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Zheng Y, Fang X, Zhou Y, Cui X, Cao L, Gao L, Yin H, Wang J, Ai S. Enhanced photoactivity of Bi2S3 nanoflowers by CS-AgBr and CeO2: Application in photoelectrochemical biosensor for the effect of antibiotics on N6-methyladenosine in rice tissues. J Electroanal Chem (Lausanne) 2022. [DOI: 10.1016/j.jelechem.2022.116640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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2
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Impact of Hydrothermally Prepared Support on the Catalytic Properties of CuCe Oxide for Preferential CO Oxidation Reaction. Catalysts 2022. [DOI: 10.3390/catal12060674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
CuCe mixed oxide is one of the most studied catalytic systems for preferential CO oxidation (CO-PrOx) for the purification of hydrogen-rich gas stream. In this study, a series of ceria supports were prepared via a citrates-hydrothermal route by altering the synthesis parameters (concentration and temperature). The resulting supports were used for the preparation of CuCe mixed-oxide catalysts via wet impregnation. Various physicochemical techniques were utilized for the characterization of the resulting materials, whereas the CuCe oxide catalysts were assessed in CO-PrOx reaction. Through the proper modification of the hydrothermal parameters, CeO2 supports with tunable properties can be formed, thus targeting the formation of highly active and selective catalysts. The nature of the reduced copper species and the optimum content in oxygen vacancies seems to be the key factors behind the remarkable catalytic performance of a CO-PrOx reaction.
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3
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Xue W, Qu M, Wang Z, Li W, Jia A, Li F, Wang Z, Wang Y. Role of Benzene-1,3,5-Tricarboxylate Ligand in CuO–CeO2 Catalysts Derived from Metal–Organic Frameworks for Carbon Monoxide Oxidation. Catal Letters 2022. [DOI: 10.1007/s10562-022-03970-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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4
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Papatheodorou G, Ntzoufra P, Hapeshi E, Vakros J, Mantzavinos D. Hybrid Biochar/Ceria Nanomaterials: Synthesis, Characterization and Activity Assessment for the Persulfate-Induced Degradation of Antibiotic Sulfamethoxazole. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:194. [PMID: 35055213 PMCID: PMC8778396 DOI: 10.3390/nano12020194] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/02/2022] [Accepted: 01/05/2022] [Indexed: 12/10/2022]
Abstract
Biochar from spent malt rootlets was employed as the template to synthesize hybrid biochar-ceria materials through a wet impregnation method. The materials were tested for the activation of persulfate (SPS) and subsequent degradation of sulfamethoxazole (SMX), a representative antibiotic, in various matrices. Different calcination temperatures in the range 300-500 °C were employed and the resulting materials were characterized by means of N2 adsorption and potentiometric mass titration as well as TGA, XRD, SEM, FTIR, DRS, and Raman spectroscopy. Calcination temperature affects the biochar content and the physicochemical properties of the hybrid materials, which were tested for the degradation of 500 μg L-1 SMX with SPS (in the range 200-500 mg L-1) in various matrices including ultrapure water (UPW), bottled water, wastewater, and UPW spiked with bicarbonate, chloride, or humic acid. Materials calcined at 300-350 °C, with a surface area of ca. 120 m2 g-1, were the most active, yielding ca. 65% SMX degradation after 120 min of reaction in UPW; materials calcined at higher temperatures as well as bare biochar were less active. Degradation decreased with increasing matrix complexity due to the interactions amongst the surface, the contaminant, and the oxidant. Experiments in the presence of scavengers (i.e., methanol, t-butanol, and sodium azide) revealed that sulfate and hydroxyl radicals as well as singlet oxygen were the main oxidative species.
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Affiliation(s)
- Golfo Papatheodorou
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (G.P.); (P.N.)
| | - Paraskevi Ntzoufra
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (G.P.); (P.N.)
| | - Evroula Hapeshi
- Department of Life and Health Sciences, School of Sciences and Engineering, University of Nicosia, Nicosia 2417, Cyprus;
| | - John Vakros
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (G.P.); (P.N.)
| | - Dionissios Mantzavinos
- Department of Chemical Engineering, University of Patras, Caratheodory 1, University Campus, GR-26504 Patras, Greece; (G.P.); (P.N.)
