Formaldehyde Electro-oxidation on Copper Metal and Copper-based Amorphous Alloys in Alkaline Media

Article abstract of DOI:10.1246/bcsj.58.2043

Copper metal and copper-based amorphous alloys, a-Cu35Ti65 and a-Cu33Zr67, exhibit a very high and stable activity for the anodic HCHO oxidation in aqueous NaOH and Na2CO3.The oxidation current was atready observable at electrode potentials as low as 0.1 V (RHE) and, in particular, the HF-treated amorphous alloys gave high current densities around 40 mA cm^-2 (apparent) at 0.2 V.Kinetic data, roughly first order both in HCHO and OH(1-) concentration, are in favour of the mechanism in which the oxidation proceeds via hydroxymethanolate ion (HOCH2O(1-)) formed from HCHO and OH(1-), producing HCOO(1-) and H2: This ion is readily oxidized on the copper metal or copper-based amorphous alloy electrodes.The Tafel slope was in general agreement with the reaction mechanism assuming a rate-determining one-electron transfer step.