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Broge NLN, Bertelsen AD, Nielsen IG, Kløve M, Roelsgaard M, Dippel AC, Jørgensen MRV, Iversen BB. Exploration of anion effects in solvothermal synthesis using in situ X-ray diffraction. Phys Chem Chem Phys 2024; 26:12121-12132. [PMID: 38587495 DOI: 10.1039/d4cp00541d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Solvothermal synthesis presents a facile and highly flexible approach to chemical processing and it is widely used for preparation of micro- and nanosized inorganic materials. The large number of synthesis parameters in combination with the richness of inorganic chemistry means that it is difficult to predict or design synthesis outcomes, and it is demanding to uncover the effect of different parameters due to the sealed and complex nature of solvothermal reactors along with the time demands related to reactor cleaning, sample purification, and characterization. This study explores the effect on formation of crystalline products of six common anions in solvothermal treatment of aqueous and ethanolic precursors. Three different cations are included in the study (Mn2+, Co2+, Cu2+) representing chemical affinities towards different regions of the periodic table with respect to the hard soft acid base (HSAB) classification and the Goldschmidt classification. They additionally belong to the commonly used 3d transition metals and display a suitable variety in solvothermal chemistry to highlight anion effects. The results of the solvothermal in situ experiments demonstrate a clear effect of the precursor anions, with respect to whether crystallization occurs or not and the characteristics of the formed phases. Additionally, some of the anions are shown to be redox active and to influence the formation temperature of certain phases which in turn relates to the observed average crystallite sizes.
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Affiliation(s)
- Nils Lau Nyborg Broge
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Andreas Dueholm Bertelsen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | | | - Magnus Kløve
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Martin Roelsgaard
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
| | - Ann-Christin Dippel
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Mads Ry Vogel Jørgensen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Bo Brummerstedt Iversen
- Center for Integrated Materials Research, Department of Chemistry and iNANO, Aarhus University, DK-8000 Aarhus C, Denmark.
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Andersen HL, Granados-Miralles C, Jensen KMØ, Saura-Múzquiz M, Christensen M. The Chemistry of Spinel Ferrite Nanoparticle Nucleation, Crystallization, and Growth. ACS NANO 2024; 18:9852-9870. [PMID: 38526912 PMCID: PMC11008356 DOI: 10.1021/acsnano.3c08772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 03/15/2024] [Accepted: 03/21/2024] [Indexed: 03/27/2024]
Abstract
The nucleation, crystallization, and growth mechanisms of MnFe2O4, CoFe2O4, NiFe2O4, and ZnFe2O4 nanocrystallites prepared from coprecipitated transition metal (TM) hydroxide precursors treated at sub-, near-, and supercritical hydrothermal conditions have been studied by in situ X-ray total scattering (TS) with pair distribution function (PDF) analysis, and in situ synchrotron powder X-ray diffraction (PXRD) with Rietveld analysis. The in situ TS experiments were carried out on 0.6 M TM hydroxide precursors prepared from aqueous metal chloride solutions using 24.5% NH4OH as the precipitating base. The PDF analysis reveals equivalent nucleation processes for the four spinel ferrite compounds under the studied hydrothermal conditions, where the TMs form edge-sharing octahedrally coordinated hydroxide units (monomers/dimers and in some cases trimers) in the aqueous precursor, which upon hydrothermal treatment nucleate through linking by tetrahedrally coordinated TMs. The in situ PXRD experiments were carried out on 1.2 M TM hydroxide precursors prepared from aqueous metal nitrate solutions using 16 M NaOH as the precipitating base. The crystallization and growth of the nanocrystallites were found to progress via different processes depending on the specific TMs and synthesis temperatures. The PXRD data show that MnFe2O4 and CoFe2O4 nanocrystallites rapidly grow (typically <1 min) to equilibrium sizes of 20-25 nm and 10-12 nm, respectively, regardless of applied temperature in the 170-420 °C range, indicating limited possibility of targeted size control. However, varying the reaction time (0-30 min) and temperature (150-400 °C) allows different sizes to be obtained for NiFe2O4 (3-30 nm) and ZnFe2O4 (3-12 nm) nanocrystallites. The mechanisms controlling the crystallization and growth (nucleation, growth by diffusion, Ostwald ripening, etc.) were examined by qualitative analysis of the evolution in refined scale factor (proportional to extent of crystallization) and mean crystallite volume (proportional to extent of growth). Interestingly, lower kinetic barriers are observed for the formation of the mixed spinels (MnFe2O4 and CoFe2O4) compared to the inverse (NiFe2O4) and normal (ZnFe2O4) spinel structured compounds, suggesting that the energy barrier for formation may be lowered when the TMs have no site preference.
