Bimetallic catalysts typically exploit unique synergetic effects between two metal species to achieve their catalytic effect.Understanding the mechanism of CO oxidation using hybrid heterogeneous catalysts is importan...Bimetallic catalysts typically exploit unique synergetic effects between two metal species to achieve their catalytic effect.Understanding the mechanism of CO oxidation using hybrid heterogeneous catalysts is important for effective catalyst design and environmental protection.Herein,we report a Bi-Au/SiO_(2)tandem bimetallic catalyst for the oxidation of CO over the Au/SiO_(2)surface,which was monitored using near-ambient-pressure X-ray photoelectron spectroscopy.The Au-decorated SiO_(2)catalyst exhibited scarce activity in the CO oxidation reaction;however,the introduction of Bi to the Au/SiO_(2)system promoted the catalytic activity.The mechanism is thought to involve the dissociation O_(2)molecules in the presence of Bi,which results in spillover of the O species to adjacent Au atoms,thereby forming Au^(δ+).Further CO adsorption,followed by thermal treatment,facilitated the oxidation of CO at the Au-Bi interface,resulting in a reversible reversion to the neutral Au valence state.Our work provides insight into the mechanism of CO oxidation on tandem surfaces and will facilitate the rational design of other Au-based catalysts.展开更多
Elucidation of a physicochemical process on nanocatalysts,especially under continuously evolving conditions,is often heavily tool-driven because of technical challenges.Recently,ambient pressure X-ray photoelectron sp...Elucidation of a physicochemical process on nanocatalysts,especially under continuously evolving conditions,is often heavily tool-driven because of technical challenges.Recently,ambient pressure X-ray photoelectron spectroscopy(APXPS)emerges as an emerging photon-in-electron-out technique in in-situ/operando analysis by bridging the pressure-gap between conventional ultra-high vacuum(UHV)and near ambient or even close to operating conditions,rendering the advancement of XPS from a UHV-based technique to a versatile and powerful tool that enables the specific probe of numerous events taking place at the gas–solid,liquid–solid and liquid–gas nanoscale interfaces which are critical to nanocatalysis research.For example,APXPS probes information on catalytically active phase and reaction kinetics in nanocatalytic processes;details inside the electric double-layer at an electrolyte/electrode interface can now be accessed;more efficient nanocatalyst design can be achieved and energy transfer venues can be optimized.Here,we aim to critically review the recent advances in instrumentation and the probe of the gas–solid,liquid–solid,and gas–liquid nanoscale interfaces using APXPS-based methodologies,followed by putting forward an outlook of development of APXPS as a rising in-situ/operando analytical means in surface science,nanocatalysis,nanoscience materials science.展开更多
基金the National Natural Science Foundation of China(Nos.11874380 and 22002183)the National Key Research and Development Program of China(No.2021YFA1600800).
文摘Bimetallic catalysts typically exploit unique synergetic effects between two metal species to achieve their catalytic effect.Understanding the mechanism of CO oxidation using hybrid heterogeneous catalysts is important for effective catalyst design and environmental protection.Herein,we report a Bi-Au/SiO_(2)tandem bimetallic catalyst for the oxidation of CO over the Au/SiO_(2)surface,which was monitored using near-ambient-pressure X-ray photoelectron spectroscopy.The Au-decorated SiO_(2)catalyst exhibited scarce activity in the CO oxidation reaction;however,the introduction of Bi to the Au/SiO_(2)system promoted the catalytic activity.The mechanism is thought to involve the dissociation O_(2)molecules in the presence of Bi,which results in spillover of the O species to adjacent Au atoms,thereby forming Au^(δ+).Further CO adsorption,followed by thermal treatment,facilitated the oxidation of CO at the Au-Bi interface,resulting in a reversible reversion to the neutral Au valence state.Our work provides insight into the mechanism of CO oxidation on tandem surfaces and will facilitate the rational design of other Au-based catalysts.
基金supported by the National Natural Science Foundation of China(NSFC),Basic Sciences Center Program(Extreme Light Field Manufacturing,No.52488301)and NSFC General Program(No.52475425)the National Key R&D Program of China(No.2022YFB4601300)Aeronautical Science Fund(No.3030021252404).
文摘Elucidation of a physicochemical process on nanocatalysts,especially under continuously evolving conditions,is often heavily tool-driven because of technical challenges.Recently,ambient pressure X-ray photoelectron spectroscopy(APXPS)emerges as an emerging photon-in-electron-out technique in in-situ/operando analysis by bridging the pressure-gap between conventional ultra-high vacuum(UHV)and near ambient or even close to operating conditions,rendering the advancement of XPS from a UHV-based technique to a versatile and powerful tool that enables the specific probe of numerous events taking place at the gas–solid,liquid–solid and liquid–gas nanoscale interfaces which are critical to nanocatalysis research.For example,APXPS probes information on catalytically active phase and reaction kinetics in nanocatalytic processes;details inside the electric double-layer at an electrolyte/electrode interface can now be accessed;more efficient nanocatalyst design can be achieved and energy transfer venues can be optimized.Here,we aim to critically review the recent advances in instrumentation and the probe of the gas–solid,liquid–solid,and gas–liquid nanoscale interfaces using APXPS-based methodologies,followed by putting forward an outlook of development of APXPS as a rising in-situ/operando analytical means in surface science,nanocatalysis,nanoscience materials science.
