Process for the production of porous inorganic materials or a matrix material containing nanoparticles
The present invention relates to a process for the production of porous inorganic materials or a matrix material containing nanoparticles with high uniformity of thickness and/or high effective surface area and to the materials obtainable by this process. By the abovementioned process materials with a defined thickness in the region of ±10%, preferably ±5%, of the average thickness are available.
1. A process for the production of porous materials, comprising the steps:
a) vapor-deposition of a separating agent onto a carrier to produce a separating agent layer,
b) the simultaneous vapor-deposition of a material selected from a metal, a metal oxide and a non-metal oxide and a separating agent onto the separating agent layer (a),
c) the separation of the material from the separating agent.
2. The process according to claim 1 , wherein the material selected from a metal, a metal oxide and a non-metal oxide is porous SiO z , wherein 0.70≦z≦2.0.
3. The process according to claim 2 , wherein in step b) a SiO y /separating agent layer is vapor-deposited from two different vaporisers, wherein the first vaporiser contains a charge comprising either a mixture of Si and SiO 2 , SiO y or a mixture thereof, wherein 0.70≦y≦1.8, and the second vaporiser contains a charge comprising the separating agent.
4. The process according to claim 3 , wherein the process comprises a further step d), wherein the SiO y is converted to SiO z with 1.40≦z≦2.0 by heating in an oxygen-containing atmosphere, or to SiO y+a , containing (1−(y/y+a)) silicon, wherein 0.70≦y≦1.8, 0.05≦a≦1.30, and the sum of y and a is smaller or equal to 2, by heating SiO y in an oxygen-free atmosphere.
5. The process according to claim 1 , wherein the separating agent is an inorganic salt soluble in water and vaporisable in vacuo or an organic substance soluble in organic solvents or water and vaporisable in vacuo.
6. A process according to claim 3 , wherein the porous SiO z comprises pores and the process comprises the further step of filling the pores of the porous SiO z with nanoparticles of TiO 2 of rutile or anatase type, or loaded with tin-donated indium oxide, SnO 2 , Sb 2 O 3 /SnO 2 , In 2 O 3 or In 2 O 3 /SnO 2 .
7. A porous SiO z flake, wherein 0.70≦z≦2.0, obtained by the process according to claim 6 , wherein the pores of the porous SiO z which has a BET specific surface area of greater than 500 m 2 /g are filled with nanoparticles of TiO 2 of rutile or anatase type, or loaded with tin-donated indium oxide, SnO 2 , Sb 2 O 3 /SnO 2 , In 2 O 3 or In 2 O 3 /SnO 2 .
8. A process according to claim 1 , wherein between two mixed layers of material and separating agent further layers of metal, or metal oxide are deposited and/or in case of unsymmetrical layer structure of the pigment further layers of metal, or metal oxide are deposited before the mixed layer of material and separating agent.
9. The process according to claim 6 , wherein the process also comprises step d), wherein the SiO y is converted to SiO z with 1.40≦z≦2.0 by heating in an oxygen-containing atmosphere, or to SiO y+a , containing (1−(y/y+a)) silicon, wherein 0.70≦y≦1.8, 0.05≦a≦1.30, and the sum of y and a is smaller or equal to 2, by heating SiO y in an oxygen-free atmosphere.
10. The process according to claim 1 , wherein in step b) a metal and optionally SiO y is vapor-deposited and a SiO y /separating agent layer is vapor-deposited from two different vaporisers, wherein the first vaporiser contains a charge comprising either a mixture of Si and SiO 2 , SiO y , or a mixture thereof, wherein 0.70≦y≦1,8, and the second vaporiser contains a charge comprising the separating agent.
11. The process according to claim 10 , wherein the process comprises a further step d), wherein the SiO y is converted to SiO z with 1.40≦z≦2.0 by heating in an oxygen-containing atmosphere, or to SiO y+a , containing (1−(y/y+a)) silicon, wherein 0.70≦y≦1.8, 0.05≦a≦1.30, and the sum of y and a is smaller or equal to 2, by heating SiO y in an oxygen-free atmosphere.
12. The process according to claim 10 , wherein the metal is aluminum.
13. The process according to claim 1 , wherein step b) comprises vapor-deposition of a mixed layer of SiO y and separating agent onto the separating agent layer, vapor-deposition of an SiO y layer onto the mixed layer, wherein 0.70≦y≦1.80, d) optionally vapor-deposition of a mixed layer of SiO y and separating agent onto the SiO y layer.
14. A process according to claim 13 , wherein the process comprises the further step of applying to the porous SiO z particles, porous SiO z /SiO z particles, or porous SiO z /SiO z /porous SiO z particles,
a metal oxide of high index of refraction selected from TiO 2 , ZrO 2 , Fe 2 O 3 , Fe 3 O 4 , Cr 2 O 3 , or
ZnO, or
a layer comprising SiC, or
a layer of carbon, especially diamond-like carbon, or
a semitransparent metal layer, or
an opaque metal layer.