Atomic-Interface Effect of Single-Atom Ru/CoOx for Selective Electrooxidation of 5-Hydroxymethylfurfural

The development of single-atom catalysts with effective interfaces for biomass conversion is a promising but challenging research area. In this study, a Ru₁/CoO_x catalyst was successfully fabricated with the impregnation method, which featured Ru single atoms on a cobalt oxide substrate. The Ru₁/CoO_x catalyst showed superior performance in the selective electrooxidation of 5-hydroxymethylfurfural (HMF) to produce 2,5-furandicarboxylic acid (FDCA), a high value-added product. The introduction of Ru single atoms with an ultralow loading of ∼0.5 wt % was revealed to accelerate the electroredox of Co²⁺/Co³⁺/Co⁴⁺ and improve the intrinsic activity of the CoO_x substrate with an FDCA selectivity of 76.5%, which is better than that of the pristine CoO_x electrocatalysts (62.7%). The interfacial synergistic effect of the Ru₁/CoO_x interface clarified that Ru single atoms can enhance the adsorption of HMF at the Ru₁/CoO_x interface, which promoted the rate-determining step of the selective C-H bond activation for FDCA production. This finding provides valuable insights into the rational design of single-atom catalysts with functional interfaces for biomass upgrading.