Single reaction synthesis of texturized catalysts
Methods are described for making a texturized catalyst. The textural promoter may be a high-surface area, high-porosity, stable metal oxide support. The catalyst is manufactured by reacting catalyst precursor materials and support materials in a single, solvent deficient reaction to form a catalyst. The catalyst may be particles or a coating or partial coating of a support surface.
1. A single-mixture mix and bake method for preparing a texturally promoted catalyst system, comprising:
mixing at least one catalyst metal salt and at least one textural promoter metal salt with a base to form a solvent deficient precursor mixture;
allowing the catalyst metal salt, textural promoter metal salt and the base to react in the solvent deficient precursor mixture to form a precursor catalyst intermediate nanoparticle material; and
heating the intermediate material to yield a stable highly porous textural promoter metal oxide having a textural promoter pore structure phase and a metal catalyst phase on the surface of the pore structure;
wherein the textural promoter metal oxide has a mean pore diameter of from about 1 nm - 55 nm.
2. A method as in claim 1 , wherein the molar ratio of catalyst metal salt to textural promoter metal salt is in a range from about 1:2 to 1:100.
3. A method as in claim 1 , wherein both the mean diameter and surface area of the metal oxide catalyst are lower by at least a factor of 1.5 to 10 than the mean pore diameter and surface area of the textural promoter metal oxide material.
4. A method as in claim 1 , wherein the heating is carried out at a temperature equal to or greater than about 250° C. for a period of at least about 30 minutes, to 1 day and for which the temperature ramp may vary from 0.05 to 10.
5. A method of claim 1 wherein the metal oxide textural promoter has a mean pore diameter of about 1 to 40 nm. including 3 to 4 nm for noble metals catalysts and 10 to 30 nm for Fischer-Tropsch catalysts.
6. A method as in claim 1 , wherein the anion of the textural promoter metal salt is selected to produce a desired pore size in the pore structure.
7. A method as in claim 1 , wherein the water in the solvent deficient precursor mixture forms a slurry with the metal salts.
8. A method as in claim 7 , wherein the water is included with an aluminum alkoxide in a molar ratio of water: alkoxide in a range from about 1:1 to 1:10.
9. A method as in claim 1 , further comprising including an additive that increases the thermal or hydrothermal stability of the textural promoter metal oxide, wherein the concentration of the additive in the precursor mixture is in a range from 1% to 40% by weight and is present in the final catalyst in the range from 0.5% to 40% by weight.
10. A method as in claim 9 , wherein the textural promoter, and/or stabilizing additive is/are selected from the group consisting of Al, Si, Ti, Zr, Ca, Ba, Mg, Mn, Cu, Zn, Ce, La, oxides thereof, and combinations thereof.
11. A method as in claim 1 further comprising addition of a salt to the reaction mixture of a metal selected from the group consisting of Na, K, Cs, Ba, Mn, La, Ce, Cu, Ag, Au, Pd, Pt, Re Ni, and Rh.
12. A method as in claim 1 , wherein the pore diameter of the textural promoter metal oxide material is in a range from 2-50 nm and the distribution of the pore diameter is in a range of ±10% to ±200% of the average pore diameter.
13. A method as in claim 1 , wherein the pore structure of the textural promoter metal oxide material has a BET surface area in a range from 50 m 2 /g to 800 m 2 /g; and/or a pore diameter in a range from 2 nm to 50 nm. and wherein the pore volume of the textural promoter metal oxide is in a range from 0.5-1.8 cm 3 /g.
14. A method as in claim 1 , wherein the textural promoter metal salt includes an aluminum salt and the resulting stable metal oxide textural promoter material includes γ-alumina stabilized by one or more additives.
15. A method as in claim 1 , wherein the textural promoter metal salt includes a titanium metal salt and the resulting stable metal oxide textural promoter includes primarily titania in the rutile or anatase phase.
16. The method of claim 1 wherein the metal catalyst material includes an iron salt, a copper salt and a potassium salt and the textural promoter salt is from the group consisting of an aluminum salt, a titanium salt and combinations thereof.
17. The method of claim 16 wherein the iron salt includes Fe(NO 3 ) 3 ·xH 2 O, the copper salt includes Cu(NO) 3 ·xH 2 O, the potassium salt includes KHCO 3 and the base includes NH 4 HCO 3 .
18. A method of claim 1 wherein water present in the solvent deficient mixture is at least in part provided by a metal salt hydrate.
19. A method of claim 2 wherein the molar ratio of catalyst metal salt to textural promoter metal salt is in a range from about 1:4 to 1:33.
20. A method of claim 3 wherein the textural promoter has mean pore diameters of 3-4 nm where noble metal catalyst nanoparticles are 1-2 nm in diameter and the textural promoter has mean pore diameters of 10-30 nm with Fischer-Tropsch catalyst nanoparticles of 6-10 nm diameter.
21. A method of claim 1 wherein the catalyst metal salt includes a cobalt salt in combination with Pt, Ru, and/or Pd salts and the textural promoter metal salt is from the group consisting of an aluminum salt, a titanium salt and combinations thereof.