Improving the Photoelectrochemical Response of Pure TiO2 Nanotube Array by Changing Anodization Voltage in Preparation Process

Introduction: Enhancing the photoelectrochemical response of TiO2 nanotube arrays (TNA) is crucial to improve the efficiency of solar energy utilization. In this work, TNA was prepared electrochemically by anodization at single voltages of 20 V, 30 V and 40 V as well as a special two-step voltage of 30 V-20 V, 30 V-40 V, respectively. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize the morphology and crystalline structure of the sample. Methods: The photoelectrochemical response was measured by electrochemical potentiostatic technique. The results show TNA evenly aligns with increasing the anodization voltage. Results: However, there is TiO2 that does not form TNA and is dispersed as fragments on TNA surface at a higher voltage, which adversely affects TNA's photoelectrochemical properties. Conclusion: During the process of anodization, the oxidation current changes due to the switch in voltage. A two-step voltage method enhances pure TNA's photoelectrochemical response to visible light.