Work

Enhanced nitrogen vacancy density induced by sulfur doping on carbon nitride facilitates selective lactic acid production

Year: 2025

Type: article

Abstract: The integration of biorefining and photocatalysis represents a highly promising approach for enabling the green and efficient synthesis of high-value chemicals derived from biomass. Herein, we successfully synthesized a metal-free carbon nitride photocatalyst with sulfur (S) doping, which induced the formation of nitrogen vacancy (NV). The optimized catalyst (S20-CN-NV) exhibits outstanding photocatalytic activity, achieving 95.5% of glucose conversion and 95.1% of lactic acid (LA) selectivity within 60 min under visible-light irradiation. Remarkably, the LA yield remains impressively high at the initial 97.5% even after 6 cycles. Experimental studies and characterizations reveal that S doping significantly increased the concentration of NV, and the synergistic effect of NV and S doping enhanced the visible-light absorption and facilitates the separation of photogenerated carriers as well as the activation of oxygen, thereby promoting the generation of superoxide radicals. Density functional theory simulations further reveal that S20-CN-NV exhibits exceptional glucose adsorption capacity and requires low activation energy in the rate-limiting step. Consequently, S doping induced the formation of NV thus boosted the photocatalytic oxidation process of glucose into LA. This study provides valuable insights for guiding the design of photocatalyst through nonmetal-doping strategy and defect engineering strategy, facilitating the efficient valorization of biomass-derived platform chemicals.

Source: Molecular Catalysis

DOI: 10.1016/j.mcat.2025.114957