SILAR法制备TiO2/CdS/Co-Pi水氧化光阳极及其性能

采用连续离子层吸附法（SILAR）沉积CdS制备type-Ⅱ异质结TiO₂/CdS光阳极，用光电化学沉积法在TiO₂/CdS表面沉积催化剂（Co-Pi）得到TiO₂/CdS/Co-Pi水氧化光阳极。通过X射线衍射（XRD）仪、扫描电子显微镜（SEM）、X射线光电子能谱（XPS）仪等对样品结构及组成进行分析，证明CdS与Co-Pi已成功负载在TiO₂表面。用已制备的光阳极在中性溶液中模拟水氧化测试，在较低外偏压（0 V（vs Ag/AgCl））和无电子牺牲剂的情况下，即使在可见光照射下，依然得到较高的初始光电流和稳定光电流，分别为1.3和0.5 mA·cm^-2，表明制备的光阳极可以在可见光照下有效地驱动水氧化反应。光电化学池的工作原理为，CdS吸收光子产生光生电子-空穴，TiO₂和Co-Pi分别传输电子和空穴，空穴进行水氧化，电子转移到阴极完成质子还原。

Preparation and Performance of a SILAR TiO2/CdS/Co-Pi Water Oxidation Photoanode

Asemiconductor heterostructure of TiO₂/CdS/cobalt phosphate water oxidation catalyst (Co-Pi WOC) photoanode was fabricated by the successive ionic layer adsorption and reaction (SILAR) procedure and photoassisted electro-deposition. The structure, morphologys and magnetic properties of the resultant particles were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). CdS and Co-Pi quantum dots loaded on to the TiO₂ nanofilm. The TiO₂/CdS/Co-Pi photoanode had an initial photocurrent of 1.3 mA·cm^-2 and a stable level of 0.5 mA·cm^-2. A relatively stable level was maintained under visible light irradiation in neutral solution, especially at the low bias voltage of 0 V (vs Ag/AgCl). In this system, CdS quantum dots serve as the light absorber and generate electron holes; the Co-Pi WOC acts as a hole transfer layer that can transfer the hole for water oxidation; and the TiO₂ is the electron conductor for efficient charge transfer to the cathode to actualize proton reduction.