Cu ions intercalated GO/Cu2O photocathode-enabled promotion on charge separation and transfer for efficient photoelectrochemical water splitting

Abstract

The development of cuprous oxide (Cu2O) photocathode for photoelectrochemical (PEC) water splitting confronts charge recombination and photocorrosion. Herein, a facile strategy for wrapping Cu2O photocathode with Cu ions intercalated graphene oxide (Cu-GO) was proposed to realize efficient PEC water splitting. The intercalating GO with Cu ions could reduce the bandgap and enhance the carrier mobility of Cu-GO. The as-formed Cu-GO could suppress surface charge recombination and accumulation of the Cu-GO/Cu2O photocathode by improving the interfacial charge transfer, which strengthens electron extraction and restrains photocorrosion. The Cu-GO/Cu2O photocathode achieved a high photocurrent density of − 7.03 mA cm−2 (at 0 V vs. RHE) under AM 1.5 G illumination and excellent photostability for PEC water splitting. This work provides a simple way to design Cu2O-based photocathodes with reliable charge transfer layers for efficient PEC water splitting.