钴掺杂氧化铜/可见光协同活化PMS降解罗丹明B及其机理研究

Co-doped CuO/Visible Light Synergistic Activation of PMS for Degradation of Rhodamine B and Its Mechanism

元素掺杂是提升催化剂性能的重要方法。研究采用快速沉淀法制备了钴掺杂氧化铜(Co-doped CuO)纳米催化材料,在可见光条件下,20 min内其活化的过氧硫酸氢钾复合盐(PMS)对罗丹明B染料的降解率达到96%以上,远优于同等条件制备的CuO。本研究还考察了溶液pH、染料初始浓度、催化剂用量等对降解效率影响。钴掺杂后氧化铜纳米颗粒由三维针梭状结构转变为近二维薄带状结构。同时钴掺杂提高了CuO的平带电位进而提升了电荷转移效率。XPS及EPR结果表明钴掺杂能够提高CuO的氧空位含量进而提升催化活性。捕获剂实验结果表明反应过程中的主要活性物种为空穴(h+VB),且羟基自由基(•OH)、单线态氧(1O_(2))、超氧自由基(•O_(2)–)、硫酸根自由基(SO4–•)也参与了降解反应。最后,本文初步阐明了Co-doped CuO协同可见光活化PMS降解有机污染物的反应机理。

Elemental doping is an important method for improving the efficiency of catalysts.In this study,cobalt-doped CuO catalysts were prepared using a rapid precipitation method for the effective degradation of organic pollutants by photo-assisted activation of potassium peroxymonosulfate(PMS).The Co-doped CuO catalyst demonstrated degradation efficiency as high as 96%within 20 min reaction under visible light conditions,which is much higher than that of the undoped CuO.Cobalt doping transformed copper oxide nanoparticles from a three-dimensional needle-shape structure to a near-two-dimensional thin ribbon-like structure.Cobalt doping increases the flat-band potential of CuO and thus enhances the charge transfer efficiency.Furthermore,the effects of solution pH,initial dye concentration and catalyst dosage on the degradation efficiency were also investigated.XPS and EPR results show that cobalt doping can increase the oxygen vacancy content in CuO and thus improves the activation properties.The result of the trapping agent experiments indicates that main active species in the reaction are holes,while hydroxyl radicals,singlet oxygen,superoxide radicals and sulfate radicals are also involved.Finally,the reaction mechanism for the photo-assisted Co-doped CuO activated PMS degradation of RhB are generally proposed.