Autonomous Interface Stabilization via Ni Doping, Sulfur Vacancy Regulation, and Carbon Encapsulation for Durable...

Designing HER catalysts that autonomously adapt to acidic environments remains a critical challenge for scalable hydrogen production. Here, a multifunctional, self-stabilizing electrocatalyst-C@Cd₀.₉Ni₀.₁S-featuring a dynamically responsive Ni-S vacancy interface embedded in a conductive carbon matrix is presented. Ni doping induces local electron accumulation and facilitates sulfur vacancy formation, thereby reprogramming the electronic structure to lower the hydrogen adsorption free energy (ΔG_H) and promote hydrogen spillover. Sulfur vacancies enhance charge redistribution and proton binding, while carbon encapsulation ensures charge continuity and structural durability under acidic stress. The catalyst achieves a low overpotential of -0.24 V at 100 mA cm^-2 for 10 days and maintains stable operation at 500 mA cm^-2 without metal leaching. DFT and operando XPS analyses confirm that the Ni-S vacancy interface adaptively modulates electronic structure and interfacial reactivity, enabling intelligent surface response during HER. This work establishes a rational design framework for acid-stable, precious-metal-free HER catalysts with autonomous interface regulation.