Method for preparing hollow nanofiber, hollow nanofiber and catalyst composition for preparing hollow nanofiber

Abstract

A method for preparing hollow nanofibers having carbon as a primary component by contacting a carbon-containing compound with a catalyst at 500 to 1200° C., wherein the catalyst is one of a zeolite exhibiting thermal resistance at 900° C. and, supported thereon, a metal; a metallosilicate zeolite containing a heteroatom except aluminum and silicon and a metal; a supporting material and fine cobalt particles exhibiting a binding energy of a cobalt 2P3/2 electron of 779.3 to 781.0 eV; a supporting material and fine cobalt particles exhibiting a cobalt atom ratio in the surface of the supporting material of 0.1 to 1.5%, as measured by the X-ray photoelectron spectroscopy at 10 kV and 18 mA; a supporting material and fine cobalt particles exhibiting a weight ratio of cobalt to a second metal component of 2.5 or more; and a zeolite having a film form and a metal.

1 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by contacting a catalyst in which a metal is supported on a zeolite having a heat resistance at 900° C. with a carbon-containing compound at 500 to 1200° C.  
     
     
         2 . The method for manufacturing hollow nanofibers according to  claim 1 , wherein powder XRD diffraction patterns of zeolite at a room temperature before and after burning of the zeolite in a nitrogen or dry air atmosphere at 900° for 30 min are identical with each other.  
     
     
         3 . The method for manufacturing hollow nanofibers according to  claim 1  or  2 , wherein the zeolite has properties of no exothermic peak at 600 to 900° C. when thermal analysis is carried out up to 900° C. while a temperature is increased by 5° C./min in a nitrogen atmosphere.  
     
     
         4 . The method for manufacturing hollow nanofibers according to  claim 1  or  2 , wherein an atomic ratio of Si/heteroatom in a framework of the zeolite is 10 or more.  
     
     
         5 . The method for manufacturing hollow nanofibers according to  claim 1  or  2 , wherein the zeolite is one selected from the group consisting of silicalite-1, silicalite-2, crystalline titanosilicate, and a high silica Y type zeolite calcined once at a reaction temperature or more.  
     
     
         6 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by contacting a catalyst in which a metal is carried on a metallosilicate zeolite containing a heteroelement other than aluminum and silicon in a framework with a carbon-containing compound at 500 to 1200° C.  
     
     
         7 . The method for manufacturing hollow nanofibers according to  claim 6 , characterized in that the metallosilicate zeolite contains at least one selected from a titanosilicate zeolite, borosilicate, cobalt silicate, and iron silicate.  
     
     
         8 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by using a supporting material which supports cobalt fine particles exhibiting a binding energy of a cobalt 2P3/2 electron of 779.3 eV or more and 781.0 eV or less as measured by X-ray photoelectron spectroscopy, and contacting the cobalt/supporting material with a carbon-containing compound at 500 to 1200° C.  
     
     
         9 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by using a supporting material which supports cobalt fine particles exhibiting an atomic ratio of cobalt, in a surface of the supporting material, of 0.1 to 1.5% as measured by X-ray photoelectron spectroscopy under a condition of 10 kV and 18 mA, and contacting the supporting material with a carbon-containing compound at 500 to 1200° C.  
     
     
         10 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by using a catalyst which supports, on a titanium-containing supporting material, cobalt fine particles exhibiting an atomic ratio of cobalt in a surface of the supporting material of 0.3 or more and 2.0 or less as measured by X-ray photoelectron spectroscopy under a condition of 10 kV and 18 mA, and contacting the catalyst with a carbon-containing compound at 500 to 1200° C.  
     
     
         11 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by using a supporting material which supports cobalt fine particles exhibiting a weight ratio of cobalt to a second metal component, in a surface of the supporting material, (weight of cobalt/weight of second metal component) of 2.5 or more, and contacting the supporting material with a carbon-containing compound at 500 to 1200° C.  
     
     
         12 . The method for manufacturing hollow nanofibers according to  claim 11 , wherein an atomic ratio of cobalt to the second metal component, in the surface of the supporting material, (atomicity of cobalt/atomicity of second metal component) is 5 to 15.  
     
     
         13 . The method for manufacturing hollow nanofibers according to any one of  claims 1  to  12 , characterized in that metals of 3 to 12 groups are contained as second components.  
     
     
         14 . The method for manufacturing hollow nanofibers according to  claim 13 , characterized in that at least one kind of a metal selected from vanadium, molybdenum, manganese, iron, nickel, and palladium is contained as a second component.  
     
     
         15 . The method for manufacturing hollow nanofibers according to any one of  claims 8  to  12 , characterized in that 80% or more of metal fine particles supported on the supporting material has a size of 0.5 to 10 nm.  
     
     
         16 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2  or  6  to  12 , characterized in that the metal fine particles are manufactured by using at least one selected from metal acetate, metal nitrate, and a metal complex as a raw material, carrying the raw material on the supporting material, and then subjecting the raw material to heat treatment.  
     
     
         17 . The method for manufacturing hollow nanofibers according to any one of  claims 8  to  12 , characterized in that the supporting material is a zeolite.  
     
     
         18 . The method for manufacturing hollow nanofibers according to  claim 17 , characterized in that the zeolite is at least one selected from a USY type zeolite, an MFI type zeolite, and an MFI type metallosilicate.  
     
     
         19 . The method for manufacturing hollow nanofibers according to  claim 18 , characterized in that the zeolite contains at least one selected from titanosilicate, cobalt silicate, and borosilicate.  
     
     
         20 . A method for manufacturing hollow nanofibers characterized in that hollow nanofibers having carbon as a primary component is produced by contacting a catalyst characterized by supporting a metal on a surface of a membranous zeolite with a carbon-containing compound at 500° C. to 1200° C.  
     
     
         21 . The method for manufacturing hollow nanofibers according to  claim 20 , wherein the membranous zeolite is manufactured by continuously coating a zeolite crystal on a surface of a support.  
     
     
         22 . The method for manufacturing hollow nanofibers according to  claim 20  or  21 , characterized in that a crystal face of the membranous zeolite is oriented.  
     
     
         23 . The method for manufacturing hollow nanofibers according to  claim 20  or  21 , characterized in that a thickness of the membranous zeolite is 10 μm or less.  
     
     
         24 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2 ,  6  to  12 ,  20  or  21 , characterized in that a reactor is a fixed bed type reactor.  
     
     
         25 . A method for manufacturing hollow nanofibers characterized in that in a method for contacting a solid catalyst with a carbon-containing compound, a concentration of the carbon-containing compound is 2 vol % or less, and solid catalyst weight (including a supporting material)/source gas flow rate (including a carrier gas) is 3.0×10 −2  (g(catalyst)·min/ml) or less.  
     
     
         26 . A method for manufacturing hollow nanofibers characterized in that in a method for contacting a solid catalyst with a carbon-containing compound, partial pressure of the carbon containing compound contacted with the solid catalyst is 15.2 Torr or less, and solid catalyst weight (including a supporting material)/source gas flow rate (including a carrier gas) is 3.0×10 −2  (g(catalyst)·min/ml) or less.  
     
     
         27 . The method for manufacturing hollow nanofibers according to any one of claims  25  and  26 , characterized in that solid catalyst weight (including a supporting material)/source gas flow rate (including a carrier gas) is 1.0×10 −3  (g(catalyst)·min/ml) or less.  
     
     
         28 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2 ,  6  to  12 ,  20 ,  21 ,  25  or  26 , wherein the carbon-containing compound is hydrocarbon or carbon monoxide.  
     
     
         29 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2 ,  6  to  12 ,  20 ,  21 ,  25  or  26 , wherein an outer diameter of the produced hollow nanofiber is 50 nm or less, and an inner diameter thereof is 0.3 nm or more and 15 nm or less.  
     
     
         30 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2 ,  6  to  12 ,  20 ,  21 ,  25  or  26 , wherein the hollow nanofiber is a carbon nanotube.  
     
     
         31 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2 ,  6  to  12 ,  20 ,  21 ,  25  or  26 , characterized in that a primary component of the carbon nanotube is a single-walled to five-walled carbon nanotube.  
     
