UK Catalysis Hub, Diamond Light Source, Southampton University, Queens University Belfast, University of Manchester, University of Glasgow, University College London and Johnson Matthey Technology Centre (JMTC)
This work was funded through the UK Catalysis Hub – JMTC studentship call in 2014.
The endeavour behind these activities is to develop operando techniques that allow for precise, accurate, and reliable measurements regarding the evolving nature of catalysts under realistic conditions. The work focussed on developing a new approach to combining X-ray absorption fine structure (XAFS) and diffuse reflectance infrared Fourier transform (DRIFTS) spectroscopies.
This combination of techniques provides complementary information; XAFS provides structural and electronic information, whilst DRIFTS provides information on the nature of surface adsorbates. However, the current reported approaches in the literature are hindered by large reactor dead volumes and cannot provide any spatial information on the state of the catalyst; considering that in a fixed bed reactor there is a gradient between reactants and products, it is important to be able to capture these changes and understand the interplay between structure and the surface adsorbates at each position.
This partnership has developed a reactor that solves both the problems linked to spatial analysis and large dead volumes (figure x) by moving away from typical ‘dome’ shaped sample chambers and exploiting a square cross-section reactor with axial windows for both XAFS and DRIFTS acquisition. The more coventional reactor geometry is not hindered by the dead volume of the dome and can collect data along the length of the fixed bed.
The cell has been integrated into the I20-EDE beamline at Diamond Light Source, which – in conjunction with a rapid scanning FTIR spectrometer – allows for ms time resolution of both the FTIR and XAFS data acquisition.
Dann, Ellie K., Gibson, Emma K., Catlow, C. Richard A., Celorrio, Verónica, Collier, Paul, Eralp, Tugce, Amboage, Monica, Hardacre, Christopher, Stere, Cristina E., Kroner, Anna, Raj, Agnes, Rogers, Scott, Goguet, Alexandre, Wells, Peter P., Combined spatially resolved operando spectroscopy: New insights into kinetic oscillations of CO oxidation on Pd/γ-Al2O3, Journal of Catalysis, 2019, Volume: 373, 201-208, DOI: 10.1016/j.jcat.2019.03.037