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

Research output: Contribution to journalArticle

Abstract

A catalyst consisting of 2 wt% Ni supported on a commercially available transition alumina is modified using TMA-H 2 O 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 (NiAl 2 O 4 ) spinel phase is unstable under the present DRM conditions and slowly undergoes reduction to metallic Ni and Al 2 O 3 . Slow reduction of the Ni 2+ from NiAl 2 O 4 is proposed as the origin of the large increase in DRM activity observed for the alumina-overcoated Ni catalysts.

Original languageEnglish
JournalCatalysis Today
DOIs
Publication statusPublished - Jan 1 2019

Fingerprint

Atomic layer deposition
Aluminum Oxide
Methane
Reforming reactions
Alumina
Catalysts
Sintering
Carbon
Deposits

Keywords

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

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

Cite this

Ni-alumina dry reforming catalysts : Atomic layer deposition and the issue of Ni aluminate. / Littlewood, Patrick; Liu, Shengsi; Weitz, Eric; Marks, Tobin J; Stair, Peter C.

In: Catalysis Today, 01.01.2019.

Research output: Contribution to journalArticle

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abstract = "A catalyst consisting of 2 wt{\%} Ni supported on a commercially available transition alumina is modified using TMA-H 2 O 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 (NiAl 2 O 4 ) spinel phase is unstable under the present DRM conditions and slowly undergoes reduction to metallic Ni and Al 2 O 3 . Slow reduction of the Ni 2+ from NiAl 2 O 4 is proposed as the origin of the large increase in DRM activity observed for the alumina-overcoated Ni catalysts.",
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