Carbon-armored Co9S8 nanoparticles as all-pH efficient and durable H2-evolving electrocatalysts

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient, non-noble-metal catalysts is crucial for sustainable hydrogen production via water splitting.
• Cobalt pentlandite (Co9S8) nanoparticles show initial promise for the hydrogen evolution reaction (HER) but lack stability across a wide pH range.

Purpose of the Study:

• To develop a durable and highly active noble-metal-free catalyst for the hydrogen evolution reaction (HER) across all pH values.
• To enhance the electrochemical performance of cobalt pentlandite (Co9S8) for water splitting.

Main Methods:

• Synthesized carbon-armored cobalt pentlandite nanoparticles (Co9S8@C) using a direct thermal treatment method with cobalt nitrate and trithiocyanuric acid.
• Investigated the catalytic activity and durability of Co9S8@C for HER in acidic, neutral, and basic media.

Main Results:

• Co9S8@C nanoparticles demonstrated excellent catalytic activity and stability for HER over a broad pH range (0-14).
• Achieved nearly 100% Faradaic efficiency for HER in acidic, neutral, and basic solutions.
• This represents the first transition-metal chalcogenide with efficient and durable all-pH electrocatalytic activity for water splitting.

Conclusions:

• Carbon-armoring is an effective strategy to improve the pH stability and catalytic performance of Co9S8 for water splitting.
• Co9S8@C is a promising noble-metal-free electrocatalyst for efficient hydrogen production.
• The findings provide a new direction for designing advanced water splitting catalysts.