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5
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Mao J, Qin L, Tian L, He L, Zhu Y, Meng Q, Zhang G. Hierarchical N-Doped CuO/Cu Composites Derived from Dual-Ligand Metal-Organic Frameworks as Cost-Effective Catalysts for Low-Temperature CO Oxidation. ACS OMEGA 2021; 6:29596-29608. [PMID: 34778631 PMCID: PMC8582074 DOI: 10.1021/acsomega.1c03877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/30/2021] [Indexed: 06/13/2023]
Abstract
Development of multi-ligand metal-organic frameworks (MOFs) and derived heteroatom-doped composites as efficient non-noble metal-based catalysts is highly desirable. However, rational design of these materials with controllable composition and structure remains a challenge. In this study, novel hierarchical N-doped CuO/Cu composites were synthesized by assembling dual-ligand MOFs via a solvent-induced coordination modulation/low-temperature pyrolysis method. Different from a homogeneous system, our heterogeneous nucleation strategy provided more flexible and cost-effective MOF production and offered efficient direction/shape-controlled synthesis, resulting in a faster reaction and more complete conversion. After pyrolysis, they further transformed to a unique metal/carbon matrix with regular morphology and, as a hot template, guided the orderly generation of metal oxides, eliminating sintering and agglomeration of metal oxides and initiating a synergistic effect between the N-doped metal oxide/metal and carbon matrix. The prepared N-doped CuO/Cu catalysts held unique water resistance and superior catalytic activity (100% CO conversion at 140 °C).
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Affiliation(s)
- Jingwen Mao
- Institute
of Oceanic and Environmental Chemical Engineering, Center for Membrane
and Water Science & Technology, State Key Lab Breeding Base of
Green Chemical Synthesis Technology, Zhejiang
University of Technology, Hangzhou 310014, P.R. China
| | - Lei Qin
- Institute
of Oceanic and Environmental Chemical Engineering, Center for Membrane
and Water Science & Technology, State Key Lab Breeding Base of
Green Chemical Synthesis Technology, Zhejiang
University of Technology, Hangzhou 310014, P.R. China
| | - Lin Tian
- Institute
of Oceanic and Environmental Chemical Engineering, Center for Membrane
and Water Science & Technology, State Key Lab Breeding Base of
Green Chemical Synthesis Technology, Zhejiang
University of Technology, Hangzhou 310014, P.R. China
| | - Lantian He
- Institute
of Oceanic and Environmental Chemical Engineering, Center for Membrane
and Water Science & Technology, State Key Lab Breeding Base of
Green Chemical Synthesis Technology, Zhejiang
University of Technology, Hangzhou 310014, P.R. China
| | - Yujie Zhu
- Institute
of Oceanic and Environmental Chemical Engineering, Center for Membrane
and Water Science & Technology, State Key Lab Breeding Base of
Green Chemical Synthesis Technology, Zhejiang
University of Technology, Hangzhou 310014, P.R. China
| | - Qin Meng
- College
of Chemical and Biochemical Engineering, State Key Laboratory of Chemical
Engineering, Zhejiang University, Hangzhou 310027, P.R. China
| | - Guoliang Zhang
- Institute
of Oceanic and Environmental Chemical Engineering, Center for Membrane
and Water Science & Technology, State Key Lab Breeding Base of
Green Chemical Synthesis Technology, Zhejiang
University of Technology, Hangzhou 310014, P.R. China
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6
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Influence of preparation method on catalytic performance of three-dimensionally ordered macroporous NiO–CuO for CO oxidation. J SOLID STATE CHEM 2021. [DOI: 10.1016/j.jssc.2021.122091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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Yakoumis I. PROMETHEUS: A Copper-Based Polymetallic Catalyst for Automotive Applications. Part I: Synthesis and Characterization. MATERIALS (BASEL, SWITZERLAND) 2021; 14:622. [PMID: 33572954 PMCID: PMC7866378 DOI: 10.3390/ma14030622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/26/2021] [Indexed: 11/22/2022]
