Synthesis of mesostructured stishovite from FDU-12/carbon composite

Nanocasting at high pressure has been recently proposed as a novel strategy for the synthesis of periodic mesoporous materials with crystalline walls. In this study we present results on the synthesis of mesostructured stishovite from mesostructured FDU-12/carbon composite precursor using the multi-anvil press. Results from quenched experiments performed at a pressure of 14 GPa indicate that a minimum temperature of 500 degrees C is needed to crystallize stishovite from the amorphous silica precursor with a preserved mesostructure. Transmission electron microscopy combined with small angle X-ray scattering measurements confirmed the mesostructure of synthetic stishovite having carbon-filled pores with a diameter of similar to 19 nm similar to the pore size of the FDU-12 precursor. Calcination of the stishovite/carbon composite at 450 degrees C in air at ambient condition leads to amorphization of the stishovite. Our results show that mesostructure materials can be synthesized at very high pressures without loss or critical modification of the mesostructure. (C) 2014 Elsevier Inc. All rights reserved.