Effect of original activated carbon support and the presence of NOx on CO oxidation over supported Wacker-type catalysts

The supported Wacker-type catalysts were prepared with different original activated carbons (wood, coconut shell and coal based carbon) as supports, and the catalytic activities for CO oxidation with or without NOx were investigated. Nitrogen adsorption, temperature-programmed desorption (TPD) and Boehm titration results showed that wood based activated carbon had developed meso-/macropore structure and rich oxygen functional groups. Oxygen-containing surface groups benefited active sites Pd2+ and Cu2+ phase enriched on the catalyst surface which were confirmed by X-ray Photoelectron Spectroscopy (XPS). H2 temperature-programmed reduction (H2-TPR) experiments indicated that the oxygen-containing surface groups increased the ratio of copper species adjacent to palladium species and promoted the reducibility of Cu2+ species. Density functional theory (DFT) calculation displayed that NOx was more active to combine with Pd2+ component than CO did, which explained the presence of NOx had an obvious inhibition effect on CO oxidation.