Summary of the invention
Technical problem to be solved by this invention is to provide a kind of lanthanum doped composite metal oxide catalyst and preparation method who is used to prepare carbon nano tube with uniform diameter at above-mentioned prior art present situation, obtains uniform-caliber nanometre in the high yield that guarantees CNT.
The present invention solves the problems of the technologies described above the technical scheme of being taked: a kind of lanthanum doped catalyst for preparing carbon nano tube with uniform diameter, it is carrier with magnesia, load has composite metal oxide component, lanthanum doping component and promotes catalyst component on the carrier, four mol ratio is 0.5~3.0: 0.1~1.0: 0.01~1.0: 0.5~3.0, wherein, the composite metal oxide component is any compound of the two or three's oxide in iron, cobalt, the nickel, the lanthanum doping component is the oxide of lanthanum, promotes that catalyst component is the oxide of molybdenum.
The mol ratio of iron and cobalt is 0.1~1.0: 0.1~1.0 in the binary complex of the oxide of described iron and cobalt, the mol ratio of cobalt and nickel is 0.1~1.0: 0.1~1.0 in the binary complex of the oxide of cobalt and nickel, the mol ratio of iron and nickel is 0.1~1.0: 0.1~1.0 in the binary complex of the oxide of iron and nickel, and the mol ratio of iron, cobalt, nickel is 0.1~1.0: 0.1~1.0 in the ternary complex of the oxide of iron, cobalt, nickel: 0.1~1.0.
This kind is used to prepare the preparation method of the lanthanum doped catalyst of carbon nano tube with uniform diameter, may further comprise the steps:
Magnesium salts is dissolved in the distilled water through stirring, adds composite metal oxide component salt, lanthanum doping component salt again and promote catalyst component salt, continue stirring it is dissolved fully, four mol ratio is 0.5~3.0: 0.1~1.0: 0.01~1.0: 0.5~3.0; Above-mentioned solution is placed 120~200 ℃ of oven dry 3~5 hours, again under aerobic environment in 550~850 ℃ of high-temperature calcinations 10~30 minutes, take out porphyrize, promptly obtain to be used to prepare the catalyst of CNT.
Described magnesium salts be selected from magnesium nitrate, magnesium chloride, magnesium sulfate, magnesium acetate or wherein appoint the two, three or four mixture.
Described composite metal oxide component salt comprises the binary or the ternary complex of the one pack system salt of iron, cobalt or nickel.
Described molysite comprises ferric nitrate, iron chloride, ferric sulfate, ferric acetate, and cobalt salt comprises cobalt nitrate, cobalt chloride, cobaltous sulfate, cobalt acetate, and nickel salt comprises nickel nitrate, nickel chloride, nickelous sulfate, nickel acetate.
The mol ratio of iron and cobalt is 0.1~1.0: 0.1~1.0 in described molysite and the cobalt salt binary complex, the mol ratio of cobalt and nickel is 0.1~1.0: 0.1~1.0 in cobalt salt and the nickel salt binary complex, the mol ratio of iron and nickel is 0.1~1.0: 0.1~1.0 in molysite and the nickel salt binary complex, and the mol ratio of iron, cobalt, nickel is 0.1~1.0: 0.1~1.0 in molysite, cobalt salt, the nickel salt ternary complex: 0.1~1.0.
Described lanthanum doping component salt comprises lanthanum nitrate, lanthanum carbonate, lanthanum acetate.
Described promotion catalyst component is the oxide of ammonium molybdate or molybdenum.
The process that this catalyst is used for preparing CNT is generally: catalyst is placed reaction chamber, feed carbon-source gas such as methane, aromatic hydrocarbon, natural gas or its mixture again, flow velocity is that 500~5000sccm, hydrogen flow rate are that 0~2000sccm, nitrogen or inert gas flow velocity are in the atmosphere of 0~500sccm, reacted 20~60 minutes down in 750~1000 ℃, promptly obtain the multi-walled carbon nano-tubes product.In addition, before carbon nano tube growth, also can utilize the air in nitrogen or other inert gas emptying reative cell, after carbon nano tube growth is finished, utilize nitrogen or other inert gas that product is protected.
Compared with prior art, catalyst of the present invention has higher catalytic efficiency, and product (containing catalyst) is higher than 35 times with catalyst weight than generally, and the purity of CNT generally is higher than 90%, the CNT caliber that is obtained is evenly distributed, between 10~20nm.Method for preparing catalyst of the present invention has repeatable good, and process is simple, the advantage of easy operating.
