A catalyst is a substance that is used to drive a chemical reaction in a particular direction with greater efficiency and control. Catalysts are used in the manufacture of almost all man-made products. These range from margarine, which depends on nickel catalysts to hydrogenate fats, to ammonia-based fertilisers that employ iron catalysts, to automotive exhaust catalytic converters, that use precious metals. Fine chemicals, such as those produced for the pharmaceutical industry, would be too expensive to produce at large scale without the use of catalysts.
Given their widespread application in industry, developing catalysts that improve the energy and chemical efficiency of chemical transformations could be key in achieving Net Zero carbon goals. With ISIS scientist, Stewart Parker, researchers from Oak Ridge National Laboratory (USA) and the University of Glasgow have reviewed the current and potential future uses of neutron scattering techniques for the investigation of heterogenous catalysis (where the catalyst is in a different phase to the reactants and/or products).
When investigating catalytic processes, techniques such as X-ray diffraction or electron microscopy can be used, but combining these with neutron scattering techniques can provide information that is otherwise inaccessible. For example, a major area of interest for catalysis research is in situ and operando studies - in other words, studying the catalyst under conditions that are relevant to their practical operation. Neutron techniques are well suited to such studies, since they can ‘see’ a sample contained within a complex sample environment, such as a thick-walled reactor. In addition, neutron scattering can offer insight into structures and reaction mechanisms involving light elements, such as hydrogen, can distinguish isotopes, and is a non-destructive technique.
The review was featured on the cover of Chemical Reviews
The paper, published in Chemical Reviews, discusses various neutron techniques and highlights the potential of using these together. Ultimately, more research and development of catalysts and how neutrons can be used to study them will have a significant impact on industrial processes and will help address the decarbonisation challenge. However, the field is threatened by the reduction in number of neutron sources, which highlights the importance of expansion ventures such as ISIS’ Endeavour project and the construction of the European Spallation Source in Sweden.