Solvent and light-controlled selective photo-oxidation of furfural into high value-added chemicals using sulfated g-C3N4 as photocatalyst†

Furfural is a compound derived from renewable lignocellulosic biomass. Furfural's highly functionalized molecular structure enables its conversion into fossil fuel alternatives and valuable chemicals. The selective oxidation of furfural into high-value-added chemicals is a pivotal process in sustainable chemical synthesis. This study explores a tunable approach to the photo-oxidation of furfural using sulfated graphitic carbon nitride (g-C₃N₄) as a photocatalyst, with reaction selectivity modulated by solvent choice and light wavelength. Sulfuric acid modification of g-C₃N₄ enhances its photocatalytic performance by increasing surface acidity and optimizing its electronic properties, improving light absorption and charge separation. Our results reveal that the choice of solvent plays a critical role in dictating the reaction pathway, enabling the selective production of key chemicals such as furan, maleic acid, and succinic acid. Furthermore, the wavelength of light irradiation provides an additional level of control, allowing fine-tuning of product selectivity under identical conditions. This dual modulation highlights the dynamic interplay between the reaction environment and photocatalytic activity. The findings present sulfated g-C₃N₄ as an efficient and versatile photocatalyst for the green transformation of biomass-derived furfural, with potential implications for industrial applications in renewable chemical production. This study underscores the importance of combining material modification with reaction environment engineering to achieve high-efficiency catalytic processes.