Oxidation State of Highly Dispersed Pt Subnanoclusters Correlates with d–p Orbital Hybridization for 100% Selectivity in Furfural Hydrogenation

The C═O selective hydrogenation of furfural (FAL) is challenging due to the competitive adsorption of C═C and C═O. Herein, Pt nanoclusters with different average valences are synthesized by the deposition precipitation strategy. Notably, the FAL hydrogenation activity shows a volcano trend with increasing Pt average valence. Importantly, the Pt nanocluster catalyst with an average valence of +0.97 (Pt cluster-300) exhibits a 99.6% FAL conversion and 100.0% furfuryl alcohol (FOL) selectivity during furfural hydrogenation, close to the world record level. UV–visible spectroscopy studies indicate that Pt cluster-300 exhibits the highest adsorption capacity for FAL compared to other catalysts in this study. Further theoretical calculations reveal the high catalytic activity of Pt cluster-300 mainly derives from the higher hybridization between the d orbital of Pt and the 2p orbital of C═O bond in FAL molecules, indicating the moderate Pt valence exhibits better ability to activate the C═O bond in FAL and thus enhancing the hydrogenation kinetics. This work provides insight into the influence mechanism of metal valence during hydrogenation reactions.