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

Abstract

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).