Boosting the Acid Sites and Lattice Oxygen Activity of the Fe–Cu Catalyst for One-Pot Producing 2,5-Diformylfuran from Fructose

In this work, we developed a novel binary phosphate catalyst FeCuPOx for the one-pot synthesis of 2,5-diformylfuran (DFF) from fructose. Under typical reaction conditions, 95% yield of DFF was achieved with a high TOF of 818 h–1. The experiment results and catalyst characterization together indicated that both the Brønsted–Lewis acid sites (B–L) and the Fe–Cu active sites contributed to the high synthetic activity of the catalysts. The effect of acid site demonstrated that the Brønsted acid sites facilitated the conversion of fructose to 5-hydroxymethylfurfural (HMF), and the Lewis acid sites promoted the adsorption of the hydroxyl group over the catalytic active centers for further efficient oxidation of HMF to DFF. In the oxidation process, a higher lattice oxygen ratio and better mobility endowed FeCuPOx with better catalytic performance in the oxidation of HMF to DFF with the redox cycle of Fe3+/Fe2+, improved by the redox cycle of Cu2+/Cu+. Moreover, the catalyst exhibited satisfying stability and recyclability, demonstrating great potential for the industrial production of DFF from fructose.