Anionic Coordination-Regulated Metal-Organic Cages for Efficient CO₂ Photoreduction

Area of Science:

• Materials Science
• Catalysis
• Chemical Engineering

Background:

• Photocatalytic reduction of carbon dioxide (CO2) is a key technology for sustainable chemical and fuel production.
• A major challenge is the instability of reaction intermediates, hindering catalyst performance.
• Developing robust photocatalysts is crucial for efficient CO2 conversion.

Purpose of the Study:

• To design and synthesize novel halogen-coordinated metal-organic cages (MOCs) for enhanced photocatalytic CO2 reduction.
• To investigate the role of anionic coordination in stabilizing reaction intermediates.
• To optimize photocatalyst performance for high-value chemical production from CO2.

Main Methods:

• Synthesis of Ni8L12X4 metal-organic cages with varying halogen coordination (X = Cl, Br, I).
• Utilizing theoretical calculations to analyze reaction mechanisms and energy barriers.
• Evaluating photocatalytic CO2 reduction performance, including CO production rate and selectivity.

Main Results:

• Halogen coordination effectively stabilizes key reaction intermediates, particularly the *COOH intermediate.
• Iodide coordination significantly lowers the energy barrier for *COOH formation by enhancing electron transfer.
• Ni8L12I4 demonstrated a superior CO production rate of 2680.23 µmol g-1 h-1 with 95% selectivity.

Conclusions:

• Anionic coordination strategy using halogenated MOCs is effective for stabilizing intermediates in CO2 reduction.
• Iodide-coordinated MOCs show exceptional performance, outperforming Cl- and Br-coordinated analogues.
• This work presents a novel approach for designing efficient photocatalysts for CO2 conversion into valuable products.