1
|
Zhou J, Zheng Y, Zhang G, Zeng X, Xu G, Cui Y. Toluene catalytic oxidation over gold catalysts supported on cerium-based high-entropy oxides. ENVIRONMENTAL TECHNOLOGY 2024; 45:3016-3028. [PMID: 37043616 DOI: 10.1080/09593330.2023.2202828] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/17/2023] [Indexed: 06/19/2023]
Abstract
A series of cerium-based high-entropy oxide catalysts (the ratio of CeO2 and HEO is 1:1) was prepared by a solid-state reaction method, which exploit their unique structural and performance advantages. The Ce-HEO-T samples can achieve 100% toluene conversion rate above 328°C when they were used as catalysts directly. Subsequently, the Ce-HEO-500 exhibited the lowest temperature for toluene oxidation was used as a support to deposit different amounts of Au for a further performance improvement. Among all of prepared samples, Au/Ce-HEO-500 with a moderate content of Au (0.5 wt%) exhibited the lowest temperature for complete combustion of toluene (260°C), which decreased nearly 70°C compared with Ce-HEO-500 support. Moreover, it also showed excellent stability for 60 h with 98% toluene conversion rate. Most importantly, under the condition of 5 vol.% H2O vapour, the toluene conversion rate remained unchanged and even increased slightly compared with that in dry air, exhibiting excellent water resistance. Combined with the characterizations of XRD, SEM, TEM, BET, Raman, H2-TPR and XPS, it was found that the high dispersion of active Au NPs, the special high-entropy structure and the synergistic effect between Au and Ce, Co, Cu are the key factors when improving the catalytic performance in the Au/Ce-HEO-500 catalyst.
Collapse
Affiliation(s)
- Jing Zhou
- School of Chemical Engineering, Shenyang University of Chemical Technology, Shenyang, Liaoning, People's Republic of China
| | - Yuhua Zheng
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Guangyi Zhang
- Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing Technology and Business University, Beijing, People's Republic of China
| | - Xi Zeng
- Key Laboratory of Cleaner Production and Integrated Resource Utilization of China National Light Industry, Beijing Technology and Business University, Beijing, People's Republic of China
| | - Guangwen Xu
- School of Chemical Engineering, Shenyang University of Chemical Technology, Shenyang, Liaoning, People's Republic of China
| | - Yanbin Cui
- State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, People's Republic of China
| |
Collapse
|
2
|
Liu D, Zhu H, Gong X, Yuan S, Ma H, He P, Fan Y, Zhao W, Ren H, Guo W. Understanding and controlling the formation of single-atom site from supported Cu 10 cluster by tuning CeO 2 reducibility: Theoretical insight into the Gd-doping effect on electronic metal-support interaction. J Colloid Interface Sci 2024; 661:720-729. [PMID: 38320408 DOI: 10.1016/j.jcis.2024.01.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/18/2024] [Accepted: 01/25/2024] [Indexed: 02/08/2024]
Abstract
Controlling the formation of single-atom (SA) sites from supported metal clusters is an important and interesting issue to effectively improve the catalytic performance of heterogeneous catalysts. For extensively studied CO oxidation over metal/CeO2 systems, the SA formation and stabilization under reaction conditions is generally attributed to CO adsorption, however, the pivotal role played by the reducible CeO2 support and the underlying electronic metal-support interaction (EMSI) are not yet fully understood. Based on a ceria-supported Cu10 catalyst model, we performed density functional theory calculations to investigate the intrinsic SA formation mechanism and discussed the synergistic effect of Gd-doped CeO2 and CO adsorption on the SA formation. The CeO2 reducibility is tuned with doped Gd content ranging from 12.5 % ∼ 25 %. Based on ab initio thermodynamic and ab initio molecular dynamics, the critical condition for SA formation was identified as 21.875 % Gd-doped CeO2 with CO-saturated adsorption on Cu10. Electronic analysis revealed that the open-shell lattice Oδ- (δ < 2) generated by Gd doping facilitates the charge transfer from the bottom-corner Cu (Cubc) to CeO2. The CO-saturated adsorption further promotes this charge transfer process and enhances the EMSI between Cubc and CeO2, leading to the disintegration of Cubc from Cu10 and subsequent formation of the active SA site.