Abstract
According to the strict European exhaust emissions standards that have been imposed by European legislation there is an elevated need for the decrease of the toxic gas emissions from vehicles. Therefore, car manufacturers have implemented a series of catalytic devices in the aftertreatment of the engine to comply with the standards. All catalytic devices (such as three-way catalysts, diesel particulate filters and diesel oxidation catalysts) accumulate concentrated loading of platinum group metals (PGMs, platinum, palladium, rhodium) as the active catalytic phase. Thus, the demand for PGMs is constantly increasing with a subsequent increase in their market prices. As a result, the research on catalytic converters of high activity and reduced cost/PGM loading is of great interest. In the present work, the Prometheus catalyst, a polymetallic nanosized copper-based catalyst for automotive emission control applications, is presented in two different metal loadings (2 wt% and 5 wt%) and metal ratios (Cu/Pd/Rh = 21/7/1 and Cu/Pd/Rh = 21/7/3). For the first time, a three-metal (copper, palladium, rhodium) nano-catalyst has been synthesized and characterized on a large scale. By using copper as an active catalytic phase, a reduction of PGMs loading is achieved (up to 85%) resulting in a novel catalytic device with similar or improved catalytic performance compared to commercial ones. The Prometheus catalyst is prepared by a wet impregnation method, using as a carrier an inorganic mixed oxide (CeZrO4) exhibiting elevated oxygen storage capacity (OSC). The heterogeneous catalytic powders produced were characterized by both spectroscopic and analytical methods. The metal content and ratio were determined by inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF) and energy-dispersive X-ray spectroscopy (EDS). The morphology and the catalyst particle size were determined with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The investigation revealed homogeneous particle formation and dispersion. The deposition of the metal nanoparticles on the porous inorganic carrier was verified with N2 sorption. Catalytic performance and reactivity of a catalyst (pure wash coat) with molar ratio 21/7/1 and a full-scale Prometheus catalyst with the desired loading of 15 g/ft3 were tested on an in-house synthetic gas bench (SGB) for the abatement of CO, CH4 and NO, both presenting high catalytic activity.
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Rood SC, Pastor‐Algaba O, Tosca‐Princep A, Pinho B, Isaacs M, Torrente‐Murciano L, Eslava S. Synergistic Effect of Simultaneous Doping of Ceria Nanorods with Cu and Cr on CO Oxidation and NO Reduction. Chemistry 2021; 27:2165-2174. [PMID: 33210814 PMCID: PMC7898804 DOI: 10.1002/chem.202004623] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 11/27/2022]
Abstract
Ceria particles play a key role in catalytic applications such as automotive three-way catalytic systems in which toxic CO and NO are oxidized and reduced to safe CO2 and N2 , respectively. In this work, we explore the incorporation of Cu and Cr metals as dopants in the crystal structure of ceria nanorods prepared by a single-step hydrothermal synthesis. XRD, Raman and XPS confirm the incorporation of Cu and Cr in the ceria crystal lattices, offering ceria nanorods with a higher concentration of oxygen vacancies. XPS also confirms the presence of Cr and Cu surface species. H2 -TPR and XPS analysis show that the simultaneous Cu and Cr co-doping results in a catalyst with a higher surface Cu concentration and a much-enhanced surface reducibility, in comparison with either undoped or singly doped (Cu or Cr) ceria nanorods. While single Cu doping enhances catalytic CO oxidation and Cr doping improves catalytic NO reduction, co-doping with both Cu and Cr enhances the benefits of both dopants in a synergistic manner employing roughly a quarter of dopant weight.
