Low-Temperature CO Oxidation over Pd/SAPO-34 Catalyst

SAPO-34, MnSAPO-34, and CuSAPO-34 were synthesized by the hydrothermal method. A series of supported Pd catalysts were prepared by the impregnation method. The effects of calcination temperature, Pd content, prereduction of the catalyst, and reaction temperature on CO oxidation were studied. The catalytic activity decreased with increasing calcination temperature. The higher reaction temperature or Pd content resulted in the higher catalytic performance for CO oxidation; however, H(2) prereduction of the catalyst led to a lower catalytic performance. The results of X-ray diffraction and transmission electron microscopy analysis showed that Pd species are highly dispersed on SAPO-34 zeolite, and the Pd dispersion of the catalysts depends on the pretreatment temperature and reaction conditions. The characterization of X-ray photoelectron spectroscopy and H(2) temperature-programmed reduction reveals that Pd(2+) species are the active sites for CO oxidation.