Iodine-doping-assisted tunable introduction of oxygen vacancies on bismuth tungstate photocatalysts for highly efficient molecular oxygen activation and pentachlorophenol mineralization  

基于钼酸铋的碘掺杂辅助氧空位可控引入及其高效活化分子氧和矿化五氯酚作用

作　　者：Shengyao Wang Zhongliang Xiong Nan Yang Xing Ding Hao Chen 汪圣尧;熊中亮;杨楠;丁星;陈浩(华中农业大学理学院,湖北武汉430070)

机构地区：[1]College of Science,Huazhong Agricultural University,Wuhan 430070,Hubei,China

出　　处：《Chinese Journal of Catalysis》2020年第10期1544-1553,共10页催化学报（英文）

基　　金：国家自然科学基金(51872107,21607047,51572101,51902121);湖北省自然科学基金(2016CFB193,2019CFB322);中央高校基本科研业务费专项基金(2662015QD047,2662016PY088,2662015PY047).

摘　　要：In this work,the tunable introduction of oxygen vacancies in bismuth tungstate was realized via asimple solvothermal method with the assistance of iodine doping.With the predictions afforded bytheoretical calculations,the as-prepared bismuth tungstate was characterized using various tech-niques,such as X-ray diffraction,Raman spectroscopy,scanning electron microscopy,transmissionelectron microscopy,X-ray photoelectron spectroscopy,electron spin resonance spectroscopy,anduV-Vis diffuse reflectance spectroscopy.The different concentrations of the oxygen vacancies onbismuth tungstate were found to be intensely correlated with iodine doping,which weakened thelattice oxygen bonds.Owing to the sufficient oxygen vacancies introduced in bismuth tungstate as aresult of iodine doping,the molecular oxygen activation was remarkably enhanced,thus endowingbismuth tungstate with high activity for the photocatalytic degradation of sodium pentachloro-phenate.More encouraging is the total organic carbon removal rate of sodium pentachlorophenateover iodine-doped bismuth tungstate that exceeded 90%in only 2 h and was 10.6 times higher thanthat of the pristine bismuth tungstate under visible light irradiation.Moreover,the mechanism,through which the degradation of sodium pentachlorophenate over iodine-doped bismuth tung-state is enhanced,was speculated based on the results of radical detection and capture experiments.This work provides a new perspective for the enhanced photocatalytic degradation of organochlo-rine pesticides from the oxygen vacancy-induced molecular oxygen activation over iodine-dopedbismuth tungstate.氧空位引入是设计带隙和电子结构以显著提高半导体光催化效率的有效策略之一.氧空位不仅可以有效地捕获载流子而加速光生电子空穴对的分离,还可以捕获电子作为惰性气体分子活化的活性位点.在分子水平上阐明氧空位在光催化中的固有功能也逐渐引起了研究者们的广泛兴趣.近年来,诸多文献报道原生氧空位可以很容易地通过局域电子对氧气进行充电,这表明光催化是分子氧在氧空位上的活化是克服三重态O2自旋禁制反应生成活性氧物种的可靠选择.由此产生的活性氧物种,如羟基自由基(·OH)、超氧阴离子自由基(·O2-)和单线态氧(1O2),通常比O2更具有氧化性.尽管在构建氧空位方面已有系列开创性的工作报道,但在光催化材料上氧空位浓度的调控策略仍处于起步阶段,依然具有很大的探索空间.因此,建立一种可控引入氧空位的方法,并揭示氧空位在增强分子氧活化中的潜在作用具有重要科学意义.我们利用还原性的乙二醇为溶剂,通过简便的溶剂热法合成了氧空位浓度可控的碘掺杂钨酸铋.在理论计算预测的基础上,采用X射线粉末衍射(XRD)、透射电子显微技术(TEM)、X射线光电子能谱(XPS)、电感耦合等离子体光谱(ICP)、拉曼光谱(Raman)和电子顺磁共振波谱(EPR)等多种表征手段研究了碘掺杂对钨酸铋氧空位构筑及理化性质的影响.理论计算结果表明,未改性钨酸铋需要2.94 eV的能量驱使晶格氧原子逸出形成氧空位,而表面碘掺杂可以将该能垒降至1.20 eV,证明了碘掺杂可以降低钨酸铋氧空位的形成能,从而促进钨酸铋上氧空位的生成.受此启发,我们利用溶剂热法合成了系列碘掺杂钨酸铋, XRD和形貌分析表明碘的引入并未改变钨酸铋的结构.而XPS和ICP分析证实了碘的成功引入.EPR结果显示随着碘含量的增加,钨酸铋的氧空位浓度也逐渐提高,证明了碘的引入促进了氧空�

关 键 词：Iodine doping Oxygen vacancy Bismuth tungstate PHOTOCATALYST Molecular oxygen activation NaPCP 

分 类 号：X703[环境科学与工程—环境工程] O643.36[理学—物理化学] O644.1[理学—化学]