Photoelectrolysis of water using heterostructural composite of TiO2 nanotubes and nanoparticles

Efficient photoelectrolysis of water to generate hydrogen (H-2) can be carried out by designing photocatalysts with good absorption as well as charge transport properties. One dimensional (1D), self-organized titania (TiO2) nanotubes are known to have excellent charge transport properties and TiO2 nanoparticles (NPs) are good for better photon absorption. This paper describes the synthesis of a composite photocatalyst combining the above two properties of TiO2 nanocomposites with different morphologies. TiO2 NPs (5-9 nm nanocrystals form 500-700 nm clusters) have been synthesized from TiCl4 precursor on TiO2 nanotubular arrays (similar to 80 nm diameter and similar to 550 nm length) synthesized by the sonoelectrochemical anodization method. This TiO2 nanotube-nanoparticle composite photoanode has enabled obtaining of enhanced photocurrent density (2.2 mA cm(-2)) as compared with NTs (0.9 mA cm(-2)) and NPs (0.65 mA cm(-2)) alone.