Engineering Double Sulfur-Vacancy in CoS_1.097@MoS₂ Core-Shell Heterojunctions for Hydrogen Evolution in a Wide pH...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Heterostructured nanomaterials offer integrated active sites for hydrogen evolution reaction (HER) catalysis.
• A key challenge is achieving sufficient active site density across a wide pH range.

Purpose of the Study:

• To design and investigate double sulfur-vacancy decorated CoS@MoS2 core-shell heterojunctions.
• To evaluate the pH-universal HER performance of these novel heterojunctions.

Main Methods:

• Synthesis of hollow CoS nanocubes with ultrathin MoS2 nanosheets.
• Electrocatalytic testing in acidic, alkaline, and neutral buffer solutions.
• Theoretical calculations to understand the role of sulfur vacancies.

Main Results:

• The CoS@MoS2 catalyst demonstrated pH-universal HER performance.
• Achieved overpotentials of 190 mV (acidic), 139 mV (alkaline), and 220 mV (neutral) at 10 mA cm-2.
• Theoretical analysis confirmed enhanced electron/mass transfer and kinetics due to sulfur vacancies.

Conclusions:

• Double sulfur vacancies are crucial for enhancing the electrocatalytic HER performance of core-shell heterojunctions.
• The designed CoS@MoS2 catalyst shows significant potential for efficient hydrogen production under diverse pH conditions.