Photo-induced Selective Oxidation Of 5-hydroxymethylfurfural Catalyzed By Co₃O₄/C₃N₄ Composite

In recent years,the depletion of fossil fuels has been increasing,and the greenhouse effect has become more and more serious.Therefore,the conversion of renewable resources to value-added chemicals has received increasing attention.From the perspective of green chemistry and sustainable development,photocatalytically oxidize 5-hydroxymethylfurfural?HMF?to 2,5-diformylfuran?DFF?and 2,5-furandicarboxylic acid?FDCA?are of great significance.In this paper,the performance of Co₃O₄/C₃N₄ composite catalyst for photocatalytic HMF selective oxidation to DFF was studied.The g-C₃N₄ catalyst was prepared by high-temperature roasting method using melamine as the raw material,and Co₃O₄ nanoparticles were successfully supported on the g-C₃N₄ surface to obtain the Co₃O₄/C₃N₄ composite catalyst for photocatalytic activity test.The study found that with the extension of the reaction time,the yield and selectivity of DFF will increase first and then decrease.When the reaction is carried out for 7 h,the yield and selectivity of DFF are 16.87% and 18.35%,respectively;using acetonitrile as the solvent The yield and selectivity of DFF increased by 43.44% and 54.66%,respectively.After loading Co₃O₄,the photocatalytic performance test was conducted and it was found that the yield and selectivity of DFF were improved.Among them,the catalyst Co₃O₄?1%?/gC₃N₄ has the best catalytic effect,the yield of DFF is 49.67%,and its selectivity is 64.81%.According to the experimental results,the mechanism of action of the catalysts g-C₃N₄ and Co₃O₄/C₃N₄ was proposed,and the main active substance was clarified as ·O2-.Co₃O₄ supported on g-C₃N₄ can avoid the electron-hole recombination on the surface of g-C₃N₄.Increase the production of active material ·O2-and improve the catalytic performance of the reaction.In order to further explore the performance of the catalyst Co₃O₄/C₃N₄ to catalyze the oxidation of HMF to produce FDCA,this thesis tested the photocatalytic performance of the catalyst Co₃O₄/C₃N₄ under alkaline conditions.It was found that under strong alkaline conditions,the Cannizzaro reaction can occur to obtain FDCA.In addition,MnO₂ can generate holes with higher energy.In order to compare it with Co₃O₄,a composite catalyst catalyst MnO₂/g-C₃N₄ was prepared and a performance test of photocatalytic oxidation of HMF to prepare FDCA was carried out.A small amount of FDCA.