and one-third to one-half of it is typically classified as ;unknown N'. Nitrogen K-edge XANES spectroscopy has been used to develop a systematic overview on spectral features of all major N functions in soil and environmental samples. The absolute calibration of the photon energy was completed using the 1s --> pi* transitions of pure gas-phase N(2). On this basis a library of spectral features is provided for mineral N, nitro N, amino acids, peptides, and substituted pyrroles, pyridines, imidazoles, pyrazoles, pyrazines, pyrimidines and purine bases. Although N XANES was previously considered ;non-destructive', effects of radiation damage were shown for two compound classes and an approach was proposed to minimize it. This new evidence is integrated into a proposal for the evaluation spectra from environmental samples with unknown composition. Thus a basis is laid to develop N K-edge XANES as a complementary standard research method to study the molecular composition and ecological functions of ;unknown N' in soil and the environment.
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Affiliation(s)
- Peter Leinweber
- Institute for Land Use, University of Rostock, Justus von Liebig Weg 6, 18057 Rostock, Germany.
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Ko JYP, Heigl F, Yiu YM, Zhou XT, Regier T, Blyth RI, Sham TK. Soft X-ray excited colour-centre luminescence and XANES studies of calcium oxide. CAN J CHEM 2007. [DOI: 10.1139/v07-109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In this study, we show that colour centres can be produced by irradiating calcium oxide with soft X-rays from a synchrotron radiation source. Using the X-ray excited optical luminescence (XEOL) technique, two colour centres, F-centre, and F+-centre can be identified. These colour centres emit photons at characteristic wavelengths. In addition, by performing time-resolved XEOL (TRXEOL), we are able to reveal timing and decay characteristics of the colour centres. We also present X-ray absorption near-edge structure (XANES) spectra collected across oxygen K-edge, calcium L3,2-edge, and calcium K-edge. Experimental results are compared with density functional theory (DFT) calculations.Key words: calcium oxide, colour centre, synchrotron, X-ray excited optical luminescence, X-ray absorption near-edge structure.
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Zhou X, Sham TK, Wu Y, Chong YM, Bello I, Lee ST, Heigl F, Regier T, Blyth RIR. X-ray Excited Optical Luminescence from Diamond Thin Films: The Contribution of sp2- and H-Bonded Carbon to the Luminescence. J Am Chem Soc 2007; 129:1476-7. [PMID: 17249664 DOI: 10.1021/ja064555r] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xingtai Zhou
- Department of Chemistry, The University of Western Ontario, London, Canada N6A 5B7
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Drivonikou GV, Kay P, Regier T, Ivry RB, Gilbert AL, Franklin A, Davies IRL. Further evidence that Whorfian effects are stronger in the right visual field than the left. Proc Natl Acad Sci U S A 2007; 104:1097-102. [PMID: 17213312 PMCID: PMC1783370 DOI: 10.1073/pnas.0610132104] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Whorf hypothesis holds that differences between languages induce differences in perception and/or cognition in their speakers. Much of the experimental work pursuing this idea has focused on the domain of color and has centered on the issue of whether linguistically coded color categories influence color discrimination. A new perspective has been cast on the debate by recent results that suggest that language influences color discrimination strongly in the right visual field but not in the left visual field (LVF). This asymmetry is likely related to the contralateral projection of visual fields to cerebral hemispheres and the specialization of the left hemisphere for language. The current study presents three independent experiments that replicate and extend these earlier results by using different tasks and testing across different color category boundaries. Our results differ in one respect: although we find that Whorfian effects on color are stronger for stimuli in the right visual field than in the LVF, we find that there are significant category effects in the LVF as well. The origin of the significant category effect in the LVF is considered, and two factors that might account for the pattern of results are proposed.
