Porous substrates filled with nanomaterials

Abstract

A composition comprising: at least one porous carbon monolith, such as a carbon aerogel, comprising internal pores, and at least one nanomaterial, such as carbon nanotubes, disposed uniformly throughout the internal pores. The nanomaterial can be disposed in the middle of the monolith. In addition, a method for making a monolithic solid with both high surface area and good bulk electrical conductivity is provided. A porous substrate having a thickness of 100 microns or more and comprising macropores throughout its thickness is prepared. At least one catalyst is deposited inside the porous substrate. Subsequently, chemical vapor deposition is used to uniformly deposit a nanomaterial in the macropores throughout the thickness of the porous substrate. Applications include electrical energy storage, such as batteries and capacitors, and hydrogen storage.

What is claimed is: 
     
       1. A composition comprising:
 at least one porous carbon monolith comprising internal pores, and at least one nanomaterial disposed throughout the internal pores, wherein the nanomaterial is a nanotube or a nanowire, and wherein the porous carbon monolith is an aerogel, a xerogel, or an open-cell foam, and wherein weight of the nanomaterial is greater than weight of the porous carbon monolith. 
 
     
     
       2. The composition of  claim 1 , wherein the nanomaterial is disposed uniformly throughout the internal pores. 
     
     
       3. The composition of  claim 1 , wherein the porous carbon monolith comprises two external surfaces which define a width and a width middle for the monolith, and the nanomaterial is disposed uniformly at the width middle. 
     
     
       4. The composition of  claim 1 , wherein the nanomaterial increases a volumetric surface area of the composition relative to a volumetric surface area of the porous carbon monolith considered independently of the nanomaterial. 
     
     
       5. The composition of  claim 1 , wherein the nanomaterial has a weight, and the porous carbon monolith has a weight, and the weight of the nanomaterial is greater than the weight of the porous carbon monolith. 
     
     
       6. The composition of  claim 1 , wherein the amount of the porous carbon monolith is less than about 75% by weight of the composition. 
     
     
       7. The composition of  claim 1 , wherein the amount of the porous carbon monolith is less than about 50% by weight of the composition. 
     
     
       8. The composition of  claim 1 , wherein the porous carbon monolith is an aerogel. 
     
     
       9. The composition of  claim 1 , wherein the porous carbon monolith is an activated carbon aerogel. 
     
     
       10. The composition of  claim 1 , wherein the internal pores comprise a bimodal pore size distribution. 
     
     
       11. The composition of  claim 1 , wherein the internal pores comprise macropores which have an average diameter of 100 nm or more. 
     
     
       12. The composition of  claim 1 , wherein the internal pores comprise one set of pores which have an average diameter of 1 micron or more and another set of pores which have an average diameter of 10 nm or less. 
     
     
       13. A composition comprising:
 at least one porous carbon monolith comprising internal pores, and at least one nanomaterial disposed throughout the internal pores, wherein the porous carbon monolith has a BET surface area of at least 2,000 m 2 /g, independently of the nanomaterial disposed in the internal pores, and wherein weight of the nanomaterial is greater than weight of the porous carbon monolith. 
 
     
     
       14. The composition of  claim 13 , wherein the nanomaterial is a carbon nanotube. 
     
     
       15. The composition of  claim 13 , wherein the nanomaterial is a multi-walled carbon nanotube. 
     
     
       16. The composition of  claim 13 , the composition further comprising catalyst adapted for nanomaterial growth. 
     
     
       17. The composition of  claim 1 , wherein the composition comprising the porous carbon monolith and the nanomaterial has a BET surface area of at least 1,000 m 2 /g. 
     
     
       18. The composition of  claim 1 , wherein said composition has a bulk electric conductivity of at least 1 S/cm. 
     
     
       19. A composition comprising:
 at least one carbon aerogel comprising internal pores and at least one dimension which is at least 100 microns, wherein carbon nanotubes are disposed in the internal pores, wherein the amount of the carbon aerogel is less than about 75% by weight of the composition, wherein the carbon aerogel is a monolith. 
 
     
     
       20. The composition of  claim 19 , wherein the amount of the carbon aerogel is less than about 50% by weight of the composition. 
     
     
       21. The composition of  claim 19 , wherein the carbon aerogel is a monolith. 
     
     
       22. The composition of  claim 19 , wherein the carbon nanotubes are disposed uniformly in the internal pores. 
     
     
       23. The composition of  claim 19 , wherein the composition further comprises catalyst for growth of the carbon nanotubes. 
     
