Structural and chemical state of doped and impregnated mesoporous Ni/CeO2 catalysts for the water-gas shift
- Stony Brook Univ., Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
- Univ. of Connecticut, Storrs, CT (United States)
- Technical Univ. of Catalonia, Barcelona (Spain)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
Mesoporous Ni/CeO2 catalysts of variable loadings were prepared using in-situ doping and impregnation synthesis techniques. The catalysts were found to exhibit activity for the water-gas shift (WGS) reaction, particularly at temperatures above 250 °C. Structural, electronic, and surface chemical characterizations of the materials were carried out using in-situ X-ray diffraction (XRD), in-situ X-ray absorption (XANES), and in-situ infrared (DRIFTS) techniques. The effects of metal loading and preparation method on these properties were studied in order to develop a more complete understanding of the design and application of Ni-loaded mesoporous CeO2 catalysts. For WGS reaction activity, the in-situ doping method was observed to be superior, and overall activity was observed to increase with increasing metal loadings. Simple normalization of activity data to nominal nickel content revealed a trend favoring lower loadings, indicating higher activity per unit nickel. The reduction of the catalyst is observed with increasing reaction temperature (Ni2+ → Ni°, Ce4+ → Ce3+) while the active states of all catalysts were identified as a stable, partially reduced ceria fluorite lattice (Ce4+/Ce3+) with Ni2+ and Ni°. In Situ DRIFTS showed nearly identical surface chemistry for both doped and impregnated samples, likely involving an associative pathway at lower temperatures and a redox pathway at higher temperatures. Structural properties and surface chemistry were observed to depend both on metal loading and preparation method. As a result, nickel loadings as low as 1 wt% prepared by in-situ doping were found to display the most favorable metal-support interactions for the WGS reaction.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States); Univ. of Connecticut, Storrs, CT (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division
- Grant/Contract Number:
- SC0012704; FG02-86ER13622
- OSTI ID:
- 1482568
- Alternate ID(s):
- OSTI ID: 1598167
- Report Number(s):
- BNL-209468-2018-JAAM
- Journal Information:
- Applied Catalysis. A, General, Vol. 567, Issue C; ISSN 0926-860X
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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