1
|
Santos MN, Lourenço TC, Mocelim M, Da Silva JLF. Theoretical study of the structural and energetic properties of Ce 1-xZr xO 2 nanoparticles via molecular dynamics simulations. Phys Chem Chem Phys 2024; 26:17838-17853. [PMID: 38884463 DOI: 10.1039/d4cp01137f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
The combination of ceria (CeO2) with different metal oxides (MO2), e.g. Ce1-xMxO2, has been strategically used to enhance its intrinsic properties. Moreover, the controlled synthesis of mixed oxide nanoparticles (NPs) opens the opportunity to explore the size dependence and chemical composition of the physical-chemical properties. However, our atomic-level understanding of how the physical-chemical and thermodynamic characteristics change with particle size and composition remains far from satisfactory. Here, we used force-field molecular dynamics simulations to investigate the effects of composition (x) and size on the physical-chemical properties of Ce1-xZrxO2 NPs with diameter from 1 (32 cations) up to 3 nm (256 cations), where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0. We found abrupt changes in potential energy versus temperature for NPs with more than 108 cations, indicating a structural phase transition from disordered to ordered structures, which was confirmed by the radial distribution function. We found a linear relationship between the phase transition temperature (Tpt) and the size and composition of the NPs: the increase in the molar fraction of Zr4+ and the reduction in particle size are related to lower Tpt temperature and less defined decays of potential energy versus temperature. NPs larger than 56 cations show a radial distribution function with several peaks, which is related to the order of cations and anions in these structures. These peaks gradually disappear as the size decreases and the fraction of Zr4+ increases. Similar trends were observed with X-ray diffraction analysis; for example, fluorite-like motifs occur even with 56 cations in the case of ceria, but only for NPs with 108 cations for zirconia. Common neighbor analysis confirmed that NPs with well-defined values of the temperature Tpt have face-centered cubic (fcc)-like domains in the core region. The number of ordered fcc cations increases with increasing NP size and decreasing Zr4+ concentration. Finally, we observed that ceria nucleate first during simulated annealing and occupy highly coordinated sites within the core, while Zr4+ prefers the lowest coordinated sites on the surface.
Collapse
Affiliation(s)
- Mylena N Santos
- São Carlos Institute of Chemistry, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil.
| | - Tuanan C Lourenço
- São Carlos Institute of Chemistry, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil.
| | - Mauricio Mocelim
- São Carlos Institute of Chemistry, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil.
| | - Juarez L F Da Silva
- São Carlos Institute of Chemistry, University of São Paulo, P.O. Box 780, 13560-970 São Carlos, SP, Brazil.
| |
Collapse
|
2
|
Wojtczak I, Brzozowska W, Trykowski G, Sprynskyy M. Diatom Biosilica Functionalised with Metabolically Deposited Cerium Oxide Nanoparticles. MATERIALS (BASEL, SWITZERLAND) 2024; 17:2390. [PMID: 38793457 PMCID: PMC11123480 DOI: 10.3390/ma17102390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 05/10/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024]
Abstract
This study introduces a novel approach to synthesising a three-dimensional (3D) micro-nanostructured amorphous biosilica. The biosilica is coated with cerium oxide nanoparticles obtained from laboratory-grown unicellular photosynthetic algae (diatoms) doped metabolically with cerium. This unique method utilises the ability of diatom cells to absorb cerium metabolically and deposit it on their silica exoskeleton as cerium oxide nanoparticles. The resulting composite (Ce-DBioSiO2) combines the unique structural and photonic properties of diatom biosilica (DBioSiO2) with the functionality of immobilised CeO2 nanoparticles. The kinetics of the cerium metabolic insertion by diatom cells and the physicochemical properties of the obtained composites were thoroughly investigated. The resulting Ce-DBioSiO2 composite exhibits intense Stokes fluorescence in the violet-blue region under ultraviolet (UV) irradiation and anti-Stokes intense violet and faint green emissions under the 800 nm near-infrared excitation with a xenon lamp at room temperature in an ambient atmosphere.
