Nanowire catalysts and methods for their use and preparation
Nanowires useful as heterogeneous catalysts are provided. The nanowire catalysts are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to C2 hydrocarbons. Related methods for use and manufacture of the same are also disclosed.
1. A method for the preparation of ethane, ethylene or combinations thereof, the method comprising contacting a catalytic material with a gas comprising methane, wherein the catalytic material comprises a plurality of catalytic nanowires and a diluent or support, the diluent or support comprising an alkaline earth metal compound, wherein the catalytic material is in the form of a pressed pellet, extrudate or monolith, and wherein the catalytic material has a C2+ yield above 5% when employed as catalytic material in the oxidative coupling of methane at an inlet temperature of 550° C. and an inlet pressure of about 2 atm in a fixed bed reactor with a gas-hour space velocity (GHSV) of at least about 20,000/hr.
2. The method of claim 1 , wherein the catalytic material is in the form of a pressed pellet.
3. The method of claim 1 , wherein the catalytic material is in the form of an extrudate.
4. The method of claim 1 , wherein the catalytic material is in the form of a monolith.
5. The method of claim 1 , wherein the catalytic nanowires comprise one or more doping elements.
6. The method of claim 1 , wherein the catalytic material is in the form of a pressure treated, pressed pellet and comprises substantially no binder material.
7. The method of claim 1 , wherein the catalytic material is in the form of a pressed pellet or extrudate and comprises pores greater than 20 nm in diameter.
8. The method of claim 1 , wherein the alkaline earth metal compound is an alkaline earth metal oxide, alkaline earth metal carbonate, alkaline earth metal sulfate or alkaline earth metal phosphate.
9. The method of claim 1 , wherein the alkaline earth metal compound is an alkaline earth metal carbonate, alkaline earth metal sulfate or alkaline earth metal phosphate.
10. The method of claim 1 , wherein the diluent or support comprises MgO, MgCO 3 , MgSO 4 , Mg 3 (PO 4 ) 2 , MgAl 2 O 4 , CaO, CaCO 3 , CaSO 4 , Ca 3 (PO 4 ) 2 , CaAl 2 O 4 , SrO, SrCO 3 , SrSO 4 , Sr 3 (PO 4 ) 2 , SrAl 2 O 4 , BaO, BaCO 3 , BaSO 4 , Ba 3 (PO 4 ) 2 , BaAl 2 O 4 or combinations thereof.
11. The method of claim 1 , wherein the diluent or support comprises MgCO 3 , MgSO 4 , Mg 3 (PO 4 ) 2 , CaO, CaCO 3 , CaSO 4 , Ca 3 (PO 4 ) 2 , CaAl 2 O 4 , SrO, SrCO 3 , SrSO 4 , Sr 3 (PO 4 ) 2 , SrAl 2 O 4 , BaO, BaCO 3 , BaSO 4 , Ba 3 (PO 4 ) 2 , BaAl 2 O 4 or combinations thereof.
12. The method of claim 1 , wherein the diluent or support comprises CaO, SrO, MgCO 3 , CaCO 3 , SrCO 3 or combinations thereof.
13. The method of claim 1 , wherein the plurality of catalytic nanowires has a ratio of average effective length to average actual length of less than one and an average aspect ratio of greater than ten as measured by TEM in bright field mode at 5 keV, wherein the plurality of catalytic nanowires comprises one or more elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof.
14. The method of claim 1 , wherein the plurality of catalytic nanowires comprises substantially straight nanowires.
15. The method of claim 1 , wherein the plurality of catalytic nanowires comprises at least one nanowire selected from any one of Tables 1-12.
16. The method of claim 1 , wherein the catalytic material has a C2 selectivity above 50% when employed as catalytic material in the oxidative coupling of methane at an inlet temperature of 550° C. and an inlet pressure of about 2 atm in a fixed bed reactor with a gas-hour space velocity (GHSV) of at least about 20,000/hr.
17. The method of claim 1 , wherein the catalytic material has a CH 4 conversion above 20% when employed as catalytic material in the oxidative coupling of methane at an inlet temperature of 550° C. and an inlet pressure of about 2 atm in a fixed bed reactor with a gas-hour space velocity (GHSV) of at least about 20,000/hr.
