Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The prese...Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The presence of water in the reaction stream results in a significant increase in NH3selectivity.This result is due to water‐induced hydroxylation promoting NH3formation and the competitive adsorption of H2O and NO at the same sites,which inhibits the reactivity of NO reduction by NH3.展开更多
Catalyst with high performance has drawn increasing attention recently due to its significant advantages in chemical reactions such as speeding up the reaction,lowering the reaction temperature or pressure,and proceed...Catalyst with high performance has drawn increasing attention recently due to its significant advantages in chemical reactions such as speeding up the reaction,lowering the reaction temperature or pressure,and proceeding without itself being consumed.Despite the superior catalytic performance of precious metal catalysts,transition metal oxides offer a promising route for substitution of precious metals in catalysis arising from their low cost,intrinsic activity and sufficient stability.Mullite-type oxide SmMn_(2)O_(5) exhibits a unique crystal structure containing double crystalline fields,and nowadays is used widely as the catalyst in different chemical reactions,including the reactions of vehicle emissions reduction and oxygen evolution reaction,gas sensors,and metal-air batteries,promoting attention in catalytic perfor-mance enhancement.To our knowledge,there is no review article covering the comprehensive informa-tion of SmMn2 O 5 and its applications.Here we review the recent progress in understanding of the crys-tal structure of SmMn_(2)O_(5) and its basic physical properties.We then summarize the catalytic sources of SmMn_(2)O_(5) and reaction mechanisms,while the strategies to improve catalytic performance of SmMn_(2)O_(5) are further presented.Finally,we provide a perspective on how to make further progress in catalytic applications.展开更多
The decomposition and identification of signals are crucial for flow vector acquisition in a multi-dimensional measurement. Here, we proposed a two-dimensional(2D) flow vector measurement system based on all-fiber las...The decomposition and identification of signals are crucial for flow vector acquisition in a multi-dimensional measurement. Here, we proposed a two-dimensional(2D) flow vector measurement system based on all-fiber laser feedback frequency-shifted multiplexing technology. The reliable performance of the system is characterized by experimental verification and numerical simulation. An orthogonal dual-beam structure is employed to eliminate the impact of an unknown incident angle in the practical application. Meanwhile, the vector velocity signals in 2D can be decomposed into one-dimensional(1D) scalar signals by adopting the frequency-shifted multiplexing,which makes it easy to obtain the vector information and velocity distribution of fluid motion through the self-mixing interference frequency spectrum.展开更多
基金supported by the National Natural Science Foundation of China (21463015)the Provincial Applied Fundamental Research Program of Yunnan (2014FA045)the National High Technology Research and Development Program of China (863 Program,2015AA034603)~~
文摘Vibrational IR spectra and light‐off investigations show that NH3forms via the“hydrogen down”reaction of adsorbed CO and NO with hydroxyl groups on a CeO2support during the catalytic reduction of NO by CO.The presence of water in the reaction stream results in a significant increase in NH3selectivity.This result is due to water‐induced hydroxylation promoting NH3formation and the competitive adsorption of H2O and NO at the same sites,which inhibits the reactivity of NO reduction by NH3.
基金supported by the National Natural Science Foundation of China(Nos.52072134,U1910209,51972128,52272205)Hubei Province(Nos.2021BCA149,2021CFA072,2022BAA087).
文摘Catalyst with high performance has drawn increasing attention recently due to its significant advantages in chemical reactions such as speeding up the reaction,lowering the reaction temperature or pressure,and proceeding without itself being consumed.Despite the superior catalytic performance of precious metal catalysts,transition metal oxides offer a promising route for substitution of precious metals in catalysis arising from their low cost,intrinsic activity and sufficient stability.Mullite-type oxide SmMn_(2)O_(5) exhibits a unique crystal structure containing double crystalline fields,and nowadays is used widely as the catalyst in different chemical reactions,including the reactions of vehicle emissions reduction and oxygen evolution reaction,gas sensors,and metal-air batteries,promoting attention in catalytic perfor-mance enhancement.To our knowledge,there is no review article covering the comprehensive informa-tion of SmMn2 O 5 and its applications.Here we review the recent progress in understanding of the crys-tal structure of SmMn_(2)O_(5) and its basic physical properties.We then summarize the catalytic sources of SmMn_(2)O_(5) and reaction mechanisms,while the strategies to improve catalytic performance of SmMn_(2)O_(5) are further presented.Finally,we provide a perspective on how to make further progress in catalytic applications.
基金National Natural Science Foundation of China(62275001, 62105001, 62205001)。
文摘The decomposition and identification of signals are crucial for flow vector acquisition in a multi-dimensional measurement. Here, we proposed a two-dimensional(2D) flow vector measurement system based on all-fiber laser feedback frequency-shifted multiplexing technology. The reliable performance of the system is characterized by experimental verification and numerical simulation. An orthogonal dual-beam structure is employed to eliminate the impact of an unknown incident angle in the practical application. Meanwhile, the vector velocity signals in 2D can be decomposed into one-dimensional(1D) scalar signals by adopting the frequency-shifted multiplexing,which makes it easy to obtain the vector information and velocity distribution of fluid motion through the self-mixing interference frequency spectrum.