Collapse
Affiliation(s)
- Izabela Wojtczak
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| | - Weronika Brzozowska
- Division of Surface Science, Faculty of Chemical Technology and Engineering, Bydgoszcz University of Science and Technology, Kaliskiego 7, 85-796 Bydgoszcz, Poland;
| | - Grzegorz Trykowski
- Department of Materials Chemistry, Adsorption and Catalysis, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| | - Myroslav Sprynskyy
- Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland;
| |
Collapse
|
3
|
Zuhra Z, Li S, Xie G, Wang X. Soot Erased: Catalysts and Their Mechanistic Chemistry. Molecules 2023; 28:6884. [PMID: 37836727 PMCID: PMC10574243 DOI: 10.3390/molecules28196884] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/25/2023] [Accepted: 09/26/2023] [Indexed: 10/15/2023] Open
Abstract
Soot formation is an inevitable consequence of the combustion of carbonaceous fuels in environments rich in reducing agents. Efficient management of pollution in various contexts, such as industrial fires, vehicle engines, and similar applications, relies heavily on the subsequent oxidation of soot particles. Among the oxidizing agents employed for this purpose, oxygen, carbon dioxide, water vapor, and nitrogen dioxide have all demonstrated effectiveness. The scientific framework of this research can be elucidated through the following key aspects: (i) This review situates itself within the broader context of pollution management, emphasizing the importance of effective soot oxidation in reducing emissions and mitigating environmental impacts. (ii) The central research question of this study pertains to the identification and evaluation of catalysts for soot oxidation, with a specific emphasis on ceria-based catalysts. The formulation of this research question arises from the need to enhance our understanding of catalytic mechanisms and their application in environmental remediation. This question serves as the guiding principle that directs the research methodology. (iii) This review seeks to investigate the catalytic mechanisms involved in soot oxidation. (iv) This review highlights the efficacy of ceria-based catalysts as well as other types of catalysts in soot oxidation and elucidate the underlying mechanistic strategies. The significance of these findings is discussed in the context of pollution management and environmental sustainability. This study contributes to the advancement of knowledge in the field of catalysis and provides valuable insights for the development of effective strategies to combat air pollution, ultimately promoting a cleaner and healthier environment.
Collapse
Affiliation(s)
- Zareen Zuhra
- Department of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, China; (Z.Z.); (S.L.); (X.W.)
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei 230026, China
| | - Shuo Li
- Department of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, China; (Z.Z.); (S.L.); (X.W.)
| | - Guanqun Xie
- Department of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, China; (Z.Z.); (S.L.); (X.W.)
| | - Xiaoxia Wang
- Department of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, China; (Z.Z.); (S.L.); (X.W.)
| |
Collapse
|
4
|
Aneggi E, Campagnolo F, Segato J, Zuccaccia D, Baratta W, Llorca J, Trovarelli A. Solvent-free selective oxidation of benzyl alcohol using Ru loaded ceria-zirconia catalysts. MOLECULAR CATALYSIS 2023. [DOI: 10.1016/j.mcat.2023.113049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
|
5
|
Gao Y, Jiang M, Yang L, Li Z, Tian FX, He Y. Recent progress of catalytic methane combustion over transition metal oxide catalysts. Front Chem 2022; 10:959422. [PMID: 36003612 PMCID: PMC9393236 DOI: 10.3389/fchem.2022.959422] [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: 06/01/2022] [Accepted: 06/28/2022] [Indexed: 11/13/2022] Open
Abstract
Methane (CH4) is one of the cleanest fossil fuel resources and is playing an increasingly indispensable role in our way to carbon neutrality, by providing less carbon-intensive heat and electricity worldwide. On the other hand, the atmospheric concentration of CH4 has raced past 1,900 ppb in 2021, almost triple its pre-industrial levels. As a greenhouse gas at least 86 times as potent as carbon dioxide (CO2) over 20 years, CH4 is becoming a major threat to the global goal of deviating Earth temperature from the +2°C scenario. Consequently, all CH4-powered facilities must be strictly coupled with remediation plans for unburned CH4 in the exhaust to avoid further exacerbating the environmental stress, among which catalytic CH4 combustion (CMC) is one of the most effective strategies to solve this issue. Most current CMC catalysts are noble-metal-based owing to their outstanding C–H bond activation capability, while their high cost and poor thermal stability have driven the search for alternative options, among which transition metal oxide (TMO) catalysts have attracted extensive attention due to their Earth abundance, high thermal stability, variable oxidation states, rich acidic and basic sites, etc. To date, many TMO catalysts have shown comparable catalytic performance with that of noble metals, while their fundamental reaction mechanisms are explored to a much less extent and remain to be controversial, which hinders the further optimization of the TMO catalytic systems. Therefore, in this review, we provide a systematic compilation of the recent research advances in TMO-based CMC reactions, together with their detailed reaction mechanisms. We start with introducing the scientific fundamentals of the CMC reaction itself as well as the unique and desirable features of TMOs applied in CMC, followed by a detailed introduction of four different kinetic reaction models proposed for the reactions. Next, we categorize the TMOs of interests into single and hybrid systems, summarizing their specific morphology characterization, catalytic performance, kinetic properties, with special emphasis on the reaction mechanisms and interfacial properties. Finally, we conclude the review with a summary and outlook on the TMOs for practical CMC applications. In addition, we also further prospect the enormous potentials of TMOs in producing value-added chemicals beyond combustion, such as direct partial oxidation to methanol.
