Effect of CuO–ZnO catalyst layer on proton-conducting electrochemical cell reactor for CO2 reduction reaction

Abstract

A catalyst layer is coated on the fuel electrode in a proton-conducting solid oxide electrolysis cell reactor, which can optimize electrochemical performance and expand the application range of the reactor. In this work, CuO–ZnO catalyst is prepared by oxalate co-precipitation method and combined with a single cell to obtain a reactor with the structure of La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) ǀ BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) ǀ NiO-BZCYYb (active layer) ǀ NiO-BZCYYb (support layer) | CuO–ZnO (catalyst layer). The electrolysis current density of this reactor with humid air as oxidant and 20%CO2–80%H2 as fuel is 2751 mA cm−2 under 1.3 V at 750 °C. It operates steadily for 138 h under 1.3 V electrolysis at 650 °C, which is better than the reactor without a catalyst layer under this condition. Additionally, CO and CH4 are detected in the exhaust gas on the fuel electrode side, and the CO selectivity reaches over 90% at 750-550 °C.