钯掺杂的TiO_(2)纳米线阵列@MoS_(2)电极光电催化高效还原六价铬和同步氧化对氯苯酚的机理研究  

Mechanism study of photoelectrocatalytic efficient reduction of hexavalent chromium and synchronous oxidation of p-chlorophenol by Pd-doped TiO_(2) nanowire arrays@MoS_(2) electrode

作　　者：李善鹏 刘春雷[2] 刘国光[1] 田夏迪 吕文英[1] LI Shanpeng;LIU Chunlei;LIU Guoguang;TIAN Xiadi;LÜWenying(School of Environmental Science and Engineering,Guangdong University of Technology,Guangzhou 510006;Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085;Beijing Drainage Group Co.Ltd(BDG),Beijing 100022)

机构地区：[1]广东工业大学环境科学与工程学院,广州510006 [2]中国科学院生态环境研究中心饮用水科学与技术重点实验室,北京100085 [3]中国排水集团有限公司,北京100022

出　　处：《环境科学学报》2022年第11期34-46,共13页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.21677040,22076029,52000176);广州市科技计划项目(No.201903010080)。

摘　　要：采用电沉积法将高分散的Pd纳米颗粒引入到TiO_(2)纳米线阵列@MoS_(2)(TNA@MoS_(2))电极表面,并用于光阴极同步还原六价铬(Cr(Ⅵ))和氧化对氯苯酚(4-CP).同时,通过X射线衍射、扫描电子显微镜和漫反射光谱对TNA@MoS_(2)/Pd电极进行了表征.光电催化实验表明,TNA@MoS_(2)/Pd光阴极在30 min内对Cr(Ⅵ)的还原效率达到99.8%,对4-CP的氧化效率达到91.5%且矿化效率为58.4%.循环伏安、电子自旋共振光谱、荧光光谱和自由基淬灭实验证实了同步还原和氧化反应的关键活性物种和作用机理.结果表明,TNA@MoS_(2)/Pd光阴极产生的稳定的原子氢(H^(*)),不仅可快速还原Cr(Ⅵ),而且与溶解的O_(2)结合产生H_(2)O_(2),提高了·OH的产量,从而同步氧化4-CP.循环实验表明,TNA@MoS_(2)/Pd电极具有良好的可重复使用性.The highly dispersed Pd nanoparticles were introduced onto the surface of TiO_(2) nanowire arrays@MoS_(2)(TNA@MoS_(2))electrode using a electrochemical deposition method,which was then used as the photocathode for synchronous reduction of Cr(Ⅵ)and oxidation of p-chlorophenol(4-CP).The prepared TNA@MoS_(2)/Pd electrode was characterized by X-ray diffraction,scanning electron microscopy,and diffuse reflectance spectroscopy.The photo-electrocatalytic experiments showed that the TNA@MoS_(2)/Pd photocathode showed excellent synchronous reduction of Cr(Ⅵ)and oxidation of 4-CP.After 30 min treatment,99.8% Cr(Ⅵ)can be reduced,and 91.5% of 4-CP was oxidized with 58.4% mineralization.Through cyclic voltammetry,electron spin resonance spectroscopy,fluorescence spectroscopy,and radicals quenching experiments,the active species were examined and the synchronous reactions mechanisms were confirmed.It was demonstrated that the stable atomic hydrogen(H^(*))was generated by the TNA@MoS_(2)/Pd photocathode,resulting in rapid reduction of Cr(Ⅵ).Moreover,the stable H^(*)was further reacted with the dissolved O_(2) to generate H_(2)O_(2) and hence promoted the production of·OH to synchronously oxidize 4-CP.Recycling experiments confirmed the good reusability of the TNA@MoS_(2)/Pd electrode.

关 键 词：原子氢(H^(*)) Pd纳米颗粒 MoS_(2) 同步还原和氧化 

分 类 号：X703[环境科学与工程—环境工程]