Combined promoting effects of low-Pd-containing and Cu-doped LaCoO3 perovskite supported on cordierite for the catalytic combustion of benzene.

Abstract

The catalytic activities for benzene oxidation and resistance to SO2 poisoning were tested for a series of Pd/La-Cu-Co-O/cordierite catalysts, which were prepared using a multiple-step impregnation method. The XRD, SEM, and IR characterization techniques were performed to investigate the relationship between the catalytic performance and its physicochemical properties. When Pd/La-Cu-Co-O/cordierite catalysts with Pd loadings of 0.06 and 0.08% were prepared at a calcination temperature of 500°C for 5h, they exhibited similar catalytic activity and sulfur resistance. When the concentration of benzene was 1500ppm and the GHSV was 20000h(-1), the benzene conversion was above 95% at a reaction temperature of 350°C in SO2 existing at 100ppm. These results were mainly attributed to the cooperation between La-Cu-Co-O perovskite and the noble metal Pd. Specifically, the addition of copper can strengthen the catalytic activity of La-Co-O/cordierite catalysts by decreasing the crystalline size of the active ingredients. A moderate Pd addition can drastically improve the sulfur resistance and further improve the catalytic activity of the La-Cu-Co-O/cordierite catalyst.