Molecular engineering optimized carbon nitride photocatalyst for CO2 reduction to solar fuels

Abstract

The structural alteration of carbon nitride (CN) for photocatalytic CO 2 reduction is a promising research topic in the environmental and energy sectors. This work discusses the fabrication of photocatalyst through a heterojunction architecture obtained from the molecular engineering of electron-rich organic monomer 2,6-pyridinedicarboxylic acid (PDA) with CN precursor (CN/PDA x ). The successful integration of PDA in the structure of CN served as a charge inducting entity to enhance charge separation and photocatalytic CO 2 reduction under visible light (λ = 420 nm). The DFT results indicated that the upshift in the HOMO level of CN after integration of PDA in its framework was the most lawful for the charge separation and for obtaining a high reduction potential. As-synthesized photocatalysts were demonstrated for various integral analysises and after evaluating the process of photocatalytic CO 2 reduction under visible light region (λ = 420 nm). The optimized sample CN/PDA 10 has the most excellent photocatalytic activity producing 85.4 μmol/h of CO and 21.3 μmol/h of H 2 , achieving a 7.5-fold enhanced catalytic efficiency as compared to pure CN. We hope that this work will attract more attention to synthesizing efficient photocatalysts for energy production and environmental remediation. • Organic monomer 2,6-pyridinedicarboxylic acid (PDA) within CN framework (CN/PDAx). • A copolymerization process occur as a nucleophilic reaction b/w CN/PDAx. • Samples demonstrating remarkable photocatalytic CO 2 reduction under visible light. • The DFT results indicate charge separation for obtaining a high reduction potential. • The optimized sample CN/PDA 10 producing 85.4 μ mole CO and 21.3 μmole H 2 .