铌的催化作用

综述了铌在酸催化和氧化催化反应中的作用。铌化合物为新型催化材料,在催化反应中,既可作为催化剂,也可作为催化剂载体或助剂。铌酸和磷酸铌在水解、水合等很多酸催化反应中具有良好的催化活性。在含铌载体负载的金属催化剂中,存在着载体与金属间的强相互作用,可用于选择性催化加氢反应。铌氧化物具备一定的氧化-还原能力,能增强用其掺杂或负载的氧化物催化剂的催化氧化活性。铌作为催化助剂,在低碳烃选择氧化反应中,可提高目标产物烯烃、醛、酸或腈的收率。铌催化剂还在光催化制氢等反应中显示出特殊的活性。

Catalysis of Niobium

Catalysis of niobium in various reactions especially in acid catalyzed and selective oxidative reactions were reviewed.Niobium compounds can be used as active components,supports or promoters in catalytic reactions.Niobic acid and niobium phosphate exhibit strong surface acidity and therefore exhibit high catalytic activities in acid catalyzed reactions such as hydrolysis and hydration of organic compounds.Strong interactions of metal with support exist in niobium pentoxide supported metallic catalysts.This effect can be used to improve activities and selectivities of metallic catalysts for hydrogenations.Another important property of niobium oxides is its weak redox behavior which enhances redox ability of other metallic oxides supported on or doped with niobium oxides.As a promoter,niobium has been doped into complex oxides mainly consisted of V and Mo to raise catalytic activity and selectivity for selective oxidation of light paraffins to corresponding olefins,organic acids and nitriles.Moreover complex niobium oxides with layered structures have been found to be photo-catalytically active for decomposition of H2O to produce H2.