Boosting oxygen evolution through asymmetric CoIII–O–MoV motif-modulated spinel active sites
The development of efficient and stable oxygen evolution reaction (OER) electrocatalysts is critical for clean energy technologies, yet conventional cobalt-based spinel catalysts often suffer from insufficient activity and structural instability under operating conditions. To address these challenges, this study proposes and constructs a cation-ordered spinel-like catalyst (HVI Metal-CoMoO4/NF). The unique crystalline framework induces significant Jahn-Teller distortion and pre-stabilizes a Co2+/Co3+ mixed-valence state at the cobalt active centers via asymmetric Co–O–Mo bridges, effectively optimizing bulk charge transport. Electrochemical tests demonstrate that its performance significantly surpasses that of benchmark materials, requiring only an overpotential of 307 mV to drive a current density of 100 mA cm−2 in 1.0 M KOH, with a Tafel slope of 63.13 mV dec−1, maintaining stable operation for over 320 h at high current density. Crucially, our structural and in situ characterization results clearly reveal a stable and well-crystallized reconstruction behavior from the surface into the bulk of the spinel-like pre-catalyst during the OER. This work fundamentally addresses the challenges of disordered reconstruction and unstable active phases in traditional spinel catalysts, providing a paradigm for regulating the dynamic evolution of electrocatalysts through precise structural design.