Accelerating the controlled synthesis of WO3 photoanode by modifying aerosol-assisted chemical vapour deposition for photoelectrochemical water splitting

Abstract Aerosol-assisted chemical vapour deposition (AACVD) is capable of producing WO3 film with good optical and electrical properties for photoelectrochemical (PEC) water splitting. However, the conventional AACVD method is time-consuming because post-annealing treatment is usually required after WO3 film was deposited under nitrogen flow. Therefore, we omitted the post-annealing treatment by employing purified air as carrier gas (known as one-step) instead of nitrogen (known as two-step) which decreases the fabrication time by 13-fold. One-step WO3 also shows improved charge separation and PEC reaction due to the coexistence of (002), (020) and (200) facets and higher oxygen vacancies. Further optimization using acetone/ethanol as solvent, 10 min deposition time and 450°C deposition temperature leads to photocurrent density of 0.32 mA cm-2 at 1.23 VRHE, which is the highest performance reported for AACVD-based WO3 photoanode. The development of rapid and industrially applicable deposition method would pave the way for real practice of PEC technology.