Collapse
Affiliation(s)
- Dongyuan Liu
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Houyu Zhu
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China.
| | - Xiaoxiao Gong
- State Key Laboratory of Molecular & Process Engineering, SINOPEC Research Institute of Petroleum Processing Co., Ltd., Beijing 10083, PR China
| | - Saifei Yuan
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Hao Ma
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Ping He
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Yucheng Fan
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Wen Zhao
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Hao Ren
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China
| | - Wenyue Guo
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, PR China.
| |
Collapse
|
3
|
Weyel J, Hess C. Refining the mechanism of CO 2 and H 2 activation over gold-ceria catalysts by IR modulation excitation spectroscopy. Phys Chem Chem Phys 2024; 26:6608-6615. [PMID: 38333955 DOI: 10.1039/d3cp05102a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024]
Abstract
The activation and utilization of the greenhouse gas CO2 is of great interest for the energy transition as a fossil-free carbon source for mitigating climate change. CO2 hydrogenation via the reverse water-gas shift reaction (RWGSR) converts CO2 to CO, a crucial component of syngas, enabling further transformation by means of the Fischer-Tropsch process. In this study, we unravel the detailed mechanism of the RWGSR on low-loaded Au/CeO2 catalysts using IR modulation excitation spectroscopy (MES), by periodically modulating the concentration of the reactants, followed by phase-sensitive detection (PSD). Applying such a MES-PSD approach to Au/CeO2 catalysts during RWGSR gives direct spectroscopic evidence for the active role of gold hydride, bidentate carbonate and hydroxyl species in the reaction mechanism, while disproving the participation of other species such as formate. Our results highlight the potential of modulation excitation spectroscopy combined with phase-sensitive detection to provide new mechanistic insight into catalytic reactions not accessible by steady-state techniques, including a profound understanding of the sequence of reaction steps.
Collapse
Affiliation(s)
- Jakob Weyel
- Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Peter-Grünberg-Str. 8, 64287 Darmstadt, Germany.
| | - Christian Hess
- Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Peter-Grünberg-Str. 8, 64287 Darmstadt, Germany.
| |
Collapse
|
4
|
Posada-Pérez S, Vidal-López A, Solà M, Poater A. 2D carbon nitride as a support with single Cu, Ag, and Au atoms for carbon dioxide reduction reaction. Phys Chem Chem Phys 2023; 25:8574-8582. [PMID: 36883855 PMCID: PMC10277901 DOI: 10.1039/d3cp00392b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/21/2023] [Indexed: 02/25/2023]
Abstract
The electrochemical conversion of CO2 into value-added chemicals is an important approach to recycling CO2. In this work, we have combined the most efficient metal catalysts for this reaction, namely Cu, Ag, and Au, as single-atom particles dispersed on a two-dimensional carbon nitride support, with the aim of exploring their performance in the CO2 reduction reaction. Here, we report density functional theory computations showing the effect of single metal-atom particles on the support. We found that bare carbon nitride needed a high overpotential to overcome the energy barrier for the first proton-electron transfer, while the second transfer was exergonic. The deposition of single metal atoms enhances the catalytic activity of the system as the first proton-electron transfer is favored in terms of energy, although strong binding energies were found for CO adsorption on Cu and Au single atoms. Our theoretical interpretations are consistent with the experimental evidence that the competitive H2 generation is favored due to the strong CO binding energies. Our computational study paves the road to finding suitable metals that catalyze the first proton-electron transfer in the carbon dioxide reduction reaction and produce reaction intermediates with moderate binding energies, promoting a spillover to the carbon nitride support and thereby serving as bifunctional electrocatalysts.
Collapse
Affiliation(s)
- Sergio Posada-Pérez
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany 69, 17003, Girona, Catalonia, Spain.
| | - Anna Vidal-López
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany 69, 17003, Girona, Catalonia, Spain.
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Cerdanyola del Vallès, Catalonia, Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany 69, 17003, Girona, Catalonia, Spain.
| | - Albert Poater
- Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/Maria Aurèlia Capmany 69, 17003, Girona, Catalonia, Spain.
| |
Collapse
|
5
|
Liu R, Qu W, Hu X, Chen J, Dong Y, Xu D, Liu J, Ma Z, Tang X. Valence states of single Au atoms dictate the catalytic activity of Au 1/CeO 2(100). Chem Commun (Camb) 2022; 58:11587-11590. [PMID: 36168912 DOI: 10.1039/d2cc04219c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We tune the valence state of single Au atoms anchored on CeO2(100) by treating the catalyst in H2 at different temperatures and obtain a series of Au1/CeO2(100). The transition from Au1+0.9 to Au1+0.3 leads to an enhancement of the CO oxidation activity of Au1/CeO2(100) by one order of magnitude. This work is of significance for an in-depth understanding of reaction mechanisms and rational design of high-performance catalysts.
