ChemInform Abstract: Formation of Porous Metal Oxides via Sol-Gel Type Hydrolysis of Metal Alkoxide Complexes Modified with Organic Templates.

ABSTRACTA major challenge in utilizing living botanical materials, such as cellular leaf structures, as templates is that they are filled with water and conventional dehydration strategies often collapse or degrade the intricate botanical structure. This restricts the ability to introduce water reactive precursors into such structures. We have developed a room-temperature chemical method using acidified 2,2-dimethoxypropane to dehydrate water-rich botanical materials (e.g., fern leaves and water-rich jade succulents). This mild dehydration process leaves much of the porous cellular leaf structure intact even with ∼90% mass loss. These chemically dehydrated templates have been utilized in the growth of porous and ordered leaf replicate structures consisting of TiO2 and SiO2 via sol-gel precursor impregnation methods. These white metal oxide products exhibit external and internal structures that look very similar to their original templates, but are shrunken intact versions of the original. This paper details the chemical procedures that enable one to effectively use sensitive botanical templates in metal oxide growth. The physical and structural properties of several dried porous templates and macroporous anatase TiO2 and amorphous or crystoballite SiO2 products will be described. Recent efforts to use these botanical templates to produce other porous metal oxides (e.g., Co3O4, NiO, and CuO) using both halide and acetate precursor impregnation strategies are noted. Porous metal oxides with interconnected pore walls may have use in electrochemical energy storage systems, including in photocatalytic, photovoltaic or battery systems.

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General routes to porous metal oxides via inorganic and organic templates

Journal of Sol-Gel Science and Technology ◽

10.1007/bf00486215 ◽

1994 ◽

Vol 2 (1-3) ◽

pp. 67-72 ◽

Cited By ~ 10

Author(s):

Christophe Roger ◽

Mark J. Hampden-Smith ◽

Dale W. Schaefer ◽

Greg B. Beaucage

Keyword(s):

Metal Oxides ◽

Porous Metal ◽

Organic Templates ◽

Porous Metal Oxides ◽

Inorganic And Organic

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Sonochemistry as a tool for preparation of porous metal oxides

Pure and Applied Chemistry ◽

10.1351/pac200274091509 ◽

2002 ◽

Vol 74 (9) ◽

pp. 1509-1517 ◽

Cited By ~ 27

Author(s):

D. N. Srivastava ◽

N. Perkas ◽

A. Zaban ◽

A. Gedanken

Keyword(s):

Metal Oxides ◽

Mesoporous Materials ◽

Porous Metal ◽

Neutral Medium ◽

Metal Alkoxide ◽

Sonochemical Method ◽

Inorganic Precursor ◽

Mesoporous Metal Oxides ◽

Porous Metal Oxides ◽

Mesoporous Metal

The porous metal oxides are an important class of materials, because the surface area/volume ratio of a material is increased by many fold, making them very useful in surface-related applications. The mesoporous materials were discovered in the 1990s, and since then they have been excellent candidates for materials science research. These mesoporous materials are prepared by hydrolyzing the inorganic precursor (usually metal alkoxide) in an acid, basic, or neutral medium in the presence of an organic structure-directing agent, the surfactant, in a conventional method. Recently, we have demonstrated that the sonochemical technique can be employed for the synthesis of mesoporous metal oxides. The sonochemical method reduced the time period required for such synthesis by many fold, and also produced more stable structures. We got excellent results with silica, titania, yittria-stabilized zirconia (YSZ), and Fe2O3. We also used an inorganic precursor other than an alkoxide for the preparation of mesoporous metal oxides. In this article, we present some of the recent results on this topic.

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