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Affiliation(s)
- Henrik L. Andersen
- Instituto
de Ciencia de Materiales de Madrid (ICMM), CSIC, Madrid 28049, Spain
- Facultad
de Ciencias Físicas, Universidad
Complutense de Madrid, Madrid 28040, Spain
| | | | - Kirsten M. Ø. Jensen
- Department
of Chemistry and Nanoscience Center, University
of Copenhagen, København Ø, 2100, Denmark
| | - Matilde Saura-Múzquiz
- Facultad
de Ciencias Físicas, Universidad
Complutense de Madrid, Madrid 28040, Spain
| | - Mogens Christensen
- Department
of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Aarhus C, 8000, Denmark
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3
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Roelsgaard M, Kløve M, Christensen R, Bertelsen AD, Broge NLN, Kantor I, Sørensen DR, Dippel AC, Banerjee S, Zimmermann MV, Glaevecke P, Gutowski O, Jørgensen MRV, Iversen BB. A reactor for time-resolved X-ray studies of nucleation and growth during solvothermal synthesis. J Appl Crystallogr 2023; 56:581-588. [PMID: 37284256 PMCID: PMC10241040 DOI: 10.1107/s1600576723002339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 03/09/2023] [Indexed: 06/08/2023] Open
Abstract
Understanding the nucleation and growth mechanisms of nanocrystals under hydro- and solvothermal conditions is key to tailoring functional nanomaterials. High-energy and high-flux synchrotron radiation is ideal for characterization by powder X-ray diffraction and X-ray total scattering in real time. Different versions of batch-type cell reactors have been employed in this work, exploiting the robustness of polyimide-coated fused quartz tubes with an inner diameter of 0.7 mm, as they can withstand pressures up to 250 bar and temperatures up to 723 K for several hours. Reported here are recent developments of the in situ setups available for general users on the P21.1 beamline at PETRA III and the DanMAX beamline at MAX IV to study nucleation and growth phenomena in solvothermal synthesis. It is shown that data suitable for both reciprocal-space Rietveld refinement and direct-space pair distribution function refinement can be obtained on a timescale of 4 ms.
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Affiliation(s)
- Martin Roelsgaard
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Magnus Kløve
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Rasmus Christensen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Andreas D. Bertelsen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Nils L. N. Broge
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Innokenty Kantor
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
- Department of Physics, Technical University of Denmark, 2880 Kongens Lyngby, Denmark
| | - Daniel Risskov Sørensen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Ann-Christin Dippel
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Soham Banerjee
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | | | - Philipp Glaevecke
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Olof Gutowski
- Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, 22607 Hamburg, Germany
| | - Mads Ry Vogel Jørgensen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- MAX IV Laboratory, Lund University, 224 84 Lund, Sweden
| | - Bo Brummerstedt Iversen
- Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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4
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Hulbert BS, Kriven WM. Specimen-displacement correction for powder X-ray diffraction in Debye-Scherrer geometry with a flat area detector. J Appl Crystallogr 2023; 56:160-166. [PMID: 36777137 PMCID: PMC9901925 DOI: 10.1107/s1600576722011360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/25/2022] [Indexed: 01/18/2023] Open
Abstract
The effect of small changes in the speci-men-to-detector distance on the unit-cell parameters is examined for synchrotron powder diffraction in Debye-Scherrer (transmission) geometry with a flat area detector. An analytical correction equation is proposed to fix the shift in 2θ values due to speci-men capillary displacement. This equation does not require the use of an internal reference material, is applied during the Rietveld refinement step, and is analogous to the speci-men-displacement correction equations for Bragg-Brentano and curved-detector Debye-Scherrer geometry experiments, but has a different functional form. The 2θ correction equation is compared with another speci-men-displacement correction based on the use of an internal reference material in which new integration and calibration parameters of area-detector images are determined. Example data sets showing the effect of a 3.3 mm speci-men displacement on the unit-cell parameters for 25°C CeO2, including both types of displacement correction, are described. These experiments were performed at powder X-ray diffraction beamlines at the National Synchrotron Light Source II at Brookhaven National Laboratory and the Advanced Photon Source at Argonne National Laboratory.
