Efficient hydrogen evolution catalysis using ternary pyrite-type cobalt phosphosulphide.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient hydrogen evolution reaction (HER) catalysts are crucial for sustainable hydrogen fuel production via water splitting.
• Earth-abundant materials are sought to replace expensive noble metal catalysts.
• Tuning catalyst properties through elemental substitution, like in pyrite structures, can enhance HER activity.

Purpose of the Study:

• To investigate ternary pyrite-type cobalt phosphosulphide (CoPS) as a novel Earth-abundant HER catalyst.
• To evaluate the performance of CoPS in both electrochemical and photoelectrochemical water splitting.
• To establish CoPS as a high-performance catalyst for hydrogen generation.

Main Methods:

• Combined theoretical and experimental approaches were used to study CoPS.
• Nanostructured CoPS electrodes were fabricated and tested for HER activity.
• CoPS was integrated onto silicon micropyramids for photoelectrochemical water splitting evaluation.

Main Results:

• CoPS electrodes exhibited a current density of 10 mA cm⁻² at a low overpotential of 48 mV.
• Outstanding long-term operational stability was observed for CoPS catalysts.
• Integrated CoPS photocathodes achieved high photocurrents (35 mA cm⁻²) and onset photovoltages (450 mV vs RHE).

Conclusions:

• Ternary cobalt phosphosulphide (CoPS) is a highly effective and stable Earth-abundant catalyst for HER.
• CoPS shows significant promise for efficient electrochemical and photoelectrochemical hydrogen production.
• This work advances the development of cost-effective systems for solar-driven hydrogen generation.