TiO_2光催化反应机理及动力学研究进展

Recent Advances in Mechanisms and Kinetics of TiO_2 Photocatalysis

光催化处理环境污染物是基于催化反应过程中的一些自由基对污染物的氧化或还原作用 ,反应途径通常是 HO·攻击或空穴直接攻击 ,对可见光敏感的化合物也可能通过激发态来分解。动力学的表述多数符合 L- H模式 ,广泛研究了 L- H模式下的吸附与催化活性的关系 。

Fundamental mechanisms of TiO(2) heterogeneous photocatalysis for degrading wastes are based on some radical reactions. Under ultraviolet light the photocatalysts produce holes and electrons, which subsequently initiate oxidation and reduction reactions. Holes and electrons can react directly with organic species adsorbed on the surface of the catalysts and also can transform into high-energy chemical species such as hydroxyl radicals. Some organics such as dyes, which are sensitive to visible light, can also be degraded via Excited states. Langmuir-Hinshelwood kinetics model describes the degradation rate expressions in terms of the disappearance of compounds. The kinetics of the photocatalysis is not only essential to practical applications but also is key aspect for understanding mechanisms of die photocatalysis.