光催化降解污染物制氢反应与原位红外表征

Photocatalytic Production of Hydrogen with Degrading Pollutants and Characterization by in situ Infrared Spectroscopy

研究了在Pt/TiO2悬浮体系中单组分和双组分污染物为电子给体光催化分解水制氢反应.比较了污染物甲醛、甲酸和草酸为电子给体光催化放氢反应效率,发现其活性为:草酸>甲酸>甲醛.原位ATR(衰减全反射)红外研究结果表明,光催化放氢活性与污染物吸附特性有关.还研究了草酸与甲酸双组分污染物体系的光解水放氢和污染物降解动力学,发现总的放氢和污染物降解速率与污染物组分在TiO2表面的吸附强度和溶液浓度有关.污染物在TiO2表面的竞争吸附决定了反应动力学.原位ATR-IR方法研究双组分混合物体系的吸附,直观地证实了上述结果.

The photocatalytic generation of hydrogen from water using single and binary component pollutants as electron donors in aqueous Pt/TiO2 suspension has been investigated. The adsorption of these donors on TiO2 was also monitored by in situ attenuated total reflection infrared spectroscopy (ATR-IR). In the single component system (formaldehyde, formic acid and oxalic acid), the efficiencies of electron donors follow the order: H2C2O4 > HCOOH > HCHO. The order is consistent with the adsorption strength of the electron donors on TiO2 determined by ATR-IR, which suggests that the hydrogen evolution efficiency is dependent on the strength of surface interaction. In the binary mixture systems consisting of oxalic acid and formic acid, the overall kinetics of hydrogen evolution and decomposition of pollutants are dependent on their adsorption strengths on TiO2 and their concentration levels as well. The result can be explained by their competitive adsorption on TiO2. ATR-IR characterization confirmed illustratively the above explanation.