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Affiliation(s)
- Benjamin S. Hulbert
- Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, Illinois 61801, USA
| | - Waltraud M. Kriven
- Materials Science and Engineering, University of Illinois at Urbana-Champaign, 1304 W. Green St., Urbana, Illinois 61801, USA,Correspondence e-mail:
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5
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Henry K, Ahlburg JV, Andersen HL, Granados-Miralles C, Stingaciu M, Saura-Múzquiz M, Christensen M. In-depth investigations of size and occupancies in cobalt ferrite nanoparticles by joint Rietveld refinements of X-ray and neutron powder diffraction data. J Appl Crystallogr 2022; 55:1336-1350. [PMID: 36249502 PMCID: PMC9533760 DOI: 10.1107/s1600576722008123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 08/14/2022] [Indexed: 12/02/2022] Open
Abstract
Combined neutron and X-ray powder diffraction investigations of CoFe2O4 are reported, aimed at investigating the robustness, reproducibility and reliability of structural parameters from Rietveld refinement. Powder X-ray diffraction (PXRD) and neutron powder diffraction (NPD) have been used to investigate the crystal structure of CoFe2O4 nanoparticles prepared via different hydrothermal synthesis routes, with particular attention given to accurately determining the spinel inversion degrees. The study is divided into four parts. In the first part, the investigations focus on the influence of using different diffraction pattern combinations (NPD, Cu-source PXRD and Co-source PXRD) for the structural modelling. It is found that combining PXRD data from a Co source with NPD data offers a robust structural model. The second part of the study evaluates the reproducibility of the employed multipattern Rietveld refinement procedure using different data sets collected on the same sample, as well as on equivalently prepared samples. The refinement procedure gives reproducible results and reveals that the synthesis method is likewise reproducible since only minor differences are noted between the samples. The third part focuses on the structural consequences of (i) the employed heating rate (achieved using three different hydrothermal reactor types) and (ii) changing the cobalt salt in the precursors [aqueous salt solutions of Co(CH3COOH)2, Co(NO3)2 and CoCl2] in the synthesis. It is found that increasing the heating rate causes a change in the crystal structure (unit cell and crystallite sizes) while the Co/Fe occupancy and magnetic parameters remain similar in all cases. Also, changing the type of cobalt salt does not alter the final crystal/magnetic structure of the CoFe2O4 nanoparticles. The last part of this study is a consideration of the chemicals and parameters used in the synthesis of the different samples. All the presented samples exhibit a similar crystal and magnetic structure, with only minor deviations. It is also evident that the refinement method used played a key role in the description of the sample.
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6
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Taşaltın N, Karakuş S, Taşaltın C, Baytemir G. Highly sensitive and selective rGO based Non-Enzymatic electrochemical sensor for propamocarb fungicide pesticide detection. Food Chem 2022; 372:131267. [PMID: 34638065 DOI: 10.1016/j.foodchem.2021.131267] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/05/2021] [Accepted: 09/28/2021] [Indexed: 01/28/2023]
Abstract
In this study, reduced graphene oxide (rGO) was prepared using a green ultrasonic microwave assisted method and investigated rGO based non-enzymatic electrochemical sensor for detecting a synthetic fungicide as a propamocarb (PM) pesticide. The rGO-based sensor exhibited rapid response within 1 min, low detection limit of 0.6 μM and wide linear range of (1-5) μM with a high sensitivity of 101.1 μAμM-1 cm-2 for PM. Besides this, the sensor detected the propamocarb pesticide on the real cucumber sample with high sensitivity in the concentration range of (1-5) μM within a 1-minute cycle. The sensor is highly selective against propamocarb pesticide. The prepared non-enzymatic electrochemical sensor exhibited high sensitivity, high selectivity, reproducibility, and rapid response.
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Affiliation(s)
- Nevin Taşaltın
- Maltepe University, Dept. of Electrical & Electronics Engineering, Istanbul, Turkey; CONSENS, Maltepe University Research Center, Istanbul, Turkey.
