Highly efficient amorphous binary cobalt-cerium metal oxides for selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran

This study reports for the first time the use of amorphous mixed cobalt-cerium metal oxides (Co10-aCeaOx), obtained by photochemical metal-organic deposition, for 5-hydroxymethylfurfural (HMF) oxidation. The optimized Co8Ce2Ox exhibites a good electrocatalytic activity toward HMF oxidation with a current density of 2.8 mA cm(-2) at 1.60 V, which is 1.4 times higher than that of pure CoOx. Operando Raman spectra reveal that the incorporation of Ce alters the electronic structure of the composite by facilitating the formation of CoOOH/CoO2, thus promoting catalytic activity. Notably, it is found that the oxidation of HMF proceeds dominantly via the oxidation of the alcohol group, followed by its subsequent oxidation in both alkaline and neutral media. Due to the stability of the aldehyde group in neutral media, high valuable 2,5-diformylfuran (DFF) with the selectivity of 60%-92% is obtained, thus open the new route for electrocatalytic DFF production. (C) 2021 Elsevier Inc. All rights reserved.