Strong Interfacial Electronic Coupling in Ni₃Mo₃C@MoO₂ for Durable Oxygen Evolution Reaction

The oxygen evolution reaction (OER) serves as a critical electrode process for electrochemical hydrogen production, yet it is hindered by its sluggish kinetics and poor stability of catalysts. Carbides anchored on highly electronegative oxide nanoparticles are attractive new catalytic materials for OER due to the unique carbide/oxide heterostructures. Herein, we report a strong carbide/oxide interfacial electronic coupling strategy to obtain high-performance OER catalysts of Ni₃Mo₃C anchored on MoO₂ nanoparticles (Ni₃Mo₃C@MoO₂-CN). Ni₃Mo₃C@MoO₂-CN catalyst exhibits excellent OER performance with a low overpotential of 197 mV at 10 mA cm^-2. Furthermore, a Pt/C || Ni₃Mo₃C@MoO₂-CN electrolyzer achieves a low cell voltage of 1.92 V at 500 mA cm^-2 with 2000 h of outstanding durability for overall water splitting. Our work reveals that carbide/oxide interfacial electronic coupling induces electron transfer from Ni₃Mo₃C to MoO₂, which facilitates π* electron back-filling effect into the Ni─O*, resulting in the optimized adsorption of O*. Consequently, the key reaction step of OOH* formation in Ni₃Mo₃C@MoO₂-CN becomes a spontaneous process, leading to a low energy barrier of the OER process and excellent catalytic performance. This study provides fundamental insights into modulating the catalytic performance by fabricating interfacial electronic coupling between carbides and highly electronegative oxide nanoparticles.