Collapse
Affiliation(s)
- Rui Liu
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Weiye Qu
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Xiaolei Hu
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Junxiao Chen
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Yangyang Dong
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Dongrun Xu
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Jing Liu
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China.
| | - Zhen Ma
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China. .,Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xingfu Tang
- Department of Environmental Science & Engineering, Fudan University, 2005 Songhu Road, Shanghai 200438, China. .,Jiangsu Collaborative Innovation Center of Atmospheric Environment & Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, China.,Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| |
Collapse
|
6
|
Schumacher L, Weyel J, Hess C. Unraveling the Active Vanadium Sites and Adsorbate Dynamics in VO x/CeO 2 Oxidation Catalysts Using Transient IR Spectroscopy. J Am Chem Soc 2022; 144:14874-14887. [PMID: 35917149 DOI: 10.1021/jacs.2c06303] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The oxidative dehydrogenation (ODH) of propane over supported vanadia catalysts is an attractive route toward propene (propylene) with the potential of industrial application and has been extensively studied over decades. Despite numerous mechanistic studies, the active vanadyl site of the reaction has not been elucidated. In this work, we unravel the ODH reaction mechanism, including the nuclearity-dependent vanadyl and surface dynamics, over ceria-supported vanadia (VOx/CeO2) catalysts by applying (isotopic) modulation excitation IR spectroscopy supported by operando Raman and UV-vis spectroscopies. Based on our loading-dependent analysis, we were able to identify two different mechanisms leading to propylene, which are characterized by isopropyl- and acrylate-like intermediates. The modulation excitation IR approach also allows for the determination of the time evolution of the vanadia, hydroxyl, and adsorbate dynamics, underlining the intimate interplay between the surface vanadia species and the ceria support. Our results highlight the potential of transient IR spectroscopy to provide a detailed understanding of reaction mechanisms in oxidation catalysis and the dynamics of surface catalytic processes in general.
Collapse
Affiliation(s)
- Leon Schumacher
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Jakob Weyel
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Christian Hess
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| |
Collapse
|
7
|
Ziemba M, Weyel J, Hess C. Approaching C1 Reaction Mechanisms Using Combined Operando and Transient Analysis: A Case Study on Cu/CeO 2 Catalysts during the LT-Water–Gas Shift Reaction. ACS Catal 2022. [DOI: 10.1021/acscatal.2c02216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Marc Ziemba
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Jakob Weyel
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Christian Hess
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| |
Collapse
|
8
|
Weyel J, Ziemba M, Hess C. Elucidating Active CO–Au Species on Au/CeO2(111): A Combined Modulation Excitation DRIFTS and Density Functional Theory Study. Top Catal 2022. [DOI: 10.1007/s11244-022-01599-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
AbstractIn this work we elucidate the main steps of the CO oxidation mechanism over Au/CeO2(111), clarifying the course of CO adsorption at a broad variety of surface sites as well as of transmutations of one CO species into another. By combining transient spectroscopy with DFT calculations we provide new evidence that the active centers for CO conversion are single gold atoms. To gain insight into the reaction mechanism, we employ Modulation Excitation (ME) DRIFT spectroscopy in combination with the mathematical tool of Phase Sensitive Detection to identify the active species and perform DFT calculations to facilitate the assignments of the observed bands. The transient nature of the ME-DRIFTS method allows us to sort the observed species temporally, providing further mechanistic insight. Our study highlights the potential of combined transient spectroscopy and theoretical calculations (DFT) to clarify the role of adsorbates observed and to elucidate the reaction mechanism of CO oxidation over supported gold and other noble-metal catalysts.
