Template preparation of multisegment PtNi nanorods as methanol electro-oxidation

2019-08-14 09:58:33

The PT Ni nanorods PtNi

责任者: Liu, Fang;Lee, Jim Yang;Zhou, Weijiang 单位: Chem. and Biomolecular Engineering, National University of Singapore, Singapore 119260, Singapore 来源出处: Journal of Physical Chemistry B,2004,108(46):17959-17963 摘要: Multisegment PtNi nanorods (Ni-Pt, Ni-Pt-Ni, Ni-Pt-Ni-Pt, and Ni-Pt-Ni-Pt-Ni) with controllable lengths of the individual metals were obtained by sequential electrodeposition of the metals into the pores of anodic aluminum oxide (AAO) membranes. Field emission scanning electron microscopy (FESEM) showed that the nanorods are about 170 nm in diameter and 1.6 μm in length, with 530 nm of total Pt segment lengths. The alternating Pt and Ni segments could be easily differentiated by FESEM. XRD characterization of the PtNi nanorods indicated that both Pt and Ni are polycrystals with a face-centered cubic structure. The presence of Pt(0), Pt(II), Pt(IV), Ni(0), and Ni(II) on the surface of the PtNi nanorods was deduced from XPS measurements. The nanorods are catalytically active in the room temperature electro-oxidation of methanol. The relative rates of reaction as recorded by cyclic voltammetry showed a linear relationship between the peak current densities and the number of Pt-Ni interfaces. The use of segmented nanorods with identifiable Pt-Ni interfaces removes many of the ambiguities in the interpretation of experimental data from conventional alloy catalysts and has provided a direct demonstration of the role of pair sites in the bifunctional mechanism. 关键词: Nanostructured materials;Platinum compounds;Catalysts;Oxidation;Carbon monoxide;Electrochemical electrodes;Chemical activation;Current density;Electroplating;Cyclic voltammetry;Scanning electron microscopy;Electrooxidation catalysts;Nanorods;Vacuum evaporation