Surface chemistry regulation on particle-support interaction of ruthenium and Cr-Fe oxides for selective oxidation of 5-hydroxymethylfurfural

The selective oxidation of 5-hydroxymethylfurfural (HMF) into 2,5-furandicarboxylic acid (FDCA) is an essential reaction to produce a wide variety of fine chemicals and polymers. To promote the selectivity and the product yield, cost-effective catalysts are highly required. Particularly, support-type catalysts, which are generally composed of a specific noble metal particle loaded onto a suitable support, are well recognized as promising candidates. Herein, ruthenium nanoparticles loaded on the Cr-Fe-O support (Ru/Cr-Fe-O) are synthesized and used for the selective oxidation of HMF to produce FDCA. Contributed by the particle-support interaction, the resultant Ru/Cr-Fe-O catalysts deliver good low-temperature reducibility and hold abundant weak acid sites. Under the optimal reaction conditions, in which the reaction time was 16 h at an oxygen pressure of 1 MPa and a reaction temperature of 100 °C in a weak base system, a HMF conversion ratio of 100 % and a FDCA yield of 99.9 % are achieved. Further characterizations reveal that the activities are largely associated with the surface chemistry states of the Ru/Cr-Fe-O catalyst. This work offers some insights into the rational selection of support-type catalysts for selective oxidization reactions.