Competitive-coordination-driven high-entropy doping in ZIF-67 with in situ reconstruction into nitrogen-doped carbon-supported Co3O4 for exceptional oxygen evolution and overall water splitting

The oxygen evolution reaction (OER) suffers from intrinsically sluggish kinetics that severely impede practical water splitting. Herein, we present a facile competitive-coordination strategy to synthesize high‑entropy‑doped ZIF‑67 (HED‑ZIF‑67) incorporating up to ten distinct metal cations. Remarkably, under alkaline OER conditions, the HED-ZIF-67 polyhedrons undergoes an irreversible in situ structural reconstruction, yielding a hierarchical architecture in which small-sized spinel-type high-entropy-doped Co 3 O 4 (HED-Co 3 O 4 ) nanosheets are intimately anchored onto large monocrystalline graphitic nitrogen-doped carbon (NC) nanosheets. Configurational entropy and lattice distortion synergistically govern the phase transition by lowering the activation barrier, thereby endowing the derived HED-Co 3 O 4 /NC with abundant active sites, multimetallic synergy, efficient charge transport, and robust resistance against metal dissolution/aggregation. Consequently, 8-HED-ZIF-67 achieves an outstanding OER overpotential of 173 mV at 10 mA cm −2 with 519 h stability, alongside appreciable HER activity (87 mV). When assembled in a symmetric two-electrode electrolytic cell, it achieves overall water splitting at 1.43 V with a current density of 10 mA cm −2 and robust durability of 220 h, demonstrating its viability for sustainable energy conversion. Beyond demonstrating a versatile route to high-entropy MOF-based materials, this work offers mechanistic insights into entropy-driven in situ reconstruction toward the rational design of durable, high-performance catalysts.