Abstract
In this contribution, we examine the effect of the promoter´s ionic charge and valence orbital energy on the catalytic activity of Fe-based catalysts, based on in situ synchrotron X-ray powder diffraction (SXRPD), temperature-programmed-based techniques (TPR, TPD, CO-TP carburization), and Fischer–Tropsch synthesis catalytic testing studies. We compared the promoting effects of K (a known promoter for longer-chained products) with Ba, which has a similar ionic radius but has double the ionic charge. Despite being partially “buried” in a crystalline BaCO3 phase, the carburization of the Ba-promoted catalyst was more effective than that of K; this was primarily due to its higher (2+) ionic charge. With Ba2+, higher selectivity to methane and lighter products were obtained compared to the K-promoted catalysts; this is likely due to Ba´s lesser capability of suppressing H adsorption on the catalyst surface. An explanation is provided in terms of a more limited mixing between electron-filled Ba2+ 5p and partially filled Fe 3d orbitals, which are expected to be important for the chemical promotion, as they are further apart in energy compared to the K+ 3p and Fe 3d orbitals.
Document Type
Article
Publication Date
10-10-2021
Digital Object Identifier (DOI)
https://doi.org/10.3390/reactions2040026
Related Content
The following are available online at https://www.mdpi.com/article/10.3390/reactions2040026/s1, Table S1: BET surface area and pore size distribution. The material is also available for download as the additional file listed at the end of this record.
Repository Citation
Leguizamón León Ribeiro, Mirtha Z.; Souza, Joice C.; Gnanamani, Muthu Kumaran; Martinelli, Michela; Upton, Gabriel F.; Jacobs, Gary; and Ribeiro, Mauro C., "Fischer–Tropsch Synthesis: Effect of the Promoter’s Ionic Charge and Valence Level Energy on Activity" (2021). Center for Applied Energy Research Faculty and Staff Publications. 41.
https://uknowledge.uky.edu/caer_facpub/41
Supplementary file
Notes/Citation Information
Published in Reactions, v. 2, issue 4.
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).