Ti-Fe2O3/In2O3 as photoactive material: The role of the substrate in photoelectrochemical water oxidation

The layers of Ti-Fe2O3/In2O3 were prepared on the different substrates using hydrothermal method: Ti/TiO2 nanotubes, Ti foil, FTO and FTO/TiO2. Materials were characterized using scanning electron microscopy, XRD, Raman, UV-Vis, and X-ray photoelectron spectroscopy and tested as photoanodes for water oxidation under illumination. The formation of heterojunction on the TiO2 nanotubes increases photocurrent of water oxidation at 0.7 V vs. RHE to over 520 μA/cm2, while Ti/Ti-Fe2O3/In2O3, FTO/Ti-Fe2O3/In2O3, and FTO/TiO2/Ti-Fe2O3/In2O3 exhibit 130, 31 and 152 μA/cm2, respectively. Thus, the work indicates that the presence of TiO2 in the form of nanotubes as a substrate increases the efficiency of photocurrent generation.