Gold nanoparticles supported on ceria-modified mesoporous titania as highly active catalysts for low-temperature water-gas shift reaction

摘要

New gold catalytic system prepared on ceria-modified mesoporous titania(CeMTi)used as water-gas shift(WGS)reaction catalyst is reported.Mesoporous titania(MTi)was synthesized using surfactant templating method through a neutral [C_(13)(EO)6-Ti(OC3H7)4] assembly pathway.Ceria modifying additive was deposited on MTi by deposition precipitation(DP)method.Gold-based catalysts with different gold content(1-5 wt.%)were synthesized by DP of gold hydroxide on mixed metal oxide support.The supports and the catalysts were characterized by powder X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM),N2 adsorption analysis and temperature-programmed reduction(TPR).The catalytic behavior of the gold-based catalysts was evaluated in WGS reaction in a wide temperature range(140-300 °C)and at different space velocities and H2O/CO ratios.The influence of gold content and particle size on the catalytic performance was investigated.The WGS activity of the new gold/ceria-modified mesoporous titania catalysts was compared with that of gold catalysts supported on simple oxides CeO2 and mesoporous TiO2,as well as gold/ceria-modified titania and reference catalyst Au/TiO2 type A(World Gold Council).A high degree of synergistic interaction between ceria and mesoporous titania and a positive modification of structural and catalytic properties by ceria has been achieved.It is clearly revealed that the ceria-modified mesoporous titania is of much interest as potential support for gold-based catalyst.The Au/ceria-modified mesoporous titania catalytic system is found to be efficient catalyst for WGSR.