Aqueous route for mesoporous metal oxides using inorganic metal source and their applications

In this paper, we report a synthetic route for mesoporous metal oxides from inorganic metal sources in aqueous media. This synthesis route offers a versatile, low cost and environmental friendly method to produce mesoporous metal oxides that have very high surface areas. As an example, the synthesis of iron oxide is described in detail. Synthesis conditions including aging time, aging temperature and amount of urea were varied to find the optimal synthesis conditions. We found that recycling the Cetyltrimethylammonium Bromide (CTAB) template is possible when the amount of urea is reduced to stoichiometric. The mesoporous metal oxides made under these conditions are self assemblies of leaf-like single crystal sub-units with randomly distributed mesopores embedded into the crystals. As a result of the crystalline nature, these mesoporous metal oxides have high thermal stabilities and their applications as gas sensors and CO disproportionation catalysts indicate promising aspects of these materials.