Dr Martin Attfield - research
Our research interests relate to the field of materials chemistry with particular specialisation in the area of crystalline nanoporous materials. Such materials are utilized on a world wide scale in a diverse array of areas including heterogeneous catalysis, ion-exchange, gas and liquid separation processes, nuclear waste remediation, optoelectronics and drug delivery.
The core of our research takes place in the Centre for Nanoporous Materials and recently, the main focus of the group has been directed towards metal organic frameworks - the newest family of nanoporous material that is receiving global research attention. These hybrid materials consist of frameworks constructed from metal cations and organic linker groups and are of particular interest because within one material the benefits of both types of chemistry are present - the metal cations impart their own particular magnetic, electronic and catalytic properties, while the organic sections enable the functionality and the overall framework architecture of the material to be rationally designed.
The major research themes involving metal organic frameworks include: (1) crystal growth (2) synthesis and design of new materials (3) properties and application.
1 Crystal growth of metal organic framework materials
We are investigating the crystal growth of porous hybrid framework materials using atomic force microscopy to monitor the details of the crystal surface structure during and after growth. This will provide fundamental understanding of the crystal growth processes of multi-component extended structure framework materials that will be applied to the synthesis of crystals of particular habit and morphology for enhanced application performance. Our studies on the metal organic framework material, HKUST-1, have revealed that this material can grow by a spiral or layer-by-layer growth mechanism, the rates of these processes and information concerning the attaching species and crystal construction (Chem. Commun. 2009, 6294; Angew. Chem. Int. Ed. 2008, 47, 8525).
Crystal structure of HKUST-1 (left) and the growth of several 1.5 nm growth steps (a - j) on the surface of a crystal of HKUST-1 (right).
2 Synthesis and design of new hybrid materials
Research in this area has focused initially on investigating the synthesis of novel group 13 metal phosphonate and diphosphonate materials with particular emphasis on rationally designing the pore architecture of the resultant nanoporous material. The pore architecture of this type of material may be designed through several methods including substitution of the diphosphonate groups for other groups, substitution of metal cations and by using different diphosphonate groups to form the framework structure of the final material. New materials that have been produced include the framework aluminium butylenediphosphonate and gallium pentylenediphosphonate materials that both contain one-dimensional channel systems (Solid State Sciences, 2008, 10, 1124; Inorg. Chem. 2010, 49, 2656).
Crystal structures of the one-dimensional channel-containing framework aluminium butylenediphosphonate (left) and gallium pentylenediphosphonate (right) materials.
3 Properties and applications of metal organic frameworks
These newer research themes are concerned with investigation of the thermal expansion properties of metal organic frameworks and their potential in the formation of composite membranes (in collaboration with Dr Peter Budd) for enhanced liquid or gas separation processes, such as carbon capture.