Effect of Amorphous Alloy CoB on Modifying Pt/TiO2 Catalyst for Low-temperature Oxidation of Carbon Monoxide

Catalytic oxidation of CO into CO2 at low-temperature is of great technological value in the purification of the air as well as the removal of CO from H2 in the development of efficient fuel cell systems. Pt nanoparticles dispersed on metal oxides, such as Pt/Al2O3 and Pt/TiO2, show good performances of catalytic oxidizing CO at a relative high temperature (above 100 o C). In this paper, a study for promoting CO oxidization over Pt/TiO2 at low-temperature (below 50 o C) was investigated. A Pt/CoB/TiO2 catalyst modified by amorphous alloy CoB was prepared by the impregnation-wetness-reduction method. The properties of the catalyst were characterized by XRD, TEM, XPS and FTIR, and its activity of oxidizing CO was performed in a fixed-bed flow reactor. It was found, compared with Pt/TiO2, Pt/CoB/TiO2 could markedly promote the activity of oxidizing CO at a low temperature. In the case of GHSV=15,000 h -1 and O2:CO≈1:1 (0.5 vol% CO and O2 in He streams), the conversion ratio of CO at 50 o C over Pt/CoB/TiO2 with 1.0wt% Pt and 1.8~2.5 wt % CoB (the atomic ratio of Co and B ≈ 1:1) could increase about 10 times with comparison to that over Pt/TiO2. However, catalysts Co/Pt/TiO2 (H2 reduction), CoB/TiO2 and Co(II)/Pt/TiO2 modified by other states of Co did not distinctly promote CO oxidation at the same temperature (Fig.1).