Efficient electrocatalytic hydrogen gas evolution by a cobalt-porphyrin-based crystalline polymer

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts for the hydrogen evolution reaction (HER) is crucial for sustainable energy technologies.
• Cobalt-porphyrin complexes are promising candidates due to their catalytic activity.

Purpose of the Study:

• To synthesize and characterize a crystalline cobalt-porphyrin-based polymeric system.
• To evaluate its performance as an electrocatalyst for HER in acidic aqueous media.

Main Methods:

• Powder X-ray diffraction (p-XRD), FT-IR, EDX, SEM, and TEM for material characterization.
• Linear sweep voltammetry to assess HER catalytic performance in 0.5 M H2SO4.
• Electrochemical stability testing over 10 hours.

Main Results:

• The polymeric system (1) exhibits a significantly higher surface area (441.74 m³ g⁻¹) compared to the discrete molecule (2) (3.44 m³ g⁻¹).
• Polymer 1 requires a lower overpotential (0.475 V) to achieve 10 mA cm⁻² cathodic current density than molecule 2 (0.666 V).
• The polymer demonstrated excellent stability and activity for HER electrolysis in acidic conditions for over 10 hours.

Conclusions:

• The extended network of the cobalt-porphyrin polymer enhances HER efficiency.
• This polymeric material represents a promising electrocatalyst for hydrogen production in acidic environments.
• The study highlights the potential of porphyrin-based polymers in catalysis.