Synthesis of Fe/Co-doped titanate nanotube as redox catalyst for photon-induced water splitting

As a step toward developing a stable and cost effective photocatalyst, Fe/Co-doped titanate nanotube has been prepared to act as a photocatalyst for the water splitting reaction. The titanate nanotube has been prepared by hydrothermal process, then, the doping was done by a simple ion exchange process during the sonication treatment. Samples with different ratios of Fe and Co in the nanotube were prepared in order to check the best atomic ratio of Fe and Co as dopant to the titanate nanotube. The prepared samples were characterized using XRD, TEM, XPS, and UV-vis spectroscopy. All characterization results affirmed the formation of Fe/Co-doped nanotube with some segregated atoms in the lattice of the titanate. The band gap calculations showed a reduction from 3.2 eV of anatase TiO2 to around 2.6 eV for Fe/Co-doped titanate nanotube. The photocatalytic results revealed that doping titanate with Fe/Co enhanced the photo-decomposition of H2O. However, Fe to Co ratio showed a distinct influence on the water photo splitting. Typically, the obtained hydrogen after 6 min residence time was 137, 116 and 89 mmol H-2/g(catalyst) for 20, 40 and 60 wt% Fe with respect to Co, respectively. On the other hand, only 29 mmol H-2/g(catalyst) was collected when pristine TiO2 nanotubes were invoked as photocatalyst. Overall, the synthesis simplicity and the effective performance of the introduced doped titanate nanotubes open a new avenue for the introduced material to be exploited as recommended photocatalyst for water splitting under direct solar radiation.