Production of ethylene with nanowire catalysts

Abstract

Nanowires useful as heterogeneous catalysts are provided. The nanowires catalysts are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to ethylene. Related methods for use and manufacture of the same are also disclosed.

1 . A catalyst comprising an inorganic catalytic nanowire, the nanowire having a ratio of effective length to actual length of less than one and an aspect ratio of greater than ten as measured by TEM in bright field mode at 5 keV, wherein the nanowire comprises one or more elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof, wherein the catalyst has a catalytic activity effective to catalyze the oxidative coupling of methane with a C 2  selectivity of greater than 30% at a temperature below 600° C. 
     
     
         2 . The catalyst of  claim 1 , wherein the one or more elements are in the form of oxides, hydroxides, oxyhydroxides, sulfates, carbonates, oxide carbonates, oxalates, phosphates, hydrogenphosphates, dihydrogenphosphates, oxyhalides, hydroxihalides, oxysulfates or combinations thereof. 
     
     
         3 . The catalyst of  claim 2 , wherein the one or more elements are in the form of oxides. 
     
     
         4 . The catalyst of  claim 2 , wherein the one or more elements are in the form of hydroxides. 
     
     
         5 . The catalyst of  claim 1 , wherein the nanowire comprises Mg, Ca, La, W, Mn, Mo, Nd, Sm, Eu, Pr, Zr or combinations thereof. 
     
     
         6 . The catalyst of  claim 1 , wherein the nanowire comprises MgO, CaO, La 2 O 3 , Na 2 WO 4 , Mn 2 O 3 , Mn 3 O 4 , Nd 2 O 3 , Sm 2 O 3 , Eu 2 O 3 , Pr 2 O 3 , Mg 6 MnO 8 , NaMnO 4 , Na/Mn/W/O, MnWO 4  or combinations thereof. 
     
     
         7 . The catalyst of  claim 1 , wherein the nanowire further comprises one or more dopants comprising metal elements, semi-metal elements, non-metal elements or combinations thereof. 
     
     
         8 . The catalyst of  claim 7 , wherein the dopant comprises Li, Na, K, Mg, Ca, Ba, Sr, Eu, Sm, Co or Mn. 
     
     
         9 . The catalyst of  claim 8 , wherein the nanowire comprises Li/MgO, Ba/MgO, Sr/La 2 O 3 , Mg/Na/La 2 O 3 , Sr/Nd 2 O 3 , or Mn/Na 2 WO 4 . 
     
     
         10 . The catalyst of  claim 7 , wherein the atomic ratio of the one or more elements from Groups 1 through 7, lanthanides or actinides to the dopant ranges from 1:1 to 10,000:1. 
     
     
         11 . The catalyst of  claim 1 , wherein the nanowire comprises a combination of two or more compounds comprising the one or more elements. 
     
     
         12 . The catalyst of  claim 11 , wherein the nanowire comprises Mn 2 O 3 /Na 2 WO 4 , Mn 3 O 4 /Na 2 WO 4  MnWO 4 /Na 2 WO 4 /Mn 2 O 3 , MnWO 4 /Na 2 WO 4 /Mn 3 O 4  or NaMnO 4 /MgO. 
     
     
         13 . The catalyst of  claim 1 , wherein the nanowire comprises a solid core. 
     
     
         14 . The catalyst of  claim 1 , wherein the nanowire comprises a hollow core. 
     
     
         15 . The catalyst of  claim 1 , wherein the nanowire has a diameter of between 7 nm and 200 nm as determined by TEM in bright field mode at 5 keV. 
     
     
         16 . The catalyst of  claim 1 , wherein the nanowire has an actual length of between 100 nm and 10 μm as determined by TEM in bright field mode at 5 keV. 
     
     
         17 . The catalyst of  claim 1 , wherein the nanowire has a ratio of effective length to actual length of less than 0.8. 
     
     
         18 . The catalyst of  claim 1 , wherein the nanowire has a bent morphology as determined by TEM in bright field mode at 5 keV. 
     
     
         19 . The catalyst of  claim 1 , wherein the powder x-ray diffraction pattern of the nanowire shows an average crystalline domain size of less than 50 nm. 
     
     
         20 . The catalyst of  claim 1 , wherein the catalyst further comprises a support material. 
     
     
         21 . The catalyst of  claim 20 , wherein the support material comprises an inorganic oxide, Al 2 O 3 , SiO 2 , TiO 2 , MgO, ZrO 2 , HfO2, CaO, ZnO, LiAlO 2 , MgAl2O 4 , MnO, MnO 2 , Mn 2 O 4 , Mn 3 O 4 , La 2 O 3 , activated carbon, silica gel, zeolites, activated clays, activated Al 2 O 3 , diatomaceous earth, magnesia, aluminosilicates, calcium aluminate, support nanowires or combinations thereof. 
     
     
         22 . The catalyst of  claim 21 , wherein the support material comprises SiO 2 , ZrO 2 , CaO, La 2 O 3  or MgO. 
     
     
         23 . The catalyst of  claim 1 , wherein the nanowire comprises an inner core and an outer layer, the inner core and outer layer each independently comprising one or more elements selected from Groups 1 through 7, lanthanides and actinides. 
     
     
         24 . The catalyst of  claim 1 , wherein a methane conversion of the oxidative coupling of methane catalyzed by the nanowire is greater than at least 1.1 times the methane conversion obtained when the same reaction is performed under the same conditions but catalyzed by a catalyst prepared from bulk material having the same chemical composition as the nanowire. 
     
     
         25 . The catalyst of  claim 1 , wherein the C 2  selectivity of the oxidative coupling of methane catalyzed by the nanowire is greater than at least 1.1 times the C 2  selectivity obtained when the same reaction is performed under the same conditions but catalyzed by a catalyst prepared from bulk material having the same chemical composition as the nanowire. 
     
