水热法制备铂掺杂二氧化钛及其可见光催化性能

以纳米管钛酸为前驱体,采用水热法制备了Pt掺杂TiO2样品.水热反应过程中,纳米管钛酸表面羟基与氯铂酸发生酸碱中和反应,导致反应后pH值升高;在130°C开始纳米管钛酸晶体结构由正交晶系转变为锐钛矿相TiO2.表面化学组成分析表明,掺杂的Pt主要以+2价形式存在.以丙烯为模型污染物,评价样品的可见光(λ≥420nm)光催化活性.结果表明,Pt-TiO2具有明显的可见光光催化降解丙烯的活性,其中160°C水热处理制得的Pt-TiO2活性最高.最后讨论了低温水热法Pt掺杂的形成机理及Pt-TiO2具有可见光响应的原因.

Preparation of Pt-Doped TiO2 by Hydrothermal Method and Its Photocatalytic Performance under Visible Light Irradiation

Pt-doped TiO2 was prepared by a hydrothermal method using nanotubular titanic acid (NTA) as the precursor. The pH values before and after the hydrothermal reaction were compared. It was found that the hydroxyl group on the surface of NTA could neutralize the chloroplatinic acid during the hydrothermal reaction, which resulted in a pH value increase. The nanotubular structure of NTA was destroyed to form nanoparticles at 130 °C accompanied by the crystal transformation from an orthorhombic system to anatase TiO2. The X-ray photo-electron spectroscopy results showed that platinum was present mainly in the form of Pt2+. The photocatalytic activity was evaluated by monitoring the oxidation of propylene under visible light irradiation. The results indicated that Pt-TiO2 prepared at 160 oC showed the highest photocatalytic activity at visible light (λ ≥ 420 nm). The mechanism of Pt-doping into TiO2 and the visible light sensitization of Pt-doped TiO2 were discussed.