Van Der Waals Heterojunction Modulated Charge Collection for H₂O₂ Production Photocathode

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/CuBi2O4 (CBO)/PtSe2 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/PtSe2 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 H2O2 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.