Journal of Applied Electrochemistry, Vol.45, No.6, 557-566, 2015
Visible light-driven photoelectrochemical water splitting on ZnO-TiO2 heterogeneous nanotube photoanodes
TiO2 nanotube arrays (TiO2NTs) with an inner average pore diameter of 80-110 nm and a length of 40 mu m were grown on titanium foils by electrochemical anodization in ammonium fluoride-water-ethylene glycol solution. ZnO was grafted on the TiO2 nanotube arrays (ZnO/TiO2NTs) by a chemical bath deposition technique in combination with a pyrolysis process. ZnO/TiO2NTs composite supported on titanium substrate was used as the photoanode for photocatalytic water splitting. Photoelectrochemical characterization shows that grafted ZnO on TiO2NTs efficiently enhanced the photocatalytic water-splitting performance of highly ordered TiO2NT. Such photoanode benefits from the capability of high specific surface and the direct conduction path through the aligned nanotubes. Moreover, the heterojunction at the ZnO/TiO2 interface favors charge separation and reduced the probability of charge recombination. This inexpensive photoanodes prepared free of noble metals, showed enhanced high photocurrent density with good stability, and is a highly promising photoanodes for visible light photocatalytic hydrogen production.