Autodrop‐Enabled Aqueous Deposition of BiVO 4 –FePO 4 Photoanodes for Stable Water Splitting

Scalable and sustainable methods for fabricating stable photoelectrodes are essential for advancing solar-driven water splitting. Here, an automated aqueous deposition approach is demonstrated, which is named “Autodrop”, for the fabrication of BiVO4–FePO4 photoanodes via a modified successive ion layer adsorption and reaction (SILAR) process. The method enables precise control over film thickness and morphology using low-toxicity precursors and ambient conditions. The integration of an amorphous FePO4 layer on top of the BiVO4 photo-absorber serves as both a passivation coating and co-catalyst, resulting in a 50% photocurrent increase and excellent operational stability, with over 80% of the initial current retained after 2 h of continuous chronoamperometry under AM 1.5G illumination at 1.23 V versus RHE. These results establish Autodrop as a versatile platform for scalable, multi-layer photoelectrode fabrication, supporting the development of next-generation PEC devices.