Open Access
Issue
Published:
05 May 2010
New Insights into the Growth Mechanism and Surface Structure of Palladium Nanocrystals
),
Younan Xia1(
)
Download citation
829
Views
19
Downloads
96
Crossref
N/A
WoS
90
Scopus
0
CSCD
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.
menu
New Insights into the Growth Mechanism and Surface Structure of Palladium Nanocrystals
), Younan Xia1(
)
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.
References(28)
Skrabalak, S. E.; Chen, J.; Sun, Y.; Lu, X.; Au, L.; Cobley, C. M.; Xia, Y. Gold nanocages: Synthesis, properties, and applications. Acc. Chem. Res. 2008, 41, 1587−1595.
Xia, Y.; Xiong, Y.; Lim, B.; Skrabalak, S. E. Shape-controlled synthesis of metal nanocrystals: Simple chemistry meets complex physics? Angew. Chem. Int. Ed. 2009, 48, 60−103.
Peng, Z.; Yang, H. Designer platinum nanoparticles: Control of shape, composition in alloy, nanostructure and electrocatalytic property. Nano Today 2009, 4, 143−164.
Tian, N.; Zhou, Z. -Y.; Sun, S. -G.; Ding, Y.; Wang, Z. L. Synthesis of tetrahexahedral platinum nanocrystals with high-index facets and high electro-oxidation activity. Science 2007, 316, 732−735.
Bratlie, K. M.; Lee, H.; Komvopoulos, K.; Yang, P.; Somorjai, G. A. Platinum nanoparticle shape effects on benzene hydrogenation selectivity. Nano Lett. 2007, 7, 3097−3101.
Lim, B.; Lu, X.; Jiang, M.; Camargo, P. H. C.; Cho, E. C.; Lee, E. P.; Xia, Y. Facile synthesis of highly faceted multioctahedral Pt nanocrystals through controlled overgrowth. Nano Lett. 2008, 8, 4043−4047.
Wang, C.; Daimon, H.; Onodera, T.; Koda, T.; Sun, S. A general approach to the size- and shape-controlled synthesis of platinum nanoparticles and their catalytic reduction of oxygen. Angew. Chem. Int. Ed. 2008, 47, 3588−3591.
Lim, B.; Jiang, M.; Camargo, P. H. C.; Cho, E. C.; Tao, J.; Lu, X.; Zhu, Y.; Xia, Y. Pd–Pt bimetallic nanodendrites with high activity for oxygen reduction. Science 2009, 324, 1302−1305.
Habas, S. E.; Lee, H.; Radmilovic, V.; Somorjai, G. A.; Yang, P. Shaping binary metal nanocrystals through epitaxial seeded growth. Nat. Mater. 2007, 6, 692−697.
LaMer, V. K.; Dinegar, R. H. Theory, production and mechanism of formation of monodispersed hydrosols. J. Am. Chem. Soc. 1950, 72, 4847−4854.
Peng, X.; Wickham, J.; Alivisatos, A. P. Kinetics of Ⅱ–Ⅵ and Ⅲ–Ⅴ colloidal semiconductor nanocrystal growth: "Focusing" of size distributions. J. Am. Chem. Soc. 1998, 120, 5343−5344.
Park, J.; Joo, J.; Kwon, S. G.; Jang, Y.; Hyeon, T. Synthesis of monodisperse spherical nanocrystals. Angew. Chem. Int. Ed. 2007, 46, 4630−4660.
Anwar, J.; Boateng, P. K. Computer simulation of crystallization from solution. J. Am. Chem. Soc. 1998, 120, 9600−9604.
Niederberger, M.; Colfen, H. Oriented attachment and mesocrystals: Non-classical crystallization mechanisms based on nanoparticle assembly. Phys. Chem. Chem. Phys. 2006, 8, 3271−3287.
Watzky, M. A.; Finney, E. E.; Finke, R. G. Transition-metal nanocluster size vs. formation time and the catalytically effective nucleus number: A mechanism-based treatment. J. Am. Chem. Soc. 2008, 130, 11959−11969.
Lim, B.; Wang, J.; Camargo, P. H. C.; Cobley, C. M.; Kim, M. J.; Xia, Y. Twin-induced growth of palladium–platinum alloy nanocrystals. Angew. Chem. Int. Ed. 2009, 48, 6304−6308.
Bisson, L.; Boissiere, C.; Nicole, L.; Grosso, D.; Jolivet, J. P.; Thomazeau, C.; Uzio, D.; Berhault, G.; Sanchez, C. Formation of palladium nanostructures in a seed-mediated synthesis through an oriented-attachment-directed aggregation. Chem. Mater. 2009, 21, 2668−2678.
Banfield, J. F.; Welch, S. A.; Zhang, H.; Ebert, T. T.; Penn, R. L. Aggregation-based crystal growth and microstructure development in natural iron oxyhydroxide biomineralization products. Science 2000, 289, 751−754.
Pacholski, C.; Kornowski, A.; Weller, H. Self-assembly of ZnO: From nanodots to nanorods. Angew. Chem. Int. Ed. 2002, 41, 1188−1191.
Tang, Z.; Kotov, N. A.; Giersig, M. Spontaneous organization of single CdTe nanoparticles into luminescent nanowires. Science 2002, 297, 237−240.
Zhang, Z.; Tang, Z.; Kotov, N. A.; Glotzer, S. C. Simulations and analysis of self-assembly of CdTe nanoparticles into wires and sheets. Nano Lett. 2007, 7, 1670−1675.
Yu, J. H.; Joo, J.; Park, H. M.; Baik, S. -I.; Kim, Y. W.; Kim, S. C.; Hyeon, T. Synthesis of quantum-sized cubic ZnS nanorods by the oriented attachment mechanism. J. Am. Chem. Soc. 2005, 127, 5662−5670.
Halder, A.; Ravishankar, N. Ultrafine single-crystalline gold nanowire arrays by oriented attachment. Adv. Mater. 2007, 19, 1854−1858.
Zheng, H.; Smith, R. K.; Jun, Y. -W.; Kisielowski, C.; Dahmen, U.; Alivisatos, A. P. Observation of single colloidal platinum nanocrystal growth trajectories. Science 2009, 324, 1309−1312.
Lim, B.; Jiang, M.; Tao, J.; Camargo, P. H. C.; Zhu, Y.; Xia, Y. Shape-controlled synthesis of Pd nanocrystals in aqueous solutions. Adv. Funct. Mater. 2009, 19, 189−200.
Xiong, Y.; Cai, H.; Wiley, B. J.; Wang, J.; Kim, M. J.; Xia, Y. Synthesis and mechanistic study of palladium nanobars and nanorods. J. Am. Chem. Soc. 2007, 129, 3665−3675.
Niu, W.; Li, Z. -Y.; Shi, L.; Liu, X.; Li, H.; Han, S.; Chen, J.; Xu, G. Seed-mediated growth of nearly monodisperse palladium nanocubes with controllable sizes. Cryst. Growth Des. 2008, 8, 4440−4444.
Zhang, Z.; Lagally, M. G. Atomistic processes in the early stages of thin-film growth. Science 1997, 276, 377−383.
Publication history
Copyright
Acknowledgements
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's High Temperature Materials Laboratory sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program.
Rights and permissions
This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited.
FEEDBACK 
TOP