Electrocatalytic synthesis of DMC over the Pd/VGCF membrane anode by gas–liquid–solid phase-boundary electrolysis

Abstract

Selective and efficient electrochemical carbonylation of MeOH to dimethyl carbonate (DMC) was investigated over a PdCl 2/VGCF (vapor-grown-carbon-fiber) membrane anode by three-phase-boundary electrolysis at 298 K. One of the advantages of this method is that it supplies higher P(CO) to the active site from the front side of the membrane anode and higher concentration of MeOH from the backside. The good performance of the DMC formation was obtained, 40 TON h −1, 67% current efficiency, and 82% CO-selectivity under suitable conditions. Electrocatalysis of the PdCl 2/VGCF anode was studied by cyclic voltammetry and stoichiometric reactions between Pd 2+, MeOH, and CO. PdCl 2 on VGCF was reduced to the Pd 0 species with CO before the electrolysis and the Pd 0 species catalyzed direct electrochemical carbonylation of MeOH to DMC. On the other hand, oxidized Pd species on VGCF were assumed to catalyze the direct electrochemical carbonylation of MeOH to dimethyl oxalate (DMO).