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

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Designing efficient and stable electrocatalysts for the hydrogen evolution reaction (HER) in acidic media is crucial for scalable hydrogen production.
• Existing catalysts often suffer from degradation or poor performance under acidic stress, limiting their practical application.

Purpose of the Study:

• To develop a multifunctional, self-stabilizing electrocatalyst capable of autonomous adaptation to acidic environments for enhanced HER.
• To investigate the role of a dynamically responsive Ni-S vacancy interface in catalyst performance and stability.

Main Methods:

• Synthesis of a carbon-encapsulated Cd₀.₉Ni₀.₁S electrocatalyst (C@Cd₀.₉Ni₀.₁S).
• Characterization using Density Functional Theory (DFT) and operando X-ray Photoelectron Spectroscopy (XPS).
• Electrochemical testing to evaluate HER performance and stability in acidic conditions.

Main Results:

• The C@Cd₀.₉Ni₀.₁S catalyst demonstrated a low overpotential of -0.24 V at 100 mA cm⁻² and maintained stability at 500 mA cm⁻² for 10 days without metal leaching.
• Ni doping and sulfur vacancies were shown to reprogram the electronic structure, lowering hydrogen adsorption free energy and promoting hydrogen spillover.
• DFT and operando XPS confirmed the adaptive modulation of the Ni-S vacancy interface, enabling intelligent surface response during HER.

Conclusions:

• The developed C@Cd₀.₉Ni₀.₁S electrocatalyst exhibits excellent acid stability and high HER activity due to its self-stabilizing and dynamically responsive interface.
• This work provides a rational design framework for developing robust, precious-metal-free HER catalysts with autonomous interface regulation for sustainable hydrogen production.