18. The method of claim 1 , wherein the catalytic material further comprises SiC or cordierite or combinations thereof.
19. The method of claim 1 , wherein the catalytic material is contacted with the gas at a temperature less than 800° C.
20. The method of claim 1 , wherein the catalytic material is contacted with the gas at a temperature less than 700° C.
21. The method of claim 1 , having a conversion of methane to ethylene of greater than 10%.
22. The method of claim 1 , having a yield of ethylene of greater than 10%.
23. The method of claim 1 , having a conversion of methane of greater than 10%.
24. The method of claim 1 , having a C2 yield of greater than 10%.
25. A method for the preparation of ethane, ethylene or combinations thereof, the method comprising contacting a catalytic material with a gas comprising methane, wherein the catalytic material comprises a plurality of catalytic nanowires and a diluent or support, the diluent or support comprising an alkaline earth metal compound, and wherein the catalytic material is in the form of a pressure treated, pressed pellet and comprises substantially no binder material.
26. The method of claim 25 , wherein the catalytic nanowires comprise one or more doping elements.
27. The method of claim 25 , wherein the catalytic material comprises pores greater than 20 nm in diameter.
28. The method of claim 25 , wherein the alkaline earth metal compound is an alkaline earth metal oxide, alkaline earth metal carbonate, alkaline earth metal sulfate or alkaline earth metal phosphate.
29. The method of claim 25 , wherein the diluent or support comprises MgO, MgCO 3 , MgSO 4 , Mg 3 (PO 4 ) 2 , MgAl 2 O 4 , CaO, CaCO 3 , CaSO 4 , Ca 3 (PO 4 ) 2 , CaAl 2 O 4 , SrO, SrCO 3 , SrSO 4 , Sr 3 (PO 4 ) 2 , SrAl 2 O 4 , BaO, BaCO 3 , BaSO 4 , Ba 3 (PO 4 ) 2 , BaAl 2 O 4 or combinations thereof.
30. The method of claim 25 , wherein the catalytic nanowires are impregnated on the diluent or support.
31. The method of claim 25 , wherein a weight percentage of the diluent or support in the catalytic material is between 0.01% and 99.9%.
32. The method of claim 25 , wherein the catalytic material has a C2 selectivity of greater than 50% and a methane conversion of greater than 20% when employed as catalytic material in the oxidative coupling of methane at a temperature of 750° C. or less.
33. A method for the preparation of ethane, ethylene or combinations thereof, the method comprising contacting a catalytic material with a gas comprising methane, wherein the catalytic material comprises a plurality of catalytic nanowires and a diluent or support, the diluent or support comprising an alkaline earth metal compound, wherein the catalytic material is in the form of a pressed pellet, extrudate or monolith, and wherein the catalytic material has a C2 selectivity above 50% when employed as catalytic material in the oxidative coupling of methane at an inlet temperature of 550° C. and an inlet pressure of about 2 atm in a fixed bed reactor with a gas-hour space velocity (GHSV) of at least about 20,000/hr.
34. The method of claim 33 , wherein the catalytic nanowires are polycrystalline nanowires.
35. The method of claim 33 , wherein the plurality of catalytic nanowires comprises one or more elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof.
36. The method of claim 33 , wherein the plurality of catalytic nanowires has a ratio of average effective length to average actual length of less than one and an average aspect ratio of greater than ten as measured by TEM in bright field mode at 5 keV.
37. The method of claim 33 , wherein the catalytic nanowires comprise one or more doping elements.
38. The method of claim 33 , wherein the catalytic material is in the form of a pressed pellet or extrudate and comprises pores greater than 20 nm in diameter.
39. The method of claim 33 , wherein the alkaline earth metal compound is an alkaline earth metal oxide, alkaline earth metal carbonate, alkaline earth metal sulfate or alkaline earth metal phosphate.
40. The method of claim 33 , wherein the diluent or support comprises MgO, MgCO 3 , MgSO 4 , Mg 3 (PO 4 ) 2 , MgAl 2 O 4 , CaO, CaCO 3 , CaSO 4 , Ca 3 (PO 4 ) 2 , CaAl 2 O 4 , SrO, SrCO 3 , SrSO 4 , Sr 3 (PO 4 ) 2 , SrAl 2 O 4 , BaO, BaCO 3 , BaSO 4 , Ba 3 (PO 4 ) 2 , BaAl 2 O 4 or combinations thereof.
