A hydride-induced-reduction strategy for fabricating palladium-based core-shell bimetallic nanocrystals.
One key challenge in making high-quality bimetallic nanocrystals is to prevent self-nucleation of individual metal components. We report in this work an effective seeded growth strategy that uses activated hydrogen atoms as the reducing agent to prepare core-shell bimetallic nanocrystals. In the developed method, Pd nanocrystals serve as the seed and catalyst as well to activate H2 for the reductive deposition of Ag. The unique feature of the developed method is that the activated hydrogen atoms are confined on the surface of the Pd seeds. Consequently, the self-nucleation of Ag is effectively inhibited so that the deposition of Ag occurs only on Pd. The mechanism studies reveal that reductive growth of Ag on Pd seeds proceeds until the Pd surface is fully covered by Ag. The Ag/Pd ratio in the prepared Pd@Ag nanocrystals is readily fine-tuned by the amount of AgNO3 or H2. The method is effective for depositing Ag on Pd nanocrystal seeds with different morphologies such as nanosheets, nanocubes, tetrahedra and nanowires. More importantly, the deposition of Ag on Pd nanowires allows preparation of flexible transparent electrode material with sheet electronic conductivity of 271 S sq(-1) at a transmittance of over 90%.
State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China. nfzheng@xmu.edu.cn.
Xingli
X
Wang
Binghui
B
Wu
Guangxu
G
Chen
Yun
Y
Zhao
Pengxin
P
Liu
Yan
Y
Dai
Nanfeng
N
Zheng