Fabrication of photoactive CaTiO₃–TiO₂ composite thin film electrodes via facile single step aerosol assisted chemical vapor deposition route

CaTiO₃–TiO₂ composite oxide films have been employed, for the first time, as photoelectrodes in photoelectrochemical (PEC) splitting of water. The transparent methanol solutions of Ti(ⁱPro)₄ and newly synthesized calcium complex [Ca₂(TFA)₃(OAc)(ⁱPrOH)(H₂O)(THF)₃] (1) (where TFA stands for trifluoroacetato; OAc stands for acetate; and ⁱPrOH stands for isopropanol) were utilized for aerosol assisted chemical vapor deposition (AACVD) of the target films. The composite electrodes were deposited on fluorine doped tin oxide (FTO) coated conducting glass substrates at varying deposition temperatures of 500–600 °C. The resulting films were extensively characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray analysis and scanning electron microscopy. PEC responses of all the composite electrodes were studied under simulated solar irradiation of AM 1.5 G (100 mW cm⁻²). The CaTiO₃–TiO₂ photoanode formed at 600 °C showed higher photocurrent density of 610 µA cm⁻² at 0.7 V versus Ag/AgCl/3 M KCl reference electrode as compared to the other two electrodes fabricated similarly with only difference of fabrication temperature (i.e., 500 and 550 °C).