Functionalised metal–organic frameworks: a novel approach to stabilising single metal atoms
We have investigated the potential of metal–organic frameworks for immobilising single atoms of transition metals using a model system of Pd supported on NH2-MIL-101(Cr). Our transmission electron microscopy and in situ Raman spectroscopy results give evidence for the first time that functionalised metal–organic frameworks may support, isolate and stabilise single atoms of palladium. Using thermal desorption spectroscopy we were able to evaluate the proportion of single Pd atoms. Furthermore, in a combined theoretical-experimental approach, we show that the H–H bonds in a H2 molecule elongate by over 15% through the formation of a complex with single atoms of Pd. Such deformation would affect any hydrogenation reaction and thus the single atoms supported on metal–organic frameworks may become promising single atom catalysts in future.