Simultaneously Activating Semiconductor/Electrocatalyst/Electrolyte Interfaces by F Engineering for Efficient Solar Water Splitting

The highly efficient performance of photoelectrochemical (PEC) water splitting is largely governed by the construction of active interfaces, especially for the star semiconductor/electrocatalyst system. However, traditional strategies struggle to optimize this critical process. To overcome this challenge, we report a fluorine (F) engineering strategy that enables the synchronous modulation of charge transfer and surface catalytic reaction dynamics in a BiVO4/FeCoOOH-integrated photoanode. Various characterization methods confirm that F engineering can activate the BiVO4/FeCoOOH/electrolyte interfaces. Benefiting from these positive effects, the optimized BiVO4/FeCoOOH-F photoanode achieves a relatively high photocurrent density of 5.46 mA/cm2 at 1.23 V vs. RHE, along with outstanding photostability and a small Tafel slope of 96.5 mV dec−1. This study provides new insights into F-based interface manipulation, offering a promising route to developing high-performance semiconductor/electrocatalyst systems for efficient and stable PEC water splitting applications.