Unassisted photoelectrochemical hydrogen peroxide production over MoOx-supported Mo on a Cu3BiS3 photocathode

Abstract

Hydrogen peroxide (H2O2) represents a valuable chemical compound and promising energy source due to its high energy density, comparable with that of compressed H-2. However, its production predominantly relies on an energy-intensive process. In this study, we present an efficient strategy for producing H2O2 through a photoelectrochemical (PEC) approach, which involves a 2e(-)-mediated oxygen reduction reaction, integrating Mo-anchored MoOx with a Cu3BiS3-based photocathode. The MoOx-supported Mo improves the adsorption strength of peroxide species and facilitates electron transport, resulting in outstanding activity toward H2O2 production. Consequently, the resulting Cu3BiS3-based photocathode demonstrates significantly enhanced performance, achieving a photocurrent density of 5.21 mA cm(-2) at 0.35 V versus the reversible hydrogen electrode (RHE), a high onset potential of 0.9 V-RHE, and 97% selectivity toward H2O2. Additionally, we successfully implemented an unassisted PEC-PEC coplanar system by coupling a Cu3BiS3-based photocathode with a perovskite-based photoanode, achieving a solar-to-chemical conversion efficiency of 1.46%.