Oxygen-tolerant hydrogen evolution in water using Schiff base copper complexes with tuneable secondary coordination...

Area of Science:

• Green hydrogen production
• Electrocatalysis
• Sustainable energy

Background:

• Green hydrogen is crucial for renewable energy transition.
• Efficient electrocatalysts are needed for hydrogen generation in water.
• Existing catalysts often lack resilience to oxygen and specific pH conditions.

Purpose of the Study:

• To design and synthesize water-soluble copper complexes for electrocatalytic hydrogen evolution.
• To investigate the effect of secondary coordination sphere modifications on catalytic activity.
• To understand the mechanism of hydrogen generation and catalyst stability.

Main Methods:

• Synthesis of N₂O₂ Schiff base copper complexes with varying ortho-substituents.
• Electrochemical techniques (e.g., cyclic voltammetry, chronoamperometry) for activity and efficiency assessment.
• Spectroscopic and spectroelectrochemical methods for mechanistic elucidation.

Main Results:

• A series of water-soluble copper complexes were synthesized and tested.
• The hydroxyl-substituted complex demonstrated the highest catalytic activity (TON ~1450, 80% Faradaic efficiency at pH 5.0).
• Mechanistic studies revealed the importance of the Cu(II/I) redox couple and proton-shuttling groups.

Conclusions:

• Developed efficient, cost-effective, and oxygen-resilient copper-based catalysts for green hydrogen production.
• Demonstrated catalyst stability under aerobic and mildly acidic conditions.
• The findings support the practical application of these catalysts in scalable green hydrogen frameworks.