Hybridization of a Metal-Organic Framework with a Two-Dimensional Metal Oxide Nanosheet: Optimization of Functionality and Stability

An effective way to improve the functionalities and stabilities of metal-organic frameworks (MOFs) is developed by employing exfoliated metal oxide 2D nanosheets as matrix for immobilization. Crystal growth of zeolitic imidazolate framework-8 (ZIF-8) nanocrystals on the surface of layered titanate nanosheets yields intimately coupled nanohybrids of ZIF-8-layered titanate. The resulting nanohybrids show much greater surface areas and larger pore volumes than do the pristine ZIF-8, leading to the remarkable improvement of the CO₂ adsorption ability of MOF upon hybridization. Of prime importance is that the thermal- and hydrostabilities of ZIF-8 are significantly enhanced by a strong chemical interaction with the robust titanate nanosheet. A strong interfacial interaction between ZIF-8 and the layered titanate is verified by molecular mechanics simulations and spectroscopic analysis. The universal applicability of the present strategy for the coupling of MOFs and metal oxide nanosheets is substantiated by the stabilization of Ti-MOF-NH₂ via the immobilization on exfoliated V₂O₅ nanosheets. The present study underscores that hybridization with metal oxide 2D nanosheets provides an efficient and universal synthetic route to novel MOF-based hybrid materials with enhanced gas adsorptivity and stability.