Assembly of Au@Pt Core-Shell Nanoparticles with a Controlled Shell Thickness at the Surface of Thiol-functionalized Multi-walled Carbon Nanotubes to Achieve High Activity Towards Electrocatalytic Methanol Oxidation
TAN Feng1, 2, XU Yangyang1, LI Wei1, 2, XU Mingli1, MIN Chungang1, SHI Qingnan2, LIU Feng3, YANG Xikun1, 2
1 College of Material Science and Engineering, Kunming University of Science and Technology, Kunming 650093; 2 Research Center for Analysis and Measure, Kunming University of Science and Technology,Kunming 650093; 3 Yunnan Sino-Precious Metals Holding Co., Ltd, Kunming 650500
Abstract: It is the aim of this work to explore the assembly of Au@Pt core-shell nanoparticles (Au@Pt NPs) on multi-walled carbon nanotubes (MWCNTs) surfaces, attempting to acquire high activity for electrocatalytic methanol oxidation. We synthesized Au@Pt NPs whose shell (Pt layer) thickness can be varied by changing the molar ratio of Au/Pt, and then assembled these Au@PtNPs onto thiol (-SH)-functionalized MWCNTs surfaces to form a series of Au@Pt/MWCNTs composites. The surface chemical state, structure, and morphology of the Au@Pt NPs and Au@Pt/MWCNTs composites were characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS). The electrochemical tests including cyclic voltammetry (CV) and chronoamperometry (CA) were conducted to determine the assembly quality of Au@Pt NPs differing in shell thickness, and to cha-racterize the activity of Au@Pt/MWCNTs catalysts. The results confirmed the successful assembly of Au@Pt NPs on MWCNTs surfaces via the covalent Pt-S/Au-S bonds formed between the monometallic Au or Pt of Au@Pt NPs and the thiol group of MWCNTs. The dispersion of Au@Pt NPs on MWCNTs highly depends on the atom ratios of Au/Pt. When the Pt envelopes outside the Au cores are incomplete, the exposed Au atoms facilitate the assembly of Au@Pt NPs. And on the contrary, if the Au cores are entirely coated by the Pt shell, the oxidation state Pt(Ⅱ) on the Au@Pt NPs surfaces will exert a negative effect. In particular, an 1∶1 atomic ratio of Au/Pt can result in the satisfactory dispersion of Au@Pt NPs on MWCNTs, also a distinctly higher activity and better stability of Au@Pt/MWCNTs (1∶1) compared with Pt/MWCNTs toward electrocatalytic methanol oxidation in alkaline media.
谭丰, 徐洋洋, 李卫, 徐明丽, 闵春刚, 史庆南, 刘锋, 杨喜昆. 在硫基功能化碳纳米管上组装壳层厚度可控的Au@Pt核壳纳米粒子以获得高的甲醇电催化氧化活性[J]. 材料导报, 2018, 32(23): 4041-4046.
TAN Feng, XU Yangyang, LI Wei, XU Mingli, MIN Chungang, SHI Qingnan, LIU Feng, YANG Xikun. Assembly of Au@Pt Core-Shell Nanoparticles with a Controlled Shell Thickness at the Surface of Thiol-functionalized Multi-walled Carbon Nanotubes to Achieve High Activity Towards Electrocatalytic Methanol Oxidation. Materials Reports, 2018, 32(23): 4041-4046.
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2018, Vol. 32 