41. The method of claim 33 , wherein the catalytic material has a C2 selectivity of greater than 50% and a methane conversion of greater than 20% when employed as catalytic material in the oxidative coupling of methane at a temperature of 750° C. or less.
42. A method for the preparation of ethane, ethylene or combinations thereof, the method comprising contacting a catalytic material with a gas comprising methane, wherein the catalytic material comprises a plurality of catalytic nanowires and a diluent or support, the diluent or support comprising an alkaline earth metal compound, wherein the catalytic material is in the form of a pressed pellet, extrudate or monolith, and wherein the catalytic material has a CH 4 conversion above 20% when employed as catalytic material in the oxidative coupling of methane at an inlet temperature of 550° C. and an inlet pressure of about 2 atm in a fixed bed reactor with a gas-hour space velocity (GHSV) of at least about 20,000/hr.
43. The method of claim 42 , wherein the catalytic nanowires are polycrystalline nanowires.
44. The method of claim 42 , wherein the plurality of catalytic nanowires comprises one or more elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof.
45. The method of claim 42 , wherein the plurality of catalytic nanowires has a ratio of average effective length to average actual length of less than one and an average aspect ratio of greater than ten as measured by TEM in bright field mode at 5 keV.
46. The method of claim 42 , wherein the catalytic nanowires comprise one or more doping elements.
47. The method of claim 42 , wherein the catalytic material is in the form of a pressed pellet or extrudate and comprises pores greater than 20 nm in diameter.
48. The method of claim 42 , wherein the alkaline earth metal compound is an alkaline earth metal oxide, alkaline earth metal carbonate, alkaline earth metal sulfate or alkaline earth metal phosphate.
49. The method of claim 42 , wherein the diluent or support comprises MgO, MgCO 3 , MgSO 4 , Mg 3 (PO 4 ) 2 , MgAl 2 O 4 , CaO, CaCO 3 , CaSO 4 , Ca 3 (PO 4 ) 2 , CaAl 2 O 4 , SrO, SrCO 3 , SrSO 4 , Sr 3 (PO 4 ) 2 , SrAl 2 O 4 , BaO, BaCO 3 , BaSO 4 , Ba 3 (PO 4 ) 2 , BaAl 2 O 4 or combinations thereof.
50. The method of claim 42 , wherein the catalytic material has a C2 selectivity of greater than 50% and a methane conversion of greater than 20% when employed as catalytic material in the oxidative coupling of methane at a temperature of 750° C. or less.
51. A method for the preparation of ethane, ethylene or combinations thereof, the method comprising contacting a catalytic material with a gas comprising methane, wherein the catalytic material comprises a plurality of catalytic nanowires and a diluent or support, the diluent or support comprising an alkaline earth metal compound, wherein the catalytic material further comprises SiC or cordierite or combinations thereof, and wherein the catalytic material is in the form of a pressed pellet, extrudate or monolith.
52. The method of claim 51 , wherein the catalytic nanowires comprise one or more doping elements.
53. The method of claim 51 , wherein the catalytic material is in the form of a pressure treated, pressed pellet and comprises substantially no binder material.
54. The method of claim 51 , wherein the catalytic material is in the form of a pressed pellet or extrudate and comprises pores greater than 20 nm in diameter.
55. The method of claim 51 , wherein the alkaline earth metal compound is an alkaline earth metal oxide, alkaline earth metal carbonate, alkaline earth metal sulfate or alkaline earth metal phosphate.
56. The method of claim 51 , wherein the diluent or support comprises MgO, MgCO 3 , MgSO 4 , Mg 3 (PO 4 ) 2 , MgAl 2 O 4 , CaO, CaCO 3 , CaSO 4 , Ca 3 (PO 4 ) 2 , CaAl 2 O 4 , SrO, SrCO 3 , SrSO 4 , Sr 3 (PO 4 ) 2 , SrAl 2 O 4 , BaO, BaCO 3 , BaSO 4 , Ba 3 (PO 4 ) 2 , BaAl 2 O 4 or combinations thereof.
57. The method of claim 51 , wherein the catalytic material has a C2 selectivity of greater than 50% and a methane conversion of greater than 20% when employed as catalytic material in the oxidative coupling of methane at a temperature of 750° C. or less.
58. The method of claim 51 , wherein the plurality of catalytic nanowires comprises one or more elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof.