Effect of anodization voltage on performance of TiO2 nanotube arrays for hydrogen generation in a two-compartment photoelectrochemical cell

Highly ordered TiO2 nanotube arrays were prepared by anodic oxidation of Ti foil under different anodization voltages in ethylene glycol electrolyte. The morphology and photoelectrochemical performance of the TiO2 nanotubes (NTs) samples were characterized by FESEM and electrochemical working station. Hydrogen production was measured by splitting water in the two-compartment photoelectrochemical (PEC) cell without any external applied voltage or sacrificial agent. The results indicated that anodization voltage significantly affects morphology structures, photoelectrochemical properties and hydrogen production of TiO2 NTs. The pore diameter and layer thickness of TiO2 samples increased linearly with the anodization voltage, which led to the enhancement of active surface area. Accordingly, the photocurrent response, photoconversion efficiency and hydrogen production of TiO2 nanotubes were also linearly correlated with the anodization voltage.