文献类型：期刊文献

中文题名：Singlet oxygen synergistic surface-adsorbed hydroxyl radicals for phenol degradation in CoP catalytic photo-Fenton

英文题名：CoP助催化光芬顿中单线态氧协同表面吸附羟基自由基降解苯酚

作者：Haoran Yu[1];Danxu Liu[1];Hengyi Wang[1];Haishuang Yu[1];Qingyun Yan[1];Jiahui Ji[1];Jinlong Zhang[1,2];Mingyang Xing[1,2]

机构：[1]Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering,Feringa Nobel Prize Scientist Joint Research Center,School of Chemistry and Molecular Engineering,East China University of Science and Technology,Shanghai 200237,China;[2]Shanghai Engineering Research Center for Multi-media Environmental Catalysis and Resource Utilization,East China University of Science and Technology,Shanghai 200237,China

年份：2022

卷号：43

期号：10

起止页码：2678

中文期刊名：Chinese Journal of Catalysis

外文期刊名：催化学报（英文）

收录：CSTPCD;;Scopus;CSCD:【CSCD2021_2022】；

基金：This work was supported by the National Natural Science Foundation of China (22176060).

语种：英文

中文关键词：Surface hydroxyl radical;Singlet oxygen;Synergistic effect;Hydroxylation;Photo-Fenton

外文关键词：表面羟基自由基;单线态氧;协同效应;羟基化;光芬顿

摘要：In recent years,there have been numerous studies on Fenton or Fenton-like reactions mediated by nonfree radicals such as singlet oxygen(1O_(2));however,there are few studies on the synergistic effect of 1O_(2) and free radicals on the degradation of organic molecules,such as phenol in Fenton reaction.In this study,a cocatalyst,CoP,commonly used in photocatalysis was synthesized using a simple two-step method,and a CoP/Fe^(2+)/AM1.5 system was constructed by introducing Fe^(2+)and simulated sunlight(AM1.5)irradiation.The newly constructed CoP/Fe^(2+)/AM1.5 system could effectively degrade various organic pollutants,including dyes,phenols,and antibiotics.Radical quenching experiments and electron paramagnetic resonance detection confirmed that there were three reactive oxygen species(ROS)in the CoP/Fe^(2+)/AM1.5 system,including·OH_(ads),·O_(2)^(-),and 1O_(2).Further,combined with the liquid chromatogram of phenol,its intermediate products,and the fluorescence diagram of o-hydroxybenzoic acid,it can be concluded that a synergistic effect exists between 1O_(2) and the surface-adsorbed·OH_(ads) in the CoP/Fe^(2+)/AM1.5 system.The controllable formation of surface 1O_(2) and·OH_(ads) was achieved through the oxidation(Co^(3+))and reduction(Pδ?)centers exposed on the CoP surface,and the synergistic effect between them results in phenol’s hydroxylation,ring-opening,and degradation.The study of this new mechanism provides a new perspective for revealing the surface interface reaction between ROS and organic pollutants.
H_(2)O_(2)是一种绿色的化学试剂,常作为氧化剂应用于水污染控制领域.近年来,科研工作者们通过光催化、电催化以及催化剂催化等手段开发了许多原位生成H_(2)O_(2)直接参与有机污染物降解的方法.而在这些基于催化反应生成的H_(2)O_(2)的非均相芬顿或类芬顿反应中,催化剂的表面或剪切面经常会发生物质吸附、H_(2)O_(2)的生成与活化以及活性氧物种(ROS)的生成等氧化还原反应.这些反应过程和机制非常复杂,而且多数研究并未对此给出清晰的解释.一般来说,不同ROS在水溶液中的氧化性、寿命和扩散距离不同.例如,·OH的氧化性非常强(2.80 V),但寿命短(<1×10^(?6) s),因而扩散距离非常有限,若在非均相催化剂表面生成便无法扩散到溶液中;而1O_(2)的氧化性相对较弱(2.20 V),寿命较长(2×10^(?6) s),扩散距离较长,可扩散到溶液中(固液界面处)去氧化弱极性有机分子.受此启发,本文采用简单的两步法制备了光催化中常用的助催化剂CoP,构建了能产生各种ROS的CoP/Fe^(2+)/AM1.5体系,并研究其对苯酚等各种污染物的降解能力以及降解机理.X射线衍射、高分辨透射电子显微镜和X射线光电子能谱等表征结果表明,成功合成了纯净的CoP材料,且由于其性质活泼,CoP表面与空气接触后被氧化生成了一层氧化层.通过引入Fe^(2+)和模拟太阳光(AM1.5)辐射构建的CoP/Fe^(2+)/AM1.5体系能有效降解染料、酚类和抗生素等多种有机污染物,其中对主要目标污染物苯酚的降解率在2 h内达79.9%.自由基猝灭实验和电子顺磁共振检测证实,CoP/Fe^(2+)/AM1.5体系存在三种活性氧物种,为·OH_(ads),·O_(2)^(-)和1O_(2).进一步结合苯酚及其中间产物的液相色谱图和邻羟基苯甲酸的荧光图可以发现,在CoP/Fe^(2+)/AM1.5体系中,1O_(2)和表面吸附的·OH_(ads)之间存在协同效应.一方面,CoP表面带负电荷,容易吸附H+和铁离子;利用暴露的还原中心(Pδ?)的还原能力,可以在其表面控制H_(2)O_(2)的生成和活化以及铁离子的循环.另一方面,通过CoP表面暴露的氧化中心(Co^(3+))实现表面·O_(2)^(-)到1O_(2)的可控生成.此外,CoP表面吸附的Fe^(2+)促进了H_(2)O_(2)活化为·OH_(ads),而AM1.5辐照则促进了CoP光生电子的产生及其表面·O_(2)^(-)向1O_(2)的转化.在降解过程中,由于1O_(2)具有迁移到剪切面的能力,有效促进了苯酚的羟基化,使苯酚变成了极性更强的有机物并吸附在CoP表面,随后该有机物被其表面的·OH_(ads)矿化.1O_(2)和·OH_(ads)之间的协同作用是苯酚发生羟基化、开环和降解等反应的原因.这一新机制的研究有望为揭示活性氧物种与有机污染物之间的表界面反应提供新的视角.