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Affiliation(s)
- Shawn C. Rood
- Centre for Sustainable Chemical TechnologiesDepartment of Chemical EngineeringUniversity of BathClaverton DownBathBA2 7AYUK
| | - Oriol Pastor‐Algaba
- Departament d'Enginyeria Química, Biològica i AmbientalUniversitat Autònoma de BarcelonaBellaterra08193Spain
| | - Albert Tosca‐Princep
- Departament d'Enginyeria Química, Biològica i AmbientalUniversitat Autònoma de BarcelonaBellaterra08193Spain
| | - Bruno Pinho
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgePhilippa Fawcett DriveCambridgeCB3 0ASUK
| | - Mark Isaacs
- Department of ChemistryUniversity College LondonLondonWC1H 0AJUK
| | - Laura Torrente‐Murciano
- Department of Chemical Engineering and BiotechnologyUniversity of CambridgePhilippa Fawcett DriveCambridgeCB3 0ASUK
| | - Salvador Eslava
- Centre for Sustainable Chemical TechnologiesDepartment of Chemical EngineeringUniversity of BathClaverton DownBathBA2 7AYUK
- Department of Chemical EngineeringImperial College LondonLondonSW7 2AZUK
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Sánchez L, Aguila G, Araya P, Quijada S, Guerrero S. A highly active Ca/Cu/YCeO 2–TiO 2 catalyst for the transient reduction of NO with CO and naphthalene under oxidizing conditions. RSC Adv 2021; 11:39896-39906. [PMID: 35494136 PMCID: PMC9044585 DOI: 10.1039/d1ra08412g] [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: 11/16/2021] [Accepted: 12/03/2021] [Indexed: 11/21/2022] Open
Abstract
The transient combustion of biomass leads to the evolution of a variety of pollutants (NO, CO, organic compounds, and many others) that can react with each other on a suitable catalyst to generate compounds of lower toxicity. Here, the transient reduction of NO with CO and naphthalene in the presence of oxygen was studied on a Ca/Cu/YCeO2–TiO2 catalyst. Response surface methodology was used to identify the optimum amounts of calcium, copper, and cerium. The optimized Ca/Cu/YCeO2–TiO2 catalyst was then extensively studied and characterized. The coupling of yttrium-stabilized ceria with TiO2 provided an active support that effectively activated naphthalene. When calcium and copper were added to the support, the obtained Ca/Cu/YCeO2–TiO2 catalyst achieved the full conversion of CO and naphthalene and 72% conversion of NO. The Ca/Cu/YCeO2–TiO2 catalyst possessed labile oxygen species, which might be related to the high catalytic activity. A highly-active Ca/Cu/YCeO2–TiO2 catalyst shows full conversion of CO and naphthalene and 72% conversion of NO under oxygen.![]()
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Affiliation(s)
- Luis Sánchez
- Departamento de Ingeniería Química, Biotecnología y Materiales, Universidad de Chile, Casilla 2777, Santiago, Chile
- Universidad de los Andes, Chile, Facultad de Ingeniería y Ciencias Aplicadas, Monseñor Álvaro del Portillo 12455, Las Condes, Chile
| | - Gonzalo Aguila
- Departamento de Ciencias de la Ingeniería, Facultad de Ingeniería, Universidad Andres Bello, 8031015, Chile
| | - Paulo Araya
- Departamento de Ingeniería Química, Biotecnología y Materiales, Universidad de Chile, Casilla 2777, Santiago, Chile
| | - Sergio Quijada
- Universidad de los Andes, Chile, Facultad de Ingeniería y Ciencias Aplicadas, Monseñor Álvaro del Portillo 12455, Las Condes, Chile
| | - Sichem Guerrero
- Universidad de los Andes, Chile, Facultad de Ingeniería y Ciencias Aplicadas, Monseñor Álvaro del Portillo 12455, Las Condes, Chile
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10
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A comparison of NiO–CuO–CeO2 composite catalysts prepared via different methods for CO oxidation. J SOLID STATE CHEM 2020. [DOI: 10.1016/j.jssc.2020.121697] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Rodriguez‐Gomez A, Lopez‐Martin A, Ramirez A, Gascon J, Caballero A. Elucidating the Promotional Effect of Cerium in the Dry Reforming of Methane. ChemCatChem 2020. [DOI: 10.1002/cctc.202001527] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Alberto Rodriguez‐Gomez
- Instituto de Ciencia de Materiales de Sevilla (CSIC-University of Seville) and Departamento de Quimica Inorganica University of Seville 41092 Seville Spain
- KAUST Catalysis Center (KCC) Advanced Catalytic Materials King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia
| | - Angeles Lopez‐Martin
- Instituto de Ciencia de Materiales de Sevilla (CSIC-University of Seville) and Departamento de Quimica Inorganica University of Seville 41092 Seville Spain
| | - Adrian Ramirez
- KAUST Catalysis Center (KCC) Advanced Catalytic Materials King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia
| | - Jorge Gascon
- KAUST Catalysis Center (KCC) Advanced Catalytic Materials King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia
| | - Alfonso Caballero
- Instituto de Ciencia de Materiales de Sevilla (CSIC-University of Seville) and Departamento de Quimica Inorganica University of Seville 41092 Seville Spain
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12
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Papavasiliou J. Interaction of atomically dispersed gold with hydrothermally prepared copper-cerium oxide for preferential CO oxidation reaction. Catal Today 2020. [DOI: 10.1016/j.cattod.2019.02.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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13
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Papadopoulos C, Kappis K, Papavasiliou J, Vakros J, Kuśmierz M, Gac W, Georgiou Y, Deligiannakis Y, Avgouropoulos G. Copper-promoted ceria catalysts for CO oxidation reaction. Catal Today 2020. [DOI: 10.1016/j.cattod.2019.06.078] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Improved SO2 Tolerance of Cu-SAPO-18 by Ce-Doping in the Selective Catalytic Reduction of NO with NH3. Catalysts 2020. [DOI: 10.3390/catal10070783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The Ce-Cu-SAPO-18 catalysts were prepared using the ion exchange method. The impact of sulfur dioxide on catalytic performance of Ce-Cu-SAPO-18 for the selective catalytic reduction (SCR) of NO with NH3 was examined. Detailed characterization of the fresh and sulfur-poisoning Cu-SAPO-18 and Ce-Cu-SAPO-18 samples was conducted. XRD and BET results show that SO2 treatment of the Ce-doped Cu-SAPO-18 (Ce-Cu-SAPO-18-S) sample did not induce a remarkable change in structure, as compared with that of the fresh counterpart. According to in situ DRIFT, H2-TPR, SEM, and EDS results, it is found that the sulfation species attached preferentially to the cerium species, rather than the isolated Cu2+ species. In particular, the TG/DSC results confirm that the sulfate species on the Ce-Cu-SAPO-18-S sample was easier to decompose than that on the Cu-SAPO-18-S sample. The catalytic active sites of Ce-Cu-SAPO-18 were less influenced after SO2 treatment, as demonstrated by the TPR and XPS results. All of the above results show that the Ce-Cu-SAPO-18 sample exhibited better sulfur-resistant performance than the Cu-SAPO-18 sample.
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15
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Recent Advances on the Rational Design of Non-Precious Metal Oxide Catalysts Exemplified by CuOx/CeO2 Binary System: Implications of Size, Shape and Electronic Effects on Intrinsic Reactivity and Metal-Support Interactions. Catalysts 2020. [DOI: 10.3390/catal10020160] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Catalysis is an indispensable part of our society, massively involved in numerous energy and environmental applications. Although, noble metals (NMs)-based catalysts are routinely employed in catalysis, their limited resources and high cost hinder the widespread practical application. In this regard, the development of NMs-free metal oxides (MOs) with improved catalytic activity, selectivity and durability is currently one of the main research pillars in the area of heterogeneous catalysis. The present review, involving our recent efforts in the field, aims to provide the latest advances—mainly in the last 10 years—on the rational design of MOs, i.e., the general optimization framework followed to fine-tune non-precious metal oxide sites and their surrounding environment by means of appropriate synthetic and promotional/modification routes, exemplified by CuOx/CeO2 binary system. The fine-tuning of size, shape and electronic/chemical state (e.g., through advanced synthetic routes, special pretreatment protocols, alkali promotion, chemical/structural modification by reduced graphene oxide (rGO)) can exert a profound influence not only to the reactivity of metal sites in its own right, but also to metal-support interfacial activity, offering highly active and stable materials for real-life energy and environmental applications. The main implications of size-, shape- and electronic/chemical-adjustment on the catalytic performance of CuOx/CeO2 binary system during some of the most relevant applications in heterogeneous catalysis, such as CO oxidation, N2O decomposition, preferential oxidation of CO (CO-PROX), water gas shift reaction (WGSR), and CO2 hydrogenation to value-added products, are thoroughly discussed. It is clearly revealed that the rational design and tailoring of NMs-free metal oxides can lead to extremely active composites, with comparable or even superior reactivity than that of NMs-based catalysts. The obtained conclusions could provide rationales and design principles towards the development of cost-effective, highly active NMs-free MOs, paving also the way for the decrease of noble metals content in NMs-based catalysts.
