Catalytic abatement of CO and volatile organic compounds in waste gases by gold catalysts supported on ceria-modified mesoporous titania and zirconia

Mesoporous oxides TiO₂ and ZrO₂, synthesized by surfactant templating via a neutral C₁₃(EO)₆–Zr(OC₃H₇)₄ assembly pathway, and ceria-modified TiO₂ and ZrO₂, prepared by a deposition–precipitation (DP) method, featuring high surface areas and uniform pore size distributions were used as supports for gold catalysts. The supported gold catalysts were assessed for the catalytic abatement of air pollutants, i.e., CO, CH₃OH, and (CH₃)₂O. The gold was supported on the mesoporous oxides by a DP method. The supports and catalysts were characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, N₂ adsorption–desorption analysis, and temperature-programmed reduction technique. A high degree of synergistic interaction between ceria and mesoporous ZrO₂ and TiO₂ as well as a positive modification of the structural and catalytic properties by ceria was observed. The ceria additive interacts with the mesoporous oxides and induces a strong effect on the reducibility of the supports. The catalytic behavior of the catalysts was discussed to determine the role of the ceria modifying additive and possible interaction between the gold nanoparticles and ceria-mesoporous oxide supports. The gold catalysts supported on ceria-modified mesoporous ZrO₂ displayed superior catalytic activity (∼100% conversion of CO at 10 °C and CH₃OH at 60 °C). The high catalytic activity can be attributed to the ability of the support to assist oxygen vacancies formation. The studies indicate that the ceria-modified mesoporous oxide supports have potential as supports for gold-based catalysts.