Direct electro-oxidation of acetic acid in a solid oxide fuel cell

Abstract

This work aims to investigate the efficiency of Cu–CeO2 as anodic composites in direct CH3COOH fed SOFC reactors for power generation. When the cell operated as an electrochemical membrane reactor, the effect of temperature, PCH3COOH and anodic overpotentials on the catalytic activity and selectivity of Cu/CeO2 for CH3COOH decomposition and electro-oxidation at both open and closed circuit operation was explored. In addition, in situ DRIFT spectroscopy was employed in order to correlate the Cu–CeO2 performance with its surface chemistry. In the fuel cell mode, the electrochemical performance of Cu–CeO2 was investigated by voltage–current density–power density and AC impedance measurements. The results reveal that at open circuit conditions, CH3COOH and its derived carbonaceous and oxygenate active intermediates are both thermally and catalytically decomposed to final products. At anodic polarization conditions, Cu–CeO2 exhibited high catalytic activity towards the electro-oxidation of all combustible species, while carbon deposition was noticeably limited. At fuel cell operation, ohmic losses were the prevailing source of polarization, mainly attributed to the anodic interfacial resistance, which is significantly influenced by temperature and fuel type. The deconvolution of the impedance spectra fitted into the Randles circuit, showed that at CH3COOH containing reacting mixtures, the electrode performance was mainly determined by the corresponding charge transfer processes of the existing combustible species. On the other hand, when H2/He mixtures were fed in the cell, diffusion resistance altered the performance of Cu–CeO2 electrodes.