Influence of KOH modification on TiO2 structure and Au/TiO2 catalyst activity in CO oxidation

KOH-modified TiO2 support was obtained by treating the hydrolysate of tetrabutyl titanate with KOH solution of various concentrations; the gold catalyst supported on the KOH-modified TiO2 was prepared through impregnation and used for CO oxidation. The support and catalyst were characterized by N2 physical sorption, thermogravimetry, thermo-analysis, X-ray powder diffraction, UV-vis diffuse reflection spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results indicate that the modification with KOH may influence the structure and property of TiO2 and Au/TiO2 significantly. KOH modification can change electronic structure of TiO2 and enhance the activity of Au/TiO2 catalyst for low-temperature CO oxidation. However, the modification with excessive KOH may also block the porous structure of TiO2 and weaken its adsorption ability, which leads an enlargement of gold particles on Au/TiO2 and a decrease of its catalytic activity for CO oxidation.