Precursor Development for Aerosol-Assisted Chemical Vapor Deposition of α-Fe2O3 and BiFeO3 as Effective Photoanodes for Photoelectrochemical Water Splitting

Photoelectrochemical (PEC) water splitting holds great potential to convert solar energy into hydrogen fuel, establishing an effective method for long-term renewable energy storage. Herein, a simple and effective approach is presented for fabricating thin films of α-Fe₂O₃ and BiFeO₃ for use as PEC photoanodes via aerosol-assisted chemical vapor deposition (AACVD). A new Fe(III) precursor bearing an amino-tris-tert-butoxide ligand is designed and coupled with a Bi-based precursor bearing the same ligand framework to deposit nanostructured films of α-Fe₂O₃ and BiFeO₃ with high phase purity. Under 1 sun solar irradiation α-Fe₂O₃ and BiFeO₃ yielded a photocurrent density of 0.38 and 0.42 mA cm⁻¹ at 1.23 V_RHE, respectively. A study reveals that the bespoke precursors exhibit remarkable compatibility with one another, producing films of significantly higher quality compared to those produced with more conventional precursors not optimized for AACVD.