Fabrication and photocatalysis of nanostructured TiO2 for solar hydrogen production

Photoelectrochemical cells (PEC) based on metal-doped (Be and Fe) and Pt-loaded nanostructured-TiO2 films were fabricated to make working electrodes for solar hydrogen production. Anatase nanocrystalline titania (nano-TiO2) thin films were deposited on glass slide and Ti metal sheet substrates by a sol–gel dip-coating method. Titanium tetraisopropoxide was used as a precursor. The synthesis process and annealing temperatures play an important role on the crystallite size and the phase transformation of nano-TiO2. The diameter of the particles in the rage of 5–50 nm was obtained in different methods of making the sol-gels and annealing temperatures. Without an external applied potential, the photocurrent density of Be-doped PEC occurred of 0.32 mA/cm2 under illumination of 75 mW/cm2 and the device produced hydrogen by water photoelectrolysis at the rate of 0.1 ml/h cm2, with a photoconversion efficiencies of 0.52%. The maximum photocurrent density of Fe-doped PEC occurred of 0.80 mA/cm2 without an external applied potential and under the illumination of 100 mW/cm2 corresponding with photoconversion efficiency of 0.98%. Impurity phase and undesired phases may be the cause of electron–hole recombination that results in decreasing photocatalytic activity.