     
         26 . The catalyst of  claim 1 , wherein C2 yield of the oxidative coupling of methane catalyzed by the nanowire is greater than at least 1.1 times the C2 yield obtained when the same reaction is performed under the same conditions but catalyzed by a catalyst prepared from bulk material having the same chemical composition as the nanowire. 
     
     
         27 - 29 . (canceled) 
     
     
         30 . The catalyst of  claim 1 , wherein the catalyst further comprises a biomolecule or modified or degraded forms thereof. 
     
     
         31 . A catalytic material comprising a plurality of inorganic catalytic nanowires, wherein the catalytic material has a catalytic activity effective to catalyze the oxidative coupling of methane with a C 2  selectivity of greater than 30% at a temperature below 600° C. 
     
     
         32 . The catalytic material of  claim 31 , wherein the plurality of inorganic catalytic nanowires has a surface area of between 0.001 and 1000 m 2 /g as measured by BET. 
     
     
         33 - 62 . (canceled) 
     
     
         63 . A catalyst comprising an inorganic nanowire, the inorganic nanowire comprising one or more metal elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof and a dopant comprising a metal element, a semi-metal element, a non-metal element or combinations thereof, wherein the catalyst has a catalytic activity effective to catalyze the oxidative coupling of methane with a C 2  selectivity of greater than 30% at a temperature below 600° C. 
     
     
         64 . The catalyst of  claim 63 , wherein the nanowire comprises MgO, CaO, La 2 O 3 , Na 2 WO 4 , Mn 2 O 3 , Mn 3 O 4 , Nd 2 O 3 , Sm2O3, Eu 2 O 3 , Pr 2 O 3 , Mg 6 MnO 8 , NaMnO 4 , MnWO4, Na/Mn/W/O or combinations thereof. 
     
     
         65 . The catalyst of  claim 63 , wherein the dopant comprises Li, Na, K, Mg, Ca, Ba, Sr, Eu, Sm, Co or Mn. 
     
     
         66 . The catalyst of  claim 63 , wherein the nanowire comprises Li/MgO, Ba/MgO, Sr/La 2 O 3 , Mg/Na/La 2 O 3 , Sr/Nd2O3, or Mn/Na 2 WO 4 . 
     
     
         67 - 113 . (canceled) 
     
     
         114 . The catalytic material of  claim 31 , wherein the plurality of inorganic catalytic nanowires comprises one or more elements from any of Groups 1 through 7, lanthanides, actinides or combinations thereof in the form of oxides, hydroxides, oxyhydroxides, sulfates, carbonates, oxide carbonates, oxalates, phosphates, hydrogenphosphates, dihydrogenphosphates, oxyhalides, hydroxihalides, oxysulfates or combinations thereof. 
     
     
         115 . The catalytic material of  claim 31 , wherein the plurality of inorganic catalytic nanowires comprises Mg, Ca, La, W, Mn, Mo, Nd, Sm, Eu, Pr, Zr or combinations thereof. 
     
     
         116 . The catalytic material of  claim 31 , wherein the plurality of inorganic catalytic nanowires comprises MgO, CaO, La 2 O 3 , Na 2 WO 4 , Mn 2 O 3 , Mn 3 O 4 , Nd 2 O 3 , Sm 2 O 2 , Eu 2 O 3 , Pr 2 O 3 , Mg 6 MnO 8 , NaMnO 4 , Na/Mn/W/O, MnWO 4  or combinations thereof. 
     
     
         117 . The catalytic material of  claim 31 , wherein the plurality of inorganic catalytic nanowires comprises one or more dopants comprising metal elements, semi-metal elements, non-metal elements or combinations thereof. 
     
     
         118 . The catalytic material of  claim 117 , wherein the dopant comprises Li, Na, K, Mg, Ca, Ba, Sr, Eu, Sm, Co or Mn. 
     
     
         119 . The catalytic material of  claim 117 , wherein the catalytic material comprises Li/MgO, Ba/MgO, Sr/La 2 O 3 , Mg/Na/La 2 O 3 , Sr/Nd 2 O 3 , or Mn/Na 2 WO 4 . 
     
     
         120 . The catalytic material of  claim 114 , wherein the plurality of inorganic catalytic nanowires comprises a combination of two or more compounds comprising the one or more elements. 
     
     
         121 . The catalytic material of  claim 120 , wherein the plurality of inorganic catalytic nanowires comprises Mn 2 O 3 /Na 2 WO 4 , Mn 3 O 4 /Na 2 WO 4  MnWO 4 /Na 2 WO 4 /Mn 2 O 3 , MnWO 4 /Na 2 WO 4 /Mn 3 O 4  or NaMnO 4 /MgO. 
     
     
         122 . The catalytic material of  claim 31 , wherein the catalytic material further comprises a support material. 
     
     
         123 . The catalytic of  claim 122 , wherein the support material comprises an inorganic oxide, Al 2 O 3 , SiO 2 , TiO 2 , MgO, ZrO 2 , HfO 2 , CaO, ZnO, LiAlO 2 , MgAl 2 O 4 , MnO, MnO 2 , Mn 2 O 4 , Mn 3 O 4 , La 2 O 3 , activated carbon, silica gel, zeolites, activated clays, activated Al 2 O 3 , diatomaceous earth, magnesia, aluminosilicates, calcium aluminate, support nanowires or combinations thereof. 
     
     
         124 . The catalytic material of  claim 31 , wherein the plurality of inorganic catalytic nanowires comprises a plurality of polycrystalline inorganic nanowires.