Dual-Functional Medium-Entropy Quinary Sulfides for Photocatalytic Hydrogen Evolution and Ethylene Glycol Oxidation
Tanu Bagaria1,2, Brajesh Rajesh Bhagat1, Srija Ghosh1
1Research Institute for Sustainable Energy (RISE), TCG Centres for Research and Education in Science and Technology (TCG-CREST), Salt Lake, Kolkata 700091, India.
Langmuir : the ACS Journal of Surfaces and Colloids
|December 30, 2025
Summary
A new quinary sulfide photocatalyst efficiently produces hydrogen from water using solar energy. This stable, earth-abundant catalyst shows enhanced performance in freshwater, seawater, and for chemical production.
Area of Science:
- Materials Science
- Photocatalysis
- Renewable Energy
Background:
- Solar hydrogen production via water splitting is crucial for clean energy.
- Developing efficient and stable hydrogen evolution reaction (HER) catalysts is key.
- Current catalysts often require cocatalysts or have limitations in stability and efficiency.
Purpose of the Study:
- To synthesize a novel medium-entropy quinary sulfide photocatalyst for direct H2 production.
- To investigate the catalyst's performance in water splitting and its stability.
- To explore its potential for value-added chemical generation and use in artificial seawater.
Main Methods:
- Hydrothermal synthesis of Cd1-x-yNixMoyZn0.45S (quinary sulfide photocatalyst).
- Characterization of crystalline structure and composition.
- Evaluation of photocatalytic H2 evolution rates under solar irradiation.
- Density Functional Theory (DFT) for active site analysis.
- Testing in freshwater, artificial seawater, and with ethylene glycol (EG) as a sacrificial agent.
Main Results:
- The optimal composition, Cd0.39Ni0.09Mo0.07Zn0.45S (CNMZS-3), showed a 6-fold increase in H2 evolution rate (2437.87 μmol g-1 h-1) compared to CdS.
- CNMZS-3 demonstrated excellent stability over 72 hours.
- DFT revealed Mo as the active site for H adsorption and Ni for photoabsorption, creating a synergistic effect.
- H2 production increased to 3746.74 μmol g-1 h-1 with EG oxidation, producing formate.
- Effective H2 evolution (1786.79 μmol g-1 h-1) was achieved in artificial seawater.
Conclusions:
- Medium-entropy quinary sulfides are effective, stable, and versatile photocatalysts for H2 production.
- The engineered catalyst reduces reliance on Cd while maintaining high performance.
- This technology shows promise for sustainable H2 generation from various water sources and for producing valuable chemicals.
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