Effect of Preparation Condition on Photocatalytic Hydrogen Evolution Properties of TiO_2 Nanotube Array Electrodes

The relationship between the preparation conditions and photocatalytic hydrogen evolution properties on TiO2 nanotube array electrodes was discussed.The influences of anodization potentials,durations,counts and thermal treatment temperature on the electrode performance were investigated via an orthogonal test.The electrodes were characterized by scanning electron microscopy,X-ray diffraction and UV-Vis diffuse reflectance spectroscopy,respectively.The photoelectrochemical properties of electrodes were also examined by an electrochemical work station.The underlying mechanism was analyzed.The results show that TiO2 nanotube-array electrodes prepared at different parameters of anodic oxidation and thermal treatment lead to different microstructures and crystalline phase compositions,and consequently affect the photocatalytic performances.The highly-ordered TiO2 nanotube arrays are achieved after first-step anodization at 60 V for 1 h.The layered mixed crystal is obtained by heat treatment at 500 ℃.Furthermore,the multiple photocatalytic experiments were conducted using one electrode in 0.5 mol/L Na2 SO4 +0.5 mol/L ethylene glycol water solutions under UV light.The H2 evolution rate is 5.3 mL/(h cm2) at a bias voltage of 0.5 V.The electrode exhibits superior photocatalytic stability.