Van Der Waals Heterojunction Modulated Charge Collection for H2O2 Production Photocathode

Abstract Efficient photocarrier generation and collection are highly desirable for solar‐fuel conversion systems. However, the latter is challenging for many photoelectrodes due to carrier losses happening in the semiconductor‐electrolyte interface and the semiconductor‐substrate interface. To overcome it, a novel Au/CuBi 2 O 4 (CBO)/PtSe 2 van der Waals heterojunction photocathode has been developed to boost photocarrier collection. As a result, the ohmic contact at Au/CBO interface shows a low resistance for hole transfer. Meanwhile, while promoting electron transfer, the Van der Waals heterojunction of CBO/PtSe 2 interface with energy barrier‐blocked holes. Concurrently, the composite photocathode exhibits significantly enhanced performance: a photocurrent of −0.59 mA cm −2 at 0.5 V versus reversible hydrogen electrode and an H 2 O 2 generation rate of 2.39 mol (Lhm 2 ) −1 . This work demonstrates the charge regulation role of Van der Waals heterojunctions in the solar‐fuel system. More broadly, Van der Waals heterojunctions provide an excellent bond‐free approach to creating versatile optoelectronic devices.