Preparation of Polymer-Covered Metal Nanorods and Metal Microcrystals by Intrinsic Two-Dimensional Crystalline Lattice Templating

Abstract

Two-dimensional layered ceramics, highly anisotropic materials in terms of structure and properties, were used to produce polymer-covered metal nanorods and metal microcrystals. The procedure took advantage of the intrinsic planar, layered ordering of the metal cations suitable to be reduced and could be further used to engineer one-dimensional metal alloy nanostructures by appropriate doping of the initial layered ceramic lattice with suitable cationic species. The procedure involved the formation in an intermediate step of a polymer-intercalated ceramic nanocomposite, highly porous to the diffusion of the polymerizable reducing agent, pyrrole. Two structurally similar layered bismuthates, Bi 2 Sr 2 CaCu 2 O 8+␦ and Bi 6 Sr 2 CaO 12 and a partially Rh-substituted ceramic, Bi 4 Rh 2 Sr 2 CaO 12 were used as the precursor layered ceramics and the reducible metal cations were Cu 2+ , Bi 3+ , and Rh 3+ , respectively. The formation of the polymer-covered metal nanorods and metal microcrystals took place at relatively high temperatures of reaction (325°C) and long reaction times (10-12 days).