In situ evolved high-valence Co active sites enable highly efficient and stable chlorine evolution reaction

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• The chlor-alkali process is essential for chemical production but is highly energy-intensive, accounting for 4% of global electricity.
• Existing chlorine evolution reaction (CER) electrocatalysts suffer from high overpotential and low selectivity, necessitating precious metals and increasing energy demands.

Purpose of the Study:

• To develop a novel, precious metal-free electrocatalyst for the chlorine evolution reaction (CER) with enhanced performance.
• To investigate the catalytic mechanism and structure-activity relationship of the new electrocatalyst.

Main Methods:

• Synthesis of a hollow nanocube structured (CoZn)3V2O8@C electrocatalyst.
• Electrochemical characterization of the catalyst for CER performance (overpotential, selectivity, durability).
• In situ characterization, comparative experiments, and density functional theory (DFT) calculations to elucidate the catalytic mechanism.

Main Results:

• The (CoZn)3V2O8@C catalyst achieved an exceptionally low overpotential of 69 mV and selectivity exceeding 90% for CER.
• The catalyst demonstrated high durability, operating for 250 hours at 10 mA/cm², outperforming commercial dimensionally stable anodes (DSA).
• DFT calculations and experimental results indicated that in situ formed high-valence Co, facilitated by Zn vacancies, is key to the enhanced catalytic activity.

Conclusions:

• The developed (CoZn)3V2O8@C hollow nanocube is a highly efficient and durable precious metal-free electrocatalyst for the chlor-alkali process.
• The presence of Zn vacancies in the catalyst structure plays a critical role in optimizing the electronic properties of cobalt, thereby boosting CER performance.
• This work offers a promising pathway towards more sustainable and energy-efficient industrial chemical production.