Collapse
|
9
|
López-Hernández I, Truttmann V, Garcia C, Lopes C, Rameshan C, Stöger-Pollach M, Barrabés N, Rupprechter G, Rey F, Palomares A. AgAu nanoclusters supported on zeolites: Structural dynamics during CO oxidation. Catal Today 2022. [DOI: 10.1016/j.cattod.2021.04.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
10
|
Zielinski M, Juszczyk W, Kaszkur Z. Studies of adsorption of α,β-unsaturated carbonyl compounds on heterogeneous Au/CeO2, Au/TiO2 and Au/SiO2 catalysts during reduction by hydrogen. RSC Adv 2022; 12:5312-5323. [PMID: 35425583 PMCID: PMC8981266 DOI: 10.1039/d1ra09434c] [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: 12/30/2021] [Accepted: 01/31/2022] [Indexed: 11/21/2022] Open
Abstract
Our research focuses on phenomena accompanying adsorption of mesityl oxide (4-methylpent-3-en-2-one) on the surface of heterogeneous supported gold catalysts: Au/CeO2, Au/TiO2 and Au/SiO2. We have studied reduction in the gas phase of (volatile) α,β-unsaturated carbonyl compounds (R-(V)ABUCC) which mesityl oxide is a basic model of. In situ infrared (IR) spectroscopy was employed to establish that the most active catalysts allow adsorption of conjugated ketones or aldehydes in the enolate (i.e. bridge-like adsorption through the oxygen from the carbonyl group and the β-carbon) and carboxylic form or with the αC
Created by potrace 1.16, written by Peter Selinger 2001-2019
]]>
βC double bond on a Lewis acidic site. Reductive properties of the catalysts and pure supports were studied by temperature-programmed reduction (TPR). We show that cerium(iv) oxide (CeO2, ceria) and titanium(iv) oxide (TiO2, titania) when decorated with gold nanoparticles (AuNP) can interact with hydrogen at temperatures approx. 150 °C lower than typical for pure oxides what includes even cyclic adsorption and instant release of H2 below 100 °C in the case of gold–ceria system. Morphology and structure characterisation by transmission electron microscopy (TEM) and powder X-ray diffraction (PXRD) confirms that, with the obtained Au loadings, we achieved excellent dispersion of AuNPs while maintaining their small size, preferably below 5 nm, even though the Au/CeO2 catalyst contained broad distribution of AuNPs sizes. We deliver spectroscopic IR data describing the adsorption phenomena accompanying reduction of conjugated carbonyl compounds aided by heterogeneous catalysts.![]()
Collapse
Affiliation(s)
- Maciej Zielinski
- Institute of Physical Chemistry, Polish Academy of Sciences, ul. M. Kasprzaka 44/52, 01-224 Warszawa, Poland
- National Centre for Nuclear Research, NOMATEN Centre of Excellence, ul. A. Soltana 7, 05-400 Otwock-Swierk, Poland
| | - Wojciech Juszczyk
- Institute of Physical Chemistry, Polish Academy of Sciences, ul. M. Kasprzaka 44/52, 01-224 Warszawa, Poland
| | - Zbigniew Kaszkur
- Institute of Physical Chemistry, Polish Academy of Sciences, ul. M. Kasprzaka 44/52, 01-224 Warszawa, Poland
| |
Collapse
|
11
|
Thang HV, Maleki F, Tosoni S, Pacchioni G. Vibrational Properties of CO Adsorbed on Au Single Atom Catalysts on TiO2(101), ZrO2(101), CeO2(111), and LaFeO3(001) Surfaces: A DFT Study. Top Catal 2021. [DOI: 10.1007/s11244-021-01514-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractThe nature and local environment of Au single atoms supported and stabilized on four different oxides is studied by means of DFT + U calculations using CO as probe molecule and its stretching frequency, ωe, as a fingerprint of the site where the Au atom is bound. Four oxides are considered, anatase TiO2, tetragonal ZrO2, cubic CeO2, and a perovskite LaFeO3. In this latter case a recently reported experimental study has detected a stretching mode for CO adsorbed on Au1/LaFeO3 of 2215 cm−1, with a large blue shift, ∆ω(CO) = 72 cm−1 with respect to free CO. In order to identify the Au adsorption site that can give rise to this large blue-shift we have considered five cases: (a) Au replacing a lattice cation, (Au)subM; (b) Au replacing a lattice O anion, (Au)subO; (c) Au adsorbed on the surface, (Au)ads; (d) Au bound to an extra O atom on the surface, (AuO)ads, or (e) Au bound to two extra O atoms on the surface, (AuO2)ads. It turns out that the correct reproduction of ∆ω for CO adsorbed on positively charged gold, Auδ+, is challenging for DFT. Therefore, we have performed a comparative study of Auδ+-CO molecular compounds for which ωe(CO) is known experimentally using various kinds of DFT functionals and accurate CCSD and CCSD(T) quantum chemistry methods. Also based on this comparison we propose a tentative assignment for the observed frequency of CO adsorbed on Au1/LaFeO3 single atom catalyst.
