aston university xps
In-situ X-ray Absorption Spectroscopy
The ability to observe dynamic structural changes of working catalysts under reaction conditions is invaluable to understanding key promotion and poisoning phenomena and tailoring the design of next-generation catalysts. EXAFS is a perfect spectroscopic tool for probing the local chemical environment and oxidation state of atoms within catalysts over a wide range of temperatures and pressures. A key advantage of this technique is that the high penetration depth of X-rays allows solid catalysts to be studied while exposed to either vapour or liquid reaction mixtures.
Time-resolved or ‘Fast’ X-ray photoelectron spectroscopy (XPS) is a powerful in-situ tool enabling us to follow surface catalysed reactions in real-time. Fast XPS represents a chemically specific, surface sensitive and quantitative technique for characterising adsorbates and the underlying interface. Synchrotron X-ray radiation is used to tune into different chemical elements at a solid surface (e.g. adsorbed molecules or metal dopants) and probe their local environment.
Time-resolved XPS is an extremely powerful method for investigating chemical transformations catalysed by solid surfaces. There are two principle modes of operation: spectra can be recorded as a function of time while exposing the surface to an adsorbate at constant temperature shedding insight into adsorption kinetics; alternatively spectra can be recorded continuously while heating a reactant adlayer to deconstruct reaction mechanism and identify metastable reaction intermediates.