Electrocatalytic Oxidation of Formic Acid on Molybdate-Modified Platinum Electrode

Abstract

The electrochemical behavior of molybdates on a platinum electrode in H 2SO 4 solutions with different H 2SO 4 concentrations was studied by cyclic voltammetry and double chronoamperometry. Molybdates were reduced to adsorb hydrogen molybdenum bronzes on the platinum electrode in H 2SO 4 solutions during cathodically potential sweep. The hydrogen molybdenum bronzes were oxidized to different forms of hydrogen molybdenum bronzes with less hydrogen, depending on the H 2SO 4 concentration. Platinum electrode was modified by these hydrogen molybdenum bronzes. However, this modified electrode was not stable in H 2SO 4 solutions. The modified electrode was used to study the oxidation of formic acid in Na 2SO 4 solutions.It was shown that there was a strong catalysis on the oxidation of formic acid on the modified electrode. The peak current of formic acid on the modified electrode was about two times that on unmodified electrode. It was also found that the catalysis was weakened when the platinum elecdtrode was under-or over-modified.