Enhanced photocatalytic water splitting of a SILAR deposited α-Fe 2 O 3 film on TiO 2 nanoparticles.

We have investigated the effect of deposition of a α-Fe 2 O 3 thin layer on a substrate of TiO 2 nanoparticles for photoelectrochemical (PEC) water splitting. The TiO 2 layer was coated on an FTO substrate using the paste of TiO 2 nanoparticles. The α-Fe 2 O 3 layer was deposited on the TiO 2 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-Fe 2 O 3 and TiO 2 nanoparticles on the electrode. The UV-visible absorption spectrum confirms a remarkable enhancement of the absorption of the α-Fe 2 O 3 /TiO 2 /FTO composite relative to the bare TiO 2 /FTO. In addition, the photocurrents of the composite samples are remarkably higher than the bare TiO 2 /FTO. This is mainly due to the low band gap of α-Fe 2 O 3 , which extends the absorption spectrum of the α-Fe 2 O 3 /TiO 2 composite toward the visible region. In addition, the impedance spectroscopy analysis shows that the recombination rate of the charge carriers in the α-Fe 2 O 3 /TiO 2 is lower than that for the bare TiO 2 . The best PEC performance of the α-Fe 2 O 3 /TiO 2 sample was achieved by the sample of 70 cycles of α-Fe 2 O 3 deposition with about 7.5 times higher photocurrent relative to the bare TiO 2 .