| | - Selcan Karakuş
- Istanbul University-Cerrahpasa, Dept. of Chemistry, Istanbul, Turkey
| | - Cihat Taşaltın
- TUBİTAK Marmara Research Center, Materials Institute, Gebze, Kocaeli, Turkey
| | - Gülsen Baytemir
- Maltepe University, Dept. of Electrical & Electronics Engineering, Istanbul, Turkey
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7
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Christensen RS, Kløve M, Roelsgaard M, Sommer S, Iversen BB. Unravelling the complex formation mechanism of HfO 2 nanocrystals using in situ pair distribution function analysis. NANOSCALE 2021; 13:12711-12719. [PMID: 34477621 DOI: 10.1039/d1nr03044b] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Hafnia, HfO2, which is a wide band gap semiconducting oxide, is much less studied than the chemically similar zirconia (ZrO2). Here, we study the formation of hafnia nanocrystals from hafnium tetrachloride in methanol under solvothermal conditions (248 bar, 225-450 °C) using complementary in situ powder X-ray diffraction (PXRD) and Pair Distribution Function (PDF) analysis. The main structural motif of the precursor solution (HfCl4 dissolved in methanol) is a Hf oxide trimer with very similar local structure to that of m-HfO2. Different measurements on precursor solutions show large intensity variation for the Hf-Cl correlations signifying different extents of HCl elimation. A few seconds of heating lead to a correlation appearing at 3.9 Å corresponding to corner-sharing Hf-polyhedra in a disordered solid matrix. During the next minutes (depending on temperature) the disordered structure rearranges and the nearest neighbour Hf-Hf distance contracts while the Hf-O coordination number increases. After approximately 90 seconds (at T = 250 °C) the structural rearrangement terminates and 1-2 nm nanocrystals of m-HfO2 nucleate. Initially the m-HfO2 nanocrystals have significant disorder as reflected in large Hf atomic displacement parameter (ADP) values, but as the nanocrystals grow to 5-6 nm in size during extended heating, the Hf ADPs decrease toward the values obtained for ordered bulk structures. The nanocrystal growth is not well modelled by the Johnson-Mehl-Avrami expression reflecting that multiple complex chemical processes occur during this highly nonclassical nanocrystal formation under solvothermal conditions.
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Affiliation(s)
- Rasmus S Christensen
- Center for Materials Crystallography, Department of Chemistry and iNano, Aarhus University, Denmark.
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8
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Andersen HL, Frandsen BA, Gunnlaugsson HP, Jørgensen MRV, Billinge SJL, Jensen KMØ, Christensen M. Local and long-range atomic/magnetic structure of non-stoichiometric spinel iron oxide nanocrystallites. IUCRJ 2021; 8:33-45. [PMID: 33520241 PMCID: PMC7792993 DOI: 10.1107/s2052252520013585] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 10/11/2020] [Indexed: 06/08/2023]
Abstract
Spinel iron oxide nanoparticles of different mean sizes in the range 10-25 nm have been prepared by surfactant-free up-scalable near- and super-critical hydro-thermal synthesis pathways and characterized using a wide range of advanced structural characterization methods to provide a highly detailed structural description. The atomic structure is examined by combined Rietveld analysis of synchrotron powder X-ray diffraction (PXRD) data and time-of-flight neutron powder-diffraction (NPD) data. The local atomic ordering is further analysed by pair distribution function (PDF) analysis of both X-ray and neutron total-scattering data. It is observed that a non-stoichiometric structural model based on a tetragonal γ-Fe2O3 phase with vacancy ordering in the structure (space group P43212) yields the best fit to the PXRD and total-scattering data. Detailed peak-profile analysis reveals a shorter coherence length for the superstructure, which may be attributed to the vacancy-ordered domains being smaller than the size of the crystallites and/or the presence of anti-phase boundaries, faulting or other disorder effects. The intermediate stoichiometry between that of γ-Fe2O3 and Fe3O4 is confirmed by refinement of the Fe/O stoichiometry in the scattering data and quantitative analysis of Mössbauer spectra. The structural characterization is complemented by nano/micro-structural analysis using transmission electron microscopy (TEM), elemental mapping using scanning TEM, energy-dispersive X-ray spectroscopy and the measurement of macroscopic magnetic properties using vibrating sample magnetometry. Notably, no evidence is found of a Fe3O4/γ-Fe2O3 core-shell nanostructure being present, which had previously been suggested for non-stoichiometric spinel iron oxide nanoparticles. Finally, the study is concluded using the magnetic PDF (mPDF) method to model the neutron total-scattering data and determine the local magnetic ordering and magnetic domain sizes in the iron oxide nanoparticles. The mPDF data analysis reveals ferrimagnetic collinear ordering of the spins in the structure and the magnetic domain sizes to be ∼60-70% of the total nanoparticle sizes. The present study is the first in which mPDF analysis has been applied to magnetic nanoparticles, establishing a successful precedent for future studies of magnetic nanoparticles using this technique.
