title: Cationic gemini surfactant-assisted synthesis of hollow Au nanostructures by stepwise reductions.
abstract: A novel synthetic approach was developed for creating versatile hollow Au nanostructures by stepwise reductions of Au(III) upon the use of cationic gemini surfactant hexamethylene-1,6-bis(dodecyl dimethylammonium bromide) (C12C6C12Br2) as a template agent. It was observed that the Au(I) ions obtained from the reduction of Au(III) by ascorbic acid can assist the gemini surfactant to form vesicles, capsule-like, and tube-like aggregates that subsequently act as soft templates for hollow Au nanostructures upon further reduction of Au(I) to Au(0) by NaBH4. It was demonstrated that the combination of C12C6C12Br2 and Au(I) plays a key role in regulating the structure of the hollow precursors not only because C12C6C12Br2 has a stronger aggregation ability in comparison with its single chain counterpart but also because the electrostatic repulsion between head groups of C12C6C12Br2 is greatly weakened after Au(III) is converted to Au(I), which is in favor of the construction of vesicles, capsule-like, and tube-like aggregates. Compared with solid Au nanospheres, the resultant hollow nanostructures exhibit enhanced electrocatalytic activities in methanol oxidation, following the order of elongated nanocapsule > nanocapsule > nanosphere. Benefiting from balanced interactions between the gemini surfactant and Au(I), this soft-template method may present a facile and versatile approach for the controlled synthesis of Au nanostructures potentially useful for fuel cells and other Au nanodevices.
authors.affiliation: Key Laboratory of Colloid and Interface Science, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Wang
authors.forename: Yuchun
authors.initials: Y
authors.lastname: Han
authors.forename: Maozhang
authors.initials: M
authors.lastname: Tian
authors.forename: Yaxun
authors.initials: Y
authors.lastname: Fan
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Tang
authors.forename: Mingyuan
authors.initials: M
authors.lastname: Gao
authors.forename: Yilin
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000475:Alkenes; D001205:Ascorbic Acid / Q000737:chemistry; D001894:Borohydrides / Q000737:chemistry; D002412:Cations / Q000737:chemistry; D055664:Electrochemical Techniques; D006046:Gold / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*
chemical_list: D000475:Alkenes; D001894:Borohydrides; D002412:Cations; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; C509664:hexamethylene-1,6-bis(dodecyldimethylammonium bromide); D006046:Gold; C025364:sodium borohydride; D001205:Ascorbic Acid; D000432:Methanol