Aqueous route to nitrogen-doped mesoporous carbons

Abstract

A method for preparation of mesoporous nitrogen-doped carbon includes forming a composition by solubilizing a nitrogen-containing polymer in an aqueous solution of ZnCl2 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.

What is claimed is: 
     
         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. 
     
     
         20 . A mesoporous nitrogen-doped carbon prepared by forming a composition by solubilizing a nitrogen-containing polymer in an aqueous solution of ZnCl 2 , drying the aqueous solution, and heating the composition after drying the aqueous solution to carbonize the nitrogen-containing polymer to form the mesoporous nitrogen-doped carbon. 
     
     
         21 . The mesoporous nitrogen-doped carbon of  claim 20  wherein a plurality of porogenic fillers are dispersed in the aqueous solution of the composition prior to drying. 
     
     
         22 . The mesoporous nitrogen-doped carbon of  claim 21  wherein the porogenic fillers comprise at least one of silica particles, cellulose-based nanocrystals or filter paper. 
     
     
         23 . The mesoporous nitrogen-doped carbon of  claim 21  wherein the composition is cast into a desired form before heating. 
     
     
         24 . The mesoporous nitrogen-doped carbon of  claim 21  wherein the nitrogen-containing polymer is polyacrylonitrile. 
     
     
         25 . The mesoporous nitrogen-doped carbon of  claim 18  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. 
     
     
         26 . The mesoporous nitrogen-doped carbon of  claim 24  wherein the degree of polymerization of the polyacrylonitrile is 100 or less. 
     
     
         27 . The mesoporous nitrogen-doped carbon of  claim 24  wherein the dispersity of the polyacrylonitrile is less than 1.5. 
     
     
         28 . The mesoporous nitrogen-doped carbon of  claim 24  wherein the mesoporous nitrogen-doped carbon comprises interconnected pores. 
     
     
         29 . The mesoporous nitrogen-doped carbon of  claim 24  having a surface area greater than or equal to 750 m 2 /g. 
     
     
         30 . The mesoporous nitrogen-doped carbon of  claim 20  having a surface area greater than 1,000 m 2 /g.