The partial oxidation of methanol using a fuel cell reactor

Abstract

Partial oxidation of methanol was performed with a gas-phase [CH₃OH|H₃PO₄|O₂] cell reactor by using noble metals as electrocatalysts over the temperature range of 343–373 K. Among the noble metal electrocatalysts tested, the Ir (anode)–Pt (cathode) combination showed the best cell performance for partial oxidation of methanol into dimethoxymethane (DMM) and methyl formate (MF). The cell gave a maximum current density of 34 mA cm⁻² at 373 K; one-pass conversion of methanol was 14% and the turn-over number per Ir was 6.6 h⁻¹. The kinetic results of the oxidation of methanol with the [CH₃OH, Ir|H₃PO₄|Pt, O₂] cell could be explained in terms of the reaction mechanism proposed. In general, the cell performance in the oxidation of methanol for different combinations of anode–cathode electrocatalysts was strongly deteriorated with the diffusion of methanol from the anode to the cathode (cross-over). However, the cell of Ir (anode)–Pt (cathode) combination was specifically resistant to this unfavorable effect.