Nature-inspired Nano- and Microstructural Control of Inorganic Materials by Soft Solution Process

Abstract

We addressed the nano- and microstructural control of inorganic crystal materials by nature-inspired aqueous route. Multi-layered WO₃·H₂O plates were obtained from (NH₄)₁₀W₁₂O₄₁·5H₂O aqueous solutions containing gelatin at 60°C. The nanostructured WO₃·H₂O precursors were converted to WO₃ particles by heating at 600°C. Nanostructured SnO particles were produced by aging Sn₆O₄(OH)₄ in HCl solutions containing biological polymers at 60°C, where the branching of SnO crystals was promoted with decreasing pH value and with increasing biological polymer contents. Hureaulite (Mn₅(PO₃OH)₂(PO₄)₂·4H₂O) single crystals were obtained from aqueous precursor solutions by keeping at 80°C, where the crystal size of the hureaulite products increased by addition of citric acid. These results suggested that nature-inspired aqueous route was effective for making hierarchical architectures of inorganic materials.