The article discusses the importance of green hydrogen production technology through photoelectrochemical (PEC) water splitting, emphasizing the need for high-performance and low-cost devices with long-term stability. The focus is on the development of BiVO4 photoanodes with a gradient distribution of oxygen vacancies, termed BVO-ΔOv, for enhanced bulk charge separation. By integrating an FeOOH layer as an oxygen evolution cocatalyst, the BiVO4-based photoanodes achieve a record performance for PEC water splitting, demonstrating a photocurrent density of 7.0 mA cm–2 at 1.23 V vs. the reversible hydrogen electrode under AM 1.5 G illumination. The stability of the system is proven by continuous operation for over 520 hours without significant degradation. Moreover, the integration with a silicon solar cell showcases an STH efficiency of 8.4% for water splitting. The scalability of the technology is demonstrated with a 21 cm × 21 cm artificial leaf achieving an STH efficiency of 2.7% under natural sunlight. Life cycle assessment (LCA) analysis reveals the eco-friendly nature of the PEC water splitting process compared to other hydrogen production methods. Overall, the advancements in BiVO4 photoanodes offer a promising path towards sustainable and efficient solar hydrogen production.