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Affiliation(s)
- Henrik L. Andersen
- Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, Aarhus C, DK-8000, Denmark
| | - Benjamin A. Frandsen
- Department of Physics and Astronomy, Brigham Young University, N283 ESC, Provo, Utah 84602, USA
| | | | - Mads R. V. Jørgensen
- Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, Aarhus C, DK-8000, Denmark
- MAX IV Laboratory, Lund University, PO Box 118, Lund, SE-221 00, Sweden
| | - Simon J. L. Billinge
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W. 120th Street, New York 10027, USA
- Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, PO Box 5000, Upton, New York 11973, USA
| | - Kirsten M. Ø. Jensen
- Department of Chemistry and Nanoscience Center, University of Copenhagen, Universitetsparken 5, København Ø, DK-2100, Denmark
| | - Mogens Christensen
- Department of Chemistry and Interdisciplinary Nanoscience Center, Aarhus University, Langelandsgade 140, Aarhus C, DK-8000, Denmark
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9
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Broge NLN, Bondesgaard M, Søndergaard-Pedersen F, Roelsgaard M, Iversen BB. Autocatalytic Formation of High-Entropy Alloy Nanoparticles. Angew Chem Int Ed Engl 2020; 59:21920-21924. [PMID: 32820603 DOI: 10.1002/anie.202009002] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Indexed: 01/03/2023]
Abstract
High-entropy alloy (HEA) nanoparticles hold great promise as tunable catalysts. Despite the fact that alloy formation is typically difficult in oxygen-rich environments, we found that Pt-Ir-Pd-Rh-Ru nanoparticles can be synthesized under benign low-temperature solvothermal conditions. In situ X-ray scattering and transmission electron microscopy reveal the solvothermal formation mechanism of Pt-Ir-Pd-Rh-Ru nanoparticles. For the individual metal acetylacetonate precursors, formation of single metal nanoparticles takes place at temperatures spanning from ca. 150 °C for Pd to ca. 350 °C for Ir. However, for the mixture, homogenous Pt-Ir-Pd-Rh-Ru HEA nanoparticles can be obtained around 200 °C due to autocatalyzed metal reduction at the (111) facets of the forming crystallites. The autocatalytic formation mechanism suggests that many types of HEA nanocatalysts should accessible with scalable solvothermal reactions, thereby providing broad availability and tunability.
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Affiliation(s)
- Nils L N Broge
- Center for Materials Crystallography, Department of Chemistry & iNANO, Aarhus University, 8000, Aarhus C, Denmark
| | - Martin Bondesgaard
- Center for Materials Crystallography, Department of Chemistry & iNANO, Aarhus University, 8000, Aarhus C, Denmark
| | | | - Martin Roelsgaard
- Center for Materials Crystallography, Department of Chemistry & iNANO, Aarhus University, 8000, Aarhus C, Denmark
| | - Bo Brummerstedt Iversen
- Center for Materials Crystallography, Department of Chemistry & iNANO, Aarhus University, 8000, Aarhus C, Denmark
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10
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Broge NLN, Bondesgaard M, Søndergaard‐Pedersen F, Roelsgaard M, Iversen BB. Autocatalytic Formation of High‐Entropy Alloy Nanoparticles. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Nils L. N. Broge
- Center for Materials Crystallography, Department of Chemistry & iNANO Aarhus University 8000 Aarhus C Denmark
| | - Martin Bondesgaard
- Center for Materials Crystallography, Department of Chemistry & iNANO Aarhus University 8000 Aarhus C Denmark
| | | | - Martin Roelsgaard
- Center for Materials Crystallography, Department of Chemistry & iNANO Aarhus University 8000 Aarhus C Denmark
| | - Bo Brummerstedt Iversen
- Center for Materials Crystallography, Department of Chemistry & iNANO Aarhus University 8000 Aarhus C Denmark
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11
