Interfacial Engineering of MoS₂@CoS₂ Heterostructure Electrocatalysts for Effective pH-Universal Hydrogen Evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient and earth-abundant electrocatalysts are crucial for practical hydrogen evolution reaction (HER).
• Developing catalysts that operate effectively across a wide pH range remains a significant challenge.

Purpose of the Study:

• To design and synthesize a novel heterojunction electrocatalyst, MoS₂@CoS₂, incorporating sulfur vacancies.
• To investigate the catalytic performance of the MoS₂@CoS₂ heterojunction for the hydrogen evolution reaction (HER) across a broad pH spectrum.

Main Methods:

• Fabrication of a MoS₂@CoS₂ heterojunction with controlled sulfur vacancies.
• Electrochemical characterization of the HER activity in various electrolytes (1.0 M KOH, 0.5 M H₂SO₄, 1.0 M PBS).
• Analysis of catalytic performance using overpotential and Tafel slope measurements.

Main Results:

• The MoS₂@CoS₂ heterojunction exhibited remarkable HER activity with low overpotentials (48 mV in KOH, 62 mV in H₂SO₄, 164 mV in PBS) at 10 mA cm^-2.
• Achieved low Tafel slopes (43 mV dec^-1 in KOH, 32 mV dec^-1 in H₂SO₄, 62 mV dec^-1 in PBS), indicating efficient kinetics.
• The synergistic effects between MoS₂ and CoS₂, enhanced by sulfur vacancies, facilitated electron transfer and improved catalytic performance.

Conclusions:

• The MoS₂@CoS₂ heterojunction with sulfur vacancies is a highly efficient electrocatalyst for HER over a wide pH range.
• The study highlights the importance of interfacial engineering and defect control in designing advanced electrocatalysts.
• This work provides a valuable model for developing next-generation earth-abundant electrocatalysts for sustainable energy applications.