Effect of carbon material on Pd catalyst for formic acid electrooxidation reaction

• Effect of carbon on palladium for formic acid oxidation was investigated.
• New active sites formed by the interaction of palladium and carbon.
• Carbon materials decrease charge transfer resistance.
• Mechanism of formic acid oxidation changed due to the presence of carbon.

Effect of several usually used carbon materials on Pd catalyst for formic acid electrooxidation reaction is studied by physical characterization and electrochemical measurements. New active sites are formed due to the Pd and carbon interaction which is confirmed by the XPS measurements, and electrochemical impedance spectroscopy confirms that the presence of the carbon material reduced the charge transfer resistance. Further, an improved fuel cell performance is observed when integrating the carbon-modified Pd catalyst in to a direct formic acid fuel cell. The results reveal that the carbon material is not only used as support, but also involves the new active sites formation.