In-situ-derived self-selective electrocatalysts for solar formate production from simultaneous CO2 reduction and methanol oxidation

Abstract

Solar-driven electrochemical CO2 reduction reaction (CO2RR) offers a promising route to achieve a carbon-neutral and energy-sustainable future. However, the anodic oxygen evolution reaction (OER) hinders the energy input utilization, and the added value of the product O2 is low. Here, through a combined CO2RR and selective methanol oxidation reaction (MOR), we report an efficient and unassisted solar-driven simultaneous cathodic and anodic production of formate on hydroxide-derived self-selective Cu-based electrocatalysts. Upon in situ treatments, Cu(OH)2-derived Cu (HOD-Cu) and CuO (HOD-CuO) electrocatalysts display efficient CO2RR and MOR performances at a wide potential range, respectively. The rational integration of the electrolyzer to a triple junction GaInP/GaAs/Ge photovoltaic cell could realize efficient solar-driven formate synthesis, leading to a solar-to-formate (STF) conversion efficiency of 3.63% and a production rate of 0.194 mmol h−1 cm−2. This work demonstrates a simultaneous formate generation by coupling CO2RR and MOR, providing new paths for solar-driven electrochemical synthesis.