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Broge NLN, Søndergaard-Pedersen F, Roelsgaard M, Hassing-Hansen X, Iversen BB. Mapping the redox chemistry of common solvents in solvothermal synthesis through in situ X-ray diffraction. NANOSCALE 2020; 12:8511-8518. [PMID: 32242591 DOI: 10.1039/d0nr01240h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Solvothermal technology shows great promise in "green" materials synthesis, processing, and recycling. The outcome of a specific solvothermal reaction depends strongly on the solvent properties, and the versatility of solvothermal synthesis hinges on the very large changes in solvent properties as a function of temperature and pressure. Here, six simple 3d transition metal nitrate salts (Cu(ii), Ni(ii), Co(ii), Fe(iii), Mn(ii), Cr(iii)) were dissolved in five common solvents (water, ethanol, ethylene glycol, glycerol, and 10% hydrogen peroxide solution) and heated stepwise up to 450 °C at a pressure of 250 bar using an in situ reactor while X-ray scattering data was recorded. A range of crystalline phases were observed in the form of metallic phases, metal oxides, and other ionic compounds. These data by themselves provide simple recipes for synthesis of many technologically important 3d transition metal nanomaterials. However, more generally the oxidation states of the metals in the synthesized materials can be used to map the solvent redox properties under solvothermal conditions. It is found that glycerol and ethylene glycol are strongly reducing, ethanol is moderately reducing, while water is weakly oxidizing. The behavior of the hydrogen peroxide solution is more complex including both oxidization and reduction. Furthermore, it is observed that the reducing powers of ethanol, ethylene glycol, and glycerol are enhanced with increasing temperature. The mapping of the redox properties of these common solvents provides a method for tailoring a given reaction through choice of solvent and reaction temperature. Solvothermal processes represent an environmentally benign alternative to the use of toxic reducing agents in chemical reactions, and quantification of the redox chemistry is a first step in rational materials design.
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Affiliation(s)
- Nils Lau Nyborg Broge
- Center for Materials Crystallography, Department of Chemistry and iNano, Aarhus University, Denmark.
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12
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Miller RC, Neilson JR, Prieto AL. Amide-Assisted Synthesis of Iron Germanium Sulfide (Fe 2GeS 4) Nanostars: The Effect of LiN(SiMe 3) 2 on Precursor Reactivity for Favoring Nanoparticle Nucleation or Growth. J Am Chem Soc 2020; 142:7023-7035. [PMID: 32212651 DOI: 10.1021/jacs.0c00260] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Olivine Fe2GeS4 has been identified as a promising photovoltaic absorber material introduced as an alternate candidate to iron pyrite, FeS2. The compounds share similar benefits in terms of elemental abundance and relative nontoxicity, but Fe2GeS4 was predicted to have higher stability with respect to decomposition to alternate phases and, therefore, more optimal device performance. Our initial report of the nanoparticle (NP) synthesis for Fe2GeS4 was not well understood and required an inefficient 24 h growth to dissolve an iron sulfide impurity. Here, we report an amide-assisted Fe2GeS4 NP synthesis that directly forms the phase-pure product in minutes. This significant advance was achieved by the replacement of the poorly understood hexamethyldisilazane (HMDS) additive and TMS2S by the conjugate base, lithium bis(trimethylsilyl)amide (LiN(SiMe3)2), and elemental S, respectively. We hypothesized that fragments of both TMS2S and HMDS had carried out the roles that Brønsted bases play in amide-assisted NP syntheses and were necessary for Ge incorporation. Convolution of this role with the supply of S in TMS2S caused the iron sulfide impurities. Separating these effects in the use of LiN(SiMe3)2 and elemental S resulted in synthetic control over the ternary phase. Herein we explore the Fe-Ge-S reaction landscape and the role of the base. Its concentration was found to increase the reactivities of the Fe, Ge, and S precursors, and we discuss possible metal-amide intermediates. This affords tunability in two areas: favorability of NP nucleation versus growth and phase formation. The phase-purity of Fe2GeS4 depends on the molar ratios of the cations, base, and amine as well as the Fe:Ge:S molar ratios. The resultant Fe2GeS4 NPs exhibit an interesting star anise-like morphology with stacks of nanoplates that intersect along a 6-fold rotation axis. The optical properties of the Fe2GeS4 NPs are consistent with previously published measurements showing a measured band gap of 1.48 eV.
