Structure and electronic properties of Aun cluster (n=2,4,6,8,10,12,14) in zirconium-based metal-organic framework (MOF-801): density functional theory studies

Incorporation of noble metal into metal-organic frameworks (MOFs) provides an opportunity to fine tune the structure and electronic properties of MOFs materials for many applications. Periodic density functional theory has been used to understand the nature of gold nanoparticle Au-n cluster (n = 2, 4, 6, 8, 10, 12 and 14) inside zirconium-based MOFs (MOF-801). The Au-n clusters were located inside the octahedral and tetrahedral pore of MOF-801 inducing confinement effect toward the structure of Au-n cluster. Various parameters were calculated including the adsorption energy, deformation energy, density of states and intermolecular interaction between Au-n cluster and MOF-801 surfaces. The studies indicate that the adsorption of Au-n cluster is overall exothermic, and the Au-n cluster inside the tetrahedral cage provides a higher stabilization energy. However, the presence of Au-n cluster also induces deformation energy toward the MOF-801 structure. The binding sites of Au-n cluster on the surface of MOF-801 has been assessed using the independent gradient model to unveil possible intermolecular forces between the host and guest system. The electronic bandgap has been assessed showing the possibility to modulate the bandgap energy by increasing the size of Au-n cluster.