Engineering Metal-Oxygen Covalency and Sacrificial Sites via GQD-Induced Oxide Reconstruction

Electrochemical reconstruction behavior under oxygen evolution reaction (OER) conditions plays a pivotal role in governing electrocatalytic performance. Despite its importance, achieving precise control over electrochemical reconstruction and directing it toward desired active structures remain a great challenge. Herein, we report an effective strategy for directing the electrochemical reconstruction of nickel oxides through the incorporation of oxidizable graphene quantum dots (GQDs). During electrochemical reconstruction, Se leaching and GQD oxidative dissolution contribute to the formation of a reconstructed NiOOH framework with modified Ni–O electronic interactions and undercoordinated Ni sites. The resulting electronic and coordination reconstruction promotes lattice oxygen reactivity, while the formation of oxygen nonbonding states helps mitigate excessive lattice oxygen activation and contributes to improved catalyst durability. Remarkably, the reconstructed g-NiOOH exhibits significantly enhanced OER activity, requiring an overpotential of only 225 mV to reach 10 mA cm–2, compared with 436 mV for NiSe2-derived NiOOH. Furthermore, an anion exchange membrane water electrolyzer employing GQDs/NiSe2 as the anode catalyst delivers 6.8 A cm–2 at 2.0 V and sustains stable operation at 2 A cm–2 for over 1000 h.