Abstract
This paper presents a systematic study of the growth mechanism for Pd nanobars synthesized by reducing Na2PdCl4 with L-ascorbic acid in an aqueous solution in the presence of bromide ions as a capping agent. Transmission electron microscopy (TEM) and high-resolution TEM analyses revealed that the growth at early stages of the synthesis was dominated by particle coalescence, followed by shape focusing via recrystallization and further growth via atomic addition. We also investigated the detailed surface structure of the nanobars using aberration-corrected scanning TEM and found that the exposed {100} surfaces contained several types of defects such as an adatom island, a vacancy pit, and atomic steps. Upon thermal annealing, the nanobars evolved into a more thermodynamically favored shape with enhanced truncation at the corners.
| Original language | English |
|---|---|
| Pages (from-to) | 180-188 |
| Number of pages | 9 |
| Journal | Nano Research |
| Volume | 3 |
| Issue number | 3 |
| DOIs | |
| State | Published - Mar 2010 |
Funding
This work was supported in part by the Natural Science Foundation (No. DMR-0804088) and startup funds from Washington University in St. Louis. P. H. C. C. was also partially supported by the Fulbright Program and the Brazilian Ministry of Education (CAPES). Part of the work was performed at the Nano Research Facility (NRF), a member of the National Nanotechnology Infrastructure Network (NNIN), which is supported by the National Science Foundation (No. ECS-0335765). It was also supported by startup funds from the University of Missouri-St. Louis. The STEM images were acquired at the Oak Ridge National Laboratory\u2019s High Temperature Materials Laboratory sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program.
Keywords
- Coalescence
- Growth
- Nanocrystals
- Palladium
- Surface evolution