Controlling the rate of change of Ni dispersion in commercial catalyst by ALD overcoat during dry reforming of methane

Shaik Afzal, Anuj V. Prakash, Patrick Littlewood, Tobin J. Marks, Eric Weitz, Peter C. Stair, Nimir O. Elbashir

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

This study investigates changes in dispersion with time-on-stream of a Ni catalyst coated with alumina by Atomic Layer Deposition (ALD) in Dry Reforming of Methane (DRM) conditions. A 20 wt% commercial Ni catalyst is coated with 5, 10, and 20 ALD cycles and tested for DRM at 650 °C, 1 atm for 40 h. Using an in-situ H2–CO pulse chemisorption technique, it is found that the rate of decline in catalyst dispersion is more rapid in the uncoated catalyst (~0.11%h−1) than 5-ALD catalyst (~0.025%h−1). TEM images before and after reaction show that the average particle size for the uncoated catalyst increases from 8.5 nm to 24.5 nm, indicating sintering, whereas the 5-ALD catalyst retained the initial particle size. The reduced particle size also explains the 50% reduction in carbon formation-rate in the 5-ALD catalyst. The developed sequential H2–CO chemisorption technique reliably measures in-situ dispersion in uncoated and ALD coated catalysts with exposed active sites.

Original languageEnglish
Pages (from-to)12835-12848
Number of pages14
JournalInternational Journal of Hydrogen Energy
Volume45
Issue number23
DOIs
Publication statusPublished - Apr 28 2020

Keywords

  • Atomic layer deposition (ALD)
  • Chemisorption
  • Dispersion
  • Methane dry reforming (DRM)
  • Ni catalyst

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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