Graphic Abstract
Collapse
|
12
|
Ziemba M, Schilling C, Ganduglia-Pirovano MV, Hess C. Toward an Atomic-Level Understanding of Ceria-Based Catalysts: When Experiment and Theory Go Hand in Hand. Acc Chem Res 2021; 54:2884-2893. [PMID: 34137246 PMCID: PMC8264949 DOI: 10.1021/acs.accounts.1c00226] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
ConspectusBecause ceria (CeO2) is a key ingredient in the formulation of many catalysts, its catalytic roles have received a great amount of attention from experiment and theory. Its primary function is to enhance the oxidation activity of catalysts, which is largely governed by the low activation barrier for creating lattice O vacancies. Such an important characteristic of ceria has been exploited in CO oxidation, methane partial oxidation, volatile organic compound oxidation, and the water-gas shift (WGS) reaction and in the context of automotive applications. A great challenge of such heterogeneously catalyzed processes remains the unambiguous identification of active sites.In oxidation reactions, closing the catalytic cycle requires ceria reoxidation by gas-phase oxygen, which includes oxygen adsorption and activation. While the general mechanistic framework of such processes is accepted, only very recently has an atomic-level understanding of oxygen activation on ceria powders been achieved by combined experimental and theoretical studies using in situ multiwavelength Raman spectroscopy and DFT.Recent studies have revealed that the adsorption and activation of gas-phase oxygen on ceria is strongly facet-dependent and involves different superoxide/peroxide species, which can now be unambiguously assigned to ceria surface sites using the combined Raman and DFT approach. Our results demonstrate that, as a result of oxygen dissociation, vacant ceria lattice sites are healed, highlighting the close relationship of surface processes with lattice oxygen dynamics, which is also of technical relevance in the context of oxygen storage-release applications.A recent DFT interpretation of Raman spectra of polycrystalline ceria enables us to take account of all (sub)surface and bulk vibrational features observed in the experimental spectra and has revealed new findings of great relevance for a mechanistic understanding of ceria-based catalysts. These include the identification of surface oxygen (Ce-O) modes and the quantification of subsurface oxygen defects. Combining these theoretical insights with operando Raman experiments now allows the (sub)surface oxygen dynamics of ceria and noble metal/ceria catalysts to be monitored under the reaction conditions.Applying these findings to Au/ceria catalysts provides univocal evidence for ceria support participation in heterogeneous catalysis. For room-temperature CO oxidation, operando Raman monitoring the (sub)surface defect dynamics clearly demonstrates the dependence of catalytic activity on the ceria reduction state. Extending the combined experimental/DFT approach to operando IR spectroscopy allows the elucidation of the nature of the active gold as (pseudo)single Au+ sites and enables us to develop a detailed mechanistic picture of the catalytic cycle. Temperature-dependent studies highlight the importance of facet-dependent defect formation energies and adsorbate stabilities (e.g., carbonates). While the latter aspects are also evidenced to play a role in the WGS reaction, the facet-dependent catalytic performance shows a correlation with the extent of gold agglomeration. Our findings are fully consistent with a redox mechanism, thus adding a new perspective to the ongoing discussion of the WGS reaction.As outlined above for ceria-based catalysts, closely combining state-of-the-art in situ/operando spectroscopy and theory constitutes a powerful approach to rational catalyst design by providing essential mechanistic information based on an atomic-level understanding of reactions.