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Affiliation(s)
- Rebecca C Miller
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - James R Neilson
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
| | - Amy L Prieto
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523, United States
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13
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Gjørup FH, Ahlburg JV, Christensen M. Laboratory setup for rapid in situ powder X-ray diffraction elucidating Ni particle formation in supercritical methanol. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2019; 90:073902. [PMID: 31370507 DOI: 10.1063/1.5089592] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 06/17/2019] [Indexed: 06/10/2023]
Abstract
The design and function of a custom-made Soller slit for a laboratory 2D area detector is presented through a series of demonstration images and an in situ experiment following the formation of nickel particles in supercritical methanol. The in situ experiment is performed in a capillary sample environment, modified for a laboratory scale Rigaku Smartlab diffractometer, and with a temperature range of 300-1050 K. The formation of nickel particles was followed successfully using laboratory in situ X-ray powder diffraction with a time resolution in the order of 27 s. Observations from the area detector images showed the appearance of three distinct phases during the reaction: Ni3(NO3)2(OH)4, NiO, and Ni. The images were linearly integrated and analyzed using Rietveld refinement. A reaction mechanism is proposed based on an evaluation of the weight fractions and scattering factors as a function of reaction time.
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Affiliation(s)
- Frederik H Gjørup
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Jakob V Ahlburg
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
| | - Mogens Christensen
- Center for Materials Crystallography, Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
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14
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Lee JM, Miller RC, Moloney LJ, Prieto AL. The development of strategies for nanoparticle synthesis: Considerations for deepening understanding of inherently complex systems. J SOLID STATE CHEM 2019. [DOI: 10.1016/j.jssc.2018.12.053] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Fujita T, Kasai H, Nishibori E. Hydrothermal reactor for in-situ synchrotron radiation powder diffraction at SPring-8 BL02B2 for quantitative design for nanoparticle. J Supercrit Fluids 2019. [DOI: 10.1016/j.supflu.2018.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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16
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Moscheni D, Bertolotti F, Piveteau L, Protesescu L, Dirin DN, Kovalenko MV, Cervellino A, Pedersen JS, Masciocchi N, Guagliardi A. Size-Dependent Fault-Driven Relaxation and Faceting in Zincblende CdSe Colloidal Quantum Dots. ACS NANO 2018; 12:12558-12570. [PMID: 30517780 DOI: 10.1021/acsnano.8b07092] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Surface chemistry and core defects are known to play a prominent role in governing the photophysical properties of nanocrystalline semiconductors. Nevertheless, investigating them in small nanocrystals remains a complex task. Here, by combining X-ray scattering techniques in the wide- and small-angle regions and using the Debye scattering equation (DSE) method of analysis, we unveil a high density of planar defects in oleate-terminated zincblende (ZB) CdSe colloidal quantum dots (QDs) and size-dependent faceting within a square-cuboid morphology. Atomistic models of faulted ZB nanocrystals, based on the probabilistic stacking of CdSe layers in cubic and hexagonal sequences, and data analysis point to the preferential location of faults near the center of nanocrystals. By finely modeling faulting and morphological effects on the X-ray scattering pattern, a relaxation of the Cd-Se bond distance parallel to the stacking direction, up to +3% (2.71 Å) with respect to the reference bulk value (2.63 Å), is detected, at the cubic/hexagonal transitions. The smallest nanocrystals show cubic {100} facets; {111} facets appear above 4 nm and progressively extend at larger sizes. These structural and morphological features likely vary depending on the synthesis conditions; nevertheless, since planar defects are nearly ubiquitous in CdSe QDs, the modeling approach here presented has a general validity. This work also points to the great potential of combining small- and wide-angle X-ray scattering and DSE-modeling techniques in gaining important knowledge on atomic-scale defects of semiconductor nanocrystals, underpinning the comprehension of the impact of structural defectiveness on the exciting properties of these QDs.
