The widely investigated oxygen reduction reaction (ORR) is well-known to proceed via two competing routes, involving two or four electrons, and yielding different reaction products, respectively. Both pathways are believed to share a common, elusive intermediate, namely, the hydroperoxyl radical. By exploiting a cobalt single-atom biomimetic model catalyst, based on a self-assembled monolayer of Co-porphyrins grown on an almost free-standing graphene sheet, we identify, in situ at room temperature in O2+H2O atmosphere, a hydroperoxyl-water cluster that is stabilized at the Co single-metal atom catalytic site. We show that the interplay between charge transfer, dipole and H-bonding, and water solvation behavior actually determines the hydroperoxyl-water complex stability, the Co-OOH bonding geometry, and, prospectively, opens to the engineered control of the selectivity of ORR pathways.

中文翻译：

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单金属原子催化剂和 ORR：氢键、溶剂化和难以捉摸的过氧化氢中间体

众所周知，广泛研究的氧还原反应 (ORR) 通过两条竞争路线进行，涉及两个或四个电子，并分别产生不同的反应产物。两种途径都被认为共享一个共同的、难以捉摸的中间体，即氢过氧自由基。通过利用钴单原子仿生模型催化剂，基于在几乎独立的石墨烯片上生长的自组装单层钴卟啉，我们在室温下在 O2+H2O 气氛中原位识别氢过氧簇稳定在 Co 单金属原子催化位点。我们表明，电荷转移、偶极子和氢键以及水溶剂化行为之间的相互作用实际上决定了氢过氧化物-水复合物的稳定性、Co-OOH 键合几何形状，并且，前瞻性地，