Abstract: The poor electrocatalytic stability of the carbon-supported palladium(Pd/C) catalyst for formic acid oxidation and the catalytic performance of the Pd/C catalyst for the decomposition of formic acid are the two problems of the direct formic acid fuel cell(DFAFC).It was found from the investigation that after the Pd/C catalyst is dipped in NaVO₃ solution,VO₃^- can be adsorbed on the Pd/C catalyst.After the Pd/C catalyst is adsorbed with VO₃^-,the catalytic performance of the Pd/C catalyst for the decomposition of formic acid would be significantly inhibited,and the amount of CO produced from the decomposition of formic acid would be reduced,with the poison probability of the Pd/C catalyst by CO significantly reduced.Consequently,the peak current density at the Pd/C catalyst after dipping in NaVO₃ solution for formic acid oxidation is 13% higher than that at the Pd/C catalyst without dipping in NaVO₃ solution.The measurements of chronoamperometric curves indicate that the peak current density for formic acid oxidation at Pd/C catalyst after dipping in NaVO₃ solution for 6000 s is 42% higher than that at the Pd/C catalyst without dipping in NaVO₃ solution.The results demonstrate that dipping in NaVO₃ solution can improve the electrocatalytic ability of Pd/C toward oxidation of formic acid,especially the electrocatalytic stability.