J. Mater. Sci. Technol. ›› 2016, Vol. 32 ›› Issue (1): 41-47.DOI: 10.1016/j.jmst.2015.10.015

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Concentration-dependent Morphology Control of Pt-coated-Ag Nanowires and Effects of Bimetallic Interfaces on Catalytic Activity

Yongguang Wang, Xiangyu Wang, Bo Sun, Shaochun Tang, Xiangkang Meng   

  1. Institute of Materials Engineering, National Laboratory of Solid State Microstructures, and College of Engineering Applied Sciences, Nanjing University, Nanjing 210093, China
  • Received:2015-04-15 Revised:2015-07-06 Online:2016-01-19
  • Supported by:
    The authors gratefully acknowledge the financial support of the project from the PAPD(No. 50831004), the Fundamental Research Funds for the Central Universities (Nos.021314380019 and 1106021343), the Innovation Fund of Jiangsu Province (No.BY2013072-06), the Natural Science Foundation of Jiangsu Province (No. 2012729), the National Natural Science Foundation of China (No. 11374136), and the State Key Program for Basic Research of China (No. 2010CB631004).

Abstract: Silver nanowires (NWs) coated with platinum (Pt) nanoparticles were synthesized via a galvanic partial replacement of Ag NWs in an aqueous K2PtCl6 solution at room temperature. The products were characterized using a combination of electron microscopies, selected area electron diffraction, energy-dispersive X-ray mapping and X-ray diffraction. The surface morphology and Pt/Ag composition ratios are controlled by adjusting the K2PtCl6 concentration. Different concentrations result in various surface morphologies including rough nanoparticle coating, porous and relatively smooth surfaces. The formation mechanism was discussed based on the lattice constants' difference, concentration driven nucleation, consumption of Ag NWs, and stoichiometry of the replacement reaction. The effects of the bimetallic interface on the catalytic activity toward the reduction of 4-nitrophenol by sodium borohydride were studied. The activity of Ag-Pt NWs is highly enhanced over monometallic nanostructures, and optimized by a low Pt loading of 1.34 at.%, which indicates a catalytic role of the inter-metallic interface for the electron transfer.

Key words: Nanowires, Silver-platinum, Catalytic activity, Bimetallic interfaces