Chiral or achiral, mesoporous carbon
A composition and a method for producing mesoporous carbon materials with a chiral or achiral organization. In the method, a polymerizable inorganic monomer is reacted in the presence of nanocrystalline cellulose to give a material of inorganic solid with cellulose nanocrystallites organized in a chiral nematic organization. The cellulose can be carbonized through thermal treatment under inert atmosphere (e.g., nitrogen or argon) and the silica may subsequently be removed using aqueous solutions of sodium hydroxide (NaOH) or hydrogen fluoride (HF) to give the stable mesoporous carbon materials that retain the chiral nematic structure of the cellulose. These materials may be obtained as free-standing films with very high surface area. Through control of the reaction conditions the pore-size distribution may be varied from predominantly microporous to predominantly mesoporous materials. These are the first materials to use cellulose as both the structural template and carbon source for a mesoporous carbon material. These are also the first carbon materials to combine mesoporosity with long-range chiral ordering. Possible applications for these materials include: charge storage devices (e.g. supercapacitors and anodes for Li-ion batteries), adsorbents, gas purifiers, light-weight nanocomposite materials, catalyst supports (e.g., for chiral transformations), gas storage, and as a hard-template to generate other materials, preferably with chiral structures.
1. A process for producing a mesoporous carbon material comprising:
i) carbonising nanocrystalline cellulose (NCC) in an inorganic matrix, and
ii) removing the inorganic matrix from the carbonised NCC.
2. A process according to claim 1 , wherein said carbonising comprises pyrolysis of the NCC under an inert atmosphere at an elevated temperature.
3. A process according to claim 2 , wherein said inert atmosphere is nitrogen and said elevated temperature is 500° C. to 2000° C.
4. A process according to claim 3 , wherein said inorganic matrix is silica and ii) comprises heating in an aqueous alkali.
5. A process according to claim 4 , wherein said alkali is sodium hydroxide and said heating is at 20° C. to 100° C.
6. A process according to claim 5 , wherein said NCC in the inorganic matrix comprises said NCC in a chiral nematic arrangement and i) and ii) are carried out with maintenance of the chiral nematic arrangement of the NCC in the carbonised NCC.
7. A process according to claim 6 , further comprising: iii) recovering said carbonised NCC as a powder.
8. A process according to claim 4 , wherein said NCC in the inorganic matrix comprises said NCC in a chiral nematic arrangement and i) and ii) are carried out with maintenance of the chiral nematic arrangement of the NCC in the carbonised NCC.
9. A process according to claim 8 , further comprising: iii) recovering said carbonised NCC as a film.
10. A process according to claim 1 , wherein said inorganic matrix is silica and ii) comprises heating in an aqueous alkali.
11. A process according to claim 10 , wherein said alkali is sodium hydroxide and said heating is at 20° C. to 100° C.
12. A process according to claim 1 , wherein said NCC in the inorganic matrix comprises said NCC in a chiral nematic arrangement and i) and ii) are carried out with maintenance of the chiral nematic arrangement of the NCC in the carbonised NCC.
13. A process according to claim 1 , further comprising: iii) recovering said carbonised NCC as a film.
14. A process according to claim 1 , further comprising: iii) recovering said carbonised NCC as a powder.