Cyano and defective co-modified carbon nitride for optimized photoreformation of glucose to arabinose

Abstract

In this study, NaNO2 and NH4I were introduced during the calcination process of melamine to construct cyano-modified defective carbon nitride (NICN). The presence of cyano groups, defects, and halogens was demonstrated through a series of characterizations, and their positions in NICN were inferred. The electronic structure of NICN was simulated through theoretical calculations (DFT) to prove the rationality of our inference. The experiments on the photocatalytic conversion of glucose using these catalysts revealed that NICN has a high conversion rate for glucose (91.04%, 1 h) and a certain selectivity for arabinose in the product (the yield reaches 0.262 g/L). In addition, the adjustment of the solvent and the atmosphere have a great impact on the product. After six cycle experiments, the material's conversion rate to glucose was almost unchanged and the structure of the material was very stable. Theoretical calculations of the Fukui function of glucose, free radical capture experiments, electron paramagnetic resonance and isotope labeling proved that superoxide radicals, electrons and holes are the main reactive activities species, which further clarify the reaction mechanism of glucose into arabinose. This work affords new ideas for designing functional carbon nitride-based photocatalysts for the photocatalytic oxidation of glucose to produce arabinose.