Collapse
Affiliation(s)
- Yuan Gao
- UM-SJTU Joint Institute, Shanghai Jiaotong University, Shanghai, China
| | - Mingxin Jiang
- UM-SJTU Joint Institute, Shanghai Jiaotong University, Shanghai, China
| | - Liuqingqing Yang
- UM-SJTU Joint Institute, Shanghai Jiaotong University, Shanghai, China
| | - Zhuo Li
- UM-SJTU Joint Institute, Shanghai Jiaotong University, Shanghai, China
| | - Fei-Xiang Tian
- State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai, China
| | - Yulian He
- UM-SJTU Joint Institute, Shanghai Jiaotong University, Shanghai, China
- Department of Chemical Engineering, Shanghai Jiao Tong University, Shanghai, China
- *Correspondence: Yulian He,
| |
Collapse
|
6
|
Wang H, Hou Y, Zhang Y, Cui M, Chen F, Huang X, Yang J, Feng Z. SO42–-modified La, Y-doped ceria-zirconia with high oxygen storage capacity and its application in Pd-only three-way catalysts. J RARE EARTH 2022. [DOI: 10.1016/j.jre.2021.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
7
|
Atomic level fluxional behavior and activity of CeO 2-supported Pt catalysts for CO oxidation. Nat Commun 2021; 12:5789. [PMID: 34608153 PMCID: PMC8490411 DOI: 10.1038/s41467-021-26047-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 09/01/2021] [Indexed: 11/08/2022] Open
Abstract
Reducible oxides are widely used catalyst supports that can increase oxidation reaction rates by transferring lattice oxygen at the metal-support interface. There are many outstanding questions regarding the atomic-scale dynamic meta-stability (i.e., fluxional behavior) of the interface during catalysis. Here, we employ aberration-corrected operando electron microscopy to visualize the structural dynamics occurring at and near Pt/CeO2 interfaces during CO oxidation. We show that the catalytic turnover frequency correlates with fluxional behavior that (a) destabilizes the supported Pt particle, (b) marks an enhanced rate of oxygen vacancy creation and annihilation, and (c) leads to increased strain and reduction in the CeO2 support surface. Overall, the results implicate the interfacial Pt-O-Ce bonds anchoring the Pt to the support as being involved also in the catalytically-driven oxygen transfer process, and they suggest that oxygen reduction takes place on the highly reduced CeO2 surface before migrating to the interfacial perimeter for reaction with CO.
