Enhancing Zn–CO2 battery with a facile Pd doped perovskite cathode for efficient CO2 to CO conversion

Abstract

Using aqueous Zn–CO2 batteries to store renewable energy and produce valuable chemicals using CO2 as the source is a promising method for CO2 mitigation, that is alternative to traditional energy-costing CO2 capture/storage technologies. However, the lack of efficient CO2-reduction catalysts significantly hinders the efficiency of such batteries. In this study, an efficient perovskite cathode, Pd-doped La2CuO4, was successfully developed for the cathodic CO2 reduction reaction (CO2RR), and the optimal doping ratio of La2Cu1-xPdxO4 (x = 0.05) was determined. Compared with the pristine La2CuO4 catalyst, the current density for the CO2RR in the H-cell and the Faraday efficiency of CO production are both increased by ∼50% when operated −1.0 V (vs RHE). As a result, the peak power density of a Zn–CO2 battery using the Pd-doped La2CuO4 catalyst reached 0.75 mW cm−2 at 2.23 mA cm−2 by an enhancement ratio of 25%. Density functional theory calculations revealed that the *CO desorption processes on the cathode were enhanced owing to Pd doping, which accounted for the enhanced CO2RR activity and selectivity. The findings of this study show the potential application of perovskite catalysts in the cathode of Zn–CO2 batteries and provide an effective method for battery performance enhancement via the facile Pd doping.