CCVD method for producing tubular carbon nanofibers
View Patent ↗The invention relates to a CCVD method for producing tubular carbon nanofibers on a support by catalytically depositing carbon out of the vapor phase. The inventive method is characterized in that a catalyst layer, which is deposited without current and which is based on nickel or cobalt, is applied to the support at least in places. Said catalyst layer is thermally activated before depositing carbon out of the vapor phase in a reducing atmosphere.
1. A CCVD method for producing tubular carbon nano-fibers on a support by catalytic deposition of carbon from the gaseous phase, wherein before applying the catalyst layer, centers of increased surface energy are created on a surface of a support, at least in parts thereof in a previously applied layer, wherein the previously applied layer at least in parts thereof comprises a compound selected from the group consisting of TiO 2 , TiN, Ta 3 O 5 , SiO 2 , SiC, SiN and AlN worked into a suitable inert matrix as discreet crystallites, and then a currentless deposited nickel- or cobalt-based catalyst layer is applied at least in parts thereof, which is thermally activated in a reducing atmosphere before carbon is deposited from the gaseous phase.
2. A method according to claim 1 , the centers of increased surface energy are created by the controlled removal of parts of the surface.
3. A method according to claim 1 , wherein the reducing atmosphere comprises a hydrogen-containing or hydrogen-supplying gas mixture.
4. A method according to claim 1 , wherein the thermal activation is carried out at a temperature ranging from 350 to 700° C.
5. A method according to claim 1 , wherein the support comprises at least in parts thereof Al 2 O 3 or a ceramics inert under the reaction conditions.
6. A method according to claim 5 , wherein the ceramics material is pickled or etched at least in parts thereof.
7. A method according to claim 1 , wherein the support at least in parts thereof comprises etched glass, or etched glass ceramics.
8. A method according to claim 1 , wherein the previously applied layer is applied by CVD.
9. A method according to claim 1 , wherein the previously applied layer is applied by PVD.
10. A method according to claim 1 , wherein the previously applied layer is applied by a spraying technique.
11. A method according to claim 1 , wherein the previously applied layer is applied by screen printing.
12. A method according to claim 1 , wherein the previously applied layer is applied by sputtering.
13. A method according to claim 1 , wherein the catalyst layer comprises a currentless deposited, phosphorus-doped nickel layer.
14. A method according to claim 13 , wherein the nickel layer contains from 0.1 to 12% by mass of phosphorus.
15. A method according to claim 1 , wherein before the currentless deposition of the catalyst layer, the support is provided with a palladium seeding by currentless deposition, the nickel- or cobalt-based catalyst layer subsequently being deposited without using a current on the seeding in the form of a catalyst nanostructure so as to provide catalyst nanoparticles.