Method for preparing NbVO5 powder with coprecipitation method

Abstract

The invention relates to a method for preparing NbVO5 powder with the coprecipitation method, belonging to the preparation field of phosphoric acid tungsten bronze (ABO5) ceramic material. The synthesis of the pure NbVO5 is very difficult, and a sol-gel method is only available internationally in the present, by which the pure NbVO5 is synthesized by using metal alkoxide and chloride as raw materials. By adopting the coprecipitation method, the high-purity phosphoric acid tungsten bronze (ABO5) material NbVO5 powder is synthesized through experimental process of raw material dissolution, coprecipitation and calcinations under the mild synthesis conditions by using analytically pure Nb2O5, NH3VO4, H2SO4, C2H2O4.2H2O and NH3.H2O as the raw materials. The method adopts the easily-obtained and cheap raw materials, does not need vacuum or protective atmosphere, utilizes the soft chemistry method, the synthesis condition is mild, the process is simple, the cost is low, the experimental period is short, and the operation and industrialization are easy.

Description

technical field [0001] The invention belongs to tungsten phosphate bronze (ABO 5 The field of preparation of )-type materials, in particular to a preparation method of a material with catalytic performance and negative thermal expansion performance. Background technique [0002] In recent years, niobium vanadate (NbVO 5 ) as a catalyst has received widespread attention. Due to its high selectivity and high catalytic kinetics, it is mainly used in the fields of oxidative dehydrogenation of alkanes to olefins or ammonolytic oxidation. It can be doped with elements such as Ta at the A site to further improve its catalytic performance. , with broad application prospects. In addition, ABOs 5 Tungsten phosphate bronze compounds have a loose structure and many vacancies. Many compounds with this structure have macroscopic negative thermal expansion characteristics. In order to study NbVO 5 It is necessary to clarify its microstructure and explore its thermal expansion mechanism...

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Problems solved by technology

But pure NbVO 5 Synthesis is very difficult, such as literature [1] J.M.Amarilla, B.Casal, E.Ruiz-hitzky, Materials Letters., 8 (1989) 132-136; [2] M.Sarzi-Amadè, .S.Morselli, P.Moggi , A.Maione, P.ruiz, M.Devillers, Applied Catalysis., 284(2005) 11-20; [3] N.Deligne, D.Bayot, M.Degand, M.Devillers, Journal of Solid State Chemistry., 180(2007) 2026-2033, at present, pure NbVO can only be synthesized by sol-gel method in the world 5 , and the raw materials used in the synthesis are metal alkoxides or chlorides, which are expensive, experimental conditions are harsh, and the reaction cycle is long, and there is no relevant report in China

Our research found that niobium vanadate NbVO 5 It is a high-temperature unstable compound and decomposes above 650°C, so it is difficult to prepare by conventional solid-phase synthesis methods

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