Carbonate-modified metal-support interfaces allow Ru/MnCO_(3) catalyst to exhibit over 99% selectivity,great specific activity and long-term anti-CO poisoning stability in atmospheric CO_(2) methanation.As a contrast,...Carbonate-modified metal-support interfaces allow Ru/MnCO_(3) catalyst to exhibit over 99% selectivity,great specific activity and long-term anti-CO poisoning stability in atmospheric CO_(2) methanation.As a contrast,Ru/MnO catalyst with metal-oxide interfaces prefers reverse water-gas shift rather than methanation route,along with a remarkably lower activity and a less than 15% CH_(4) selectivity.The carbonatemodified interfaces are found to stabilize the Ru species and activate CO_(2) and H_(2) molecules.Ru-CO^(4) species are identified as the reaction intermediates steadily formed from CO_(2) dissociation,which show moderate adsorption strength and high reactivity in further hydrogenation to CH_(4),Furthermore,carbonates of Ru/MnCO_(3) are found to be consumed by hydrogenation to form CH_(4) and replenished by exchange with CO_(2),which are in a dynamic equilibrium during the reaction.Modification with surface carbonates is proved as an efficient strategy to endow metal-support interfaces of Ru-based catalysts with unique catalytic functions for selective CO_(2) hydrogenation.展开更多
The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially,...The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate(active components are Mn:Cu=3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m 3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.展开更多
Using density functional theory calculations,we investigate the growth habit and structural stability of Ni_(4) tetramer on TiO_(2)(Ni_(4)/TiO_(2)),which acts as a representative of oxide-supported few-atom catalysts(...Using density functional theory calculations,we investigate the growth habit and structural stability of Ni_(4) tetramer on TiO_(2)(Ni_(4)/TiO_(2)),which acts as a representative of oxide-supported few-atom catalysts(FACs)ideally with high atomic utilization.We further analyze the structural characteristics and valence state distribution of metals of two structurally different Ni_(4)/TiO_(2) for comparative study in catalysis,typically as hydrogen-related applications.The planar rhombic and tetrahedral Ni_(4)/TiO_(2) feature the coordination environment of central metal atoms and the interfacial bonding from support interactions,respectively.Both structure-dependent binding characteristics and metal valence state distributions determine the active sites,catalytic activity,and reaction pathways and mechanisms in hydrogen production of the two catalysts.The planar rhombic structure exhibits high atomic utilization and outstanding catalytic activity,far exceeding those of the tetrahedral structure in this reaction.According to the atomic utilization and structure-dependent catalytic performance,we define and conceptualize the rising FACs,independent of cluster catalysts.These findings have implications for the design of suitable FACs and the creation of favorable conditions for multi-step reactions.展开更多
In supported catalysts,strong metal-support interaction(SMSI)is pivotal for modulating catalytic performance.Challenges,such as active site shielding and insufficient interfacial reactivity,have emerged as key points ...In supported catalysts,strong metal-support interaction(SMSI)is pivotal for modulating catalytic performance.Challenges,such as active site shielding and insufficient interfacial reactivity,have emerged as key points of attention.Here,we propose an amorphous encapsulation strategy creating permeable overlayers that preserve metal accessibility while maximizing metal-support interfaces.The engineered Pt@a-Nb_(2)O_(5) catalyst is synthesized through a two-step process involving the heat treatment of the Nb_(2)O_(5) support followed by wet chemical reduction.This catalyst exhibits exceptional CO oxidation performance,achieving complete CO conversion at 165℃ and demonstrating remarkable stability for over 30 h at 205℃.The amorphous Nb_(2)O_(5) shell,rich in oxygen vacancies,modulates the electronic structure of Pt,creating dual adsorption sites for CO and O_(2) and significantly improving catalytic activity.The catalyst design,which features an amorphous-coated heterostructure,along with the amorphous encapsulation preparation method,is expected to be applicable to a wider variety of supported catalyst systems and catalytic reactions.展开更多
基金the National Key R&D Program of China(2018YFE0122600)the National Natural Science Foundation of China(21802070).
