(Ni–Mo)/TiO_2纳米薄膜光电催化降解罗丹明B的性能

Photoelectrocatalytic Property of(Ni–Mo)/TiO_2 Thin Film for Rhodamine B

采用恒电流复合电沉积制备了(Ni–Mo)/TiO2薄膜,对薄膜的表面形貌、晶相结构和光谱特性进行了表征,以罗丹明B为模拟污染物对薄膜的光电催化性能进行了测定,并分析了光电催化机理。结果表明:(Ni–Mo)/TiO2薄膜是粒径为50～100 nm的TiO2纳米粒子相和纳米晶Ni–Mo固溶体相构成的复合薄膜。薄膜具有优异的光电催化活性和显著的光电协同效应,与未加阳极偏压相比,在最佳阳极偏压(0.2 V)下,光催化降解率提高了1.09倍,复合薄膜的光电催化降解率是多孔P25 TiO2/ITO(indium tin oxide)纳米薄膜的2.05倍。复合薄膜光电催化活性的提高,主要源于在薄膜中有效形成了(Ni–Mo)/TiO2异质结和良好的电子通道,它一方面可以促使光生电荷的分离;另一方面加速了氧气与激发电子的还原反应。

（Ni–Mo）/TiO2 composite films were prepared by composite electroplating at a constant current.The surface morphology,phase structure and optical characteristics of the composite film were analyzed.The photoelectrocatalytic property was evaluated with Rhodamine B as a simulation pollutant,and the photoelectrocatalytic reaction mechanism was discussed.The results show that the（Ni–Mo）/TiO2 film consists of crystalline grains of TiO2 in the size range of 50–100 nm and the nano-crystalline of Ni–Mo in solid solution.The composite film has a superior photoelectrocatalytic activity and a photoelectric synergistic effect.Compared with no anodic bias,the photoeletrocatalytic degradation rate for the（Ni–Mo）/TiO2 film to Rhodamine B was increased by 1.09 times at an optimum anodic bias（0.2 V）.The photoeletrocatalytic degradation rate of（Ni–Mo）/TiO2 film is 2.05 times as that of porous P25 TiO2/ITO（indium tin oxide） film.The improvement in photoelectrocatalytic activity for the composite film could be mainly attributed to the heterojunction of（Ni–Mo）/TiO2 and the electronic passage-way of Ni–Mo in the composite film,both of which efficiently pro-moted the separation of photogenerated charges and accelerated the reaction of excited electrons with oxygen relatively to TiO2/ITO nano-film in the photoelectrocatalytic degradation for Rhodamine B.