A Co-MOF-derived Co₉S₈@NS-C electrocatalyst for efficient hydrogen evolution reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient hydrogen evolution reaction (HER) electrocatalysts are crucial for sustainable clean energy.
• Developing high-performance and durable HER catalysts remains a significant challenge.

Purpose of the Study:

• To fabricate and characterize a novel Co9S8 nanoparticles embedded in a porous N,S-dual doped carbon composite (Co9S8@NS-C-900).
• To evaluate the electrocatalytic activity and long-term durability of the Co9S8@NS-C-900 for HER in alkaline media.

Main Methods:

• Synthesis of Co9S8@NS-C-900 via pyrolysis of a single crystal Co-MOF with thiourea.
• Electrochemical characterization of the catalyst for HER performance, including overpotential, Tafel slope, and exchange current density.
• Assessment of long-term durability through potential cycling and extended chronoamperometry tests.

Main Results:

• The Co9S8@NS-C-900 catalyst exhibited excellent HER activity with a low overpotential of -86.4 mV at 10.0 mA cm-2 and a Tafel slope of 81.1 mV dec-1.
• A high exchange current density (J0) of 0.40 mA cm-2 was achieved, comparable to commercial Pt/C catalysts.
• The catalyst demonstrated exceptional long-term durability, retaining 99.5% of its initial current after 48 hours and showing no significant decay after 1000 potential cycles.

Conclusions:

• The synergistic effect between Co9S8 nanoparticles and the N,S-dual doped carbon matrix enhances HER electrocatalytic performance.
• The N,S-dual doped carbon shell effectively protects the Co9S8 nanoparticles, leading to superior stability.
• Co9S8@NS-C-900 is a promising, cost-effective alternative to noble metal catalysts for HER in alkaline environments.