Title: Combined XAS + XRD Studies to Probe the Structure and Dynamics of Heterogeneous Catalysts Across Different Length Scales
Speaker: Dr. Paula Abdala (ETH, Zurich)
Abstract: The inherent complexity of heterogeneous catalysts and other energy–related materials requires complementary information to understand relationships between structure and performance, making multi-probe operando studies powerful tools for investigating such complex and dynamic systems. In this presentation the use of combined X-ray powder diffraction (XRD) and X-ray absorption spectroscopy (XAS) studies, in a single experiment, to reveal structure-performance relationships in heterogeneous catalysts will be discussed.[1] While XAS provides key information on a selected element's local atomic and electronic structure, XRD gives complementary insight into the coherent atomic arrangement. Thus, this combined analysis allows study of structure across different length scales, from the atomic length scale to nano- and microcrystalline structure, and the changes thereof. Past and recent examples of the application of XAS + XRD studies on catalysts for CO2 valorization reactions, such as dry reforming of methane and CO2 hydrogenation, will be described.[2-5]
Suggested reading:
[1] Abdala, P. M. et al. Scientific opportunities for heterogeneous catalysis research at the SuperXAS and SNBL beam lines. CHIMIA 66, 699-705 (2012). [ Ссылка ]
[2] Tsoukalou, A. et al. Operando X-ray Absorption Spectroscopy Identifies a Monoclinic ZrO2: In Solid Solution as the Active Phase for the Hydrogenation of CO2 to Methanol. ACS Catal. 10, 10060-10067 (2020). [ Ссылка ]
[3] Tsoukalou, A. et al. Structural Evolution and Dynamics of an In2O3 Catalyst for CO2 Hydrogenation to Methanol: an Operando XAS-XRD and In Situ TEM Study. J. Am. Chem. Soc. 141, 13497-13505 (2019). [ Ссылка ]
[4] Naeem, M. A. et al. Exsolution of Metallic Ru Nanoparticles from Defective, Fluorite-Type Solid Solutions Sm2RuxCe2–xO7 To Impart Stability on Dry Reforming Catalysts. ACS Catal. 10, 1923-1937 (2019). [ Ссылка ]
[5] Kim, S. M. et al. Cooperativity And Dynamics Increase the Performance of NiFe Dry Reforming Catalysts. J. Am. Chem. Soc. 139, 1937-1949 (2017). [ Ссылка ]
