Metal-Free Hydrogen-Bonded Polymers Mimic Noble Metal Electrocatalysts.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Platinum-based catalysts are highly active and efficient for the electrochemical hydrogen evolution reaction (HER).
• The high cost of platinum limits the widespread adoption of hydrogen as a fuel.
• Developing cost-effective and efficient alternatives to platinum is crucial for sustainable hydrogen production.

Purpose of the Study:

• To introduce a metal-free organic electrocatalyst that mimics platinum's properties for the HER.
• To investigate the efficacy of keto-amine hydrogen-bond motifs as selective reaction centers.
• To demonstrate the potential for scalable and continuous hydrogen production.

Main Methods:

• Design and synthesis of keto-amine-functionalized polymers.
• Electrochemical characterization of the catalyst's performance in HER.
• Assessment of electrochemical stability and chemical robustness over extended operation.
• Demonstration of scaled continuous-flow electrolysis.

Main Results:

• The keto-amine motif enhances the rate-determining step in proton reduction.
• The developed polymer catalyst evolves hydrogen at an overpotential of 190 mV.
• The catalyst exhibits a high work function, excellent electrochemical stability, and chemical robustness, similar to platinum.
• Continuous HER operation for one week without degradation was demonstrated.
• 1 L of molecular hydrogen was produced in under 9 hours using a small amount of polymer catalyst in a scaled continuous-flow system.

Conclusions:

• Metal-free organic electrocatalysts can effectively mimic platinum's performance for HER.
• Keto-amine functionalization provides selective reaction centers that improve catalytic efficiency.
• The developed polymer catalyst offers a stable, robust, and scalable alternative for cost-effective hydrogen production.