Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol ...Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.展开更多
Two-dimensional(2D)BiOBr has garnered significant interest due to its exceptional optoelectronic properties.Currently,reported 2D BiOBr primarily exhibits n-type conductivity.However,in the field of optoelectronics,pa...Two-dimensional(2D)BiOBr has garnered significant interest due to its exceptional optoelectronic properties.Currently,reported 2D BiOBr primarily exhibits n-type conductivity.However,in the field of optoelectronics,particularly within complementary metal oxide semiconductor(CMOS)integrated circuits,there is an urgent demand for high-quality p-type 2D semiconductors.In this study,we present the synthesis of high-quality,large-scale p-type 2D BiOBr crystals using chemical potential modulation chemical vapor deposition(CPMCVD).Notably,the conduction polarity of 2D BiOBr can be precisely controlled by modulating the oxygen chemical potential during the synthesis process.Density functional theory(DFT)calculations indicate that high oxygen chemical potential promotes the formation of bismuth vacancies in 2D BiOBr,resulting in p-type conductivity.Conversely,as the oxygen chemical potential decreases,oxygen vacancies become the predominant defects,leading to n-type BiOBr.Furthermore,both p-type and n-type high-performance field-effect transistors(FETs)based on 2D BiOBr have been fabricated.The p-type FETs exhibit a superior hole mobility of 26.28 cm^(2)V^(−1)s^(−1)and on/off ratio exceeding 104.The n-type FETs demonstrate an electron mobility of 59.59 cm^(2)V^(−1)s^(−1),surpassing those reported for most n-type FETs.This breakthrough in the precise control of conduction polarity in 2D BiOBr using CPMCVD not only represents a significant milestone but also greatly expands its potential applications in advancing CMOS technology.展开更多
基金supported by the Key Technologies Research and Development Program(No.2022YFB3504102)the National Natural Science Foundation of China(Nos.22035009,22002050,and 22202087)+2 种基金the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2020B01)Fuyang Normal University Open Fund(No.FSKFKT006D)the Postdoctoral Science Foundation of China(Nos.2022T150765 and 2020M683154).
文摘Nitrogen oxides(NO_(x))from diesel engine exhaust,is one of the major sources of environmental pollution.Currently,selective catalytic reduction with ammonia(NH_(3)-SCR)is considered to be the most effective protocol for reducing NO_(x)emissions.Nowadays,zeolitebased NH_(3)-SCR catalysts have been industrialized and widespread used in this field.Nevertheless,with the increasingly stringent environmental regulations and implementation of the requirement of“zero emission”of diesel engine exhaust,it is extremely urgent to prepare catalysts with superior NH_(3)-SCR activity and exceptional resistance to poisons(SO2,alkali metals,hydrocarbons,etc.).Core-shell structure zeolite-based catalysts(CSCs)have shown great promise in NH_(3)-SCR of NO_(x)in recent years by virtue of its relatively higher low-temperature activity,broader operation temperature window and outstanding resistance to poisons.This review mainly focuses on the recent progress of CSCs for NH_(3)-SCR of NO_(x)with three extensively investigated SSZ-13,ZSM-5,Beta zeolites as cores.The reaction mechanisms of resistance to sulfur poisoning,alkali metal poisoning,hydrocarbon poisoning,and hydrothermal aging are summarized.Moreover,the important role of interfacial effect between core and shell in the reaction of NH_(3)-SCR was clarified.Finally,the future development and application outlook of CSCs are prospected.
基金financially supported by the National Natural Science Foundation of China(62375227)the Natural Science Basic Research Program of Shaanxi(2025JC-QYCX-059)。
文摘Two-dimensional(2D)BiOBr has garnered significant interest due to its exceptional optoelectronic properties.Currently,reported 2D BiOBr primarily exhibits n-type conductivity.However,in the field of optoelectronics,particularly within complementary metal oxide semiconductor(CMOS)integrated circuits,there is an urgent demand for high-quality p-type 2D semiconductors.In this study,we present the synthesis of high-quality,large-scale p-type 2D BiOBr crystals using chemical potential modulation chemical vapor deposition(CPMCVD).Notably,the conduction polarity of 2D BiOBr can be precisely controlled by modulating the oxygen chemical potential during the synthesis process.Density functional theory(DFT)calculations indicate that high oxygen chemical potential promotes the formation of bismuth vacancies in 2D BiOBr,resulting in p-type conductivity.Conversely,as the oxygen chemical potential decreases,oxygen vacancies become the predominant defects,leading to n-type BiOBr.Furthermore,both p-type and n-type high-performance field-effect transistors(FETs)based on 2D BiOBr have been fabricated.The p-type FETs exhibit a superior hole mobility of 26.28 cm^(2)V^(−1)s^(−1)and on/off ratio exceeding 104.The n-type FETs demonstrate an electron mobility of 59.59 cm^(2)V^(−1)s^(−1),surpassing those reported for most n-type FETs.This breakthrough in the precise control of conduction polarity in 2D BiOBr using CPMCVD not only represents a significant milestone but also greatly expands its potential applications in advancing CMOS technology.