Collapse
Affiliation(s)
- Marc Ziemba
- Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - Christian Schilling
- Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - M. Verónica Ganduglia-Pirovano
- Instituto de Catálisis y Petroleoquímica - Consejo Superior de Investigaciones Científicas, Marie Curie 2, 28049 Madrid, Spain
| | - Christian Hess
- Eduard-Zintl-Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| |
Collapse
|
13
|
Abdel-Mageed AM, Chen S, Fauth C, Häring T, Bansmann J. Fundamental Aspects of Ceria Supported Au Catalysts Probed by In Situ/Operando Spectroscopy and TAP Reactor Studies. Chemphyschem 2021; 22:1302-1315. [PMID: 33908151 PMCID: PMC8362095 DOI: 10.1002/cphc.202100027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 04/17/2021] [Indexed: 11/30/2022]
Abstract
The discovery of the activity of dispersed gold nanoparticles three decades ago paved the way for a new era in catalysis. The unusual behavior of these catalysts sparked many questions about their working mechanism. In particular, Au/CeO2 proved to be an efficient catalyst in several reactions such as CO oxidation, water gas shift, and CO2 reduction. Here, by employing findings from operando X‐ray absorption spectroscopy at the near and extended Au and Ce LIII energy edges, we focus on the fundamental aspects of highly active Au/CeO2 catalysts, mainly in the CO oxidation for understanding their complex structure‐reactivity relationship. These results were combined with findings from in situ diffuse reflectance FTIR and Raman spectroscopy, highlighting the changes of adlayer and ceria defects. For a comprehensive understanding, the spectroscopic findings will be supplemented by results of the dynamics of O2 activation obtained from Temporal Analysis of Products (TAP). Merging these results illuminates the complex relationship among the oxidation state, size of the Au nanoparticles, the redox properties of CeO2 support, and the dynamics of O2 activation.
Collapse
Affiliation(s)
- Ali M Abdel-Mageed
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany.,Department of Chemistry, Faculty of Science, Cairo University, 12613, Giza, Egypt
| | - Shilong Chen
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany.,Institute of Inorganic Chemistry, Kiel University, Max-Eyth-Str. 2, 24118, Kiel, Germany
| | - Corinna Fauth
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany
| | - Thomas Häring
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany
| | - Joachim Bansmann
- Institute of Surface Chemistry and Catalysis, Ulm University, Albert-Einstein-Allee 47, 89081, Ulm, Germany
| |
Collapse
|
14
|
Hensley AJR, Collinge G, Wang Y, McEwen JS. Guiding the design of oxidation-resistant Fe-based single atom alloy catalysts with insights from configurational space. J Chem Phys 2021; 154:174709. [PMID: 34241058 DOI: 10.1063/5.0048698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The high activity and selectivity of Fe-based heterogeneous catalysts toward a variety of reactions that require the breaking of strong bonds are offset in large part by their considerable instability with respect to oxidative deactivation. While it has been shown that the stability of Fe catalysts is considerably enhanced by alloying them with precious metals (even at the single-atom limit), rational design criteria for choosing such secondary metals are still missing. Since oxidative deactivation occurs due to the strong binding of oxygen to Fe and reduction by adsorbed hydrogen mitigates the deactivation, we propose here to use the binding affinity of oxygen and hydrogen adatoms as the basis for rational design. As it would also be beneficial to use cheaper secondary metals, we have scanned over a large subset of 3d-5d mid-to-late transition metal single atoms and computationally determined their effect on the oxygen and hydrogen adlayer binding as a function of chemical potential and adsorbate coverage. We further determine the underlying chemical origins that are responsible for these effects and connect them to experimentally tunable quantities. Our results reveal a reliable periodic trend wherein oxygen binding is weakened greatest as one moves right and down the periodic table. Hydrogen binding shows the same trend only at high (but relevant) coverages and otherwise tends to have its binding slightly increased in all systems. Trends with secondary metal coverage are also uncovered and connected to experimentally tunable parameters.
Collapse
Affiliation(s)
- Alyssa J R Hensley
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA
| | - Greg Collinge
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA
| | - Yong Wang
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA
| | - Jean-Sabin McEwen
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, USA
| |
Collapse
|
15
|
Bezkrovnyi OS, Kraszkiewicz P, Mista W, Kepinski L. The Sintering of Au Nanoparticles on Flat {100}, {111} and Zigzagged {111}-Nanofacetted Structures of Ceria and Its Influence on Catalytic Activity in CO Oxidation and CO PROX. Catal Letters 2021. [DOI: 10.1007/s10562-020-03370-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
AbstractThe thermal stability of Au nanoparticles on ceria support of various morphology (nanocubes, nanooctahedra, and {111}-nanofacetted nanocubes) in oxidizing and reducing atmospheres was investigated by electron microscopy. A beneficial effect of the reconstruction of edges of ceria nanocubes into zigzagged {111}-nanofacetted structures on the inhibition of sintering of Au nanoparticles was shown. The influence of different morphology of Au particles on various ceria supports on the reducibility and catalytic activity in CO oxidation, and CO PROX of Au/ceria catalysts was also investigated and discussed. It was shown, that ceria nanocubes with flat {110} terminated edges are more suitable as a support for Au nanoparticles, used to catalyze CO oxidation, than zigzagged {111}- nanofacetted structures.
