A facile route for the flowerlike Mg7B4O13•7H2O nanostuctures: Synthesis, growth mechanism and thermal treatment

In the presence of the surfactant poly(vinyl pyrrolidone) (PVP), 3D hierarchical flower-shaped Mg7B4O13 center dot 7H(2)O nanostructures were synthesized via a facile precipitation process using Mg(NO3)(2)center dot 6H(2)O and Na2B4O7 center dot 10H(2)O as the raw materials. The nanostructures with diameters of 0.8-1.2 12 mu m are composed of numerous polycrystalline nanosheets with thickness of about 10 mu m. The possible growth mechanism for the flower-shaped nanostructures was proposed based on the systematic structural and property characterizations including XRD, SEM, TEM, IR and N-2 adsorption-desorption. The phase transformation can be observed during the calcination process, and the flower-shaped nanostructures can be successfully maintained after calcination at 550 degrees C and 650 degrees C. The adsorption-desorption experiments show the appearance of mesopores before and after calcination co-existed with small amount of macropores. The highest surface area of 111 m(2)/g and largest pore volume of 0.37 cm(3)/g are obtained in these hierarchical porous Mg3B2O6 nanoflowers. These novel porous borate-based materials could be applied in drug delivery, catalysis, environmental abatement, energy storage, etc. (C) 2014 Elsevier B.V. All rights reserved.