METAL CATALYST COMPOSITION

• US 20140094635A1
• Filed: 05/24/2012
• Published: 04/03/2014
• Est. Priority Date: 06/03/2011
• Status: Active Grant

• Current Assignee: Northwestern University
• Original Assignee: Dow Global Technologies LLC (Dow, Inc.)
• Inventors: Kung, Harold H., Lu, Junling, Stair, Peter, Fu, Baosong, Kung, Mayfair C
• Granted Patent: US 9,403,150 B2
• Time in Patent Office: Days
• US Class Current: 585/658
• CPC Class Codes: B01J 21/04 Alumina
• CPC Class Codes: B01J 23/38 of noble metals
• CPC Class Codes: B01J 23/44 Palladium
• CPC Class Codes: B01J 35/002 Catalysts characterised by their physical properties
• CPC Class Codes: B01J 35/006 metal crystallite size
• CPC Class Codes: B01J 35/0073 Distribution of the active metal ingredient
• CPC Class Codes: B01J 35/1019 100-500 m2/g
• CPC Class Codes: B01J 35/1057 less than 2 nm
• CPC Class Codes: B01J 35/1061 2-50 nm
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 35/396 Distribution of the active metal ingredient
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/643 less than 2 nm
• CPC Class Codes: B01J 35/647 2-50 nm
• CPC Class Codes: B01J 37/0209 involving a reaction between the support and a fluid
• CPC Class Codes: B01J 37/0228 in several steps
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: B01J 37/08 Heat treatment B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 37/12 Oxidising
• CPC Class Codes: B01J 37/14 : with gases containing free oxygen
• CPC Class Codes: B01J 37/18 : with gases containing free hydrogen
• CPC Class Codes: C07C 11/02 : Alkenes
• CPC Class Codes: C07C 11/04 : Ethylene
• CPC Class Codes: C07C 2521/04 : Alumina
• CPC Class Codes: C07C 2521/06 : Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
• CPC Class Codes: C07C 2521/08 : Silica
• CPC Class Codes: C07C 2521/18 : Carbon
• CPC Class Codes: C07C 2523/02 : of the alkali- or alkaline earth metals or beryllium
• CPC Class Codes: C07C 2523/06 : of zinc, cadmium or mercury
• CPC Class Codes: C07C 2523/10 : of rare earths
• CPC Class Codes: C07C 2523/20 : Vanadium, niobium or tantalum
• CPC Class Codes: C07C 2523/36 : Rhenium
• CPC Class Codes: C07C 2523/42 : Platinum
• CPC Class Codes: C07C 2523/44 : Palladium
• CPC Class Codes: C07C 2523/46 : Ruthenium, rhodium, osmium or iridium
• CPC Class Codes: C07C 2523/50 : Silver
• CPC Class Codes: C07C 2523/52 : Gold
• CPC Class Codes: C07C 2523/72 : Copper
• CPC Class Codes: C07C 2523/745 : Iron
• CPC Class Codes: C07C 2523/755 : Nickel
• CPC Class Codes: C07C 5/3335 : with metals
• CPC Class Codes: C07C 5/3337 : of the platinum group
• CPC Class Codes: C07C 5/42 : by dehydrogenation with a hydrogen acceptor
• CPC Class Codes: C07C 5/48 : with oxygen as an acceptor
• CPC Class Codes: C23C 16/30 : Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 16/45531 : specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45555 : applied in non-semiconductor technology
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts

Abstract

Embodiments include metal catalyst compositions and methods of forming metal catalyst compositions. A metal catalyst composition can be formed by (a) contacting a supported metal catalyst surface with a ligand-containing alumina precursor for a predetermined contact time to form an intermediate layer having a plurality of aluminum moieties that chemically bond to the supported metal catalyst surface, optionally, contacting the intermediate layer of aluminum moieties with an inert gas for a predetermined intermediate stripping time to remove unreacted ligand-containing alumina precursors, (b) reacting the aluminum moieties with an oxidation reagent for a predetermined reaction time to convert at least a portion of the ligands to hydroxyl groups thereby forming a layer of the alumina over-coat on the supported metal catalyst surface or a previously formed layer of the alumina over-coat, (c) contacting the layer of the alumina over-coat formed in step (b) with an inert gas for a predetermined stripping time to remove unreacted oxidation reagents, replicating the sequential steps (a-c) to form an additional layer of the alumina over-coat, and (d) activating the alumina over-coat, after forming a final layer of the alumina over-coat, to form a plurality of pores therein.

Claims

1. A method of forming a metal catalyst composition, comprising:

performing a plurality of atomic layer deposition cycles to form metal oxide over-coat on a supported metal catalyst, where one or more of the atomic layer deposition cycles include sequential steps;

(a) contacting a supported metal catalyst surface with a ligand-containing metal oxide precursor for a predetermined contact time to form an intermediate layer having a plurality of metal moieties that chemically bond to the supported metal catalyst surface;

(b) reacting the metal moieties with water for a predetermined reaction time to convert at least a portion of the ligands to hydroxyl groups thereby forming a layer of the metal oxide, metal hydroxide, or metal oxyhydroxide over-coat on the supported metal catalyst surface or a previously formed layer of the metal oxide, metal hydroxide, or metal oxyhydroxide over-coat;

(c) prior to replicating sequential steps (a) and (b) to form an additional layer of the metal oxide over-coat, contacting the layer of the metal oxide, hydroxide, oxyhydroxide over-coat formed in step b) with an inert gas for a predetermined final stripping time to remove unreacted water; and

(d) activating the metal oxide in the presence of a non-reducing gas at a temperature within a range from 500°

C. to 800°

C. for 60 minutes to 10 hours, metal hydroxide, metal oxyhydroxide over-coat, after forming a final layer of the said over-coat, to form a layer of metal oxide having a thickness of from 1 nanometer to 100 nanometers with a plurality of pores therein, where at least 80 percent of the plurality of pores have a diameter within a range of 0.3 nanometers to 5 nanometers, and where the metal catalyst composition reduces an amount of coke formed during a dehydrogenation or an oxidative dehydrogenation reaction, as compared to same supported metal catalysts without the metal oxide over-coat.

2. The method of claim 1, where the metal oxide is aluminum oxide.

3. The method of claim 1, where the ligand-containing metal oxide precursor is selected from the group consisting of M(R¹)₃, where M is the metal and where each R¹ is independently methyl, ethyl, propyl, chloride, bromide, dialkylamino, or alkoxide.

5. The method of claim 1, where the supported metal catalyst includes a support having metal particles.

8. The method of claim 1, further including contacting the intermediate layer with an inert gas for a predetermined intermediate stripping time to remove unreacted ligand-containing alumina precursors.

9. The method of claim 1, where the dehydrogenation reaction and the oxidative dehydrogenation reaction includes contacting an alkane with the metal catalyst composition in the presence of inert gas and oxygen, where the alkane is selected from the group consisting of a C2 alkane and a C3 alkane.

4. (canceled)

6-7. -7. (canceled)

10. A metal catalyst composition, comprising:

a supported metal catalyst including a support having a plurality of metal particles; and

an alumina over-coat deposited on a surface of the supported metal catalyst by atomic layer deposition followed by activating the alumina over-coat by heating in the presence of a non-reducing gas at a temperature within a range from 500°

C. to 800°

C. for 60 minutes to 10 hours, where activating the alumina over-coat forms pores, where at least 80 percent of the pores have a diameter within a range of 0.3 nanometers to 5 nanometers, where the alumina over-coat has a thickness within a range of from 1 nanometer to 100 nanometers, and where the metal catalyst composition reduces an amount of coke formation during a dehydrogenation reaction, as compared to metal catalysts without the alumina over-coat.

11. The metal catalyst of claim 10, where the alumina over-coat has a thickness within a range of from 1 nanometer to 15 nanometers.

12. The metal catalyst of claim 10, where depositing alumina layers on the surface of the supported metal catalyst includes a plurality of atomic layer deposition cycles including a ligand-containing alumina precursor and an oxidizing reagent.

13. The metal catalyst of claim 10, where at least 80 percent of the pores in the alumina over-coat have a diameter within a range of from 0.5 nanometers to 3 nanometers.

14. The metal catalyst of claim 10, where the ligand-containing alumina precursor is trimethylaluminum and the oxidizing reagent is water.

15. A method for reducing coke formation during a dehydrogenation reaction, comprising:

contacting an alkane with a metal catalyst composition in the presence of inert gas, oxygen, and combinations thereof, and at a temperature within a range of 300 degrees Celsius to 800 degrees Celsius, where the metal catalyst composition is formed by performing a plurality of atomic layer deposition cycles to form an alumina over-coat on a supported metal catalyst, where one or more of the atomic layer deposition cycles include sequentially;

contacting a supported metal catalyst surface with a ligand-containing alumina precursor for a predetermined contact time to form an intermediate layer having a plurality of aluminum moieties that chemically bond to the supported metal catalyst surface;

contacting the intermediate layer with an inert gas for a predetermined intermediate stripping time to remove unreacted ligand-containing alumina precursors;

reacting the aluminum moieties with water for a predetermined reaction time to convert at least a portion of the ligands to hydroxyl groups thereby forming a layer of the alumina over-coat on the supported metal catalyst surface or a previously formed layer of the alumina over-coat;

contacting the layer of the alumina over-coat formed with an inert gas for a predetermined final stripping time to remove unreacted water; and

activating the alumina over-coat in the presence of a non-reducing gas at a temperature within a range from 500°

C. to 800°

C. for 60 minutes to 10 hours, after forming a final layer of the alumina over-coat having a thickness of from 1 nanometer to 100 nanometers, to form a plurality of pores in the alumina over-coat, where at least 80 percent of the plurality of pores have a diameter within a range of from 0.3 nm to 5 nanometers, and where the metal catalyst composition reduces an amount of coke formed during a dehydrogenation reaction or an oxidative dehydrogenation reaction, as compared to metal catalysts without the alumina over-coat.