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.
Huang
Jianfeng
J
National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China.
Vongehr
Sascha
S
Tang
Shaochun
S
Lu
Haiming
H
Shen
Jiancang
J
Meng
Xiangkang
X
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