GUO Lihong1,2, LI Jing1, TIAN Ye1, LI Xingang1*
(1 Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin Key Laboratory of Applied Catalysis Science and Engineering, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300354, China; 2 College of Chemistry, Chemical and Environmental Engineering, Henan University of Technology, Zhengzhou 450001, Henan, China)
Abstract:
The PdO/SnxCeyO2 catalysts were synthesized by the co-precipitation-impregnation method.XRD, N2 adsorption-desorption, CO-TPD and CO-DRIFT techniques were used to investigate the structural and surface properties of the catalysts, and their catalytic activity by CO oxidation were evaluated.The results show that the CO oxidation activity of the catalysts is irrelevant with the surface area, but directly correlates with the reactivity of surface lattice oxygen species. Compared with the Pd/Sn0.7Ce0.3O2 catalyst，the higher reactivity of surface lattice oxygen species on the Pd/Sn0.3Ce0.7O2 catalyst plays a vital role in better CO oxidation performance at low temperatures. The in-situ DRIFT spectra of CO adsorption show that, the PdO species can be reduced by CO even at room temperature and form the Pd0/Pd+ species. The linearly bonded CO-Pd0 is the dominate adsorption species. Furthermore, compared with the inert pre-treatment method, the oxidative pre-treatment method facilitates the oxidation of CO and decreases the formation of carbonates.
KeyWords:
SnO2; CeO2; Pd; CO catalytic oxidation
