Catalyst and methods for producing multi-wall carbon nanotubes
The present invention provides a catalyst precursor and a catalyst suitable for preparing multi-wall carbon nanotubes. The resulting multi-wall carbon nanotubes have a narrow distribution as to the number of walls forming the tubes and a narrow distribution in the range of diameters for the tubes. Additionally, the present invention provides methods for producing multi-wall carbon nanotubes having narrow distributions in the number of walls and diameters. Further, the present invention provides a composition of spent catalyst carrying multi-wall nanotubes having narrow distribution ranges of walls and diameters.
1. A catalyst precursor composition comprising:
a support comprising alumina and magnesium aluminate; and
with magnesium oxide and mixed metal oxides on a surface of the support,
wherein the mixed metal oxides are selected from the group consisting of Co x Fe y MoO 4 , Fe 2 (MoO 4 ) 3 and blends thereof and wherein the atomic ratio of magnesium oxide to alumina is between about 0.02 to about 0.04,
wherein x and y for the mixed metal oxides represented by Co x Fe y MoO 4 is from about 1.6 to 6.5, and 0 to 10.5, respectively.
2. The catalyst precursor composition of claim 1 , wherein x is from about 2.44 to 4.88 and y is from about 1.75 to 6.98.
3. The catalyst precursor composition of claim 1 , wherein the mixed metal oxide is selected from the group consisting of Co 3.3 Fe 2.62 MoO 4 and blends thereof.
4. The catalyst precursor composition of claim 1 , wherein the mixed metal oxide is selected from the group consisting of Co 3.3 FeyMoO 4 and blends thereof, where y may range from 2.6 to 6.3.
5. The catalyst precursor composition of claim 1 wherein the alumina is gamma-alumina.