Rapid room temperature conversion of hydroxy double salt to MOF-505 for CO2 capture

Abstract

Given the fact that solvothermal synthesis is the most common synthetic method to obtain metal–organic frameworks (MOFs) on a gram scale, it still remains a great challenge to produce MOFs in a scalable and sustainable synthetic process. In this work, we develop a facile and rapid synthesis of copper-based MOF-505 by the exploitation of layered (Zn,Cu) hydroxy double salt as the intermediate for efficient MOF-505 crystallization at room temperature, in which [(Zn,Cu)(OH)NO₃] is synthesized by reacting ZnO with Cu(NO₃)₂. Under an optimized reaction time of 25 min, MOF-505-25 exhibits a Brunauer–Emmett–Teller (BET) surface area of 1076 m² g⁻¹ and the pore size is narrowly distributed at 5.9 and 8.0 Å. With respect to CO₂ adsorption and separation performance, MOF-505-25 shows a moderate CO₂ uptake of 3.51 mmol g⁻¹ at 298 K and 100 kPa and high CO₂/CH₄ and CO₂/N₂ adsorption selectivities of 7 and 29. Particularly, the formation of MOF-505 can be completed within a short reaction time (less than 30 min) whilst maintaining high quality. This facile and rapid room temperature synthetic procedure would pave the way for promoting the development of MOF materials large-scale production with minimizing the energy input.