Insight into Electrochemical Promotion of Cu/Co3O4 Catalysts for the Reverse Water Gas Shift Reaction

Abstract

AbstractIn this study, Copper‐modified Co3O4 (Cu/Co3O4) catalysts were investigated for the reverse water gas shift (RWGS) reaction at 200–400 °C under different CO2 : H2 ratios. It was found that the electrocatalytic performance of Co3O4 was improved by loading 4 weight percent (wt.%) Cu nanoparticles (average size: 13 nm), which could be then used as an electrode in electrochemical promotion of catalysis (EPOC) studies. Under the applied voltages of +2 V and −1 V, the catalytic rates were suppressed and increased by about 40 % and 14 %, respectively. This was due to the changes in the active oxidation states of Cu and Co caused by O2− migration under polarization, as confirmed by XPS, XRD, and cyclic voltammetry (CV). The study also revealed that the exchange current density (i0) was counter‐correlated with the open‐circuit catalytic rate (r0) and could serve as an informative tool for predicting the catalytic rate, which was demonstrated for the first time in the instance of RWGS reaction.