Growth of graphite nanofibers from the decomposition of CO/H{sub 2} over silica-supported iron{endash}nickel particles

Journal Article · Thu Jul 01 04:00:00 EDT 1999 · Journal of Materials Research

DOI:https://doi.org/10.1557/JMR.1999.0389· OSTI ID:686864

Anderson, P E; Rodriguez, N M ^[1]

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1. Department of Chemistry, Northeastern University, Boston, Massachusetts 02115 (United States)

Extremely fine, tubular graphite nanofibers of varying geometries and degrees of crystallinity were produced by the decomposition of CO and hydrogen over various compositions of nickel{endash}iron particles supported on silica. High-resolution transmission electron microscopy coupled with temperature programmed oxidation studies revealed that, as the iron content of the catalyst was increased, the bimetallic particles precipitated a chainlike graphitic fibrous structure in a stepwise mechanism. The high-iron-content system Fe{endash}Ni (8:2) yielded a small amount of these chainlike graphite fibers that were extremely resilient to oxidation, suggesting a highly crystalline structure. When the catalyst particles consisted of a nickel-iron mixture, Fe{endash}Ni (5:5), there was a decrease in the degree of crystallinity of the fibers (78{percent} graphite) and a corresponding increase in the amount of amorphous carbon precipitated (22{percent} amorphous) within the structure. The high-nickel catalyst Fe{endash}Ni (2:8) generated the largest amount of the tubular nanofiber product. It was significant that there was an increase in the amorphous carbon content (58{percent}) precipitated as opposed to graphitic carbon (42{percent}) in the structures. In some cases, amorphous carbon was deposited inside the graphite core of the nanofibers. The influence of the catalyst composition and nature of the metal-support interaction are key factors in the continuing development of graphite nanofibers possessing desired structures for potential uses in a variety of applications. {copyright} {ital 1999 Materials Research Society.}

• OSTI ID: 686864
• Journal Information: Journal of Materials Research, Journal Name: Journal of Materials Research Journal Issue: 7 Vol. 14; ISSN JMREEE; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AMORPHOUS STATE
CARBON FIBERS
CATALYSTS
CHEMICAL PREPARATION
GRAPHITE
MICROSTRUCTURE