MASS-SPECTROMETRIC CYCLIC VOLTAMMETRY OF COPPER IN ALKALINE FORMALDEHYDE SOLUTIONS

Electrode processes proceeding on copper with the formation of hydrogen, methanol and CO2 were investigated over the wide potential range from -1.2 V to 0.7 V (SHE) in alkaline formaldehyde solutions applying on-line mass spectrometry measurements along with cyclic voltammetry and the use of a deuterium tracer. The dependences of the evolution of hydrogen from formaldehyde and water on the solution pH, formaldehyde concentration, temperature and electrode potential were studied. Hydrogen was determined to evolve from formaldehyde alone both during anodic oxidation of formaldehyde and under open-circuit conditions. Oxidation of formaldehyde to CO2 was found to proceed at potentials more positive than 0.6 V. The reduction of formaldehyde to methanol was determined at potentials more negative than -1.0 V. as was cathodic hydrogen evolution from water. A mechanism for the anodic formaldehyde oxidation on copper is proposed.