Photocatalytic activation of persulfate for the synergistic degradation of pollutants has become a major research hotspot, but the activation effect is poor due to the problems of low catalyst carrier separation efficiency and insufficient active sites. In this study, direct Z-Scheme heterojunctions of MoO2@CoFe LDHs were prepared by a simple hydrothermal method and a Co and Fe dual active site system was constructed to activate Na2S2O8 (PS) for the synergistic degradation of tetracycline under visible light. The results showed that the synergistic degradation of tetracycline was 3.7 times and 2.7 times more efficient than the original heterojunction and PS, respectively. Combining material characterisation, photovoltaic performance tests and theoretical calculations revealed that the high efficiency is attributed to the formation of an internal electric field under the Z-Scheme heterostructure type generating effective electron-hole separation, with more photo-generated electrons converted into radicals acting together with holes to degrade the TC and activate the PS. More importantly, Co(II) and Fe(II) provide electrons to synergistically activate PS, and a portion of the photogenerated electrons and PS activation intermediates can facilitate cycling between Co(II)/Co(III) and Fe(II)/Fe(III) to accelerate PS activation. This paper's work on activating PS-assisted Z-Scheme heterojunctions for the efficient degradation of TC provides a reference for the study of high-performance photocatalytic catalysts for the degradation of organic pollutants.

中文翻译：

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过硫酸盐活化的性能和机理促进了 Z 型异质结MoO2@LDHs用于高效光催化降解四环素


光催化活化过硫酸盐协同降解污染物已成为主要研究热点，但由于催化剂载流子分离效率低、活性位点不足等问题，活化效果不佳。本研究采用简单的水热法制备了 MoO2@CoFe LDHs 的直接 Z 型异质结，并构建了 Co 和 Fe 双活性位点系统，以激活 Na2S2O8 （PS） 在可见光下协同降解四环素。结果表明，四环素的协同降解效率分别是原始异质结和 PS 的 3.7 倍和 2.7 倍。结合材料特性、光伏性能测试和理论计算，高效率归因于在 Z 型异质结构类型下形成内部电场，产生有效的电子-空穴分离，更多的光生电子转化为自由基，与空穴一起作用，降解 TC 并激活 PS。更重要的是，Co（II） 和 Fe（II） 提供电子协同激活 PS，部分光生电子和 PS 活化中间体可以促进 Co（II）/Co（III） 和 Fe（II）/Fe（III） 之间的循环，以加速 PS 激活。本文关于激活 PS 辅助 Z 型异质结以高效降解 TC 的工作为研究用于降解有机污染物的高性能光催化催化剂提供了参考。