Flower-like porous hematite nanoarchitectures achieved by complexation–mediated oxidation–hydrolysis reaction

Flower-like porous hematite (α-Fe2O3) nanoarchitectures composed of ultra-thin nanoflakes were prepared by annealing the iron oxide precursor formed via the oxidation-hydrolysis reaction between Fe(II) ions and Tris(hydroxymethyl)aminomethane (abbreviated as Tris). The microstructure of the prepared FeOOH and hematite samples were fully characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, Fourier-transforming infrared spectra, thermogravimetric analysis, and nitrogen adsorption–desorption isotherm. Based on the influences of reactant concentrations, reaction time and reaction temperature on the morphologies of the resultant samples, a formation mechanism of etching was proposed, Fe(II)–Tris complexes were self-assembled via hydrogen bonds into brick-like building blocks, which then aggregated into rudimentary nanoparticles, and the synergistic effect between the crystallization of FeOOH and dissociation of Fe(II)–Tris complexes make the rudimentary nanoparticles evolve into the flower-like products. The as-prepared flower-like α-Fe2O3 nanostructures possessed a Brunauer–Emmett–Teller specific surface area of 191.63 m2 g−1, hierarchical pore distribution ranging from micropores to macropores, and good crystallinity, and excellent visible photocatalysis in terms of removing chemical oxygen demand of dimethyl sulfoxide industrial wastewater. The current work provides a reliable approach for building functional hierarchical nanoarchitectures and the prepared iron oxide nanomaterials demonstrate an excellent ability to remove toxic pollutants in industrial wastewater.

Taking advantage of the unique complexing ability of Tris(hydroxymethyl)aminomethane with Fe(II) ions, the iron oxide precursor composed of ultra-thin nanoflakes was prepared. Flower-like hematite (α-Fe2O3) nanoparticles with hierarchical porous structures were further obtained through annealing the iron oxide precursor.Figure optionsDownload high-quality image (65 K)Download as PowerPoint slideResearch highlights
► Flower-like porous iron oxide nanostructures are prepared via a solution-based reaction utilizing the complexing ability of Tris with Fe(II) ions.
► The morphology of resultant nanostructures is controlled by a balance between the crystallization rate of γ-FeOOH with the dissociation rate of the Fe(II)–Tris complex.
► They exhibit excellent visible photocatalysis in treating DMSO industrial wastewater.