Atomically dispersed dinuclear iridium active sites for efficient and stable electrocatalytic chlorine evolution...

Area of Science:

• Electrochemistry
• Catalysis
• Materials Science

Background:

• The chlorine evolution reaction (CER) is crucial for chlor-alkali electrolysis.
• Current precious metal catalysts are expensive and lack selectivity due to competing oxygen evolution reaction (OER).
• Single-atom catalysts (SACs) offer high atom efficiency but often overlook site interactions.

Purpose of the Study:

• To design and synthesize a novel catalyst with atomically dispersed dinuclear active sites for enhanced CER.
• To investigate the role of adjacent atomic site interactions in catalytic performance.
• To improve the selectivity and efficiency of the chlorine evolution reaction.

Main Methods:

• A "precursor-preselected" cage-encapsulation strategy was employed.
• Synthesis of atomically dispersed dinuclear iridium active sites bridged by oxygen on nitrogen-doped carbon (Ir₂-ONC).
• Electrochemical characterization and Density Functional Theory (DFT) & ab initio molecular dynamics (AIMD) simulations.

Main Results:

• The Ir₂-ONC catalyst demonstrated a low CER onset potential (1.375 V vs. NHE).
• Achieved high faradaic efficiency (>95%) and mass activity (14321.6 A gIr⁻¹).
• Outperformed conventional Ir SACs, indicating the benefit of dinuclear active sites.

Conclusions:

• The unique dinuclear iridium structure significantly enhances CER performance.
• Coordination and electronic structure regulation of atomically dispersed sites are critical.
• This work provides a new avenue for designing advanced catalysts by considering adjacent site synergy.