Hemin Molecular Catalyst with Axial Cl-Fe Coordination for Selective and Stable Acidic Chlorine Evolution

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• The chlorine evolution reaction (CER) is crucial for industrial chlorine production.
• Noble oxide catalysts face challenges in selectivity and cost for CER, with competition from the oxygen evolution reaction (OER).

Purpose of the Study:

• To investigate Hemin as a molecular catalyst for the chlorine evolution reaction (CER).
• To understand the mechanism behind Hemin's high selectivity and stability in CER.
• To provide insights for designing efficient molecular electrocatalysts.

Main Methods:

• Electrochemical analysis
• Spectroscopic analysis
• Using Hemin as a model molecular catalyst for CER in acidic brine.

Main Results:

• Hemin achieved an overpotential of ~190 mV at 10 mA cm⁻² with ~100% chlorine selectivity.
• Demonstrated excellent stability over 100 hours in corrosive acidic brine.
• Identified the axial Cl-Fe interaction and the macrocycle's electronic effects as key to stability and selectivity.

Conclusions:

• Hemin acts as an efficient and stable molecular catalyst for CER.
• The molecular structure and electronic properties of Hemin are crucial for suppressing side reactions and enhancing durability.
• This work provides a foundation for designing advanced molecular electrocatalysts for chlorine production.