Facile and Efficient Two-Step Formation of a Renewable Monomer 2,5-Furandicarboxylic Acid from Carbohydrates over the NiOx Catalyst

The formation of 2,5-furandicarboxylic acid (FDCA) from carbohydrates without a cumbersome 5-(hydroxymethyl)furfural (HMF) separation/purification process remains a formidable challenge. Herein, we prepared an innovative NiOx catalyst for the efficient oxidation of HMF to FDCA by using budget NaCIO as oxidant, which can afford high FDCA yields (94-97%) from both pure HMF and carbohydrate-derived crude HMF in only 30 min at 25 degrees C. Remarkably, an impressive FDCA formation rate of 404 mu mol g(-1) min(-1) (13-67-fold higher than those of recently reported catalytic systems for FDCA production) could be achieved over the NiOx catalyst at 25 degrees C. During the catalytic oxidation process, -Ni4+-O- sites over the NiOx catalyst are responsible for the efficient oxidation of HMF to FDCA, Furthermore, we also demonstrated a 50 g scale production of FDCA from HMF in a high yield of 96%. Therefor; the NiOx catalyst holds great promise to produce FDCA from biomassderived carbohydrates in an effective and cost-competitive two-step process.