PHOTOLYSIS OF CHLOROFORM AND OTHER ORGANIC-MOLECULES IN AQUEOUS TIO2 SUSPENSIONS
PHOTOLYSIS OF CHLOROFORM AND OTHER ORGANIC-MOLECULES IN AQUEOUS TIO2 SUSPENSIONS
复制标题
DOI：
10.1021/es00015a018
复制
发表时间：
1991-03-01
影响因子：
11.4
通讯作者：
HOFFMANN, MR
中科院分区：
文献类型：
--
作者：
KORMANN, C;BAHNEMANN, DW;HOFFMANN, MR
在310-380 nm波长范围内，研究了TiO 2水悬浮液光催化降解氯仿的性能。提出了一个详细的反应机理，其中的速率控制步骤是表面结合的.OH与吸附的CHCl 3的反应。建立了一种测定氯代烃降解速率的恒pH滴定法。发现CHCl 3降解的量子效率（在λ = 330 nm处PHI = 0.56）与入射光强度的平方根成反比。这种关系可以解释为表面结合的.OH的二级重组和表面结合的.OH与CHCl 3的速率决定反应之间的直接竞争。几个电子供体的降解率已与其计算的表面形态。本研究的结果表明，吸附的电子供体和受体的TiO 2表面起着更重要的作用，在确定的光催化反应的速率比pH值依赖的费米能级位移的影响。
The photocatalytic degradation of chloroform has been investigated in aqueous suspensions of TiO2 over the wavelength range of 310-380 nm. A detailed reaction mechanism has been proposed in which the rate-determining step is the reaction of surface-bound .OH with adsorbed CHCl3. A pH-stat titration technique was developed for the measurement of the rates of degradation of chlorinated hydrocarbons. The quantum efficiency (PHI = 0.56 at lambda = 330 nm) of the degradation of CHCl3 was found to be inversely proportional to the square root of the incident light intensity. This relationship can be explained in terms of a direct competition between a second-order recombination of surface-bound .OH and the rate-determining reaction of surface-bound .OH with CHCl3. The rates of degradation of several electron donors have been correlated with their computed surface speciation. The results of this study show that the adsorption of electron donors and acceptors to the TiO2 surface plays a more important role in determining the rate of the photocatalytic reactions than the effect of pH-dependent Fermi-level shifts.