It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization appli...It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization applications of nano gold catalysts. In this work, some theoretical works on CO adsorp‐tion, O2 adsorption, atomic oxygen adsorption, formation of surface gold oxide films, reaction mechanisms of CO oxidation involving O2 reaction with CO and O2 dissociation before reacting with CO on gold surfaces and Au/metal oxide were summarized, and the influences of coordination number, charge transfer and relativity of gold on CO oxidation reaction were briefly reviewed. It was found that CO reaction mechanism depended on the systems with or without oxide and the strong relativistic effects might play an important role in CO oxidation reaction on gold catalysts. In particular, the relativistic effects are related to the unique behaviors of CO adsorption, O adsorption, O2 activation on gold surfaces, effects of coordination number and the wide gap between the chem‐ical inertness of bulk gold and high catalytic activity of nano gold. The present work helps us to understand the CO oxidation reaction mechanism on gold catalysts and the influence of relativistic effects on gold catalysis.展开更多
The idea that single metal atoms dispersed on a solid support can act as an efficient heterogeneous catalyst was raised in2011when single Pt atoms on an FeOx surface were reported to be active for CO oxidation and pre...The idea that single metal atoms dispersed on a solid support can act as an efficient heterogeneous catalyst was raised in2011when single Pt atoms on an FeOx surface were reported to be active for CO oxidation and preferential oxidation of CO in H2.The last six years have witnessed tremendous progress in the field of single‐atom catalysis.Here we introduce the major achievements on this topic in2015and2016.Some particular aspects of single‐atom catalysis are discussed in depth,including new approaches in single‐atom catalyst(SAC)synthesis,stable gold SACs for various reactions,the high selectivity of Pt and Pd SACs in hydrogenation,and the superior performance of non‐noble metal SACs in electrochemistry.These accomplishments will encourage more efforts by researchers to achieve the controllable fabrication of SACs and explore their potential applications.展开更多
We describe the reaction mechanism and active sites for CO oxidation over a Au/TiO2（110） model surface and Au single‐crystal surfaces, along with the role of H2O, on a molecular scale. At low tem‐perature （＆lt;3...We describe the reaction mechanism and active sites for CO oxidation over a Au/TiO2（110） model surface and Au single‐crystal surfaces, along with the role of H2O, on a molecular scale. At low tem‐perature （＆lt;320 K）, H2O played an essential role in promoting CO oxidation, and the active site for CO oxidation was the perimeter of the interface between the gold nanoparticles and the TiO2 sup‐port （Auδ＋–Oδ––Ti）. We believe that the O–O bond was activated by the formation of OOH, which was produced directly from O2 and H2O at the perimeter of the interface between the gold nanoparticles and the TiO2 support, and consequently OOH reacted with CO to form CO2. This reaction mechanism explains the dependence of the CO2 formation rate on O2 pressure at 300 K. In contrast, at high temperature （＆gt;320 K）, low‐coordinated gold atoms built up on the surface as a result of surface reconstruction due to exposure to CO. The low‐coordinated gold atoms adsorbed O2, which then dissociated and oxidized CO on the metallic gold surface.展开更多
Applying quantitative temporal analysis of products reactor measurements, we studied the reactive removal of active oxygen present on Au/TiO2 catalysts after calcination at elevated temperatures （400 ＆#176;C） by CO...Applying quantitative temporal analysis of products reactor measurements, we studied the reactive removal of active oxygen present on Au/TiO2 catalysts after calcination at elevated temperatures （400 ＆#176;C） by CO pulses and its replenishment by O2 pulses at 80 ＆#176;C, focusing on the nature of the active oxygen species. In contrast to previous studies, which mainly focused on and clarified the nature of the active oxygen species for the catalytic CO oxidation, which is reversibly formed and replenished under typical reaction conditions, this study demonstrates that directly after calcina‐tion an additional oxygen species is present. This species is also active for the CO oxidation, but it is not or only very little formed under typical reaction conditions. Implications of these results on the mechanistic understanding of the CO oxidation on Au/TiO2, in particular on the role of different active oxygen species, will be discussed.展开更多
基金supported by the National Natural Science Foundation of China (21103165)
文摘It is crucial to understand the mechanism of low temperature CO oxidation reaction catalyzed by gold nanoparticles so as to find out the origin of the high catalytic reactivity and extend the indus‐trialization applications of nano gold catalysts. In this work, some theoretical works on CO adsorp‐tion, O2 adsorption, atomic oxygen adsorption, formation of surface gold oxide films, reaction mechanisms of CO oxidation involving O2 reaction with CO and O2 dissociation before reacting with CO on gold surfaces and Au/metal oxide were summarized, and the influences of coordination number, charge transfer and relativity of gold on CO oxidation reaction were briefly reviewed. It was found that CO reaction mechanism depended on the systems with or without oxide and the strong relativistic effects might play an important role in CO oxidation reaction on gold catalysts. In particular, the relativistic effects are related to the unique behaviors of CO adsorption, O adsorption, O2 activation on gold surfaces, effects of coordination number and the wide gap between the chem‐ical inertness of bulk gold and high catalytic activity of nano gold. The present work helps us to understand the CO oxidation reaction mechanism on gold catalysts and the influence of relativistic effects on gold catalysis.
