Enhanced photocatalytic water splitting of a SILAR deposited α-FeO film on TiO nanoparticles.

We have investigated the effect of deposition of a α-FeO thin layer on a substrate of TiO nanoparticles for photoelectrochemical (PEC) water splitting. The TiO layer was coated on an FTO substrate using the paste of TiO nanoparticles. The α-FeO layer was deposited on the TiO thin film, using the method of Successive Ionic Layer Adsorption and Reaction (SILAR) with different cycles. Various characterizations including XRD, EDX and FE-SEM confirm the formation of α-FeO and TiO nanoparticles on the electrode. The UV-visible absorption spectrum confirms a remarkable enhancement of the absorption of the α-FeO/TiO/FTO composite relative to the bare TiO/FTO. In addition, the photocurrents of the composite samples are remarkably higher than the bare TiO/FTO. This is mainly due to the low band gap of α-FeO, which extends the absorption spectrum of the α-FeO/TiO composite toward the visible region. In addition, the impedance spectroscopy analysis shows that the recombination rate of the charge carriers in the α-FeO/TiO is lower than that for the bare TiO. The best PEC performance of the α-FeO/TiO sample was achieved by the sample of 70 cycles of α-FeO deposition with about 7.5 times higher photocurrent relative to the bare TiO.