Collapse
|
8
|
Huang X, Zhang K, Peng B, Wang G, Muhler M, Wang F. Ceria-Based Materials for Thermocatalytic and Photocatalytic Organic Synthesis. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02443] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Xiubing Huang
- Beijing Key Laboratory of Function Materials for Molecule & Structure Construction, School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 10083, PR China
| | - Kaiyue Zhang
- Beijing Key Laboratory of Function Materials for Molecule & Structure Construction, School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 10083, PR China
| | - Baoxiang Peng
- Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44780 Bochum, Nordrhein-Westfalen, Germany
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Nordrhein-Westfalen, Germany
| | - Ge Wang
- Beijing Key Laboratory of Function Materials for Molecule & Structure Construction, School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 10083, PR China
| | - Martin Muhler
- Laboratory of Industrial Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44780 Bochum, Nordrhein-Westfalen, Germany
- Max Planck Institute for Chemical Energy Conversion, Stiftstrasse 34−36, 45470 Mülheim an der Ruhr, Nordrhein-Westfalen, Germany
| | - Feng Wang
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, PR China
| |
Collapse
|
9
|
Brugnoli L, Menziani MC, Urata S, Pedone A. Development and Application of a ReaxFF Reactive Force Field for Cerium Oxide/Water Interfaces. J Phys Chem A 2021; 125:5693-5708. [PMID: 34152149 DOI: 10.1021/acs.jpca.1c04078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ceria (CeO2) is a well-known catalytic oxide with many environmental, energy production, and industrial applications, most of them involving water as a reactant, byproduct, solvent, or simple spectator. In this work, we parameterized a Ce/O/H ReaxFF for the study of ceria and ceria/water interfaces. The parameters were fitted to an ab initio training set obtained at the DFT/PBE0 level, including the structures, cohesive energies, and elastic properties of the crystalline phases Ce, CeO2, and Ce2O3; the O-defective structures and energies of vacancy formation on CeO2 bulk and CeO2 (111) surface, as well as the absorption and reaction energies of H2 and H2O molecules on CeO2 (111). The new potential reproduced reasonably well all the fitted properties as well as the relative stabilities of the different ceria surfaces, the oxygen vacancies formation, and the energies and structures of associative and dissociative water molecules on them. Molecular dynamics simulations of the liquid water on the CeO2 (111) and CeO2 (100) surfaces were carried out to study the coverage and the mechanism of water dissociation. After equilibration, on average, 35% of surface sites of CeO2 (111) are hydroxylated whereas 15% of them are saturated with molecular water associatively adsorbed. As for the CeO2 (100) surface, we observed that water preferentially dissociates covering 90% of the available surface sites in excellent agreement with recent experimental findings.
Collapse
Affiliation(s)
- Luca Brugnoli
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via G. Campi 103, Modena 41125, , Italy
| | - Maria Cristina Menziani
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via G. Campi 103, Modena 41125, , Italy
| | - Shingo Urata
- Innovative Technology Laboratories, AGC Inc., Yokohama, Kanagawa 230-0045, Japan
| | - Alfonso Pedone
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, via G. Campi 103, Modena 41125, , Italy
| |
Collapse
|
10
|
Facet-Dependent Reactivity of Ceria Nanoparticles Exemplified by CeO2-Based Transition Metal Catalysts: A Critical Review. Catalysts 2021. [DOI: 10.3390/catal11040452] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The rational design and fabrication of highly-active and cost-efficient catalytic materials constitutes the main research pillar in catalysis field. In this context, the fine-tuning of size and shape at the nanometer scale can exert an intense impact not only on the inherent reactivity of catalyst’s counterparts but also on their interfacial interactions; it can also opening up new horizons for the development of highly active and robust materials. The present critical review, focusing mainly on our recent advances on the topic, aims to highlight the pivotal role of shape engineering in catalysis, exemplified by noble metal-free, CeO2-based transition metal catalysts (TMs/CeO2). The underlying mechanism of facet-dependent reactivity is initially discussed. The main implications of ceria nanoparticles’ shape engineering (rods, cubes, and polyhedra) in catalysis are next discussed, on the ground of some of the most pertinent heterogeneous reactions, such as CO2 hydrogenation, CO oxidation, and N2O decomposition. It is clearly revealed that shape functionalization can remarkably affect the intrinsic features and in turn the reactivity of ceria nanoparticles. More importantly, by combining ceria nanoparticles (CeO2 NPs) of specific architecture with various transition metals (e.g., Cu, Fe, Co, and Ni) remarkably active multifunctional composites can be obtained due mainly to the synergistic metalceria interactions. From the practical point of view, novel catalyst formulations with similar or even superior reactivity to that of noble metals can be obtained by co-adjusting the shape and composition of mixed oxides, such as Cu/ceria nanorods for CO oxidation and Ni/ceria nanorods for CO2 hydrogenation. The conclusions derived could provide the design principles of earth-abundant metal oxide catalysts for various real-life environmental and energy applications.
