▎ 摘　　要

Hierarchical Cu2O/RGO nanocomposites were synthesized via a sustainable photoredox strategy and utilized as bifunctional electrocatalysts for oxygen and hydrogen evolution reactions (OER and HER) under alkaline conditions. The photoredox Cu2O/RGO electrocatalyst has potential for bifunctional electrocatalytic applications, owing to their small overpotentials (OER: 215 mV and HER: 142 mV), fast kinetics, Tafel slope of 58.2 mV dec-1, high mass performance (613.49 A g-1), high exchange current density (10.9 mA cm-2), long-term stability, and maximum Faradaic efficiency of 97% compared with hierarchical Cu2O, in situ synthesized Cu2O/RGO-1 catalyst, and most electrocatalysts reported thus far. The Cu2O/RGO-2 (+) parallel to Cu2O/ RGO-2 (-) cell exhibits excellent durability for overall water splitting compared to the existing benchmark Pt@C (+) parallel to IrO2 (-) cell. This study presents a sustainable approach toward hydrogen fuel generation via overall water splitting and other catalytic and electrocatalytic applications.