Electrosynthesis of methanol from methane: The role of V2O5 in the reaction selectivity for methanol of a TiO2/RuO2/V2O5 gas diffusion electrode

Methane fed TiO2/RuO2/PTFE gas diffusion electrodes (GDEs) have been used for the electrosynthesis of methanol in 0.1 mol L−1 of Na2SO4 supporting electrolyte. By-products such as formaldehyde and formic acid are usually also formed during electrolyses, with the latter formed at a similar rate as that of methanol. In this study, V2O5 was added to the composition of the GDE to improve its selectivity for methanol. TiO2/RuO2/V2O5 powder hot-pressed with PTFE resulted in a GDE suitable for oxidative electrosynthesis with simultaneous oxygen evolution. By feeding the TiO2/RuO2/V2O5/PTFE GDE with methane, it was possible to enhance its selectivity for methanol at low values of current density. Furthermore, the formation of formic acid and formaldehyde was suppressed, allowing for higher current efficiencies. The addition of 5.6% of V2O5 increased the electrode's current efficiency to 57% at 2.0 V, which is 2-fold higher than the efficiency achieved in the absence of vanadium oxide.