Electro-catalytic oxidation of formaldehyde on copper electrode: a new kinetics model.

Abstract

Electro-catalytic oxidation of formaldehyde on copper electrode in 100 mM NaOH solution at different concentrations of formaldehyde was studied in the steady state polarization technique. The CV curve shows evidence for two processes occurring at the interface: one is associated with the formaldehyde electro-oxidation leading to formic acid formation on the surface and the other is assigned to the oxidation of formic acid that leads to CO2 evolutions with low yield. Reaction orders for the faradic current on copper electrode have been determined as 0.21 for the higher and 0.76 for the lower concentration of formaldehyde. Reaction orders for CO2 evolution during formaldehyde oxidation are 1.4 times higher in each case. Tafel slopes in the range of 140-160 mV are found. This signifies that the first reaction step involving the formation of adsorbed CO2 is largely determining the overall reaction rate.