Whereas previous studies that explored the application of metal–carbon composites as persulfate activators have focused on synergistic performance improvements, the potential advantages or features that can be acquired by integrating metal and carbon constituents that differ in terms of reactivity toward persulfate precursors and their preferred activation routes have been overlooked. With ZIF-67-derived cobalt/N-doped carbon composites (Co@N-C) as the model metal–carbon composite, this study takes a look into a switch in the primary degradative pathway depending on the persulfate precursor used and investigates this kind of composite fabrication as a strategy to overcome the drawbacks of single-component activators. In Co@N-C, Co embedded in the carbon matrix caused radical-induced oxidation in the presence of peroxymonosulfate (PMS) whereas peroxydisulfate (PDS) activation using a carbon framework involved mediated electron transfer. The different nature of the dominant oxidant was confirmed by investigating the quenching effects of alcohols, bromate formation yield, substrate-specificity, electron paramagnetic resonance spectral features, current generation upon sequential organic and persulfate injection, and product distribution. The Co and N-doped carbon serving as separate reactive sites allowed Co@N-C to exploit both PMS and PDS so it could outperform benchmark metal- and carbon-derived materials. Electrochemical measurements linked with X-ray spectroscopic analysis implied that a moderate pyrolysis temperature optimized the Co@N-C activity due to high fractions of graphitic N and Co-N species. Density functional theory calculations reveal that the peroxide bond of PMS is more susceptible to elongation over Co@N-C, thus it is preferentially dissociated to yield sulfate radicals.

以前探讨过将金属-碳复合材料用作过硫酸盐活化剂的研究集中于协同性能的改善，而通过整合对过硫酸盐前体的反应性及其优选活化方式不同的金属和碳成分，可以获得潜在的优势或特征。路线已被忽略。以ZIF-67衍生的钴/ N掺杂碳复合物（Co @ NC）为模型金属-碳复合物，本研究根据所使用的过硫酸盐前体来研究主要降解途径的转变，并研究了这种复合制造作为克服单组分活化剂缺点的策略。在Co @ NC中，嵌入碳基质中的钴在过氧一硫酸盐（PMS）的存在下引起自由基诱导的氧化，而使用碳骨架的过氧二硫酸盐（PDS）活化涉及介导的电子转移。通过研究醇的猝灭作用，溴酸盐的形成产率，底物特异性，电子顺磁共振光谱特征，依次注入有机和过硫酸盐时产生的电流以及产物分布，证实了主要氧化剂的不同性质。Co和N掺杂的碳作为单独的反应位，使Co @ NC可以利用PMS和PDS，因此它可以胜过基准的金属和碳衍生材料。与X射线光谱分析有关的电化学测量结果表明，适中的热解温度可优化Co @ NC活性，这是由于石墨N和Co-N物种的比例较高。密度泛函理论计算表明，PMS的过氧化物键比Co @ NC更易伸长，因此优先解离生成硫酸根。