     
         32 . The method for manufacturing hollow nanofibers according to any one of claims  1 ,  2 ,  6  to  12 ,  20 ,  21 ,  25  or  26 , characterized in that a primary component of the carbon nanotube is a double-walled to five-walled carbon nanotube.  
     
     
         33 . Walled hollow nanofibers characterized in that a distribution curve of an outer diameter of a fibrous substance contained in the hollow nanofiber has one or more peaks in a diameter range of 0.4 to 10 nm.  
     
     
         34 . The hollow nanofibers according to  claim 33 , characterized in that the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber has two or more peaks, and peak positions are in two different ranges of the following: 
 1) a diameter range of 0.4 to 1 nm;    2) a diameter range of 1 to 3 nm;    3) a diameter range of 3 to 5 nm; and    4) a diameter range of 5 to 10 nm.    
     
     
         35 . The hollow nanofibers according to  claim 33  or  34 , characterized in that the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber has one or more peaks in one of the ranges 1) to 4), and one or more peaks in a diameter range of 10 to 50 nm.  
     
     
         36 . The hollow nanofibers according to  claim 33  or  34 , characterized in that the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber has (1) one or more peaks in any one of the ranges 1) to 4), and (2) one or more peaks in a diameter range of 10 to 50 nm, and a peak intensity ratio of (1) and (2) is (1)/(2)=1 or more.  
     
     
         37 . The hollow nanofibers according to  claim 33  or  34 , characterized in that the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber has (1) one or more peaks in one of the ranges 1) to 4), and (2) one or more peaks in a diameter range 10 to 50 nm, and a hollow inner diameter of the fibrous substance of (2) is 30% or less of an outer diameter of the hollow nanofiber.  
     
     
         38 . The hollow nanofibers according to  claim 33  or  34 , characterized in that the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber has (1) one or more peaks in any one of the ranges 1) to 4), and (2) one or more peaks in a diameter range 10 to 50 nm, and the fibrous substance of (2) has one or more knot-shaped structures within a length of 500 nm.  
     
     
         39 . The hollow nanofibers according to  claim 33  or  34 , characterized in that, in the hollow nanofiber, there are no contaminants in a hollow part of a fibrous substance having an outer diameter near a peak of the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber.  
     
     
         40 . The hollow nanofibers according to  claim 33  or  34 , characterized in that, in the hollow nanofiber, there are no particular materials stuck on an outer surface of the fibrous substance having an outer diameter near the peak of the distribution curve of the outer diameter of the fibrous substance contained in the hollow nanofiber.  
     
     
         41 . The hollow nanofibers characterized by containing a multi-walled carbon nanotube bundle which has a constitution of a bundle of double-walled or double-walled to five-walled carbon nanotubes and in which a difference between maximum and minimum inner diameters of the double-walled to five-walled carbon nanotube measured in a range of a length 30 nm is less than 1 nm.  
     
     
         42 . The hollow nanofibers according to  claim 41 , characterized by containing a double-walled to five-walled carbon nanotube whose inner diameter is 5 to 12 nm.  
     
     
         43 . The hollow nanofibers according to  claim 41 , characterized by containing a double-walled to five-walled carbon nanotube whose inner diameter is not more than 1 nm.  
     
     
         44 . The hollow nanofibers according to any one of  claims 41  to  43 , characterized in that a primary component of the double-walled to five-walled carbon nanotube is the double-walled carbon nanotube.  
     
     
         45 . The hollow nanofibers according to any one of  claims 41  to  43 , characterized by a double-walled carbon nanotube whose difference between a maximum and minimum inner diameters measured in a range of a length 30 nm is less than 1 nm and which partially has a three or more layer portion.  
     
     
         46 . The method for manufacturing hollow nanofibers according to any one of claims  33 ,  34  or  41  to  43 , characterized in that a primary component of the hollow nanofiber is the double-walled carbon nanotube.  
     
