Transition metal oxides are promising heterogeneous catalysts for peroxymonosulfate (PMS) activation. However, the catalytic degradation performance was unsatisfactory. Herein, nitrogen doping was applied to construct electron-rich metal sites in bimetallic oxides (Mn0.5Co0.5O, Fe0.5Co0.5O, Cu0.5Co0.5O) to boost their PMS activation performance for sulfamethoxazole (SMX) degradation. The N-doped bimetallic oxides (Mn0.5Co0.5O-N, Fe0.5Co0.5O-N, Cu0.5Co0.5O-N), obtaining through a facile ammonia-assisted medium-temperature heat treatment method, displayed enhanced PMS activation performance for SMX degradation compared with the pristine bimetallic oxides. Especially, Mn0.5Co0.5O-N was the optimal option with 100% SMX degradation efficiency within 2 min, wide pH application range (3.5–11.5), and excellent cycling performance. The density functional theory (DFT) calculations confirmed that Mn0.5Co0.5O-N with more negative adsorption energy (Eads) and higher electron transfer number was more beneficial for PMS adsorption and activation. Quenching experiments, electron paramagnetic resonance (EPR), and solvent exchange (H2O to D2O) indicated that 1O2 contributed predominantly to SMX degradation. This research offers an economical strategy for boosting the PMS activation activity to degrade pollutants of transition metal oxides through constructing electron-rich metal sites in bimetallic oxides by N substitution.

中文翻译：

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通过 N 取代在 M0.5Co0.5O 中构建富电子金属位点，以实现高效的过氧一硫酸盐活化以降解有机污染物


过渡金属氧化物是有前途的过氧一硫酸盐 （PMS） 活化异相催化剂。然而，催化降解性能并不令人满意。本文采用氮掺杂在双金属氧化物 （Mn0.5Co0.5O、Fe0.5Co0.5O、Cu0.5Co0.5O） 中构建富电子金属位点，以提高其 PMS 活化性能，用于磺胺甲噁唑 （SMX） 降解。通过简单的氨辅助中温热处理方法获得的 N 掺杂双金属氧化物 （Mn0.5Co0.5O-N、Fe0.5Co0.5O-N、Cu0.5Co0.5O-N） 与原始双金属氧化物相比，显示出增强的 PMS 活化性能，用于 SMX 降解。特别是，Mn0.5Co0.5O-N 是最佳选择，在 2 分钟内 SMX 降解效率达到 100%，pH 应用范围广 （3.5–11.5），循环性能优异。密度泛函理论 （DFT） 计算证实，负吸附能 （Eads） 较高、电子转移数较高的 Mn0.5Co0.5O-N 更有利于 PMS 的吸附和活化。淬灭实验、电子顺磁共振 （EPR） 和溶剂交换 （H2O 到 D2O） 表明 1O2 主要导致 SMX 降解。这项研究提供了一种经济的策略，通过氮取代在双金属氧化物中构建富电子金属位点，从而提高 PMS 活化活性以降解过渡金属氧化物的污染物。