Porous Gold Nanobelts Templated by Metal−Surfactant Complex Nanobelts

Abstract

Unique, porous gold nanobelts consisting of self-organized nanoparticles were synthesized in a high yield by morphology-preserved transformation from metal−surfactant complex precursor nanobelts formed by a bolaform surfactant dodecane-1,12-bis(trimethylammonium bromide) (N-C₁₂-NBr₂) and HAuCl₄. It was revealed that the precursor nanobelts of the stoichiometric N-C₁₂-N(AuCl₄)₂ complex formed through electrostatic combination of the positively charged quaternary ammonium headgroups of N-C_<i>n</i>-NBr₂ and the negatively charged AuCl₄⁻ ions. They were subsequently converted into porous gold nanobelts with shrunken sizes upon reduction by NaBH₄. The morphology of the produced gold nanostructures could be adjusted by changing the mixing ratio between N-C₁₂-NBr₂ and HAuCl₄ in the reaction solution. It was found that the obtained porous Au nanobelts exhibited enhanced catalytic activity toward reduction of 4-nitrophenol compared with solid gold nanobelts, probably owing to their larger surface area and more active sites.