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16
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The Influence of Preparation Method on the Physicochemical Characteristics and Catalytic Activity of Co/TiO2 Catalysts. Catalysts 2020. [DOI: 10.3390/catal10010088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Two Co/TiO2 catalysts with 7% CoO/g loading were prepared using equilibrium deposition filtration and the dry impregnation method. The two catalysts were characterized with various physicochemical techniques and tested for the degradation of sulfamethaxazole (SMX) using sodium persulfate (SPS) as the oxidant. It was found that the two catalysts exhibit different physicochemical characteristics. The equilibrium deposition filtration (EDF) catalyst had a higher dispersion of cobalt phase, more easily reduced Co(III) species, and a higher ratio of Co(III)/Co(II) species. The interactions between Co-deposited species and the titania surface were monitored with diffuse reflectance spectroscopy in all the preparation steps, and it was found that they increased during drying and calcination, while EDF favored the formation of surface species with strong interactions with the support. Finally, the EDF catalyst was more active for the degradation of sulfamethaxazole due to its better physicochemical characteristics.
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17
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Kappis K, Papavasiliou J. Influence of the Hydrothermal Parameters on the Physicochemical Characteristics of Cu−Ce Oxide Nanostructures. ChemCatChem 2019. [DOI: 10.1002/cctc.201901108] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Joan Papavasiliou
- Department of Materials ScienceUniversity of Patras Patras GR-26504 Greece
- Foundation for Research and Technology-Hellas (FORTH)Institute of Chemical Engineering Sciences (ICE-HT) Patras GR-26504 Greece
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18
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Abstract
Copper-cerium mixed oxide catalysts have gained ground over the years in the field of heterogeneous catalysis and especially in CO oxidation reaction due to their remarkable performance. In this study, a series of highly active, atomically dispersed copper-ceria nanocatalysts were synthesized via appropriate tuning of a novel hydrothermal method. Various physicochemical techniques including electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction (XRD), N2 adsorption, scanning electron microscopy (SEM), Raman spectroscopy, and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed in the characterization of the synthesized materials, while all the catalysts were evaluated in the CO oxidation reaction. Moreover, discussion of the employed mechanism during hydrothermal route was provided. The observed catalytic activity in CO oxidation reaction was strongly dependent on the nanostructured morphology, oxygen vacancy concentration, and nature of atomically dispersed Cu2+ clusters.
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19
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Steam Reforming of Methanol over Nanostructured Pt/TiO2 and Pt/CeO2 Catalysts for Fuel Cell Applications. Catalysts 2018. [DOI: 10.3390/catal8110544] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
A research and technological challenge for fuel processors integrated with High Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFCs), also known as Internal Reforming Methanol Fuel Cells (IRMFCs), operating at 200–220 °C, is the development of highly efficient catalysts, which will be able to selectively (low CO and other by-products formation) produce the required quantity of hydrogen at these temperatures. In this work, various amounts of platinum were dispersed via deposition-precipitation (DP) and impregnation (I) methods onto the surface of hydrothermally prepared ceria nanorods (CNRs) and titania nanotubes (TNTs). These nanostructured catalysts were evaluated in steam reforming of methanol process targeting the operation level of IRMFCs. The (DP) method resulted in highly (atomically) dispersed platinum-based catalysts, as confirmed with Scanning Transmission Electron Microscopy (STEM) analysis, with a mean particle size of less than 1 nm in the case of 0.35 wt.% Pt/CNRs catalyst. Ultra-fine dispersion of platinum species correlated with the presence of oxygen vacancies, together with the enrichment of CNRs surface with active metallic phase resulted in a highly active catalyst achieving at 220 °C a hydrogen production rate of 5500 cm3 min−1 per g of loaded platinum.
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20
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Papavasiliou J, Vakros J, Avgouropoulos G. Impact of acid treatment of CuO-CeO2 catalysts on the preferential oxidation of CO reaction. CATAL COMMUN 2018. [DOI: 10.1016/j.catcom.2018.07.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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