Near-infrared responsive reduced graphene oxide supported CuS: Enhanced electrocatalytic hydrogen evolution performance

Abstract

Various reduced graphene oxide supported CuS (RGO-CuS) composites were obtained via a hydrothermal way in this work. The as-obtained RGO-CuS with a low bandgap of ~1.24 eV showed significant light absorption in near-infrared (NIR) region. In acidic media, the optimized 0.1RGO-CuS needed an overpotential of 179 mV (at 10 mA cm−2) to trigger the hydrogen evolution reaction under NIR light. And the lowest Tafel slope of 0.1RGO-CuS (61 mV dec−1), suggesting that the photoelectrocatalytic hydrogen evolution was performed under the Volmer-Heyrovsky mechanism. The 0.1RGO-CuS displayed a good durability after 5000 cycles in acid. According to the results of EIS measurement, both NIR irradiation and RGO modification could effectively lower charge transfer resistance and improve charge transport rate of the photoelectrochemical process. The introduction of RGO could improve the electron and hole separation ability of the photoelectrochemical process, which resulted in an enhanced photoelectrocatalytic HER performance.