Transition metal and transition metal oxides have many
useful applications, including catalysis, photo catalysis, sensors, and the
preparation of electrodes. In many of these applications, a high surface area is
desirable in order to increase the efficiency and cost-effectiveness of these
applications. Higher surface areas can be realized by the formation of
mesoporous structures. However, fully metallic or transition metal oxide
materials are not ideal for many of the aforementioned applications as only the
surface is active. Thus, composite materials are desired.
While it is recognized that organized mesoporous materials
containing transition metals would be highly desirable for many applications,
this presents a challenge when forming composites to control the location of the
active material. Furthermore, the presence of high concentrations of metal ions
during synthesis yields an uncontrolled pore size and morphology for mesoporous
structures. Additionally, post-synthesis deposition of metal ions within
mesopores limits the ability to precisely control the deposited metal and
requires additional processing steps. For example, significant improvements in
catalytic efficiency could be realized through improved control of the catalyst
dispersion.
Researchers at Arizona State University have developed a
method to control the metal quantity on the pore surfaces of mesoporous
structures based upon interfacial thermodynamics. This method uses a non-ionic
surfactant template containing a specialized metal/metal oxide precursor and a
molecule that can be cross-linked or carbonized. After carbonization, removal of
the template material yields a mesoporous inorganic support with well defined
pore sizes, and the pore walls decorated by the metal or metal oxide.
Potential Applications
- Catalysts and photocatalysts
- Electrode formation
- Sensors
- Hydrogen storage
Benefits and Advantages
- Simple process – single step process with relatively
short cycle times
- Control of porosity/pore size – well defined templated
pore size and morphology
- Compatible with broad range of materials – different
metal (oxide) possible with limited changes in processing
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