Synergistic interaction between Cu single atoms and Cu nanoclusters boosting the selective oxidation of 5-hydroxymethylfurfural

Catalysts with both metal single atoms and nanoclusters have drawn great attention due to their distinctive catalytic activity and selectivity. Herein, Cu single atoms and Cu nanoclusters are homogeneously dispersed on a porous N-doped carbon framework (Cu 1 Cu n @CN) via an encapsulation pyrolysis strategy. In the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), around 100% yield of DFF is achieved over the as-synthesized Cu 1 Cu n @CN under air atmosphere and mild reaction conditions. Density function theory studies demonstrate that the strong interaction between the CuN and Cu cluster sites contributes to the up-shift of the d-orbital center of Cu in Cu 1 Cu n @CN and the Cu clusters can induce obvious electron redistribution around the CuN active center, which significantly improves the capability in substrate adsorption and activation. This work might provide new insights into the design and construction of catalysts with both metal single atoms and nanoclusters and investigations on their synergistic interactions for advanced catalysis applications.