Reprogramming Interfacial Hydrogen-Bond Networks via Asymmetric Single-Atom Catalysts

Abstract

Interfacial water plays a pivotal role in electrocatalysis by governing proton-coupled electron transfer and reaction kinetics. However, strategies to actively regulate interfacial hydrogen-bond networks remain limited, and the role of atomic-scale catalytic sites in controlling water organization is still poorly understood. Here, we report a rapid Joule-heating strategy that converts symmetric Co-N4 sites into asymmetric Co-N3O1 single-atom sites, enabling precise modulation of the interfacial hydrogen-bond network during catalysis. Combined experimental characterization and theoretical simulations reveal that O coordination breaks the local symmetry of Co centers, reconstructs interfacial water, and weakens over-connected hydrogen-bond networks, providing a more favorable interfacial environment for water-mediated proton transfer and oxygenated-intermediate conversion. As a result, the reconstructed interfacial hydrogen-bond network promotes efficient four-electron oxygen reduction, enabling Co-NC-N3O1 to achieve a half-wave potential of 0.866 V, substantially outperforming its symmetric Co-N4 counterpart and surpassing commercial Pt/C. When integrated into aqueous zinc-air batteries (ZABs), Co-NC-N3O1 delivers a peak power density of 217.2 mW cm–2 and a specific capacity of 805.1 mAh gZn–1. This work reveals that asymmetric single-atom modulation can actively reprogram the interfacial hydrogen-bond network, providing a paradigm for catalyst-water interface engineering.