Preparation of polymer-covered metal nanorods and metal microcrystals by intrinsic two-dimensional crystalline lattice templating

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, Bi₂Sr₂CaCu₂O_8+δ and Bi₆Sr₂CaO₁₂ and a partially Rh-substituted ceramic, Bi₄Rh₂Sr₂ CaO₁₂ were used as the precursor layered ceramics and the reducible metal cations were Cu²⁺, Bi³⁺, and Rh³⁺, 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).