Preparation and performance of Pd nano-crystallite decorated TiO2 nano-tubes arrays photoelectrode

Abstract:

To improve the visible light photocatalytic activity of TiO₂, in this study, TiO₂ nano-tubes arrays (TNTAs) were in-situ grown by anodization of Ti foils, and noble Pd nano-crystallites were electrochemical deposited onto the as-prepared TNTAs photoelectrode. The morphology, surface state and light absorption ability of the resulting electrodes were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and UV-visible light diffuse reflection spectroscopy (UV-vis DRS), respectively. It was found that Pd nano-crystallites were successfully decorated onto the surface of TNTAs electrode, and existed as the form of Pd⁰. In addition, the light absorption of Pd／TNTAs photoelectrode was greatly red-shifted to visible region. Furthermore, methyl blue (MB) was served as the probe molecules, and the effects of deposition voltage and time on the photocatalytic (PC) performance were mainly investigated. It was found that when the deposition voltage and time were -0.8 V and 10 min, respectively, the optimal photodegradation of MB could be obtained, which fitted well with the pseudo-first-order kinetics formula. Under the simulated sunlight irradiation within 120 min, the 71.4％ degradation rate of MB could be achieved, which was 1.5 times larger than that of bare TNTAs photoelectrode.