Imprinted Mesoporous Carbons and a Method of Manufacture Thereof
Abstract: Although porous carbons have been in use for thousands of years and have become adsorbents of great industrial importance, their porous structure is usually heterogeneous. Recent discoveries in the area of ordered nanomaterials created new opportunities in designing structures of porous carbons. For instance, the use of ordered mesoporous silicas and siliceous colloidal crystals as templates afforded the synthesis of ordered carbons with pores below c. 7 nm and above c. 50 nm, respectively. However the mesopore range (7-50nm) is still not covered by the aforementioned procedures. It should be noted that several of the template carbons contain disordered fine (micropores) pores present in the walls of ordered mesopores or macropores, formed during carbonization of many common carbon precursors. Also synthesis of high-quality templates is time-consuming and increases the price of the resulting carbons.
This invention relates to the field of carbon materials and more particularly to the synthesis of porous carbons with spherical mesopores of desired pore size. It is a novel approach to the synthesis of carbonaceous materials, which involves creation of mesopores in carbon precursor particles by imprinting them with colloidal silica particles. In contrast to the colloidal templating, which involves a fluid-type precursor, the colloid-imprinted carbons (CIC) are synthesized by imprinting solid particles of the mesophase pitch or other pitch used as carbon precursor with colloidal silica particles. The pitch particles are mixed with colloidal silica solution, stabilized at a temperature slightly above the pitch softening point, and carbonized under neutral atmosphere. The final step involves dissolution of silica colloids from carbon particles. The colloidal imprinting (CI), depending on the synthesis conditions, allows the creation of spherical pores in the volume of precursor particles as well as on their surface. Also the use of colloidal particles of different sizes, and/or chemical nature in the CI process, allows one to design the pores of desired sizes in the CIC materials and to tailor their sorption and catalytic properties.
- Colloidal imprinting procedure can be used to produce mesoporous carbons of desired pore size
- Useful for adsorption of large molecules – for
- Biomolecules, Catalysts supports, Electrode materials
- Simplicity of the carbon preparation
- Involves commercially available and relatively inexpensive pitch and colloidal silica
- Easy carbonization of the pitch - Leads to almost non-microporous carbons
Inventors: Dr. Mietek Jaroniec, Dr. Zuojiang Li
Associate Director, Technology Commercialization
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