Abstract
A TiN0.3/CeO2 photo-anode was synthesized by the electro-deposition of CeO2 on TiN0.3 supported on a Ti substrate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to study its structure and morphology. The crystalline nature of TiN0.3 and CeO2 was confirmed by XRD, and SEM images showed that CeO2 spheres uniformly distributed on the TiN0.3 surface. In addition to visible light absorption by TiN0.3, UV light was also harvested by the outer CeO2 component on the TiN0.3/CeO2 combined photo-anode. In the photo-electrochemical measurement, TiN0.3/CeO2 showed four times higher photo-current density than TiN0.3 or CeO2, and the photo-current stabilization was also significantly improved compared to TiN0.3 or CeO2. The specific double-layer structure of TiN0.3/CeO2 contributed to its improved photo-electrocatalytic performance. Electron transfer from CeO2 to TiN0.3 driven by the hetero-junction and hole consumption by Ce3+ at the TiN0.3/CeO2 interface promoted the separation of electron and hole in the CeO2 layer, which improved the photo-current generation. Ce3+ that existed in CeO2 acted as the adsorption and activation site for H2O and accelerated the oxidation of H2O on the CeO2 surface, which further led to the high and stable photo-current density generated in TiN0.3/CeO2. This finding is useful for the design and synthesis of an effective photo-electrocatalysis material for solar energy conversion.
