MoS2修饰TiO2纳米管阵列光电化学性能研究

通过阳极氧化法在乙二醇电解液中制备TiO₂纳米管阵列, 以钼酸钠和硫脲作为钼源和硫源, 并添加半胱氨酸为辅助剂, 水热法制备纳米花状二硫化钼修饰的TiO₂纳米管阵列。用X射线衍射仪、扫描电子显微镜、能谱仪和拉曼光谱对复合材料的晶型、形貌、物相等进行分析, 通过电化学工作站测试复合材料的线性扫描伏安曲线、电化学阻抗谱和莫特-肖特基曲线。结果表明: MoS₂/TiO₂复合材料形貌比较规整均匀, MoS₂纳米花尺寸约为200 nm; MoS₂与TiO₂复合有利于形成异质结, 促进光生电子和空穴的分离; 当钼酸钠浓度为0.8 mmol/L时制备的复合材料光化学能转化率为纯氧化钛的2.89倍, 达到了1.65%, 而且复合材料的电荷转移电阻降低了约50%, 光生载流子浓度提高了24倍, 达到了3.38×10²³ cm^-3, 具有非常优异的光电化学性能。

Photoelectrochemical Properties of MoS2 Modified TiO2 Nanotube Arrays

Well aligned TiO₂ nanotube arrays were grown by anodization method on Ti foils in ethylene glycol electrolyte. Flowers-like molybdenum disulfide composed with nanoflakes was synthesized by hydrothermal process on TiO₂ nanotube arrays, using sodium molybdate, thiourea and L-Cysteine as reactants. The obtained samples were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with energy dispersive X-ray detector. Linear sweeps voltammetry, electrochemical impedance spectroscopy and Mott-Schottky plots of samples were analyzed by electrochemical workstation. The results showed that a flowers-like MoS₂ with diameter of c.a. 200 nm was synthesized, forming a heterojunction between TiO₂ nanotube arrays and MoS₂, which can effectively promote the separation of photogenerated charges, reduce the electron-hole recombination. Optimum concentration of sodium molybdate was obtained at 0.8 mmol/L, its corresponding photoconversion efficiency reached 1.65%, which was 2.89 times as high as that of pure TiO₂, and the charge transfer resistance decreased approximately 50%. The MoS₂/TiO₂ composite exhibited high carrier density of 3.38×10²³ cm^-3, which was about 24 times higher than that of pure TiO₂ nanotube arrays.