In a pioneering study recently published online in the National Science Review, a team led by Professors Hai-long Jiang and Tao Yao from the University of Science and Technology of China has made a significant discovery. The research indicates that the catalytic performance of metal nanoclusters can be significantly enhanced by systematically modulating the interactions between metal nanoclusters and the ligands on their surface when encapsulated within MOFs.
Using a synergistic self-assembly strategy, the team successfully embedded Au25(Cys)18 nanoclusters into M-MOF-74 (where M = Zn, Ni, Co, Mg). The study revealed that the encapsulated Au25(Cys)18 nanoclusters exhibited different fluorescent properties compared to their free state, attributed to the spatial confinement imposed by the MOF on the vibrational patterns of the surface ligands, which in turn significantly improved the catalytic performance of the nanoclusters in the tandem hydrogenation reaction of 2-nitrobenzonitrile.
Furthermore, X-ray absorption spectroscopy analysis showed that the electronic density and the core Au–Au bond length of the Au25(Cys)18 nanoclusters could be systematically adjusted based on the interaction strength between M-MOF-74 and nanoclusters. This adjustment enhanced the catalytic accessibility of the nanoclusters and facilitated electron transfer between the nanoclusters and the substrate during the catalytic process, effectively improving catalytic efficiency. The experimental results demonstrated that the catalytic activity of the nanoclusters was influenced by the different metal nodes in the MOFs in the following order: Ni > Co > Zn > Mg.
This is the first study to report the enhancement of catalytic performance of metal nanoclusters by modulating the interactions between MOFs and the ligands on the surface of the nanoclusters. The findings provide a new strategy for the design and optimization of metal nanocluster/MOF composite materials with high catalytic performance.
