Effect of TiO^sub 2^ Crystal Phase and Preparation Method on the Catalytic Performance of Au/TiO^sub 2^ for CO Oxidation

Titania-supported gold nanoparticles exhibit excellent low-temperature carbon monoxide (CO) oxidation activity, which is sensitive to the structure of the TiO^sub 2^ support and the preparation method. In this paper, gold catalysts were prepared on TiO^sub 2^ with different anatase-to-rutile ratios by the deposition-precipitation method (Au/TiO^sub 2^-C) and plasma-assisted deposition-precipitation method (Au/TiO^sub 2^-PC). The highest performance for CO oxidation was obtained over Au/TiO^sub 2^ for an anatase-to-rutile ratio of 4:6, which may be ascribed to the phase transformation mechanism of TiO^sub 2^ and the preferential deposition of Au nanoparticles on rutile TiO^sub 2^ in the deposition-precipitation process. Therefore, enlarged contact surface between the Au nanoparticles and the TiO^sub 2^ support was obtained, and more oxygen vacancies may be formed, which are beneficial to CO oxidation. Interestingly, compared with Au/TiO^sub 2^-C, Au/TiO^sub 2^-PC exhibited enhanced CO oxidation activity. For example, the reaction rate (...) at 30 ...C for CO oxidation over Au/TiO^sub 2^-PC was about 5.8 times greater than that over Au/TiO^sub 2^-C for an anatase-to-rutile ratio of about 4:6, which was primarily caused by the more active gold species on the surface of TiO^sub 2^ support in Au/TiO^sub 2^-PC due to the Coulomb interaction during plasma preparation. (ProQuest: ... denotes formulae/symbols omitted.)