基金supported by the National Natural Science Foundation of China(21606222,21303184,21573232)China Postdoctoral Science Foundation(2016M601350)+2 种基金Strategic Priority Research Program of the Chinese Academy of Sciences(XDB17020100)National Key Projects for Fundamental Research and Development of China(2016YFA0202801)Department of Science and Technology of Liaoning Province(2015020086-101)~~
文摘The idea that single metal atoms dispersed on a solid support can act as an efficient heterogeneous catalyst was raised in2011when single Pt atoms on an FeOx surface were reported to be active for CO oxidation and preferential oxidation of CO in H2.The last six years have witnessed tremendous progress in the field of single‐atom catalysis.Here we introduce the major achievements on this topic in2015and2016.Some particular aspects of single‐atom catalysis are discussed in depth,including new approaches in single‐atom catalyst(SAC)synthesis,stable gold SACs for various reactions,the high selectivity of Pt and Pd SACs in hydrogenation,and the superior performance of non‐noble metal SACs in electrochemistry.These accomplishments will encourage more efforts by researchers to achieve the controllable fabrication of SACs and explore their potential applications.
文摘We describe the reaction mechanism and active sites for CO oxidation over a Au/TiO2（110） model surface and Au single‐crystal surfaces, along with the role of H2O, on a molecular scale. At low tem‐perature （＆lt;320 K）, H2O played an essential role in promoting CO oxidation, and the active site for CO oxidation was the perimeter of the interface between the gold nanoparticles and the TiO2 sup‐port （Auδ＋–Oδ––Ti）. We believe that the O–O bond was activated by the formation of OOH, which was produced directly from O2 and H2O at the perimeter of the interface between the gold nanoparticles and the TiO2 support, and consequently OOH reacted with CO to form CO2. This reaction mechanism explains the dependence of the CO2 formation rate on O2 pressure at 300 K. In contrast, at high temperature （＆gt;320 K）, low‐coordinated gold atoms built up on the surface as a result of surface reconstruction due to exposure to CO. The low‐coordinated gold atoms adsorbed O2, which then dissociated and oxidized CO on the metallic gold surface.
文摘Applying quantitative temporal analysis of products reactor measurements, we studied the reactive removal of active oxygen present on Au/TiO2 catalysts after calcination at elevated temperatures （400 ＆#176;C） by CO pulses and its replenishment by O2 pulses at 80 ＆#176;C, focusing on the nature of the active oxygen species. In contrast to previous studies, which mainly focused on and clarified the nature of the active oxygen species for the catalytic CO oxidation, which is reversibly formed and replenished under typical reaction conditions, this study demonstrates that directly after calcina‐tion an additional oxygen species is present. This species is also active for the CO oxidation, but it is not or only very little formed under typical reaction conditions. Implications of these results on the mechanistic understanding of the CO oxidation on Au/TiO2, in particular on the role of different active oxygen species, will be discussed.
