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Oxidation of Ni-Cr and Ni-Cr-Mo was studied in operando with near ambient pressure x-ray photoelectron spectroscopy in the Cabrera-Mott regime. The oxidation temperature was 200°C—a severely diffusion-limited regime. The near-surface alloy is Cr-enriched after the reduction of native oxide in vacuum, and especially so for Ni-15Cr-6Mo. Mo-cations are integrated into the oxide and Mo(VI) dominates at the surface. The surface chemistry-driven promotion of chromia by Mo predicted by theory is negated by the limited surface diffusion of reactants. Preoxidation processing is proposed to control the oxide properties for the use of Ni-Cr superalloys at low temperatures.
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Implication of surface oxidation of nanoscale molybdenum carbide on electrocatalytic activity
The surface oxidation of molybdenum carbide nanoparticles was controlled by the electrochemical method. The impact of surface oxidation on catalytic properties was studied by both spectroscopic and computational methods.
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- PAR ID:
- 10522260
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 12
- Issue:
- 25
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 15163 to 15176
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d4ta01746c
