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

Using aqueous Zn–CO 2 batteries to store renewable energy and produce valuable chemicals using CO 2 as the source is a promising method for CO 2 mitigation, that is alternative to traditional energy-costing CO 2 capture/storage technologies. However, the lack of efficient CO 2 -reduction catalysts significantly hinders the efficiency of such batteries. In this study, an efficient perovskite cathode, Pd-doped La 2 CuO 4 , was successfully developed for the cathodic CO 2 reduction reaction (CO 2 RR), and the optimal doping ratio of La 2 Cu 1-x Pd x O 4 ( x  = 0.05) was determined. Compared with the pristine La 2 CuO 4 catalyst, the current density for the CO 2 RR 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–CO 2 battery using the Pd-doped La 2 CuO 4 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 CO 2 RR activity and selectivity. The findings of this study show the potential application of perovskite catalysts in the cathode of Zn–CO 2 batteries and provide an effective method for battery performance enhancement via the facile Pd doping.