Determination of the Catalytic Properties of Metal Coated Nanowires
EMSL Project ID
10291
Abstract
Coating of nanowires is being investigated to broaden potential uses for future applications. Coatings of Ni and Pt nanoparticles have been synthesized on silicon carbide nanowires by plasma enhanced chemical vapor deposition. Coatings with high particle densities with average particle diameters of 2.76 and 3.28 nm for Pt and Ni, respectively, were formed with narrow size distributions. Plasma enhanced chemical vapor deposition appears to be an efficient method for production of metal coatings on nanowires.We are reporting Pt and Ni coatings formed on SiC nanowires (NWs) using plasma enhanced chemical vapor deposition (PECVD). To our knowledge, there exists no previous reports regarding the coating of NWs or CNTs using the PECVD method. Particle geometries produced by PECVD are similar to those previously reported in the literature, however particle densities are substantially greater. The coatings that we are reporting are relatively simple to produce and require a short processing time. This PECVD method may be a new way to produce superior coatings of metal on NWs and may be applicable to CNTs.
NWs have been observed to receive a complete coating of Pt. The presence of distinct rings in electron diffraction patterns taken from the samples indicates the polycrystalline nature of the coating. The diffraction pattern was indexed and the coating was confirmed to be metallic Pt. Particle analysis was performed on Pt coated NWs with initial NW diameters of approximately 60, 80, 105, 120, and 140 nm. An average overall particle size was determined to be 2.76 nm with a standard deviation of 0.46 nm. The particle density for the Pt coating was found to be nearly 31,000 particles per m2.
NWs coated with Ni have been observed to receive continuous coatings on both the minimum and maximum NW diameters, showing that the PECVD technique is applicable to coating NWs with a range of diameters. The distinct rings seen in diffraction patterns indicate the polycrystalline nature of the coating. The diffraction pattern was indexed to confirm the metallic Ni coating. Particle analysis was also performed on the Ni coated NWs with wire diameters of approximately 45, 80, 110, and 125 nm. The average overall particle size was determined to be 3.28 nm with a standard deviation of 0.74 nm. The particle density for the Ni coating was found to be approximately 12,000 particles per m2.
The catalytic properties of Pt and Ni are well documented. The coatings reported in this study offer the possibility of possessing excellent catalytic properties because of the large surface area present due to large particle densities and small particle size. The use of highly stable support materials, taking advantage of excellent mechanical and thermal properties, is also a motivation for using SiC NWs as a template for metal coated nanostructures. The goal of forthcoming work of our group will be investigation of the catalytic properties of metal coated NWs that have been produced as a result of the current study.
Project Details
Project type
Exploratory Research
Start Date
2004-08-09
End Date
2006-04-11
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members