Recent advancements in MOFs synthesis and their green applications

Abstract

Metal organic frameworks (MOFs) are crystalline, hybrid, materials containing metal ions and organic molecules; components that together form three-dimensional structures. At the present, the large-scale production necessary for the commercialization of MOFs based industrial processes seems to be the greatest challenge, mainly due to the fact that MOFs require harsh operating conditions and large amounts of toxic solvents during their synthesis which result in added production costs and raise safety and environmental related concerns. This review provides an overview on the recent developments in the synthesis of MOFs and their green applications. The currently used solvothermal processes for the synthesis of MOFs necessitate the use of hazardous and non-renewable solvents such as such as dimethylformamide (DMF), dimethylformamide (DEF), methanol, ethanol, and acetonitrile. Green and economical routes for MOFs synthesis that are non-solvent based have been rigorously under study to facilitate the commercialization of synthesis processes that are safe and environmentally benign. Such processes include water-based MOF synthesis, mechanochemical MOFs synthesis and the use of super-critical fluids and ionic liquids as solvents to replace the conventionally used ones. The paper also discusses the recent developments in the applications of MOFs in innovative and vital applications such as hydrogen production, fuel cells, and water desalination. Challenges and corrective actions attributed to the use of MOFs in these applications are also presented and discussed.