Modulation strategies are widely developed to regulate electronic state of single-atom catalysts (SACs) to reinforce the catalytic activity of oxygen reduction reaction (ORR). However, the modulation effect using only single coordination regulation is often insufficient to optimize the electronic and geometric structure of metal active centers. Herein, a general strategy to modify the activity of single-atomic Fe site is achieved by dual decoration of Fe centers with contiguous sulfur atoms and metal nanoclusters via an aggregation-redispersion route. Under near-range engagement, the adjacent S atoms and Fe nanoclusters can break the symmetric electronic interface of Fe-N moiety, and act as the modulators to synergistically tune the electronic configurations of Fe centers, leading to less electron transfer to *OH, and subsequent favorable desorption. In situ spectroscopic characterization and theoretical results reinforces the significant roles of S atoms and metal clusters in tandem by correlating their induced electron redistribution with ORR activity, which ultimately accelerates the adsorption/desorption of oxygenated intermediates for robust catalytic performance. Due to the improvement of graphitization degree, carbon supports possess efficient active sites and exhibit superior anti-corrosion. The resultant FeNC-2 M demonstrates outstanding ORR activity with high power density, maintaining remarkable durability in Zn-air batteries and microbial fuel cells. This work provides effective and universal way to modulate microenvironment of single metal sites, facilitating the open up of potential application spaces for various SACs.

中文翻译：

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通过同时整合杂原子和纳米团簇对单原子 Fe 位点进行近程调制，以实现高效的氧还原

调制策略被广泛开发来调节单原子催化剂（SAC）的电子态，以增强氧还原反应（ORR）的催化活性。然而，仅使用单一配位调控的调制效应往往不足以优化金属活性中心的电子和几何结构。在此，改变单原子Fe位点活性的一般策略是通过聚集-再分散途径用连续的硫原子和金属纳米团簇对Fe中心进行双重修饰来实现。在近距离接触下，相邻的S原子和Fe纳米团簇可以打破Fe-N部分的对称电子界面，并作为调制器协同调节Fe中心的电子构型，从而减少电子向*OH的转移，并且随后有利的解吸。原位光谱表征和理论结果通过将诱导电子重新分布与 ORR 活性相关联，强化了 S 原子和金属簇串联的重要作用，最终加速了含氧中间体的吸附/解吸，从而实现了强大的催化性能。由于石墨化程度的提高，碳载体具有高效的活性位点并表现出优异的防腐蚀性能。所得的 FeNC-2 M 表现出出色的 ORR 活性和高功率密度，在锌空气电池和微生物燃料电池中保持卓越的耐用性。这项工作提供了有效且通用的方法来调节单金属位点的微环境，有助于为各种 SAC 开辟潜在的应用空间。