The specific embodiment
Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.
Embodiment one
A kind of lanthanum doped catalyst for preparing carbon nano tube with uniform diameter, it is carrier with magnesia, load has the binary complex of the oxide of nickel and cobalt on the carrier, the oxide of lanthanum and the oxide of molybdenum, four mol ratio is 105: 10: 5: 120, the mol ratio of nickel and cobalt is 6: 4 in the binary complex of the oxide of nickel and cobalt, the mol ratio of nickel and iron is 0.1: 1.0 in the binary complex of the oxide of nickel and iron, the mol ratio of iron and cobalt is 1.0: 0.1 in the binary complex of the oxide of iron and cobalt, iron, cobalt, iron in the ternary complex of the oxide of nickel, cobalt, the mol ratio of nickel is 0.1: 0.5: 1.0.
Embodiment two
A kind of lanthanum doped catalyst for preparing carbon nano tube with uniform diameter, it is carrier with magnesia, load has the binary complex of the oxide of nickel and cobalt on the carrier, the oxide of lanthanum and the oxide of molybdenum, four mol ratio is 10: 1: 0.25: 12.5, the mol ratio of nickel and cobalt is 5: 5 in the binary complex of the oxide of nickel and cobalt, the mol ratio of nickel and iron is 1.0: 0.5 in the binary complex of the oxide of nickel and iron, the mol ratio of iron and cobalt is 1.0: 0.8 in the binary complex of the oxide of iron and cobalt, iron, cobalt, iron in the ternary complex of the oxide of nickel, cobalt, the mol ratio of nickel is 0.4: 0.6: 1.0.
Embodiment three
A kind of lanthanum doped catalyst for preparing carbon nano tube with uniform diameter, it is carrier with magnesia, load has the binary complex of the oxide of nickel and cobalt on the carrier, the oxide of lanthanum and the oxide of molybdenum, four mol ratio is 15: 1: 0.1: 8, the mol ratio of nickel and cobalt is 4: 1 in the binary complex of the oxide of nickel and cobalt, the mol ratio of nickel and iron is 0.5: 0.5 in the binary complex of the oxide of nickel and iron, the mol ratio of iron and cobalt is 0.1: 1.0 in the binary complex of the oxide of iron and cobalt, iron, cobalt, iron in the ternary complex of the oxide of nickel, cobalt, the mol ratio of nickel is 0.1: 1.0: 0.1.
Embodiment four
A kind of lanthanum doped catalyst for preparing carbon nano tube with uniform diameter, it is carrier with magnesia, load has the binary complex of the oxide of nickel and cobalt on the carrier, the oxide of lanthanum and the oxide of molybdenum, four mol ratio is 20: 1: 1: 10, the mol ratio of nickel and cobalt is 9: 1 in the binary complex of the oxide of nickel and cobalt, the mol ratio of nickel and iron is 7: 3 in the binary complex of the oxide of nickel and iron, the mol ratio of iron and cobalt is 5: 5 in the binary complex of the oxide of iron and cobalt, iron, cobalt, iron in the ternary complex of the oxide of nickel, cobalt, the mol ratio of nickel is 1.0: 1.0: 1.0.
