Scalable conformal FeOOH cocatalyst deposition by interfacial precipitation layer deposition for photoelectrochemical water splitting†

Abstract

Photoelectrochemical (PEC) water splitting is a promising method for sustainable hydrogen production, but challenges remain in achieving high performance and stability, particularly for large-area photoanodes. In this study, we introduce a novel interfacial precipitation layer deposition (IPLD) method for the fabrication of uniform, dense, and conformal cocatalyst layers on photoanodes. The IPLD method enables precise control of the cocatalyst layer deposition, ensuring excellent coverage and strong adhesion on the surface of photoanodes with complex nanostructures. The method involves the creation of a controlled water layer on the photoanode to guide the hydrolysis of Fe(acac)₃, facilitating the formation of the FeOOH cocatalyst layer. This approach addresses the limitations of conventional deposition techniques, enhancing both the PEC efficiency and long-term stability of the photoanode. The IPLD-FeOOH/BiVO₄ photoanode achieved a photocurrent density 3.5 times that of pure BiVO₄ at 1.23 V vs. RHE. Notably, the IPLD-FeOOH/BiVO₄ photoanode demonstrated excellent stability, maintaining high performance for over 100 hours under operational conditions. The IPLD method was also successfully scaled up to large-area photoanodes (∼5 × 7 cm²), showing remarkable operational stability with no degradation for over 60 hours. This work highlights the scalability and effectiveness of IPLD as a promising strategy for large-area, high-performance PEC devices, offering a potential pathway for practical applications in solar hydrogen production.