Collapse
|
11
|
Akil J, Siffert S, Pirault-Roy L, Royer S, Shen F, Chen W, Cousin R, Poupin C. Investigation of catalysts M/CeO 2 (M = Pt, Rh, or Pd) for purification of CO 2 derived from oxycombustion in the absence or presence of water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:12521-12532. [PMID: 33083953 DOI: 10.1007/s11356-020-11252-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 10/13/2020] [Indexed: 06/11/2023]
Abstract
Oxyfuel combustion is a promising technology to produce a CO2-rich flue gas ready suitable for sequestration or valorization. But its storage as well as its further valorization requires to increase the CO2 purification as a small amount of CO and NOx are produced during combustion. Based on the technology developed for three-way converters, similar systems, i.e., M/CeO2 where M is Pt, Pd, or Rh, were studied for NO-CO abatement in a gas stream similar to those obtained when an oxyfuel combustion is performed. The results evidenced that the role of the metal nature influences the performances obtained on NO-CO abatement, platinum supported on ceria being the most efficient catalyst. We also measured the impact of the presence of water in the reaction stream on the catalytic activity of these materials. It appears that the presence of water has a beneficial effect on the different reactions due to a water gas shift reaction that increases the reduction of the NO and favors the formation of N2. The study pointed out that platinum supported on ceria remained the best catalyst, under these wet operating conditions close to industrial ones, for purification of oxyfuel combustion exhausts.
Collapse
Affiliation(s)
- Joudia Akil
- SFR Condorcet FR CNRS 3417, Univ. Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant, UR 4492, 145 avenue Maurice Schumann, Dunkerque, 59140, France
| | - Stéphane Siffert
- SFR Condorcet FR CNRS 3417, Univ. Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant, UR 4492, 145 avenue Maurice Schumann, Dunkerque, 59140, France
| | - Laurence Pirault-Roy
- Institut de chimie des milieux et matériaux de Poitiers (IC2MP), Université de Poitiers, UMR 7285 CNRS, 4, rue Michel Brunet, 86073, Poitiers cedex 9, France
| | - Sebastien Royer
- Univ. Lille, CNRS, Centrale Lille, Univ. Artois, University of Artois, UMR 8181 - UCCS - Unité de Catalyse et Chimie du Solide, F-59000, Lille, France
| | - Fengjiao Shen
- Univ. Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France
| | - Weidong Chen
- Univ. Littoral Côte d'Opale, UR 4493, LPCA, Laboratoire de Physico-Chimie de l'Atmosphère, F-59140, Dunkerque, France
| | - Renaud Cousin
- SFR Condorcet FR CNRS 3417, Univ. Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant, UR 4492, 145 avenue Maurice Schumann, Dunkerque, 59140, France
| | - Christophe Poupin
- SFR Condorcet FR CNRS 3417, Univ. Littoral Côte d'Opale, Unité de Chimie Environnementale et Interactions sur le Vivant, UR 4492, 145 avenue Maurice Schumann, Dunkerque, 59140, France.
| |
Collapse
|
12
|
Lawrence EL, Levin BDA, Boland T, Chang SLY, Crozier PA. Atomic Scale Characterization of Fluxional Cation Behavior on Nanoparticle Surfaces: Probing Oxygen Vacancy Creation/Annihilation at Surface Sites. ACS NANO 2021; 15:2624-2634. [PMID: 33507063 DOI: 10.1021/acsnano.0c07584] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Oxygen vacancy creation and annihilation are key processes in nonstoichiometric oxides such as CeO2. The oxygen vacancy creation and annihilation rates on an oxide's surface partly govern its ability to exchange oxygen with the ambient environment, which is critical for a number of applications including energy technologies, environmental pollutant remediation, and chemical synthesis. Experimental methods to probe and correlate local oxygen vacancy reaction rates with atomic-level structural heterogeneities would provide significant information for the rational design and control of surface functionality; however, such methods have been unavailable to date. Here, we characterize picoscale fluxional behavior in cations using time-resolved in situ aberration-corrected transmission electron microscopy to locate atomic-level variations in oxygen vacancy creation and annihilation rates on oxide nanoparticle surfaces. Low coordination number sites such as steps and edges, as well as locally strained sites, exhibited the greatest number of cation displacements, implying enhanced surface oxygen vacancy activity at these sites. The approach has potential applications to a much wider class of materials and catalysis problems involving surface and interfacial transport functionalities.