Embodiment five
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Fe: Co: La: Mo: Mg=1 in molar ratio: 10: 1: 330: 155, take by weighing ferric nitrate, cobalt nitrate, lanthanum nitrate, ammonium molybdate, magnesium nitrate, earlier magnesium nitrate is dissolved in an amount of distilled water, add ferric nitrate, cobalt nitrate, lanthanum nitrate and ammonium molybdate more successively, treat four all dissolvings fully, 180 ℃ of oven dry, the time is 3 hours with solution.The product that obtains is calcined porphyrize after 30 minutes in 700 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment six
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Fe: Co: La: Mo: Mg=10 in molar ratio: 1: 10: 55: 175, take by weighing ferric sulfate, cobaltous sulfate, lanthanum acetate, ammonium molybdate, magnesium sulfate, earlier magnesium sulfate is dissolved in an amount of distilled water, add ferric sulfate, cobaltous sulfate, lanthanum acetate and ammonium molybdate more successively, treat four all dissolvings fully, 140 ℃ of oven dry, the time is 5 hours with solution.The product that obtains is calcined porphyrize after 20 minutes in 750 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment seven
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Fe: Ni: La: Mo: Mg=1 in molar ratio: 10: 7: 230: 275, take by weighing iron chloride, nickel chloride, lanthanum carbonate, ammonium molybdate, magnesium chloride, earlier magnesium chloride is dissolved in an amount of distilled water, add iron chloride, nickel chloride, lanthanum carbonate and ammonium molybdate more successively, treat four all dissolvings fully, 150 ℃ of oven dry, the time is 3 hours with solution.The product that obtains is calcined porphyrize after 30 minutes in 600 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment eight
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Ni: Co: La: Mo: Mg=1 in molar ratio: 10: 4: 55: 55, take by weighing nickel acetate, cobalt acetate, lanthanum carbonate, ammonium molybdate, magnesium acetate, earlier magnesium acetate is dissolved in an amount of distilled water, add nickel acetate, cobalt acetate, lanthanum carbonate and ammonium molybdate more successively, treat that it dissolves fully, 160 ℃ of oven dry, the time is 4 hours with solution.The product that obtains is calcined porphyrize after 10 minutes in 650 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment nine
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Fe: Ni: La: Mo: Mg=10 in molar ratio: 1: 8: 250: 150, take by weighing ferric nitrate, nickel nitrate, lanthanum carbonate, ammonium molybdate, magnesium nitrate, earlier magnesium nitrate is dissolved in an amount of distilled water, add ferric nitrate, nickel nitrate, lanthanum carbonate and ammonium molybdate more successively, treat four all dissolvings fully, 140 ℃ of oven dry, the time is 4 hours with solution.The product that obtains is calcined porphyrize after 30 minutes in 550 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment ten
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Ni: Co: La: Mo: Mg=10 in molar ratio: 1: 1: 100: 275, take by weighing nickelous sulfate, cobaltous sulfate, lanthanum nitrate, ammonium molybdate, magnesium nitrate, earlier magnesium nitrate is dissolved in an amount of distilled water, add nickelous sulfate, cobaltous sulfate, lanthanum nitrate and ammonium molybdate more successively, treat four all dissolvings fully, 170 ℃ of oven dry, the time is 3 hours with solution.The product that obtains is calcined porphyrize after 20 minutes in 700 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment 11
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Fe: Co: Ni: La: Mo: Mg=4 in molar ratio: 5: 1: 8: 160: 200, take by weighing iron chloride, cobalt chloride, nickel chloride, lanthanum acetate, ammonium molybdate, magnesium chloride, earlier magnesium chloride is dissolved in an amount of distilled water, add iron chloride, cobalt chloride, nickel chloride, lanthanum carbonate and ammonium molybdate more successively, treat that it dissolves fully, 150 ℃ of oven dry, the time is 3 hours with solution.The product that obtains is calcined porphyrize after 30 minutes in 600 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment 12
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Ni: Fe: Co: La: Mo: Mg=1 in molar ratio: 1: 10: 1: 360: 60, take by weighing nickel nitrate, ferric nitrate, cobalt nitrate, lanthanum nitrate, ammonium molybdate, magnesium nitrate, earlier magnesium nitrate is dissolved in an amount of distilled water, add nickel nitrate, ferric nitrate, cobalt nitrate, lanthanum nitrate and ammonium molybdate more successively, treat that it dissolves fully, 180 ℃ of oven dry, the time is 3 hours with solution.The product that obtains is calcined porphyrize after 10 minutes in 750 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.
Embodiment 13
A kind of preparation method who prepares the lanthanum doped catalyst of carbon nano tube with uniform diameter, Fe: Co: Ni: La: Mo: Mg=1 in molar ratio: 10: 1: 12: 170: 275, take by weighing ferric sulfate, cobaltous sulfate, nickelous sulfate, lanthanum acetate, ammonium molybdate, magnesium nitrate, earlier magnesium nitrate is dissolved in an amount of distilled water, add ferric sulfate, cobaltous sulfate, nickelous sulfate, lanthanum acetate and ammonium molybdate more successively, treat four all dissolvings fully, 150 ℃ of oven dry, the time is 4 hours with solution.The product that obtains is calcined porphyrize after 20 minutes in 600 ℃ of air, promptly obtain can be used to prepare the catalyst of CNT.