Direct Synthesis of Controllable Microstructures of Thermally Stable and Ordered Mesoporous Crystalline Titanium Oxides and Carbide/Carbon Composites

Abstract

The mesoporous titanium oxides- and carbide-carbon nanocomposites (Ti−C nanocomposites) with different morphologies at various Ti/C mass ratios were directly synthesized via supramolecular self-assembly with in situ crystallization process. The microstructures including surface area, morphology, and crystallinity were characterized by surface area analyzer, TEM, and SAXS/XRD, respectively. The specific BET surface areas (178−639 m2 g−1), micropore surface areas (6.3−47.3%), and total pore volumes (0.18−0.46 cm3 g−1) increase with the increase in calcination temperatures and Ti/C mass ratios. The calcination temperature and carbon content have significant effect on the thermal stability of titanium-based nanomaterials. The crystallinity changes from anatase, rutile, Magneli phases, and then to TiC when the carbon content is lower than 35 wt %, while the crystal phase of Ti−C composites at 50 wt % changes directly from anatase to TiC. However, Mageli products lose the mesostructures. The sizes of TiO2 nanoc...