Regulating Intermediate Adsorption and Promoting Charge Transfer of CoCr-LDHs by Ce Doping for Enhancing Electrooxidation of 5-Hydroxymethylfurfural

Electrochemical oxidation of 5-hydroxymethylfurfural (HMFOR) to generate high-value chemicals under mild conditions acts as an energy-saving and sustainable strategy. However, it is still challenging to develop electrocatalysts with high efficiency and good durability. Here, nickel foam (NF) supported CoCrCe(7.5%)-LDH (layered double hydroxides) by doping Ce into CoCr-LDH show high 5-hydroxymethylfurfural (HMF) conversion (99%), 2,5-furandicarboxylic acid (FDCA) yield (99%), and Faraday efficiency (100%) at 1.4 V_RHE. The CoCrCe(7.5%)-LDH also exhibits remarkable stability with 97% conversion of HMF after 10 cycles. The X-ray absorption near-edge spectroscopy (XANES) and theoretical calculation show that Ce doping into CoCr-LDH is beneficial to the formation of high-valance Co and significantly facilitates the electron transfer, regulates the adsorption behavior of intermediates, reduces the Gibbs free energy barrier and accelerates the reaction rate. This work promotes the use of rare earth elements as electrocatalysts to promote the oxidation of HMF.