Highly selective oxidation of 5-HMF to HMFCA via a facile Pt-Ag co-catalytic strategy

5-Hydroxymethyl-2-furancarboxylic acid (HMFCA) is an important feedstock in chemical and pharmaceutical industries. Its production through aerobic conversion of 5-hydroxymethylfurfural (5-HMF) has promising prospects but is challenged by the over-oxidation. In this work, we develop a refined Pt-Ag co-catalytic strategy to tailor the selectivity of 5-HMF’s aerobic oxidation. By simple in situ addition of AgNO to the thermal catalytic system of Pt nanoparticles, the main products of 5-HMF oxidation could be shifted from 2,5-furandicarboxylic acid (FDCA) to HMFCA with an ultrahigh selectivity of over 99 %. Density functional theory calculations demonstrate that such strategy could alter the HMFCA adsorption sites from Pt to Ag sites and prevent the oxidation of hydroxymethyl group. In addition, this strategy can be extended to other Ag species, such as AgCl, AgO and AgO. This work provides insights into the Pt-Ag synergistic catalysis and opens up a simple avenue to control the product selectivity for biomass refinement.