The preparation and characterization of co–ni nanoparticles and the testing of a heterogenized co–ni/alumina catalyst for co hydrogenation

Julián López-Tinoco, Rubén Mendoza-Cruz, Lourdes Bazán-Díaz, Sai Charan Karuturi, Michela Martinelli, Donald C. Cronauer, A. Jeremy Kropf, Christopher L. Marshall, Gary Jacobs

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Samples of well-controlled nanoparticles consisting of alloys of cobalt and nickel of different atomic ratios were synthesized using wet chemical methods with oleylamine as the solvent and the reducing agent. These materials were characterized by a variety of techniques, including high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Small amounts of heterogenized catalysts were prepared using alumina as the support. However, the potential for use of Co–Ni catalysts in CO hydrogenation was explored using a larger amount of Co–Ni/alumina catalyst prepared from standard aqueous impregnation methods and tested in a continuously stirred tank reactor (CSTR) for Fischer–Tropsch synthesis (FTS). Results are compared to a reference catalyst containing only cobalt. The heterogenized catalysts were characterized using synchrotron methods, including temperature programmed reduction with extended X-ray absorption fine structure spectroscopy and X-ray absorption near edge spectroscopy (TPR-EXAFS/XANES). The characterization results support intimate contact between Co and Ni, strongly suggesting alloy formation. In FTS testing, drawbacks of Ni addition included decreased CO conversion on a per gram catalyst basis, although Ni did not significantly impact the turnover number of cobalt, and produced slightly higher light gas selectivity. Benefits of Ni addition included an inverted induction period relative to undoped Co/Al2O3, where CO conversion increased with time on-stream in the initial period, and the stabilization of cobalt nanoparticles at a lower weight % of Co.

Original languageEnglish
Article number18
JournalCatalysts
Volume10
Issue number1
DOIs
StatePublished - Jan 2020

Bibliographical note

Publisher Copyright:
© 2019 by the authors. Licensee MDPI, Basel, Switzerland.

Keywords

  • Alumina
  • CO hydrogenation
  • Cobalt
  • Cobalt-Nickel alloys
  • Cobalt-Nickel nanoparticles
  • CSTR
  • Fischer-Tropsch synthesis
  • HAADF-STEM
  • Nickel
  • TPR-EXAFS/XANES

ASJC Scopus subject areas

  • Catalysis
  • General Environmental Science
  • Physical and Theoretical Chemistry

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