Synthesis of bimetallic metal-organic frameworks and their application

Abstract

A mixed metal Co-Zn based metal organic framework with ligand 2-methyl imidazole has been prepared with different doping percentages of Co (25~75% of Co2+) along with monometallic ZIFs at room temperature. The tuneability of pore size, pore volume and surface area of Co doped ZIF-8 has been extensively studied by Brunauer–Emmett–Teller (BET). The highest surface area (enhanced by ~40% compared to ZIF-8) and pore volume (enhanced by ~33% compared to ZIF-8) was observed with 75% doping of the Cobalt in ZIF-8 (Co75%-ZIF-8). The particle size of various doped Co-ZIF-8 particles by Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that they were 150-300 nm in size. The crystal lattice structure of the doped ZIFs-8 framework is continuously maintained as parent ZIF-8, regardless of the doping percentage. The synthesized material was characterized by powder Xray diffraction (PXRD), thermo gravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The prepared material showed a high CO2 uptake capacity, recorded at room temperature up to 1 bar pressure. Noteworthy enhancement of ~30% in the CO2 uptake was displayed by Co75%-ZIF-8 frameworks as compared to Zn-ZIF-8 under analogous conditions.