Synthesis of a Cu2O/Carbon Film/NiCoB‐Graphene Oxide Heterostructure as Photocathode for Photoelectrochemical Water Splitting

Abstract Photoelectrochemical cells (PECs) for water splitting offer a promising way to convert solar energy into chemical energy. The electron transfer rate and surface‐catalyzed ability toward the hydrogen evolution reaction (HER) play key roles in the efficiency of PEC water splitting. In this work, a photocathode based on a Cu 2 O/Carbon film/NiCoB‐graphene oxide (Cu 2 O/C/NiCoB−GO) heterostructure is fabricated. The thickness‐controllable carbon film served as the electron transport and protective layer with favorable optical properties. The NiCoB‐GO amorphous catalyst displays efficient performance towards HER in neutral condition. The optimized photocathode shows a PEC‐HER performance with a photocurrent density of −2.9 mA/cm 2 at 0 V vs. RHE, and it also presents better stability than bare Cu 2 O. This work provides a novel heterostructure photocathode for promoting solar‐driven PEC water splitting efficiently.