Enhanced hydrothermal stability of Cu MOF by post synthetic modification with amino acids

Abstract

In this work, we report the solvothermal synthesis of copper metal organic framework (Cu MOF) also known as HKUST 1 and its functionalization with amino acids to increase hydrothermal stability. MOFs are porous materials made up of organic and inorganic components. Owing to properties like large surface area, tunable pore size, pore volume and desirable functionality via Post Synthetic Modification (PSM), MOFs are gaining attention in various applications such as catalysis, energy storage, pollutant removal and sensing. But most of the MOFs show poor hydrothermal stability that limits their applications in aqueous samples. Various characterization techniques such as Powder X-Ray Diffraction (PXRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS), Zeta potential study indicated successful modification of Cu MOF with different amino acids. Thermogravimetric analysis (TGA), contact angle and SEM results after hydrothermal conditioning showed enhanced water stability for glycine, lysine and tyrosine functionalized Cu MOF compared to pristine MOF. The pristine Cu MOF possessed contact angle of 39.6° which got increased for modified Cu MOFs showing transition behaviour of Cu MOF from hydrophilic to hydrophobic after functionalization.