Effect of Pd precursors on the catalytic properties of Pd/CeO2 catalysts for CH4 and CO oxidation

Herein, Pd/CeO2 catalysts were prepared using different Pd precursors and applied to CH4 and CO oxidation. Significantly, the Pd/CeO2 catalyst prepared using palladium nitrate (Pd(2)/CeO2 (N)) was highly active toward CH4 oxidation, whereas the catalyst prepared using palladium acetate (Pd(2)/CeO2 (A)) exhibited high CO oxidation activity. The effects of the precursor on the catalytic activity and other properties were studied using various characterization techniques. The Pd(2)/CeO2 (N) catalyst contained surface PdO nanoparticles, which were active sites for CH4 oxidation. On the contrary, the Pd(2)/CeO2 (A) catalyst possessed Pd ions stabilized at CeO2 defect sites, which were not very reactive. However, the high Pd dispersion was beneficial for the CO oxidation reaction. Therefore, the Pd precursor clearly altered the Pd dispersion and state in the Pd/CeO2, which are critical for catalytic activity.