2025-01-08 SLAC国立加速器研究所
＜関連情報＞
- https://www6.slac.stanford.edu/news/2025-01-08-pioneering-new-tool-will-spur-advances-catalysis
- https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/cmtd.202400020
QuantEXAFSを用いた不均一触媒のサイト不均一性の定量化 Quantifying the Site Heterogeneities of Non-Uniform Catalysts Using QuantEXAFS
Rachita Rana, Jiyun Hong, Adam S. Hoffman, Baraa Werghi, Simon R. Bare, Ambarish R. Kulkarni
Chemistry–Methods Published: 21 November 2024
DOI:https://doi.org/10.1002/cmtd.202400020
Graphical Abstract
MS-QuantEXAFS extends QuantEXAFS to model multiple bonding geometries in EXAFS data, accurately determining fractional contributions from distinct sites. Applied to Pt/MgO samples, it precisely identifies atomically dispersed and nanoparticle site fractions, enhancing catalyst speciation analysis.
Abstract
We present the Multi-site (MS) QuantEXAFS approach, designed to model the EXAFS data from samples containing an element in different local bonding geometries. Building upon our QuantEXAFS method, which maps experimental extended X-ray absorption fine structures (EXAFS) data to DFT-optimized structures, MS-QuantEXAFS introduces the key capability to probe fractional contributions of multiple sites that may be present in an experimental sample. Specifically, we demonstrate effectiveness of this technique by investigating mixed samples containing known fractions of site-isolated subsurface Pt/MgO with Pt nanoparticles uniformly supported on MgO. The ‘site-fractions’ obtained through MS-QuantEXAFS closely match (i. e., ±6%) the known fractions of the physically mixed samples. This approach has been generalized to other oxides, and thus represents an important advance in quantifying the speciation of non-uniform catalyst samples.
