The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity.However,it is still challenging to construct an appropriate interaction starting from the catalyst fabrication ...The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity.However,it is still challenging to construct an appropriate interaction starting from the catalyst fabrication and/or activation.We herein established low-temperature treatment of Ni^(2+)ions impregnated on ceria in reductive atmosphere and reduction-oxidation cycles as effective approachs to regulate the metal-support interaction and raise the catalytic performance in the CO_(2)methanation.The proposed construction approach yielded Ni/Ce O_(2)that displayed highly dispersed Ni nanoparticles in contact with Ce O_(2)(111)and(100)facet,higher density of surface oxygen vacancies and larger amounts of weak basic sites relative to the reference samples,which increased the capacity for H2 and CO_(2)adsorption/activation.The interaction resulted in appreciably(2-3 fold)higher activity in the CO_(2)methanation with maintaining almost full selectivity to CH4 and high stability.Coverage of Ni surface by Ce O_(2)-x thin layer as a typical structure of strong metal-support interaction resulting from high-temperature reduction,can be alleviated via reduction-oxidation cycles.We also demonstrate the activation treatment-determined metalsupport interaction effect can generally extend to(Ti O_(2)and Zr O_(2))supported Ni catalysts.展开更多
Downy mildew is an important disease of cucumber,seriously threatening the production of cucumber.This article briefly described the symptoms and pathogen characteristics of cucumber downy mildew,the pathogenesis of t...Downy mildew is an important disease of cucumber,seriously threatening the production of cucumber.This article briefly described the symptoms and pathogen characteristics of cucumber downy mildew,the pathogenesis of the pathogen,plant disease resistance,pathogen drug resistance and integrated prevention and control techniques.In addition,officially registered fungicides,which are used against cucumber downy mildew,were summarized and categorized.We emphatically analyzed the active ingredients and formula combinations of the fungicides for controlling cucumber downy mildew,and the problems of the registered fungicides.The characteristics and control techniques of the newly registered fungicides for controlling cucumber downy mildew in the past two years are introduced.The problems existing in the research of cucumber downy mildew are discussed.Finally,the future research direction is put forward.展开更多
基金financially supported by the Tianjin Key Science and Technology Project(19ZXNCGX00030)。
文摘The metal-support interaction is of critical importance to enhance the catalytic activity and selectivity.However,it is still challenging to construct an appropriate interaction starting from the catalyst fabrication and/or activation.We herein established low-temperature treatment of Ni^(2+)ions impregnated on ceria in reductive atmosphere and reduction-oxidation cycles as effective approachs to regulate the metal-support interaction and raise the catalytic performance in the CO_(2)methanation.The proposed construction approach yielded Ni/Ce O_(2)that displayed highly dispersed Ni nanoparticles in contact with Ce O_(2)(111)and(100)facet,higher density of surface oxygen vacancies and larger amounts of weak basic sites relative to the reference samples,which increased the capacity for H2 and CO_(2)adsorption/activation.The interaction resulted in appreciably(2-3 fold)higher activity in the CO_(2)methanation with maintaining almost full selectivity to CH4 and high stability.Coverage of Ni surface by Ce O_(2)-x thin layer as a typical structure of strong metal-support interaction resulting from high-temperature reduction,can be alleviated via reduction-oxidation cycles.We also demonstrate the activation treatment-determined metalsupport interaction effect can generally extend to(Ti O_(2)and Zr O_(2))supported Ni catalysts.
文摘Downy mildew is an important disease of cucumber,seriously threatening the production of cucumber.This article briefly described the symptoms and pathogen characteristics of cucumber downy mildew,the pathogenesis of the pathogen,plant disease resistance,pathogen drug resistance and integrated prevention and control techniques.In addition,officially registered fungicides,which are used against cucumber downy mildew,were summarized and categorized.We emphatically analyzed the active ingredients and formula combinations of the fungicides for controlling cucumber downy mildew,and the problems of the registered fungicides.The characteristics and control techniques of the newly registered fungicides for controlling cucumber downy mildew in the past two years are introduced.The problems existing in the research of cucumber downy mildew are discussed.Finally,the future research direction is put forward.