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Affiliation(s)
- Daniele Moscheni
- Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab , Università dell'Insubria , Via Valleggio 11 , I-22100 Como , Italy
| | - Federica Bertolotti
- Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab , Università dell'Insubria , Via Valleggio 11 , I-22100 Como , Italy
- Aarhus Institute of Advanced Studies (AIAS) , Aarhus University , Høegh-Guldbergs Gade 6B , 8000 Aarhus , Denmark
| | - Laura Piveteau
- Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir Prelog Weg 1 , Zürich CH-8093 , Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , Dübendorf CH-8600 , Switzerland
| | - Loredana Protesescu
- Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir Prelog Weg 1 , Zürich CH-8093 , Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , Dübendorf CH-8600 , Switzerland
| | - Dmitry N Dirin
- Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir Prelog Weg 1 , Zürich CH-8093 , Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , Dübendorf CH-8600 , Switzerland
| | - Maksym V Kovalenko
- Department of Chemistry and Applied Biosciences , ETH Zürich , Vladimir Prelog Weg 1 , Zürich CH-8093 , Switzerland
- Empa-Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129 , Dübendorf CH-8600 , Switzerland
| | - Antonio Cervellino
- SLS, Laboratory for Synchrotron Radiation-Condensed Matter , Paul Scherrer Institut , Villigen CH-5232 , Switzerland
| | - Jan Skov Pedersen
- Department of Chemistry and Interdisciplinary Nanoscience Center (iNANO) , Aarhus University , Gustav Wieds Vej 14 , 8000 Aarhus , Denmark
| | - Norberto Masciocchi
- Dipartimento di Scienza e Alta Tecnologia and To.Sca.Lab , Università dell'Insubria , Via Valleggio 11 , I-22100 Como , Italy
| | - Antonietta Guagliardi
- Istituto di Cristallografia and To.Sca.Lab , Consiglio Nazionale delle Ricerche , Via Valleggio 11 , I-22100 Como , Italy
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17
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Bertolotti F, Moscheni D, Guagliardi A, Masciocchi N. When Crystals Go Nano - The Role of Advanced X-ray Total Scattering Methods in Nanotechnology. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800534] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Federica Bertolotti
- Aarhus Institute of Advanced Studies (AIAS); Aarhus University; Høegh-Guldbergs Gade 6B 8000 Aarhus C Denmark
- Department of Science and High Technology and To.Sca.Lab. University of Insubria; Via Valleggio 11 22100 Como Italy
| | - Daniele Moscheni
- Department of Science and High Technology and To.Sca.Lab. University of Insubria; Via Valleggio 11 22100 Como Italy
| | - Antonietta Guagliardi
- Institute of Crystallography and To.Sca.Lab.; Consiglio Nazionale delle Ricerche; Via Valleggio 11 22100 Como Italy
| | - Norberto Masciocchi
- Department of Science and High Technology and To.Sca.Lab. University of Insubria; Via Valleggio 11 22100 Como Italy
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18
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Granados-Miralles C, Saura-Múzquiz M, Andersen HL, Quesada A, Ahlburg JV, Dippel AC, Canévet E, Christensen M. Approaching Ferrite-Based Exchange-Coupled Nanocomposites as Permanent Magnets. ACS APPLIED NANO MATERIALS 2018; 1:3693-3704. [PMID: 30087953 PMCID: PMC6066756 DOI: 10.1021/acsanm.8b00808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/28/2018] [Indexed: 06/08/2023]
Abstract
During the past decade, CoFe2O4 (hard)/Co-Fe alloy (soft) magnetic nanocomposites have been routinely prepared by partial reduction of CoFe2O4 nanoparticles. Monoxide (i.e., FeO or CoO) has often been detected as a byproduct of the reduction, although it remains unclear whether the formation of this phase occurs during the reduction itself or at a later stage. Here, a novel reaction cell was designed to monitor the reduction in situ using synchrotron powder X-ray diffraction (PXRD). Sequential Rietveld refinements of the in situ data yielded time-resolved information on the sample composition and confirmed that the monoxide is generated as an intermediate phase. The macroscopic magnetic properties of samples at different reduction stages were measured by means of vibrating sample magnetometry (VSM), revealing a magnetic softening with increasing soft phase content, which was too pronounced to be exclusively explained by the introduction of soft material in the system. The elemental compositions of the constituent phases were obtained from joint Rietveld refinements of ex situ high-resolution PXRD and neutron powder diffraction (NPD) data. It was found that the alloy has a tendency to emerge in a Co-rich form, inducing a Co deficiency on the remaining spinel phase, which can explain the early softening of the magnetic material.
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Affiliation(s)
- Cecilia Granados-Miralles
- Center for Materials
Crystallography, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Matilde Saura-Múzquiz
- Center for Materials
Crystallography, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Henrik L. Andersen
- Center for Materials
Crystallography, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Adrián Quesada
- Electroceramic Department, Instituto de Cerámica y Vidrio, CSIC, Kelsen 5, 28049 Madrid, Spain
| | - Jakob V. Ahlburg
- Center for Materials
Crystallography, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
| | - Ann-Christin Dippel
- Deutsches Elektronen-Synchrotron (DESY), Photon Science, Notkestrasse
85, 22607 Hamburg, Germany
| | - Emmanuel Canévet
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut (PSI), 5232 Villigen, Switzerland
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Mogens Christensen
- Center for Materials
Crystallography, Department of Chemistry and iNANO, Aarhus University, Langelandsgade 140, 8000 Aarhus, Denmark
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