Optional construction of Cu2O@Fe2O3@CC architecture as a robust multifunctional photoelectronic catalyst for overall water splitting and CO2 reduction

Abstract Herein, the flexible self-supported Cu2O@Fe2O3@carbon cloth electrode (named as Cu2O@Fe2O3@CC) has been synthesized by a facile and scalable thermal method. This Cu2O@Fe2O3@CC-500 hierarchical assembly needs ultralow overpotential of 296 mV (for oxygen evolution reaction, OER) and 188 mV (for hydrogen evolution reaction, HER) to afford the 10 mA cm−2 current density, and with the Tafel slope of 66 mV dec−1 (for OER) and 59 mV dec−1 (for HER) in alkaline medium (1.0 M KOH), respectively. The assembled water electrolyzer using bifunctional Cu2O@Fe2O3@CC-500 as both anode and cathode exhibited high stability with a cell voltage of only 1.675 V at 10 mA cm−2. More interestingly, this composite also exhibited excellent photocatalytic performance in CO2 reduction. For the Cu2O@Fe2O3@CC-500, the CO yield attained 172.2 µmol·gcatalyst−1·h−1 under visible light irradiation. Based on the measurements and density functional theory (DFT) calculation, an enhanced OER kinetics and a plausible mechanism for CO2 photo-reduction have been proposed. Our study will open a special door to provide multifunctional phtoelectrocatalyst to be widely used in the clean energy field.