Metal-Organic Frameworks (MOFs) - Production, properties and application

Metal-Organic Frameworks (MOFs) or coordination polymer solids are a family of ordered porous hybrid compounds that are attracting growing academic and industrial interest. Discovered in the late 1990s, the number of publications concerning MOFs has increased exponentially since the early 2000s. Scientific research initially focused on the discovery of new crystalline and porous structures of application interest in fields linked to the environment, energy and health (storage, gas separation, catalysis, detection, heat transfer, water production, controlled delivery of active ingredients, etc.). These solids offer a highly versatile, ordered structure thanks to: (i) the possibility of adjusting the physico-chemical properties of the framework through the choice of constituent metals, as well as the nature of the organic ligand, its functionalization or the use of extended ligands; and (ii) the wide range of pore sizes (3 to 70 Å), shapes and organization (cages to tunnels, connected or isolated) offering sometimes very high accessible specific surface areas (from a few hundred to over 7,000 m ² .g ^-1 ), etc.

Although the academic interest in terms of properties and associated potential applications is great, the manufacture of chemically, thermally and mechanically stable MOFs under real conditions of use (e.g., in the presence of moisture), capable of retaining the property expected for a given application, is not so obvious. While the cost of synthesizing these materials (precursors) is still relatively high, the growing efforts of the community (patents, start-ups, demonstration projects) testify to a gradual transition towards the commercialization and industrial integration of MOFs. The aim of this article is to provide the reader with a non-exhaustive but comprehensive overview of MOFs. Manufacturing, shaping and characterization conditions are outlined, so as to provide an understanding of the fundamental parameters for producing porous solids that are robust, stable and open to a variety of applications. Criteria for cost-effective manufacture and scale-up, while respecting the environment as far as possible, are also discussed.

Readers will find a summary of the terms used at the end of the article.