Porous solids are a class of material with high scientific and technological significance. Porosity permits molecules to access the surface and the bulk of the solid. MOFs or Metal-Organic Frameworks are hybrid organic/inorganic materials that are the latest class of crystalline porous solids. MOFs are synthetically made and are among the most porous materials, with in some case record surface areas, one gram of solid reaching up to 8000 m² i.e., higher than the surface area of a football field. Their high surface area combined to their almost infinite structural and chemical diversity permits a unprecedented facility to tune the host/guest interactions and therefore optimum and tailored properties can be attained, paving the way for

Fig. 1. Schematic representation of Cerium doped UiO-66 material. a) the material is composed of Zr/Ce metal clusters (in yellow and blue respectively) and benzenedicarboxylic acid linkers to form a 3D network composed of b) two types of cages i.e., tetrahedral (left) and octahedral (right).

potential applications in catalysis, sensing, separation, biomedicine etc… Among the large number of porous MOFs reported so far, UiO-66, a MOF material discovered conjointly by the University of Oslo (Universitetet I Oslo) and by CNRS (French center of national scientific research, is made of zirconium metal ions in octahedral geometry connected to benzene dicarboxylic linkers to form a tridimensional network (see the schematic representation below). Its high chemical and thermal stability associated to its easy functionalization make this solid one of the archetypal MOFs reported so far.

When it comes to design a MOF material toward specific properties for potential applications, a rational design is challenging but not impossible. Cerium(IV), a very active redox cation, based materials find many industrial applications such as catalytic converters or redox applications but porous Cerium(IV) based solids are very difficult to obtain, relying mostly on doping various metal oxides. The authors report the introduction of Ce(IV) ions into a porous MOF framework through the doping of UiO-66 by Cerium atoms (2 to 5 % randomly distributed in the UiO material, see scheme below), replacing some of the constitutive Zirconium atoms from the MOF framework. This is just enough to improve its catalytic performance while retaining its structural integrity. Here an example is given in which methanol (a toxic solvent) can be degraded in more environmentally friendly molecules.

Also, Cerium charge in the MOF can change (from Ce⁴⁺ to Ce³⁺ and vice versa), which means that electron can circulate within the material. This opens up a whole set of various applications for this type of doped material. The potential targeted applications of the material comprise electron transport in batteries, sensing and redox catalysis applications.

Publication

Tuning the properties of the UiO-66 metal organic framework by Ce substitution.
Nouar F, Breeze MI, Campo BC, Vimont A, Clet G, Daturi M, Devic T, Walton RI, Serre C.
Chem Commun (Camb). 2015 Oct 4

Read offline:     

Related Articles:

	DFT for designing efficient supercapacitor electrode… Josef MacDouall once said “Chemistry is a game that electrons play”. If one were able to know the roles, they could control the game and uncover the mysteries of materials,…
	When will my mouse die? The maintenance of health is ensured by the function of the three homeostatic systems of the body: the nervous, endocrine and immune systems, and by the net that allows crosstalk…
	A functionally-graded scaffold and bone marrow-derived… Osteonecrosis of the femoral head (ONFH) is a debilitating disease that may progress to femoral head collapse and subsequently, degenerative arthritis. Core decompression (CD) is a commonly used joint-preserving procedure…
	What are the chemical properties of water in the world’s… The Sansha Yongle Blue Hole (SYBH), located on the Yongle Atoll of the Xiasha Islands in the northern South China Sea, has been discovered to be the world’s deepest blue…
	Imaging metal nanoparticle adsorption on graphene aerogels The functionalization of porous carbon aerogels and sponge-like materials with metal nanoparticles (NPs) has shown significant promise for several applications, including energy storage and harvesting and environmental remediation. Methods for…
	New antimicrobial strategies against multidrug-resistant… Due to current antibiotic resistance worldwide, there is an urgent need to find new alternative antibacterial approaches capable of dealing with multidrug-resistant pathogens. In fact, the World Health Organization has…