### 连续流动化学发光法在线定量检测二氧化钛光催化产生的O2·-和H2O2及其生成动力学研究

1. 中国科学院生态环境研究中心 环境化学与生态毒理学国家重点实验室 100085
• 投稿日期:2015-01-14 发布日期:2015-03-20
• 通讯作者: 赵利霞 E-mail:zlx@rcees.ac.cn,lhguo@rcees.ac.cn
• 基金资助:

项目受国家重点基础研究计划(No. 2011CB936001)和国家自然科学基金(Nos. 21177138, 21207146, 21477146, 21377142)资助.

### Online Quantification of O2·- and H2O2 and Their Formation Kinetics in Ultraviolet (UV)-Irradiated Nano-TiO2 Suspensions by Continuous Flow Chemiluminescence

Wang Dabin, Zhao Lixia, Guo Lianghong, Zhang Hui, Wan Bin, Yang Yu

1. State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085
• Received:2015-01-14 Published:2015-03-20
• Supported by:

Project supported by the National Basic Research Program of China (No. 2011CB936001) and the National Natural Science Foundation of China (Nos. 21177138, 21207146, 21477146, 21377142).

O2·-和H2O2是TiO2光催化反应过程中产生的重要活性氧物种. 本文使用鲁米诺作为化学发光探针, 针对两者寿命不同, 建立了连续流动化学发光在线定量检测方法. 对于O2·-, 由于寿命短, 标准品不易得到, 将光照后TiO2样品10 s内与鲁米诺混合产生化学发光, 根据鲁米诺和O2·-化学计量关系, 将该发光强度对应的鲁米诺浓度转换成O2·-的浓度, 实现间接定量; 对于H2O2, 将光照后的TiO2溶液于黑暗处30 min后进行定量. 该方法测得TiO2光催化产生O2·-和H2O2的浓度范围分别为7.5～30 nmol/L和0.60～3.0 μmol/L, 检测限分别为1.95 nmol/L和18.0 nmol/L. O2·-和H2O2的生成动力学研究发现, 两者的生成均符合指数衰减函数增长, 通过拟合计算, 其生成速率常数(kf)分别为0.0653 nmol·s-1和15.0 nmol·s-1, 表明在TiO2光催化反应中H2O2的生成速率高于O2·-.

O2·- and H2O2, the two reactive oxygen species (ROS) produced in TiO2 photocatalytic reactions, play important roles in the photodegradation of pollutants. In this work, according to the different lifetime of O2·- and H2O2, online quantification of O2·- and H2O2 was successfully achieved based on the two established continuous flow chemiluminescence (CFCL) methods using luminol as the chemiluminescence probe. For O2·-, the CL intensity was detected by mixing the irradiated TiO2 suspension containing O2·- with luminol within 10 s due to its short lifetime and poor stability, and thus the concentration of O2·- was indirectly quantified according to the linear relationship between the CL intensity and the luminol concentration. For H2O2 detection with the luminol/K3Fe(CN)6 system, the CL intensity was detected after the irradiated TiO2 suspension was placed in darkness for 30 min to ensure the complete disappearance of O2·-, and the concentration of H2O2 produced was directly quantified by the calibration curve between the CL intensity and H2O2 concentration. The concentration of O2·- and H2O2 was determined approximately in the range of 7.5～30 nmol/L and 0.60～3.0 μmol/L, and the detection limit was 1.95 nmol/L and 18.0 nmol/L respectively. Based on the proposed models of O2·- and H2O2 formation, the kinetic process of O2·- and H2O2 formation was studied, and both of them followed the increase of exponential decay function. By simulating the time-dependent concentration change of O2·- and H2O2 with their kinetic formulas, the formation rate constants (kf) of O2·- and H2O2 were calculated to be 0.0653 nmol·s-1, and 15.0 nmol·s-1 respectively. The formation rate of H2O2 was higher than that of O2·- in the TiO2 photocatalytic reactions. This work provides us more insight into the formation process of ROS, and may help to improve the photocatalytic efficiency of TiO2 photocatalysis.