Engineering surface bromination in carbon nitride for efficient CO₂ photoconversion to CH₄.

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Photocatalytic conversion of carbon dioxide (CO2) to methane (CH4) offers a sustainable solution for energy crisis and carbon emissions.
• Current challenges include low conversion efficiency and poor selectivity in CO2 reduction.
• Developing efficient photocatalysts is crucial for practical applications.

Purpose of the Study:

• To fabricate a stable and efficient photocatalyst for CO2 reduction to CH4.
• To investigate the role of surface bromination in enhancing photocatalytic performance.
• To understand the mechanism of enhanced CO2 activation and conversion.

Main Methods:

• Synthesis of surface brominated carbon nitride (CNBr).
• Characterization of the synthesized material.
• Photocatalytic evaluation of CO2 reduction to CH4 under solar energy.
• Density functional theory (DFT) calculations to elucidate the reaction mechanism.

Main Results:

• CNBr achieved a CO2 conversion rate of 16.68 μmol h⁻¹ g⁻¹ with 70.27% selectivity for CH4.
• Bromine substitution in CNBr promoted charge separation, narrowed the band gap, and deepened the conduction band.
• DFT calculations confirmed reduced energy barriers and accelerated reaction rates for CH4 formation.

Conclusions:

• Surface bromination of carbon nitride is an effective strategy to enhance photocatalytic CO2 reduction to CH4.
• CNBr acts as an efficient catalyst with improved light absorption, charge separation, and CO2 activation.
• This work provides a foundation for designing high-performance carbon nitride-based photocatalysts.