     
       24. The composition of  claim 19 , wherein the carbon nanotubes increase the volumetric surface area of the composition compared to the carbon aerogel. 
     
     
       25. The composition of  claim 19 , wherein the carbon nanotubes increase the electrical conductivity of the composition compared to the carbon aerogel. 
     
     
       26. The composition of  claim 19 , wherein the carbon aerogel comprise macropores having an average pore diameter of at least 100 nm. 
     
     
       27. The composition of  claim 19 , wherein the carbon aerogel comprises a bimodal pore size distribution. 
     
     
       28. The composition of  claim 19 , wherein the composition comprising the carbon aerogel and the carbon nanotubes has a BET surface area of at least 1,000 m 2 /g. 
     
     
       29. A method for making the composition of  claim 1 , comprising:
 providing a porous substrate having a thickness of 100 microns or more, wherein the porous substrate comprises a plurality of macropores throughout the thickness of the porous substrate; 
 disposing a catalyst inside the porous substrate; and 
 forming a nanomaterial in the macropores by vapor deposition, wherein the catalyst catalyzes the growth of the nanomaterial, and wherein the nanomaterial is deposited throughout a thickness of porous substrate. 
 
     
     
       30. The method of  claim 29 , the forming step comprises allowing a precursor to the nanomaterial to fill up the macropores and then react the precursor in presence of catalyst to form the nanomaterial in the macropores. 
     
     
       31. The method of  claim 29 , wherein the substrate is an aerogel, a xerogel, or an open-cell foam. 
     
     
       32. The method of  claim 29 , wherein the catalyst comprises at least one metal. 
     
     
       33. The method of  claim 29 , wherein the average diameter of the macropores is 100 nm or more. 
     
     
       34. The method of  claim 29 , wherein the nanomaterial is a carbon nanotube. 
     
     
       35. The method of  claim 29 , wherein the deposition of the nanomaterial increases the bulk electric conductivity of the porous substrate by 50% or more. 
     
     
       36. The method of  claim 29 , wherein the deposition of the nanomaterial increases the mass of the porous substrate by 50% or more. 
     
     
       37. The method of  claim 29 , wherein the deposition of the nanomaterial increases the volumetric surface area of the porous substrate by 10% or more. 
     
     
       38. The method of  claim 29 , further comprising the step of removing the porous substrate from the nanomaterial. 
     
     
       39. A method for making the composition of  claim 19 , comprising:
 providing a carbon aerogel having a thickness of 100 microns or more, wherein the carbon aerogel comprises a plurality of macropores throughout the thickness of the carbon aerogel; 
 disposing a catalyst inside the carbon aerogel; and 
 growing carbon nanotubes in the macropores by vapor deposition, wherein the catalyst catalyzes the growth of the carbon nanotubes, and wherein the carbon nanotubes are deposited throughout the thickness of carbon aerogel. 
 
     
     
       40. The method of  claim 39 , wherein the carbon nanotubes are formed from a carbon-containing precursor gas, and the carbon aerogel is first filled with the carbon-containing precursor gas before heating to grow the carbon nanotubes. 
     
     
       41. The method of  claim 39 , wherein the carbon aerogel comprises a bimodal pore size distribution. 
     
     
       42. The method of  claim 39 , wherein the carbon nanotubes are multi-walled carbon nanotubes. 
     
     
       43. An article comprising the composition of  claim 1 , wherein the article is a capacitor, a battery, an electrode, sensor, a membrane, a catalyst support, or hydrogen storage device. 
     
     
       44. The composition of  claim 1 , wherein the nanomaterial is a carbon nanotube. 
     
     
       45. The composition of  claim 1 , wherein the nanomaterial is a silicon nanowire. 
     
     
       46. The composition of  claim 19 , wherein the carbon aerogel is an activated carbon aerogel. 
     
     
       47. A device comprising the composition of claim 1 for desalination, catalysis or electrocatalysis. 
     
     
       48. A device comprising the composition of claim 13 for desalination, catalysis or electrocatalysis. 
     
     
       49. A device comprising the composition of claim 19 for desalination, catalysis or electrocatalysis. 
     
     
       50. The composition of claim 1, further comprising metal oxide or metal nanoparticles coating the internal pores of the porous carbon monolith. 
     
     
       51. The composition of claim 13, further comprising metal oxide or metal nanoparticles coating the internal pores of the porous carbon monolith. 
     
     
       52. The composition of claim 19, further comprising metal oxide or metal nanoparticles coating the internal pores of the carbon aerogel.