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Affiliation(s)
- G. V. Drivonikou
- Department of Psychology, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - P. Kay
- International Computer Science Institute, 1947 Center Street, Berkeley, CA 94704
- Department of Linguistics and
- To whom correspondence may be addressed. E-mail:
or
| | - T. Regier
- Helen Wills Neuroscience Institute and Department of Psychology, University of Calfornia, Berkeley, CA 94720; and
| | - R. B. Ivry
- Department of Psychology, The University of Chicago, Chicago, IL 60637
| | - A. L. Gilbert
- Department of Psychology, The University of Chicago, Chicago, IL 60637
| | - A. Franklin
- Department of Psychology, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - I. R. L. Davies
- Department of Psychology, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
- To whom correspondence may be addressed. E-mail:
or
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Regier T, Paulsen J, Wright G, Coulthard I, Tan K, Sham TK, Blyth RIR. Commissioning of the Spherical Grating Monochromator Soft X-ray Spectroscopy Beamline at the Canadian Light Source. ACTA ACUST UNITED AC 2007. [DOI: 10.1063/1.2436101] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Heigl F, Jürgensen A, Zhou XT, Lam S, Murphy M, Ko JYP, Sham TK, Rosenberg RA, Gordon R, Brewe D, Regier T, Armelao L. Dynamic View on Nanostructures: A Technique for Time Resolved Optical Luminescence using Synchrotron Light Pulses at SRC, APS, and CLS. ACTA ACUST UNITED AC 2007. [DOI: 10.1063/1.2436279] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Heigl F, Lam S, Regier T, Coulthard I, Sham TK. Time-Resolved X-ray Excited Optical Luminescence from Tris(2-phenyl bipyridine)iridium [ J. Am. Chem. Soc. 2006, 128, 3906−3907]. J Am Chem Soc 2006. [DOI: 10.1021/ja069967e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wilks RG, MacNaughton JB, Kraatz HB, Regier T, Moewes A. Combined X-ray Absorption Spectroscopy and Density Functional Theory Examination of Ferrocene-Labeled Peptides. J Phys Chem B 2006; 110:5955-65. [PMID: 16553403 DOI: 10.1021/jp056573l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A combination of soft X-ray absorption spectroscopy (XAS) measurements and StoBe density functional theory (DFT) calculations has been used to study the electronic structures of the ferrocene-labeled peptides Fc-Pro(n)-OBz (n = 1-4). Excellent agreement between the measured and the simulated data is observed in all cases, and the origin of all major spectral features was assigned. The breaking of the degeneracy of the ferrocene 3e(2u)-like unoccupied molecular orbital under the influence of a substituent attached to a Cp ring was observed experimentally. The influence of the bonding environment on the O 1s and N 1s XAS spectra was examined. A corrected assignment of one of the major features in the Fe 2p XAS spectra of ferrocene is proposed and supported by the DFT simulations, as well as the measured spectra.
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Affiliation(s)
- R G Wilks
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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Heigl F, Lam S, Regier T, Coulthard I, Sham TK. Time-Resolved X-ray Excited Optical Luminescence from Tris(2-phenyl bipyridine)iridium. J Am Chem Soc 2006; 128:3906-7. [PMID: 16551087 DOI: 10.1021/ja060243c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Time-resolved X-ray Excited Optical Luminescence (TRXEOL) has been developed to investigate the optical properties of a green organometallic phosphor, tris(2-phenyl pyridine)iridium, Ir(ppy)3. Using time-gated measurements, we find that the characteristic luminescence band from a neat Ir(ppy)3 film is composed of a fast channel at approximately 534 nm and a slower channel at approximately 580 nm. The implication of this study and the applicability of the technique in the study of light emitting materials are noted.
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Affiliation(s)
- Franziskus Heigl
- Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7
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Abstract
The present paper grounds the linguistic cdategorization of space in aspects of visual perception; specifically, the structure of projective spatial terms such as above are grounded in the process of attention and in vector-sum coding of overall direction. This is formalized in the attentional vector-sum (AVS) model. This computational model accurately predicts linguistic acceptability judgments for spatial terms, under a variety of spatial configurations. In 7 experiments, the predictions of the AVS model are tested against those of 3 competing models. The results support the AVS model and disconfirm its competitors. The authors conclude that the structure of linguistic spatial categories can be partially explained in terms of independently motivated perceptual processes.
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Affiliation(s)
- T Regier
- Department of Psychology, University of Chicago, Green 414, 5848 South University Avenue, Chicago, Illinois 60637, USA
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Abstract
The present paper grounds the linguistic cdategorization of space in aspects of visual perception; specifically, the structure of projective spatial terms such as above are grounded in the process of attention and in vector-sum coding of overall direction. This is formalized in the attentional vector-sum (AVS) model. This computational model accurately predicts linguistic acceptability judgments for spatial terms, under a variety of spatial configurations. In 7 experiments, the predictions of the AVS model are tested against those of 3 competing models. The results support the AVS model and disconfirm its competitors. The authors conclude that the structure of linguistic spatial categories can be partially explained in terms of independently motivated perceptual processes.
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Affiliation(s)
- T Regier
- Department of Psychology, University of Chicago, Green 414, 5848 South University Avenue, Chicago, Illinois 60637, USA
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Abstract
Three experiments examine the relation between linguistic and non-linguistic categorization of spatial relations. We compare linguistic and non-linguistic responses to the same spatial stimuli. Contrary to earlier claims in the literature (Hayward, W. G. & Tarr, M. J. (1995). Spatial language and spatial representation. Cognition, 55, 39-84), we find that linguistic and non-linguistic spatial categories do not correspond. Rather, they appear to have an inverse relation such that the prototypes of linguistic categories, such as 'above', are boundaries in non-linguistic spatial categorization. Evidence for this inverse relation comes from linguistic acceptability judgments and the pattern of bias in participants' reproductions of location. Our findings suggest that while linguistic and non-linguistic spatial organization rely on a common underlying structure, that structure may play different roles in the two organizational systems.
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Affiliation(s)
- L E Crawford
- Department of Psychology, University of Chicago, 5848 S. University Avenue, Chicago 60615, USA.
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