title: Coke Formation in a Zeolite Crystal During the Methanol-to-Hydrocarbons Reaction as Studied with Atom Probe Tomography.
abstract: Understanding the formation of carbon deposits in zeolites is vital to developing new, superior materials for various applications, including oil and gas conversion processes. Herein, atom probe tomography (APT) has been used to spatially resolve the 3D compositional changes at the sub-nm length scale in a single zeolite ZSM-5 crystal, which has been partially deactivated by the methanol-to-hydrocarbons reaction using (13) C-labeled methanol. The results reveal the formation of coke in agglomerates that span length scales from tens of nanometers to atomic clusters with a median size of 30-60 (13) C atoms. These clusters correlate with local increases in Brønsted acid site density, demonstrating that the formation of the first deactivating coke precursor molecules occurs in nanoscopic regions enriched in aluminum. This nanoscale correlation underscores the importance of carefully engineering materials to suppress detrimental coke formation.
authors.affiliation: Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG, Utrecht, The Netherlands.
authors.forename: Joel E
authors.initials: JE
authors.lastname: Schmidt
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Poplawsky
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA.
authors.forename: Baishakhi
authors.initials: B
authors.lastname: Mazumder
authors.affiliation: Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG, Utrecht, The Netherlands.
authors.forename: Özgün
authors.initials: Ö
authors.lastname: Attila
authors.affiliation: Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG, Utrecht, The Netherlands.
authors.forename: Donglong
authors.initials: D
authors.lastname: Fu
authors.affiliation: Structural Geology & EM, Utrecht University, Postbus 80.021, 3508, TA, Utrecht, The Netherlands.
authors.forename: D A Matthijs
authors.initials: DA
authors.lastname: de Winter
authors.affiliation: Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG, Utrecht, The Netherlands.
authors.forename: Florian
authors.initials: F
authors.lastname: Meirer
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA, 94025, USA. simon.bare@slac.stanford.edu.
authors.forename: Simon R
authors.initials: SR
authors.lastname: Bare
authors.affiliation: Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584, CG, Utrecht, The Netherlands. b.m.weckhuysen@uu.nl.
authors.forename: Bert M
authors.initials: BM
authors.lastname: Weckhuysen
keywords: Al zoning; atom probe tomography; carbon deposits; methanol to hydrocarbons; zeolites