Vitamin B₁₂ on Graphene for Highly Efficient CO₂ Electroreduction.

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• Developing efficient catalysts for electrochemical CO2 reduction is crucial for sustainable energy.
• Hybrid catalysts combining homogeneous and heterogeneous systems offer advantages but face challenges in robustness and availability.
• Vitamin B12, a naturally abundant molecule, presents potential as a catalytic component.

Purpose of the Study:

• To develop a highly active, selective, and stable electrocatalyst for CO2 reduction.
• To investigate the synergistic effects of Vitamin B12 immobilized on reduced graphene oxide (rGO).
• To understand the role of the benzimidazole unit in the catalytic mechanism using DFT.

Main Methods:

• Immobilization of cobalt and benzimidazole-containing Vitamin B12 onto reduced graphene oxide (rGO).
• Electrochemical CO2 reduction experiments in an aqueous buffer solution (pH 7.2).
• Characterization of catalytic performance including Faradaic efficiency (FE), partial current density (jCO), and turnover frequency (TOF).
• Density Functional Theory (DFT) calculations to elucidate the catalytic mechanism.

Main Results:

• The hybrid catalyst achieved high selectivity (>94%) for CO production from CO2 reduction.
• Constant current density was maintained for over 10 hours, demonstrating excellent stability.
• A Faradaic efficiency of 94.5% for CO was obtained at an overpotential of 690 mV.
• High partial current density (up to 13.6 mA cm-2) and turnover frequency (up to 52.4 s-1) were achieved.

Conclusions:

• The immobilized Vitamin B12 on rGO serves as an efficient and robust electrocatalyst for CO2 reduction.
• This work demonstrates the first use of a naturally abundant vitamin immobilized on a conductive surface for highly efficient CO2 electroreduction.
• The findings highlight a promising strategy for developing sustainable catalysts for CO2 conversion.