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X-ray Spectroscopy Interest Group
March 13 @ 11:00 am - 12:00 pm CDT
Speaker: Christian Wittee Lopes, Federal University of Paraná, Brazil
Title: Analysis of Local Environment and Spatial Distribution of Active Sites in Molecular Sieves and Bimetallic Supported Catalysts Using Synchrotron Radiation
Date: Wednesday, March 13, 2024
Time: 11:00AM (Central Time)
Location Remote:
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Abstract:
In recent years, the catalytic community has greatly benefited from the widespread adoption of X-ray methods, particularly X-ray absorption spectroscopy (XAS), owing to its element-selective nature. XAS has become crucial for understanding the local environment of specific elements considered as active sites in catalytic materials. A notable example is the characterization of catalysts consisting of single atoms, where an XAS study is (almost) a prerequisite. Among X-ray techniques, XRF is not a novel method; nevertheless, it holds promise in unveiling the spatial distribution of active sites across catalyst particles, especially when utilizing nanoprobes. In this presentation, I will provide two specific examples in which XAS was employed to investigate the metallic phases in Rh2P@C and Co2P@C catalysts, as well as in the study of speciation of bimetallic metal-organic frameworks (MOFs). In the latter case, micro/nanoXRF was used to evaluate the spatial distribution of Ni and Zn across MOF particles obtained through different approaches. In both instances, the catalysts were utilized in the conversion of olefins into high-value-added products, such as aldehydes and butenes.