Aqueous route to nitrogen-doped mesoporous carbons
A method for preparation of mesoporous nitrogen-doped carbon includes forming a composition by solubilizing a nitrogen-containing polymer in an aqueous solution of ZnCl 2 and drying the aqueous solution, the method further includes heating the composition after drying to a temperature sufficiently high to carbonize the nitrogen-containing polymer to form the mesoporous nitrogen-doped carbon.
1. A method for preparation of mesoporous nitrogen-doped carbon comprising forming a composition by solubilizing a nitrogen-containing polymer in an aqueous solution of ZnCl 2 and drying the aqueous solution, the method further comprising heating the composition after drying to a temperature to carbonize the nitrogen-containing polymer to form the mesoporous nitrogen-doped carbon.
2. The method of claim 1 further comprising dispersing a plurality of porogenic fillers in the aqueous solution of the composition prior to drying the composition.
3. The method of claim 2 wherein the porogenic fillers comprise at least one of silica particles, cellulose-based nanocrystals or filter paper.
4. The method of claim 2 wherein the composition is cast into a desired form before heating.
5. The method of claim 2 wherein drying comprises freeze-drying.
6. The method of claim 2 wherein the nitrogen-containing polymer is polyacrylonitrile.
7. The method of claim 6 wherein the composition is stabilized by heating at a temperature below 300° C. after drying and before heating the composition to carbonize the nitrogen-containing polymer, wherein the temperature to carbonize the nitrogen-containing polymer is less than 850° C.
8. The method of claim 6 wherein the degree of polymerization of the polyacrylonitrile is 100 or less.
9. The method of claim 6 wherein the degree of polymerization of the polyacrylonitrile is 50 or less.
10. The method of claim 6 wherein the dispersity of the polyacrylonitrile is less than 2.0.
11. The method of claim 6 wherein the dispersity of the polyacrylonitrile is less than 1.5.
12. The method of claim 6 wherein the dispersity of the polyacrylonitrile is less than 1.3.
13. The method of claim 6 wherein the mesoporous nitrogen-doped carbon comprises interconnected pores.
14. The method of claim 6 wherein the mesoporous nitrogen-doped carbon has a surface area greater than or equal to 750 m 2 /g.
15. The method of claim 6 wherein the mesoporous nitrogen-doped carbon has a surface area greater than or equal to 1,000 m 2 /g.
16. The method of claim 14 wherein a percentage of the surface area arising from mesopores is at least 84%.
17. The method of claim 6 wherein the mesoporous nitrogen-doped carbon comprise both graphitic and disordered carbons.
18. The method of claim 17 wherein the graphitic carbons comprise catalytically active edge on pyridine oxide-N, pyrrolic- or pyridonic-N, and pyridinic-N(N—P) nitrogens.
19. The method of claim 6 wherein the ratio of fillers to PAN is selected to provide sufficient PAN to fill the majority of the interstitial volume between the fillers, thereby forming a coherent structure.