Hematite nanostructures synthesized by a silk fibroin-assisted hydrothermal method

A green, simple and economical route based on an efficient Bombyx mori silk fibroin assisted hydrothermal process has been developed to synthesize monodisperse hematite (α-Fe₂O₃) nanostructures with fine shape control. The effects of reaction time and silk fibroin concentration on the morphology of α-Fe₂O₃ have been investigated systematically. Several morphologies including quasi-nanocubes, nanospheres that are composed of primary nanoparticles, and the coexistence of nanospheres and primary nanoparticles were obtained by varying the silk fibroin concentration. The formation mechanism of different α-Fe₂O₃ morphologies are discussed based on the silk fibroin template effect. In addition, these α-Fe₂O₃ nanostructures exhibit interesting shape-dependent magnetic properties. We believe that such a synthesis method of α-Fe₂O₃ provides an efficient shape control and cost-effective approach that is potentially competitive for scaling-up industrial production.