Collapse
Affiliation(s)
- Ethan L Lawrence
- School for the Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Barnaby D A Levin
- School for the Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Tara Boland
- School for the Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Shery L Y Chang
- Eyring Materials Center, Arizona State University, Tempe, Arizona 85287, United States
| | - Peter A Crozier
- School for the Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| |
Collapse
|
13
|
Kogut I, Wollbrink A, Steiner C, Wulfmeier H, El Azzouzi FE, Moos R, Fritze H. Linking the Electrical Conductivity and Non-Stoichiometry of Thin Film Ce 1-xZr xO 2-δ by a Resonant Nanobalance Approach. MATERIALS 2021; 14:ma14040748. [PMID: 33562638 PMCID: PMC7915746 DOI: 10.3390/ma14040748] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/20/2021] [Accepted: 01/31/2021] [Indexed: 11/20/2022]
Abstract
Bulk ceria-zirconia solid solutions (Ce1−xZrxO2−δ, CZO) are highly suited for application as oxygen storage materials in automotive three-way catalytic converters (TWC) due to the high levels of achievable oxygen non-stoichiometry δ. In thin film CZO, the oxygen storage properties are expected to be further enhanced. The present study addresses this aspect. CZO thin films with 0 ≤ x ≤ 1 were investigated. A unique nano-thermogravimetric method for thin films that is based on the resonant nanobalance approach for high-temperature characterization of oxygen non-stoichiometry in CZO was implemented. The high-temperature electrical conductivity and the non-stoichiometry δ of CZO were measured under oxygen partial pressures pO2 in the range of 10−24–0.2 bar. Markedly enhanced reducibility and electronic conductivity of CeO2-ZrO2 as compared to CeO2−δ and ZrO2 were observed. A comparison of temperature- and pO2-dependences of the non-stoichiometry of thin films with literature data for bulk Ce1−xZrxO2−δ shows enhanced reducibility in the former. The maximum conductivity was found for Ce0.8Zr0.2O2−δ, whereas Ce0.5Zr0.5O2-δ showed the highest non-stoichiometry, yielding δ = 0.16 at 900 °C and pO2 of 10−14 bar. The defect interactions in Ce1−xZrxO2−δ are analyzed in the framework of defect models for ceria and zirconia.
Collapse
Affiliation(s)
- Iurii Kogut
- Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany; (A.W.); (H.W.); (F.-E.E.A.); (H.F.)
- Correspondence: ; Tel.: +49-5321-3816-8304
| | - Alexander Wollbrink
- Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany; (A.W.); (H.W.); (F.-E.E.A.); (H.F.)
| | - Carsten Steiner
- Department of Functional Materials, Bayreuth Engine Research Center (BERC), University of Bayreuth, 95440 Bayreuth, Germany; (C.S. & R.M.)
| | - Hendrik Wulfmeier
- Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany; (A.W.); (H.W.); (F.-E.E.A.); (H.F.)
| | - Fatima-Ezzahrae El Azzouzi
- Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany; (A.W.); (H.W.); (F.-E.E.A.); (H.F.)
| | - Ralf Moos
- Department of Functional Materials, Bayreuth Engine Research Center (BERC), University of Bayreuth, 95440 Bayreuth, Germany; (C.S. & R.M.)
| | - Holger Fritze
- Institute of Energy Research and Physical Technologies, Clausthal University of Technology, 38640 Goslar, Germany; (A.W.); (H.W.); (F.-E.E.A.); (H.F.)
