(231d) Enhancement Of The Oxidation Of Formic Acid On Palladium And Platinum Blacks By An Increase In The Formic Acid pH

Small organic molecule fuel cells such as the direct formic acid fuel cell (DFAFC) show great promise to meet the demand of high power density for portable electronic devices. Despite the many advantages of the DFAFC, a primary goal of research is to enhance its sluggish anode kinetics through study of catalysis. Noble metals such as Pd and Pt have been used as catalysts for the oxidation of formic acid. This work reports that an increase in the pH of the formic acid solution results in significant enhancement to the oxidation of formic acid. The current density for oxidation on palladium was approximately 3-4 times greater at higher pH, while the current density on platinum was approximately 10-12 times greater. The difference between catalysts suggests that the increase in hydroxide ions at higher pH assists in the removal of CO poison from the Pt, which is more susceptible to the poison than Pd. In addition, the potential at which CO can be removed from the catalyst surface decreases by ~60 mV/pH as the solution pH is increased. This holds promise for simplified catalyst regeneration at lower potentials during extended fuel cell use.