The Effect of Adsorbed Layers on the Anodic Oxidation of Simple Organic Compounds. 1. Time Variations During the Oxidation of Hcooh and the Effect of Added Cl(-)

摘要

The deterioration of currents with time (time effects) during the oxidation of 0.1M HCOOH on Pt electrodes in 1M H2SO4 at 40C has been examined. The effect of added Cl(-) on the HCOOH oxidation rate at 0.65 and 0.75 V (versus RHE) has been studied. HCOOH oxidation currents have been measured at 0.75 V (versus RHE) as a function of HCOOH purity. The current decays with time; results indicate that this decay is, to a large extent, due to an anionic type impurity in the solution. This impurity is present at very low levels and the behavior is similar to that with a solution containing 5 x 10 to the -7th M Cl(-). Results are reported for HCOOH oxidation at 0.65 and 0.75 V (versus RHE) as a function of Cl(-) concentration. The reaction is extensively inhibited by increased addition of Cl(-) as a direct consequence of Cl(-) adsorption on the electrode. These observations imply that the electroactive species in HCOOH oxidation at these potentials is HCOO(-). (Author)