| In the field of heterogeneous catalysis,there are many structural factors that affect the catalytic performance of catalysts,among which the morphology-dependent effect of oxide supports and the interaction between metal and oxide supports are quite important.Recently the morphology controllable nanocrystalline synthesis technology has been greatly developed,which provides a system close to the real powder catalyst,and discusses the influence of catalyst surface structure on catalytic performance under different reaction atmosphere.CuOx/TiO2 nanocatalysts?x=0 or 1?with?11%wt.Cu loading employing TiO2 nanocrystals with various morphologies pre dominantly exposing {001},{100},and{101} facets as supports have been synthesized as catalysts for CO oxidation with excess of O2?oxidative atmosphere?and water gas shift?WGS?reaction?reductive atmosphere?.Strong TiO2 morphology effects were observed.The strongest Cu2O-TiO2 interaction was observed in CuO-TiO2{001} nanocatalyst,while the strongest Cu-TiO2 interaction occurred in Cu-TiO2{110} nanocatalyst.Catalytic activities of various CuO/TiO2 nanocatalysts in CO oxidation and of various Cu/TiO2 nanocatalysts in WGS reaction follow the same order of CuOx/TiO2{100}>CuOx/TiO2{101}>CuOx/[T1O2{001},and all CuO/TiO2 nanocatalysts are stable in CO oxidation but all Cu/TiO2 nanocatalysts suffer from serious deactivation in WGS reaction.The active structure of CuO/TiO2 nanocatalysts in CO oxidation was found to be the CuO species,while the active structure of Cu/TiO2 nanocatalysts in WGS reaction to be the Cu-TiO2 interface which is relevant to the Cu-TiO2 interaction.The supported Cu nanoparticles in Cu/TiO2 nanocatalysts tend to agglomerate at high temperatures in 5%CO/Ar atmosphere,responsible for the deactivation in WGS reaction.These results not only demonstrate the morphology-dependent CuOx-TiO2 interaction in CuOx/TiO2 nanocatalysts,but also reveal reaction dependent active structures of CuOx/TiO2 nanocatalysts. |
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