Demonstration of direct conversion of CO2/H2O into syngas in a symmetrical proton-conducting solid oxide electrolyzer

Abstract

We have previously reported the electrochemical reduction of CO2 to CO with simultaneous steam electrolysis in a proton conducting solid oxide electrolyzer (PCSOE); however, the conventional Ni-cermet electrode is rapidly oxidized by H2O/CO2 in cathode that causes cell performance degradation. In this work, we report a novel symmetrical PCSOE with redox-stable LSCM ((La0.75Sr0.25)0.95Cr0.5Mn0.5O3−δ) electrode for the electrochemical conversion of CO2/H2O into syngas (CO/H2). The Ru catalyst is impregnated to LSCM to improve electrode activity. Electrochemical measurements demonstrate that the CO2 is electrochemically reduced to syngas (CO/H2) with simultaneous steam electrolysis. The loading of Ru catalyst promotes the electrochemical process with higher Faradic efficiency while induces a more competitive process of hydrogen evolution at 700 °C.