Ag dendrite-based Au/Ag bimetallic nanostructures with strongly enhanced catalytic activity.
Dendritic Ag/Au bimetallic nanostructures have been synthesized via a galvanic replacement reaction (GRR) of Ag dendrites in a chlorauric acid (HAuCl4) solution. After short periods of time, one obtains structures with protruding flakes; these will mature into very porous structures with little Ag left over. The morphological, compositional, and crystal structural changes involved with reaction time t were analyzed by using scanning and transmission electron microscopy (SEM and TEM, respectively), energy-dispersive X-ray spectrometry (EDX), and X-ray diffraction. High-resolution TEM combined with EDX and selected area electron diffraction confirmed the replacement of Ag with Au. A proposed formation mechanism of the original Ag dendrites developing pores while growing Au flakes cover this underlying structure at longer reaction times is confirmed by exploiting surface-enhanced Raman scattering (SERS). Catalytic reduction of 4-nitrophenol (4-NP) by sodium borohydride (NaBH4) is strongly enhanced, implying promising applications in catalysis.
National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
Jianfeng
J
Huang
Sascha
S
Vongehr
Shaochun
S
Tang
Haiming
H
Lu
Jiancang
J
Shen
Xiangkang
X
Meng
D001894:Borohydrides / Q000737:chemistry; D002384:Catalysis; D003712:Dendrites / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D009596:Nitrophenols / Q000737:chemistry; D010084:Oxidation-Reduction; D012834:Silver / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
D001894:Borohydrides; D009596:Nitrophenols; D012834:Silver; D006046:Gold; C025364:sodium borohydride; C024836:4-nitrophenol