Ni-alumina dry reforming catalysts: Atomic layer deposition and the issue of Ni aluminate

Patrick Littlewood, Shengsi Liu, Eric Weitz, Tobin J. Marks*, Peter C. Stair

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

A catalyst consisting of 2 wt% Ni supported on a commercially available transition alumina is modified using TMA-H2O ALD cycles to deposit thin alumina overcoats on the catalyst, and it is then investigated for the catalytic dry reforming of methane (DRM) at 700 °C. Highly dispersed Ni rapidly sinters to form bulk Ni particles on the uncoated catalyst. In contrast, deposition of an alumina overcoat by ALD significantly lowers the rate of Ni sintering, and also lowers the propensity towards carbon deposition during DRM. Additionally, it is experimentally demonstrated that the Ni aluminate (NiAl2O4) spinel phase is unstable under the present DRM conditions and slowly undergoes reduction to metallic Ni and Al2O3. Slow reduction of the Ni2+ from NiAl2O4 is proposed as the origin of the large increase in DRM activity observed for the alumina-overcoated Ni catalysts.

Original languageEnglish (US)
Pages (from-to)18-25
Number of pages8
JournalCatalysis Today
Volume343
DOIs
StatePublished - Mar 1 2020

Keywords

  • Alumina
  • Atomic layer deposition
  • Catalyst deactivation
  • Dry reforming
  • Nickel aluminate
  • Sintering

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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