Control over the branched structures of platinum nanocrystals for electrocatalytic applications.
Structural control of branched nanocrystals allows tuning two parameters that are critical to their catalytic activity--the surface-to-volume ratio, and the number of atomic steps, ledges, and kinks on surface. In this work, we have developed a simple synthetic system that allows tailoring the numbers of branches in Pt nanocrystals by tuning the concentration of additional HCl. In the synthesis, HCl plays triple functions in tuning branched structures via oxidative etching: (i) the crystallinity of seeds and nanocrystals; (ii) the number of {111} or {100} faces provided for growth sites; (iii) the supply kinetics of freshly formed Pt atoms in solution. As a result, tunable Pt branched structures--tripods, tetrapods, hexapods, and octopods with identical chemical environment--can be rationally synthesized in a single system by simply altering the etching strength. The controllability in branched structures enables to reveal that their electrocatalytic performance can be optimized by constructing complex structures. Among various branched structures, Pt octopods exhibit particularly high activity in formic acid oxidation as compared with their counterparts and commercial Pt/C catalysts. It is anticipated that this work will open a door to design more complex nanostructures and to achieve specific functions for various applications.
Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, PR China.
Liang
L
Ma
Chengming
C
Wang
Ming
M
Gong
Lingwen
L
Liao
Ran
R
Long
Jinguo
J
Wang
Di
D
Wu
Wei
W
Zhong
Moon J
MJ
Kim
Yanxia
Y
Chen
Yi
Y
Xie
Yujie
Y
Xiong
D002384:Catalysis; D003460:Crystallization / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D005561:Formates / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D010984:Platinum / Q000737:chemistry*; D013499:Surface Properties
D005561:Formates; D046911:Macromolecular Substances; C030544:formic acid; D010984:Platinum