氮掺杂碳催化剂活化过一硫酸盐的活性位点分析及其对双酚A的降解机制

Analysis of active sites in nitrogen-doped carbocatalysts for peroxymonosulfate activation and the degradation mechanism of bisphenol A

为了探究氮掺杂碳催化剂中不同类型缺陷点位在活化过一硫酸盐((PMS))时的反应活性,以碳黑和二氰二胺混合物为前驱体,通过热解得到了一系列不同氮掺杂量的碳催化剂(CN_(x)),并对所制备催化剂的缺陷度、化学组分以及PMS活化性能进行了研究。结果表明,增加碳催化剂中的高活性氮杂质缺陷点位可有效促进催化剂的PMS活化性能;不同本征缺陷点位对PMS活化性能也表现出显著差异。活性物种淬灭实验、顺磁共振分析和电化学分析等结果表明,CN_(x)/PMS体系对双酚A(BPA)的降解过程遵循以单线态氧(^(1)O_(2))为主导的非自由基途径,催化剂表面的电子传递机制也有一定贡献。以上研究结果可为识别氮掺杂碳催化剂中的活性点位和高活性催化剂的定向合成提供参考。

In order to understand the reactivity of different defect sites in nitrogen-doped carbocatalysts with peroxymonosulfate(PMS),a series of carbocatalysts(CN_(x))with different nitrogen contents were prepared by pyrolyzing a mixture precursor consisted of carbon black and dicyandiamide.The defect degree,chemical composition and PMS activation performance of CNx were studied.The results showed that increased nitrogen defect sites with high-reactivity could promote the activation of PMS,and different intrinsic defect sites also exhibited significant differences in PMS activation.The results of reactive oxidation species quenching experiment,electron paramagnetic resonance analysis and electrochemical analysis showed that the bisphenol A(BPA)degradation by CN_(x)/PMS was a non-radical pathway process,which was dominated by singlet oxygen(^(1)O_(2)),and the electron transfer mechanism also contributed to some extent.The above results could shed light on the identification of active sites in nitrogen-doped carbocatalysts and the oriented synthesis of catalysts with high catalytic activity.