Bi-active sites of stable and highly dispersed platinum and oxygen vacancy constructed by reducing a loaded perovskite-type oxide for CO oxidation

摘要

A new scheme for constructing bi-active sites of highly dispersed N and oxygen vacancies on a catalyst was put forward in this study. Pt/LaCoxNi1-xO3/SiO2 was synthesized by reducing LaCoxNi0.87-xPt0.13O3 with the structure of perovskite loaded on silica. The catalytic performance for carbon monoxide oxidation over the catalysts were studied. The catalysts were characterized via using XRD, XPS, XAFS, N-2 adsorption-desorption, H-2-TPR, TEM, O-2 and CO-TPD techniques. The results pointed out that nanocrystal lines of LaCoxNi0.87Pt0.13O3 were supported on SiO2. N clusters could be formed through reduction process at 300 degrees C and highly dispersed on catalyst's surface, and the catalyst transformed to Pt/LaCoxNi1-xO3/SiO2; at the same time, oxygen vacancies also formed on the surface of LaCoxNi1-xO3. The catalytic WA revealed that LaCo0.44Ni0.43Pt0.13O3/SiO2 displayed high activity and good stability for the oxidation of CO. The highly dispersed closely contact bi-active sites, the confinement of oxygen vacancies and strong interaction between N clusters and support were responsible for the significant catalytic activity and stability of LaCo0.44Ni0.43Pt0.13O3/SiO2 catalyst.