Synthesis of stephanoporate molybdenum carbide nano-wire

Abstract

The invention relates to the technical field of the nanometer material, and relates to a method for synthesizing the porous molybdenum carbide nanometer wire, and adopts the following steps: molybdate is dissolved in the water, and the mol concentration of the molybdenum atom is 0.02 to 1.5 mol / L; organic amine is filled in, and the mol ratio between the organic amine and the molybdenum atom is 20.0 to 1.0: 1; inorganic acid is dropped into the solution, and the pH value is adjusted to be 3 to 6 until the white precipitate appears; the reaction solution is moved into an oil bath with the temperature of 30 to 60 DEG C to be reacted for 6 to 24 hours; (5) the product is washed, pumped, filtered and dried; the product is baked in the inert gases atmosphere at the temperature of 675 to 750 DEG C for 4 to 10 hours. The invention has the advantages that abundant nanometer hole structure is arranged between the nanometer particles, the granularity of the molybdenum carbide is small, the molybdenum carbide has rich porous structure and large specific surface area, the carbon on the surface is small, thereby favoring the secondary assembling of the catalyst and having wide application fields; the productivity can reach 95 percent or more; the conditions are simple and easy to be controlled; the preparation efficiency is high; the invention has favorable application and industrialization prospect.

Description

technical field [0001] The invention belongs to the technical field of nanometer materials, and in particular relates to a synthesis method of porous molybdenum carbide nanowires. Background technique [0002] Transition metal carbide catalysts represented by molybdenum carbide have become the most promising in the past 10 to 20 years because of their unique electronic structure and catalytic performance, anti-sulfur and anti-coking properties, and good thermal stability. one of the catalytic materials. Especially in recent years, with the rapid rise of oil prices, the calls for efficient and green utilization of energy and resources have been increasing, and the development of carbide catalytic performance and new catalytic reactions has further attracted people's attention. In addition, since the raw materials for carbide synthesis are relatively cheap and easy to obtain, it is also of great significance in saving precious metal resources and reducing the cost of catalyti...

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Problems solved by technology

[0003] According to literature reports, the current synthesis methods of molybdenum carbide catalytic materials can be roughly divided into the following categories: 1) High-temperature carbonization method (1500~2000°C), carbonization of metal species (molybdenum oxide) with C and CO at high temperature , there are disadvantages such as high temperature, serious surface area carbon, particle sintering, etc.

2) CVD and plasma sputtering methods, which use CVD or plasma sputtering methods to vaporize Mo species and C species and then deposit them into nanoparticles, which have the disadvantages of high temperature, high atmosphere requirements, and high cost.

3) Temperature Programmed Reaction (TPR), by MoO 3 (or molybdenum nitride) in CH 4 / H 2 (or C 2 h 4 / H 2 ) slowly heating carbonization in the mixed gas, this method is currently the most widely used method in the carbide catalyst synthesis literature, but due to the presence of surface area carbon in the reaction product, uneven reaction, and H 2 Dangerous and explosive, difficult mass production and other disadvantages

4) Carbothermal hydrogenation (carbothermal hydrogenation) method, compared with the temperature-programmed method, this method is based on highly dispersed MoO supported by multi-walled carbon nanotubes or high specific surface carbon / polymer aerosols 3 (or soluble molybdenum compound), direct use of the interfacial reaction between the carrier carbon source and the load in the hydrogen atmosphere is beneficial to improve the dispersion, reduce the reaction temperature, and increase the specific surface, but still cannot completely eliminate the gas-solid phase reaction of the temperature-programmed method. some problems of

6) Cracking of metal precursors, including metal-organic compounds and cracking of mixtures of ammonium molybdate and hexamethylenetetramine, etc. The preparation of the former precursor is complicated, and the entire operation process requires an inert atmosphere and harsh conditions; the latter precursor The body structure is not clear, which is not conducive to product optimization, and the product is mixed with Mo 2 N impurities; large particles

In addition there are reports such as microwave method, ultrasonic wave dispersion[etc., but also exist yield is little, reaction is insufficient, difficult problems such as product particle is bigger (R B.Levy.Advanced Materials in Catalysis (eds.Burton J J., Garten RL). New York: Academic Press, 1977; M.Saito, R.B.Anderson.J.Catal., 1980, 63, 438; M.J.Ledoux, C.Phamr Huu.Catal.Today, 1992, 15, 263; P.Ronsheim, A. Mazza, A.N. Christensen, Plasma Chem. Plasma Process, 1981, 1, 135; T. Miyao, I. Shishikura, M. Matsuoka, M. Nagal, S.T. Oyama. Appl. Catal. A: General, 1997, 165, 419; J.X.Wang, S.F.Ji, J.Yang, Q.L.Zhu, S.B.Li.Catal.Comm., 2005, 6, 389; T.C.Xiao, A.P.E.York, V.C.Williams, H.Al-Megren, A.Hanif, X.Y.Zhou, M.L.H. Green.Chem.Mater.2000, 12, 3896; Y.Z.Li, Y.N.Fan, Y.Chen.J.Solid State Chem.2003, 170, 135; X.L.Li, Y.D.Li, Chem.Eur.J.2004, 10, 433; H.M.Wang, X.H.Wang, M.H.Zhang, X.Y.Du, W.Li, K.Y.Tao, Chem.Mater.2007, 19, 1801; S.R.Vallance, S.Kingman, D.H.Gregory.Chem.Commun., 2007, 742; N.A.Dhas, A.Gedanken.Chem.Mater.1997, 9, 3144.)

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