| |
Collapse
|
14
|
Microemulsion vs. Precipitation: Which Is the Best Synthesis of Nickel–Ceria Catalysts for Ethanol Steam Reforming? Processes (Basel) 2020. [DOI: 10.3390/pr9010077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ethanol steam reforming is one of the most promising ways to produce hydrogen from biomass, and the goal of this research is to investigate robust, selective and active catalysts for this reaction. In particular, this work is focused on the effect of the different ceria support preparation methods on the Ni active phase stabilization. Two synthetic approaches were evaluated: precipitation (with urea) and microemulsion. The effects of lanthanum doping were investigated too. All catalysts were characterized using N2-physisorption, temperature programmed reduction (TPR), XRD and SEM, to understand the influence of the synthetic approach on the morphological and structural features and their relationship with catalytic properties. Two synthesis methods gave strongly different features. Catalysts prepared by precipitation showed higher reducibility (which involves higher oxygen mobility) and a more homogeneous Ni particle size distribution. Catalytic tests (at 500 °C for 5 h using severe Gas Hourly Space Velocity conditions) revealed also different behaviors. Though the initial conversion (near complete) and H2 yield (60%, i.e., 3.6 mol H2/mol ethanol) were the same, the catalyst prepared by microemulsion was deactivated much faster. Similar trends were found for La-promoted supports. Catalyst deactivation was mainly related to coke deposition as was shown by SEM of the used samples. Higher reducibility of the catalysts prepared by the precipitation method led to a decrease in coke deposition rate by facilitating the removal of coke precursors, which made them the more stable catalysts of the reaction.
Collapse
|
15
|
|
16
|
Influence of Nanoscale Surface Arrangements on the Oxygen Transfer Ability of Ceria–Zirconia Mixed Oxide. INORGANICS 2020. [DOI: 10.3390/inorganics8050034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ceria-based materials, and particularly CeO2–ZrO2 (CZ) solid solutions are key ingredient in catalyst formulations for several applications due to the ability of ceria to easily cycling its oxidation state between Ce4+ and Ce3+. Ceria-based catalysts have a great soot oxidation potential and the mechanism deeply relies on the degree of contact between CeO2 and carbon. In this study, carbon soot has been used as solid reductant to better understand the oxygen transfer ability of ceria–zirconia at low temperatures; the effect of different atmosphere and contact conditions has been investigated. The difference in the contact morphology between carbon soot and CZ particles is shown to strongly affect the oxygen transfer ability of ceria; in particular, increasing the carbon–ceria interfacial area, the reactivity of CZ lattice oxygen is significantly improved. In addition, with a higher degree of contact, the soot oxidation is less affected by the presence of NOx. The NO oxidation over CZ in the presence of soot has also been analyzed. The existence of a core/shell structure strongly enhances reactivity of interfacial oxygen species while affecting negatively NO oxidation characteristics. These findings are significant in the understanding of the redox chemistry of substituted ceria and help determining the role of active species in soot oxidation reaction as a function of the degree of contact between ceria and carbon.
Collapse
|
17
|
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.
Collapse
|
18
|
Abstract
Nowadays, one of the most important challenges that humanity faces is to find alternative ways of reducing pollutant emissions. CeO2/Bi2Mo1−xRuxO6 and Au/Bi2Mo1−xRuxO6 catalysts were prepared to efficiently transform carbon monoxide (CO) to carbon dioxide (CO2) at low temperatures. The systems were prepared in a two-step process. First, Bi2Mo1−xRuxO6 supports were synthesized through the hydrothermal procedure under microwave heating. Then, CeO2 was deposited on Bi2Mo1−xRuxO6 using the wet impregnation method, while the incipient impregnation method was selected to deposit gold nanoparticles. The CeO2/Bi2Mo1−xRuxO6 and Au/Bi2Mo1−xRuxO6 catalysts were characterized using SEM microscopy and XRD. Furthermore, energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy were used. Tests were carried out for the supported catalysts in CO oxidation, and high conversion values, nearing 100%, was observed in a temperature range of 100 to 250 °C. The results showed that the best system was the Au/Bi2Mo0.95Ru0.05O6 catalyst, with CO oxidation starting at 50 °C and reaching 100% conversion at 186 °C.
Collapse
|
19
|
Pentyala P, Deshpande PA. CO Oxidation over Ce1–xPdxO2−δ Takes Place via Vacancy Hopping. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b00734] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Phanikumar Pentyala
- Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Parag A. Deshpande
- Quantum and Molecular Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| |
Collapse
|
20
|
Influence of Catalytic Activity of CeO2/SnO2 Nanocomposites on Sensitivity to Hydrogen of Sensors on Their Base. THEOR EXP CHEM+ 2018. [DOI: 10.1007/s11237-018-9568-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|