文摘Carbonate-modified metal-support interfaces allow Ru/MnCO_(3) catalyst to exhibit over 99% selectivity,great specific activity and long-term anti-CO poisoning stability in atmospheric CO_(2) methanation.As a contrast,Ru/MnO catalyst with metal-oxide interfaces prefers reverse water-gas shift rather than methanation route,along with a remarkably lower activity and a less than 15% CH_(4) selectivity.The carbonatemodified interfaces are found to stabilize the Ru species and activate CO_(2) and H_(2) molecules.Ru-CO^(4) species are identified as the reaction intermediates steadily formed from CO_(2) dissociation,which show moderate adsorption strength and high reactivity in further hydrogenation to CH_(4),Furthermore,carbonates of Ru/MnCO_(3) are found to be consumed by hydrogenation to form CH_(4) and replenished by exchange with CO_(2),which are in a dynamic equilibrium during the reaction.Modification with surface carbonates is proved as an efficient strategy to endow metal-support interfaces of Ru-based catalysts with unique catalytic functions for selective CO_(2) hydrogenation.
文摘The preparation of immobilizing-catalysts for decomposing ozone by using dipping method was studied. XRD, XPS and TEM were used to characterize the catalysts. The three kinds of catalysts were selected preferentially, and their catalytic activities were investigated. The results showed that the catalyst with activated carbon dipping acetate(active components are Mn:Cu=3:2, active component proportion in catalyst is 15%, calcination temperature is 200℃) has the best catalytic activity for ozone decomposing. One gram of catalyst can decompose 17.6 g ozone at initial ozone concentration of 2.5 g/m 3 and the residence time in reactor of 0.1 s. The experimental results also indicated that humidity of reaction system had negative effect on catalytic activity.
基金supported by the National Natural Science Foundation of China(No.52272199).
文摘Using density functional theory calculations,we investigate the growth habit and structural stability of Ni_(4) tetramer on TiO_(2)(Ni_(4)/TiO_(2)),which acts as a representative of oxide-supported few-atom catalysts(FACs)ideally with high atomic utilization.We further analyze the structural characteristics and valence state distribution of metals of two structurally different Ni_(4)/TiO_(2) for comparative study in catalysis,typically as hydrogen-related applications.The planar rhombic and tetrahedral Ni_(4)/TiO_(2) feature the coordination environment of central metal atoms and the interfacial bonding from support interactions,respectively.Both structure-dependent binding characteristics and metal valence state distributions determine the active sites,catalytic activity,and reaction pathways and mechanisms in hydrogen production of the two catalysts.The planar rhombic structure exhibits high atomic utilization and outstanding catalytic activity,far exceeding those of the tetrahedral structure in this reaction.According to the atomic utilization and structure-dependent catalytic performance,we define and conceptualize the rising FACs,independent of cluster catalysts.These findings have implications for the design of suitable FACs and the creation of favorable conditions for multi-step reactions.
基金supported by the National Natural Science Foundation of China(Nos.12034002 and U24A2023).
文摘In supported catalysts,strong metal-support interaction(SMSI)is pivotal for modulating catalytic performance.Challenges,such as active site shielding and insufficient interfacial reactivity,have emerged as key points of attention.Here,we propose an amorphous encapsulation strategy creating permeable overlayers that preserve metal accessibility while maximizing metal-support interfaces.The engineered Pt@a-Nb_(2)O_(5) catalyst is synthesized through a two-step process involving the heat treatment of the Nb_(2)O_(5) support followed by wet chemical reduction.This catalyst exhibits exceptional CO oxidation performance,achieving complete CO conversion at 165℃ and demonstrating remarkable stability for over 30 h at 205℃.The amorphous Nb_(2)O_(5) shell,rich in oxygen vacancies,modulates the electronic structure of Pt,creating dual adsorption sites for CO and O_(2) and significantly improving catalytic activity.The catalyst design,which features an amorphous-coated heterostructure,along with the amorphous encapsulation preparation method,is expected to be applicable to a wider variety of supported catalyst systems and catalytic reactions.