Graphic Abstract
Collapse
|
16
|
Hess C. New advances in using Raman spectroscopy for the characterization of catalysts and catalytic reactions. Chem Soc Rev 2021; 50:3519-3564. [PMID: 33501926 DOI: 10.1039/d0cs01059f] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Gaining insight into the mode of operation of heterogeneous catalysts is of great scientific and economic interest. Raman spectroscopy has proven its potential as a powerful vibrational spectroscopic technique for a fundamental and molecular-level characterization of catalysts and catalytic reactions. Raman spectra provide important insight into reaction mechanisms by revealing specific information on the catalysts' (defect) structure in the bulk and at the surface, as well as the presence of adsorbates and reaction intermediates. Modern Raman instrumentation based on single-stage spectrometers allows high throughput and versatility in design of in situ/operando cells to study working catalysts. This review highlights major advances in the use of Raman spectroscopy for the characterization of heterogeneous catalysts made during the past decade, including the development of new methods and potential directions of research for applying Raman spectroscopy to working catalysts. The main focus will be on gas-solid catalytic reactions, but (photo)catalytic reactions in the liquid phase will be touched on if it appears appropriate. The discussion begins with the main instrumentation now available for applying vibrational Raman spectroscopy to catalysis research, including in situ/operando cells for studying gas-solid catalytic processes. The focus then moves to the different types of information available from Raman spectra in the bulk and on the surface of solid catalysts, including adsorbates and surface depositions, as well as the use of theoretical calculations to facilitate band assignments and to describe (resonance) Raman effects. This is followed by a presentation of major developments in enhancing the Raman signal of heterogeneous catalysts by use of UV resonance Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), and shell-isolated nanoparticle surface-enhanced Raman spectroscopy (SHINERS). The application of time-resolved Raman studies to structural and kinetic characterization is then discussed. Finally, recent developments in spatially resolved Raman analysis of catalysts and catalytic processes are presented, including the use of coherent anti-Stokes Raman spectroscopy (CARS) and tip-enhanced Raman spectroscopy (TERS). The review concludes with an outlook on potential future developments and applications of Raman spectroscopy in heterogeneous catalysis.
Collapse
Affiliation(s)
- Christian Hess
- Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, Alarich-Weiss-Str. 8, 64287, Darmstadt, Germany.
| |
Collapse
|
17
|
Ziemba M, Ganduglia-Pirovano MV, Hess C. Elucidating the Oxygen Storage-Release Dynamics in Ceria Nanorods by Combined Multi-Wavelength Raman Spectroscopy and DFT. J Phys Chem Lett 2020; 11:8554-8559. [PMID: 32970436 DOI: 10.1021/acs.jpclett.0c02607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The oxygen storage-release dynamics in ceria nanorods is elucidated by using a combination of in situ multi-wavelength Raman spectroscopy and density functional theory calculations. Ceria nanorods exposing CeO2(100) and CeO2(110) facets are shown to be characterized by highly facet-dependent properties regarding molecular oxygen activation and decomposition as well as lattice oxygen dynamics. Temperature-dependent Raman results show that oxygen is stored in the form of peroxide species on the (100) facets, which are then released as gaseous oxygen, whereas lattice oxygen is involved with the (110) facets. On the latter, peroxide species first decompose into oxygen atoms that heal vacant lattice oxygen sites before being released as gaseous oxygen. The exposure of different facets makes ceria nanorods an interesting material for catalytic applications, because they allow the use of a mixture of oxygen storage-release functions, as well as their synergistic interactions, in a single system.
