Dr Albert Carley - MA(Cantab), PhD
- The application of surface sensitive techniques (XPS, UPS, LEED, HREELS, STM) to the study of surface chemical reactions of relevance to heterogeneous catalysis, including co-adsorption at metal surfaces. Recent projects include a study of the reactivity of the actinide elements thorium and uranium, which made use of a recently installed facility for inverse photoemission spectroscopy (IPES).
- Metal oxidation and reactivity of oxygen states at metal surfaces. Many molecules, in particular hydrocarbons, may be activated at metal surfaces by pre-adsorbed or dynamically co-adsorbed oxygen species. The latter phenomenon is studied using gas mixtures, which often react differently to the individual components, which is clearly relevant to heterogeneous catalysis.
- Preparation and reactivity of model supported metal catalysts. These analogues of high area powdered catalysts allow us to use surface science techniques to probe aspects of the mechanisms of heterogeneously catalysed reactions, such as particle size and support effects. A recent project investigated the mechanism of CO oxidation over Au/Fe2O3 planar model catalysts; this is a key test reaction for supported gold catalysts.
- Surface characterisation of heterogeneous catalysts used for a wide range of reactions, including: the direct synthesis of hydrogen peroxide, the destruction of volatile organic compounds (VOCs), Fischer-Tropsch synthesis and the selective oxidation of methane.
Much of my recent work has focussed on catalysis by supported gold catalysts which have received increasing amounts of attention, since the discovery in ca 1987 that nanoparticulate gold shows high activity for some catalytic reactions, in marked contrast to the bulk metal. We have been exploring the activity and selectivity of supported gold-palladium materials which are particularly effective for the direct synthesis of hydrogen peroxide from H2 and O2. The in situ generation and utilisation of H2O2 for selective oxidation of hydrocarbons is likely to be of great importance in the fine chemicals industry. An important finding from the characterisation of several supported Au-Pd catalyst systems by XPS and STEM-EDAX is that the alloy particles after calcination adopt an unexpected core shell structure, with a Pd shell surrounding a gold core.