     
         47 . Hollow nanofibers characterized in that 50% or more of a double-walled to five-walled carbon nanotube forms no bundle, and a primary component is a double-walled to five-walled carbon nanotube.  
     
     
         48 . Hollow nanofibers containing composition satisfying the following requirements: 
 (1) a bundle of a double-walled carbon nanotube is observed by a high-resolution transmission electron microscope; and    (2) a peak is observed at 150 to 350 cm −1  by measuring of resonance Raman scattering measurement method.    
     
     
         49 . The hollow nanofibers containing composition according to  claim 48 , characterized in that a peak in a range of 1500 to 1650 cm −1  is observed in a split state by measuring of the resonance Raman scattering measurement method.  
     
     
         50 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) a double-walled carbon nanotube is observed by a high-resolution transmission electron microscope;    (2) 50% or more is a fibrous substance when observation is made by a scanning electron microscope;    (3) a total amount of transition metal is 1 wt % or less; and    (4) a peak is observed at 150 to 350 cm −1  by measuring of resonance Raman scattering measurement method.    
     
     
         51 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) a G/D ratio is 1.5 or more and 20 or less if maximum peak intensity in a range of 1560 to 1600 cm −1  is G, and maximum peak intensity in a range of 1310 to 1350 cm −1  is D, in a spectrum obtained by measuring of resonance Raman scattering measurement method; and    (2) a double-walled carbon nanotube is observed by a high-resolution transmission electron microscope.    
     
     
         52 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) the following relations are satisfied if maximum peak intensity in 195 to 200 cm −1  is A, maximum peak intensity in 217 to 222 cm −1  is B, and maximum peak intensity in 197 cm −1  or less is C, in a region of 350 cm −1  or less in a spectrum obtained by measuring of resonance Raman scattering measurement method of a laser wavelength 630 to 650 cm −1 ,      A/B> 1.2,  A/C> 2;    and    (2) a double-walled carbon nanotube is observed by a high-resolution transmission electron microscope.    
     
     
         53 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) a following relation is satisfied if maximum peak intensity in 195 to 200 cm −1  is A, and maximum peak intensity in 220 to 350 cm −1  is D, in a spectrum obtained by measuring of resonance Raman scattering measurement method of a laser wavelength 630 to 650 cm −1 ,      A/D> 1.2;    and    (2) a double-walled carbon nanotube is observed by a high-resolution transmission electron microscope.    
     
     
         54 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) a double-walled to five-walled carbon nanotube outermost layers of at least one end of which are open ends is observed by a high-resolution transmission electron microscope; and    (2) 50% or more is a fibrous material when observation is made by a scanning electron microscope.    
     
     
         55 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) a double-walled to five-walled carbon nanotube all layers of at least one end of which are open ends is observed by a high-resolution transmission electron microscope; and    (2) 50% or more is a fibrous material when observation is made by a scanning electron microscope.    
     
     
         56 . Hollow nanofibers containing composition satisfying all the following requirements: 
 (1) a double-walled to five-walled carbon nanotube all layers of both ends of which are open ends is observed by a high-resolution transmission electronrmicroscope; and    (2) 50% or more is a fibrous material when observation is made by a scanning electron microscope.    
     
     
         57 . The hollow nanofibers according to any one of claims  33 ,  34  or  41  to  43 , characterized in that lengths of 80% or more of the produced hollow nanofibers are within ±10% of average length.  
     
     
         58 . A catalyst composition for manufacturing hollow nanofibers having carbon as a primary component, constituted by carrying a metal on a zeolite having a property that there is no exothermic peak at 600 to 900° C. when thermal analysis is carried out up to 900° C. in a nitrogen atmosphere while a temperature is increased by 5° C./min.  
     
     
         59 . The catalyst composition for hollow nanofibers according to  claim 58 , having the carbon as the primary component, constituted by carrying metal on a metallosilicate zeolite containing a heteroelement other than aluminum and silicon in a framework.  
     
     
         60 . An electron emission material containing the hollow nanofibers containing composition of any one of  claims 48  to  56 .  
     
     
         61 . An electron emission material containing the hollow nanofibers of any one of claims  33 ,  34  or  41  to  43 .