Synergistic Co-doping and Te-defects engineering in NiTe₂ single-crystals for enhanced hydrogen evolution in acidic...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Transition metal dichalcogenides (TMDs) are promising hydrogen evolution reaction (HER) catalysts.
• Nickel telluride (NiTe₂) exhibits limitations in hydrogen adsorption energy and active site density for efficient HER.

Purpose of the Study:

• To enhance the HER performance of NiTe₂ in both acidic and alkaline electrolytes.
• To develop a synergistic strategy involving cobalt doping and tellurium vacancy engineering.

Main Methods:

• Synthesized single-crystal Ni₁-ₓCoₓTe₂ with controlled cobalt doping and Te vacancies.
• Characterized the structural and electronic properties of the modified catalysts.
• Evaluated the electrocatalytic activity and stability for HER.

Main Results:

• Co doping reduced charge transfer resistance by 80% and induced lattice contraction.
• Te vacancies increased active site density, enhancing double-layer capacitance by 31%.
• Optimized Ni₀.₆Co₀.₄Te₂ achieved near-ideal hydrogen adsorption energy and ultralow overpotentials (419 mV acidic, 362 mV alkaline) with >80 h stability.

Conclusions:

• Synergistic Co doping and Te vacancy engineering effectively optimize NiTe₂ for bifunctional HER catalysis.
• The developed strategy offers a scalable approach for designing efficient electrocatalysts for acidic and alkaline media.