Formic Acid Decomposition on Polycrystalline Platinum and Palladized Platinum Electrodes

Abstract

This is a comprehensive study in which a formic acid decomposition reaction is examined as a probe of catalytic properties of polycrystalline platinum and palladized platinum electrodes. The electrode potential varies in a broad range, and the reaction is carried out in perchloric acid and sulfuric acid solutions containing different concentrations of HCOOH. Analytical methods used to access the decomposition reaction are chronoamperometry and cyclic voltammetry. At very short times, we prove that only a negligible amount of surface CO is formed, and the CO unaffected decomposition reaction, leading to CO2 formation, can be interrogated. Surprisingly, the decomposition reaction displays Tafel behavior only in a very narrow potential range. This observation, made with both clean Pt and Pt/Pd electrodes, suggests that water−surface interactions, and/or (bi)sulfate−surface interactions, increase with increasing electrode potential and create a steric/electronic barrier for the decomposition of formic acid (a...