Titania Morphology‐Dependent Catalysis of CuOx/TiO2 Catalysts in CO Oxidation and Water Gas Shift Reactions

Abstract

AbstractCuOx/TiO2 nanocatalysts (x=0 or 1) with ∼11 % wt. Cu loading employing TiO2 nanocrystals with various morphologies predominantly 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{100} 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/TiO2{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.