Subnanometric Cu clusters on atomically Fe-doped MoO for furfural upgrading to aviation biofuels.

Single cluster catalysts (SCCs) are considered as versatile boosters in heterogeneous catalysis due to their modifiable single cluster sites and supports. In this work, we report subnanometric Cu clusters dispersed on Fe-doped MoO support for biomass-derived furfural upgrading. Systematical characterizations suggest uniform Cu clusters (composing four Cu atoms in average) are homogeneously immobilized on the atomically Fe-doped ultrafine MoO nanocrystals (Cu/FeMoO@C). The atomic doping of Fe into MoO leads to significantly modified electronic structure and consequently charge redistribution inside the supported Cu clusters. The as-prepared Cu/FeMoO@C shows superior catalytic performance in the oxidative coupling of furfural with CC primary/secondary alcohols to produce CC aldehydes/ketones (aviation biofuel intermediates), outperforming the conventionally prepared counterparts. DFT calculations and control experiments are further carried out to interpret the structural and compositional merits of Cu/FeMoO@C in the oxidative coupling reaction, and elucidate the reaction pathway and related intermediates.