Collapse
Affiliation(s)
- Marc Ziemba
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| | - M Verónica Ganduglia-Pirovano
- Instituto de Catálisis y Petroleoquímica, Consejo Superior de Investigaciones Científicas, Marie Curie 2, 28049 Madrid, Spain
| | - Christian Hess
- Eduard Zintl Institute of Inorganic and Physical Chemistry, Technical University of Darmstadt, Alarich-Weiss-Str. 8, 64287 Darmstadt, Germany
| |
Collapse
|
18
|
Glöckler J, Jaeschke C, Tütüncü E, Kokoric V, Kocaöz Y, Mizaikoff B. Characterization of metal oxide gas sensors via optical techniques. Anal Bioanal Chem 2020; 412:4575-4584. [PMID: 32548766 PMCID: PMC7329784 DOI: 10.1007/s00216-020-02705-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 05/05/2020] [Accepted: 05/13/2020] [Indexed: 11/29/2022]
Abstract
Metal oxide (MOX) sensors are increasingly gaining attention in analytical applications. Their fundamental operation principle is based on conversion reactions of selected molecular species at their semiconducting surface. However, the exact turnover of analyte gas in relation to the concentration has not been investigated in detail to date. In the present study, two optical sensing techniques—luminescence quenching for molecular oxygen and infrared spectroscopy for carbon dioxide and methane—have been coupled for characterizing the behavior of an example semiconducting MOX methane gas sensor integrated into a recently developed low-volume gas cell. Thereby, oxygen consumption during MOX operation as well as the generation of carbon dioxide from the methane conversion reaction could be quantitatively monitored. The latter was analyzed via a direct mid-infrared gas sensor system based on substrate-integrated hollow waveguide (iHWG) technology combined with a portable Fourier transform infrared spectrometer, which has been able to not only detect the amount of generated carbon dioxide but also the consumption of methane during MOX operation. Hence, a method based entirely on direct optical detection schemes was developed for characterizing the actual signal generating processes—here for the detection of methane—via MOX sensing devices via near real-time online analysis. Graphical Abstract ![]()
Collapse
Affiliation(s)
- Johannes Glöckler
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Carsten Jaeschke
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Erhan Tütüncü
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Vjekoslav Kokoric
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Yusuf Kocaöz
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Boris Mizaikoff
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
| |
Collapse
|
19
|
Ziemba M, Hess C. Influence of gold on the reactivity behaviour of ceria nanorods in CO oxidation: combining operando spectroscopies and DFT calculations. Catal Sci Technol 2020. [DOI: 10.1039/d0cy00392a] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this combined Raman/UV-Vis and DFT study, structure-activity relations for CO oxidation over ceria nanorods (with/without gold) with CeO2(110) and CeO2(100) termination are elucidated using ceria nanocubes with CeO2(100) termination as reference.
Collapse
Affiliation(s)
- Marc Ziemba
- Eduard Zintl Institute of Inorganic and Physical Chemistry
- Technical University of Darmstadt
- 64287 Darmstadt
- Germany
| | - Christian Hess
- Eduard Zintl Institute of Inorganic and Physical Chemistry
- Technical University of Darmstadt
- 64287 Darmstadt
- Germany
| |
Collapse
|
20
|
Chen CS, Chen TC, Wu HC, Wu JH, Lee JF. The influence of ceria on Cu/TiO2 catalysts to produce abundant oxygen vacancies and induce highly efficient CO oxidation. Catal Sci Technol 2020. [DOI: 10.1039/d0cy00792g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ce and Cu species deposited on TiO2 can apparently provide a higher turnover frequency rate and lower activation energy than the Cu/TiO2 catalyst and the Ce and Cu species on SiO2 catalysts.
Collapse
Affiliation(s)
- Ching-Shiun Chen
- Center for General Education
- Chang Gung University
- Taoyuan City 33302
- Republic of China
- Department of Pathology
| | - Tse-Ching Chen
- Department of Pathology
- Chang Gung Memorial Hospital Linkou
- Taoyuan City 33302
- Republic of China
| | - Hung-Chi Wu
- Center for General Education
- Chang Gung University
- Taoyuan City 33302
- Republic of China
| | - Jia-Huang Wu
- Center for General Education
- Chang Gung University
- Taoyuan City 33302
- Republic of China
| | - Jyh-Fu Lee
- National Synchrotron Radiation Research Center
- Hsinchu 30076
- Republic of China
| |
Collapse
|