Origin of active sites on silica–magnesia catalysts and control of reactive environment in the one-step ethanol-to-butadiene process

Sang Ho Chung*, Teng Li, Tuiana Shoinkhorova, Sarah Komaty, Adrian Ramirez, Ildar Mukhambetov, Edy Abou-Hamad, Genrikh Shterk, Selvedin Telalovic, Alla Dikhtiarenko, Bart Sirks, Polina Lavrik, Xinqi Tang, Bert M. Weckhuysen, Pieter C.A. Bruijnicx, Jorge Gascon, Javier Ruiz-Martínez*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Wet-kneaded silica–magnesia is a benchmark catalyst for the one-step ethanol-to-butadiene Lebedev process. Magnesium silicates, formed during wet kneading, have been proposed as the active sites for butadiene formation, and their properties are mainly explained in terms of the ratio of acid and base sites. However, their mechanism of formation and reactivity have not yet been fully established. Here we show that magnesium silicates are formed by the dissolution of Si and Mg subunits from their precursors, initiated by the alkaline pH of the wet-kneading medium, followed by cross-deposition on the precursor surfaces. Using two individual model systems (Mg/SiO2 and Si/MgO), we demonstrate that the location of the magnesium silicates (that is, Mg on SiO2 or Si on MgO) governs not only their chemical nature, but also the configuration of adsorbed ethanol and resulting selectivity. By using an NMR approach together with probe molecules, we demonstrate that acid and basic sites in close atomic proximity (~5 Å) promote butadiene formation. [Figure not available: see fulltext.].

Original languageEnglish (US)
Pages (from-to)363-376
Number of pages14
JournalNature Catalysis
Volume6
Issue number4
DOIs
StatePublished - Apr 2023

Bibliographical note

Funding Information:
The authors are grateful for financial support from King Abdullah University of Science and Technology. We thank J. Vittenet and E. Kaliyamoorthy for ICP-OES analysis, S. Lopatin for TEM–EDX measurements, C. Canlas for technical support in recording solid-state NMR spectra, Y. Yuan for in situ PXRD measurements and K. Eichele (Universität Tübingen) for WSolids1 software support. The preliminary experiments in this research were performed within the framework of the CatchBio programme. B.M.W. and P.C.A.B. acknowledge the support of the Smart Mix Program of the Netherlands Ministry of Economic Affairs, the Netherlands Ministry of Education, Culture and Science, and NWO (Middelgroot programme, grant no. 700.58.102).

Funding Information:
The authors are grateful for financial support from King Abdullah University of Science and Technology. We thank J. Vittenet and E. Kaliyamoorthy for ICP-OES analysis, S. Lopatin for TEM–EDX measurements, C. Canlas for technical support in recording solid-state NMR spectra, Y. Yuan for in situ PXRD measurements and K. Eichele (Universität Tübingen) for WSolids1 software support. The preliminary experiments in this research were performed within the framework of the CatchBio programme. B.M.W. and P.C.A.B. acknowledge the support of the Smart Mix Program of the Netherlands Ministry of Economic Affairs, the Netherlands Ministry of Education, Culture and Science, and NWO (Middelgroot programme, grant no. 700.58.102).

Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer Nature Limited.

ASJC Scopus subject areas

  • Catalysis
  • Bioengineering
  • Biochemistry
  • Process Chemistry and Technology

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