Titania Morphology‐Dependent Catalysis of CuO<sub>x</sub>/TiO<sub>2</sub> Catalysts in CO Oxidation and Water Gas Shift Reactions
Zongyou Yu, Zhenhua Zhang, Yunshang Zhang, Weixin Huang
Abstract
Abstract CuO x /TiO 2 nanocatalysts (x=0 or 1) with ∼11 % wt. Cu loading employing TiO 2 nanocrystals with various morphologies predominantly exposing {001}, {100}, and {101} facets as supports have been synthesized as catalysts for CO oxidation with excess of O 2 (oxidative atmosphere) and water gas shift (WGS) reaction (reductive atmosphere). Strong TiO 2 morphology effects were observed. The strongest Cu 2 O−TiO 2 interaction was observed in CuO−TiO 2 {001} nanocatalyst, while the strongest Cu‐TiO 2 interaction occurred in Cu‐TiO 2 {100} nanocatalyst. Catalytic activities of various CuO/TiO 2 nanocatalysts in CO oxidation and of various Cu/TiO 2 nanocatalysts in WGS reaction follow the same order of CuO x /TiO 2 {100}>CuO x /TiO 2 {101}>CuO x /TiO 2 {001}, and all CuO/TiO 2 nanocatalysts are stable in CO oxidation but all Cu/TiO 2 nanocatalysts suffer from serious deactivation in WGS reaction. The active structure of CuO/TiO 2 nanocatalysts in CO oxidation was found to be the CuO species, while the active structure of Cu/TiO 2 nanocatalysts in WGS reaction to be the Cu‐TiO 2 interface which is relevant to the Cu‐TiO 2 interaction. The supported Cu nanoparticles in Cu/TiO 2 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 CuO x ‐TiO 2 interaction in CuO x /TiO 2 nanocatalysts, but also reveal reaction‐dependent active structures of CuO x /TiO 2 nanocatalysts.