Understanding the local structure around active catalysts is a longstanding challenge of huge scientific interest and commercial significance. As these important chemical components are present in very low concentration, direct studies of their environment and interaction with chemical reactants is a challenging area that will benefit from the unique capabilities of the scanning branch of the beamline. The fundamental field of solution chemistry will also benefit, as the spectrometer is ideally suited to studying interactions taking place in solution under very dilute conditions. Reaching the infinite dilution limit is of major importance as it allows direct access to the chemical interactions between solute and solvent species without the complication of solute-solute terms.
The study of catalysts in operating conditions is a particular challenge as they suffer rapid structural transformation under rapidly changing environmental conditions, such as the temperature of the reaction, or composition and flow rates of gasses. The possibility of following reaction processes from the atomic viewpoint on second and millisecond time scales opens unique possibilities for the study of heterogeneous and homogeneous catalysis. The high flux of I20 will further enhance capabilities for time resolved chemistry by extending the time resolution of this technique to the micro-second range and such developments now raise many tantalising possibilities in, for example, the study of photochemical processes.
The determination of the structure of metalloproteins is often a central component in improving our understanding of the biological processes in which they take part. Example biochemical pathways that fall into this field of research include the life-critical mechanisms of photosynthesis or respiration. The structure around metal centres in disordered metalloproteins is beginning to become accessible by x-ray absorption spectroscopy methods, but the concentrations at which these materials are found in real biological systems are usually in the micro molar range. I20 will play an important role in the study of these dilute systems as investigations performed at higher concentrations often run into problems with insoluble proteins or the formation of oligomers, which can seriously compromise any structural study.
The study of metal speciation of environmentally relevant elements, such as lead, cadmium or mercury is central when investigating better methods to dispose of these toxic materials, and to handle the remediation of environmental contamination. As the relevant concentrations of these toxic materials often fall in the range of parts per million, or even parts per billion, the ability to study systems under these challenging conditions is an important component of the envisaged I20 research programme.
A major suspended constituent of discharges from waste disposal sites are amorphous phases in the first few milliseconds after precipitation. Studying the development and properties of these phases can provide key information in the processes used in waste disposal, and the time-resolved capabilities of the I20 dispersive spectrometer would be ideally suited to investigating these.
Developing new light weight, high charge density, battery materials often requires adding small quantities of chemical dopant species to the electrolytes to improve their electrical or mechanical properties. It is envisaged that I20 will enable the study of the local structure around such dopants, allowing us to better understand their role and improve the performance of this next generation technology.
Studying samples under extreme conditions of high pressures and temperatures often requires the use of small sample volumes, for example diamond anvil cells. The small focal spot produced by I20 is ideally suited for this scenario.
Another technological area that will benefit from the time resolved capabilities and small focal size of an energy dispersive spectrometer is the study of kinetic processes in operating electrochemical cells. In these systems spatially resolved investigations are often essential, as the physio-chemical mechanisms of interest often depend on proximity to an electrode