Poly-Phosphamide Catalyzed Visible-Light-Driven CH₄ and Dark-Phase-Mediated Cyclic Carbonate Productions Utilizing...

Area of Science:

• Materials Science
• Photocatalysis
• Green Chemistry

Background:

• Carbon dioxide (CO2) utilization is crucial for mitigating climate change.
• Developing efficient and recyclable catalysts for CO2 conversion is a significant challenge.

Purpose of the Study:

• To synthesize and characterize a poly-phosphamide (POP) material for CO2 conversion.
• To investigate the photocatalytic and chemical conversion of CO2 into valuable feedstocks.
• To evaluate the recyclability and efficiency of the POP material.

Main Methods:

• Synthesis of poly-phosphamide (POP).
• Photocatalytic conversion of CO2 to CH4 using visible light (420 nm) with co-catalysts (triethanolamine or ascorbic acid).
• Chemical conversion of CO2 and organo-epoxides to cyclic carbonates under solvent-free conditions.
• Characterization using Tauc plot, Mott Schottky analysis, FTIR, and electrochemical methods.
• Recyclability tests over multiple cycles.

Main Results:

• POP exhibits a band gap of 2.8 eV and a conduction band potential of -1.49 V (vs NHE).
• Photocatalytic conversion of CO2 to CH4 achieved ≈99% selectivity and 4.6 mmol g⁻¹ yield.
• Chemical conversion of CO2 to cyclic carbonates yielded >98%.
• POP demonstrated high photon-harvesting efficiency and stability, with successful recycling at least five times without degradation.

Conclusions:

• Poly-phosphamide (POP) is a bifunctional, recyclable polymeric organic material for efficient CO2 conversion.
• POP effectively converts CO2 into methane and cyclic carbonates under mild conditions.
• The material shows promise for sustainable CO2 utilization and feedstock production.