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

Abstract

Flower-like porous hematite (α-Fe 2O 3) 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-Fe 2O 3 nanostructures possessed a Brunauer–Emmett–Teller specific surface area of 191.63 m 2 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.