Tóm tắt: Pd nanoparticles were successfully deposited on CeO2/C, which was prepared through the microwave-assisted heating process under presence of ammonium. For comparison, the conventional Pd/C was also synthesized. In order to demonstrate the promotional role of CeO2 in the Pd-CeO2/C system, various electrochemical characterization methods were performed for the formic acid electrooxidation based on the above electrocatalysts. It was found that Pd-CeO2/C showed the enhanced electrocatalytic activity and better reaction kinetics than Pd/C. It was proposed that the presence of OHad species on the surface of CeO2 at lower potentials can oxidize CO-like poisonous species on the surface of Pd to CO2, releasing the active sites on Pd. This explains the significantly promotive effect of CeO2 in the Pd-CeO2/C electrocatalysts for the electrooxidation of formic acid.