Surfactant-assisted nanoparticle assembly of mesoporous β-FeOOH (akaganeite)

A new mesoporous form of crystalline β-FeOOH (akaganeite) was successfully prepared by a technology of surfactant-assisted nanoparticle assembly in the presence of a nonionic PEO-surfactant. The synthesized mesoporous β-FeOOH has a high surface area of 228 m2/g and a pore size of 4.3 nm with a hierarchical scaffold-like structure formed through the aggregation and intergrowth of akaganeite nano-rods. To our knowledge, this is first known report of mesostructured crystalline akaganeite material. Thermal treatment at 200 °C afforded the retention of the akaganeite structure. A complete transformation to hematite occurred after calcination at 300 °C with structural collapse.