Our primary interest is in gas-solid reactions. In particular we are interested in ion-conducting solids and their interaction with the gas phase. If two charge carriers are present in the solid phase we can construct highly selective gas permeable membranes (highly selective because solid state diffusion is very selective). So oxygen ion and electron conductivity can be used for oxygen permeable membranes, proton and electron conductivity can be used for hydrogen permeable membranes and oxygen-ion and proton conductivity can be used for water permeable membranes. Dual phase membranes conducting oxygen ions, in the solid phase, and carbonate ions, within a molten salt in the pores of the solid, could be used to develop carbon dioxide permeable membranes. Membrane transport requires a gas-solid reaction followed by transport of the charge carriers within the membrane. The very same processes are critical to the operation of a chemical looping cycle. We are using our knowledge of such processes to develop new materials for e.g. chemical looping hydrogen production.
Looping and membrane processes have clear similarities. In the schematic below, a CO2 separation is shown in both a looping and membrane process. In each, there are (i) adsorption/uptake, (ii) diffusion and, (iii) desorption/release steps. Click on the links at the left hand side, or those in the text, to find out more about our research in these areas.