Application of hydrated molybdenum trioxide in nitrogen fixation reaction
阅读说明：本技术 水合三氧化钼在固氮反应中的应用 (Application of hydrated molybdenum trioxide in nitrogen fixation reaction ) 是由 滕飞 杨志成 顾文浩 杨小嫚 刘喆 郝唯一 滕怡然 于 2020-06-28 设计创作，主要内容包括：本发明公开了水合三氧化钼在固氮反应中的应用,该水合三氧化钼的化学式为MoO<Sub>3</Sub>·0.55H<Sub>2</Sub>O。本发明在室温、常压、室内自然弱光条件下,以廉价的纯水和氮气为原料,以高效的水合三氧化钼为催化剂,在密封搅拌条件下即可得到高附加值的氨,且产率高达13.23μmol·g<Sup>-1</Sup>·h<Sup>-1</Sup>,有着巨大的科学价值和广阔的应用前景。(The invention discloses application of hydrated molybdenum trioxide in nitrogen fixation reaction, wherein the chemical formula of the hydrated molybdenum trioxide is MoO 3 ·0.55H 2 And O. The invention can obtain ammonia with high added value under the conditions of room temperature, normal pressure and natural weak light in the room by taking cheap pure water and nitrogen as raw materials and taking high-efficiency hydrated molybdenum trioxide as a catalyst under the condition of sealed stirring, and the yield reaches up to 13.23 mu mol g ‑1 ·h ‑1 Has great scientific value and wide application prospect.)
1. Application of hydrated molybdenum trioxide in nitrogen fixation reaction, wherein the chemical formula of the hydrated molybdenum trioxide is MoO3·0.55H2O。
2. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as claimed in claim 1, wherein: the hydrated molybdenum trioxide is hexagonal phase hydrated molybdenum trioxide, is in a nano rod shape, and the length of the nano rod is 4-6 mu m.
3. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as claimed in claim 1, wherein: the hydrated molybdenum trioxide is prepared by the following steps: adding 10mL of water into a beaker, and adding 2.46g of ammonium paramolybdate under the stirring condition; heating in water bath to 80 ℃, adding 2ml of nitric acid with the mass fraction of 68%, and continuously stirring for one hour; centrifugally washing, and drying at 60 ℃.
4. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as claimed in claim 1, wherein: the nitrogen fixation reaction comprises the following specific steps:
(1) adding pure water into the reaction vessel, and then adding the hydrated molybdenum trioxide;
(2) continuously introducing nitrogen into the reaction container until the air in the reaction container is exhausted and the reaction container is filled with nitrogen;
(3) sealing the reaction vessel;
(4) and (3) carrying out reaction under the stirring condition, wherein the reaction time is 2-6 hours.
5. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as claimed in claim 4, wherein: the adding amount of the hydrated molybdenum trioxide and the adding proportion of the pure water are 50-100 mg/100-150 mL of pure water.
6. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as claimed in claim 5, wherein: the reaction time of the step (4) is 5-6 hours.
7. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as recited in claim 6, wherein: the reaction time of the step (4) is 6 hours.
8. The use of hydrated molybdenum trioxide in a nitrogen fixation reaction as claimed in claim 4, wherein: the reaction in the step (4) is carried out at room temperature, normal pressure and room natural low light.
Technical Field
The invention relates to a new application of hydrated molybdenum trioxide, in particular to an application of a hexagonal phase hydrated molybdenum trioxide photocatalyst in a nitrogen fixation reaction.
Background
Ammonia is a chemical product with the largest yield except sulfuric acid in the world, and is mainly used for synthesizing products with high added values such as chemical fertilizers and the like. Traditional nitrogen fixation pathways can be divided into biological nitrogen fixation and chemical nitrogen fixation. Biological nitrogen fixation occurs mainly in plants and microorganisms and is difficult to apply on a large scale due to too low a content. Whereas chemical nitrogen fixation has traditionally been accomplished by the Haber-Bosch process. The process typically employs an iron-based catalyst to react nitrogen (N) under severe reaction conditions (i.e., 15-25MPa and 673-2) With hydrogen (H)2) Fixed together, the consumption accounts for more than 1 percent of the global energy supply, and the environmental pollution is large. At present, the world faces serious problems of grains, environment, energy and the like, so that the exploration of a new synthetic ammonia path is a hot topic in recent years.
The photocatalysis nitrogen fixation is a technology for converting nitrogen into ammonia and converting light energy into chemical energy by utilizing the response of materials to light, and the difficulty lies in that N is2And (4) activating. Although N is2Has extremely high stability (941 kJ. mol)-1) But when electrons are transferred from the catalyst to N2The N azo bond may be weakened and activated to promote bond dissociation. Illustratively, photocatalysis is the photocatalysis of a semiconductor to directly harvest solar energy to produce electron-hole pairs, which may be N2Activation provides energetic electrons to be N2Fixation to ammonia provides a promising approach. Among the reports, Bi reported in the King et al2O3 x/nBiaMOb（x=0~1，n=0~1，a=0~2，b= 0-6, M = V, Mo, W) composite catalyst has higher photocatalytic nitrogen fixation activity and stability (application publication number: CN 106955699 a). However, the preparation process is complicated, and the generated waste liquid has great harm to the environment and is not suitable for large-scale practical application.
Disclosure of Invention
The invention aims to overcome the defects in the prior art, provides a catalyst which can be used for synthesizing ammonia by photocatalysis and has high catalytic activity and simple preparation process conditions, and provides a nitrogen fixation method which is simple and feasible and is beneficial to large-scale popularization.
In order to achieve the purpose, the invention adopts the following technical scheme:
application of hydrated molybdenum trioxide in nitrogen fixation reaction, wherein the chemical formula of the hydrated molybdenum trioxide is MoO3·0.55H2O。
The hydrated molybdenum trioxide is hexagonal phase hydrated molybdenum trioxide, is in a nano rod shape, and has the length of 4-6 mu m.
The hydrated molybdenum trioxide is prepared by the following steps: adding 10mL of water into a beaker, and adding 2.46g of ammonium paramolybdate under the stirring condition; heating in water bath to 80 ℃, adding 2ml of nitric acid with the mass fraction of 68%, and continuously stirring for one hour; centrifugally washing, and drying at 60 ℃.
The nitrogen fixation reaction comprises the following specific steps:
(1) adding pure water into the reaction vessel, and then adding the hydrated molybdenum trioxide;
(2) continuously introducing nitrogen into the reaction container until the air in the reaction container is exhausted and the reaction container is filled with nitrogen;
(3) sealing the reaction vessel;
(4) and (3) carrying out reaction under the stirring condition, wherein the reaction time is 2-6 hours.
The adding amount of the hydrated molybdenum trioxide in the step (1) is as follows: 50-100 mg of hydrated molybdenum trioxide is added to 100-150 mL of pure water.
The reaction time of the step (4) is preferably 5-6 hours, and the optimal reaction time is 6 hours.
The nitrogen fixation reaction is carried out under room temperature, normal pressure and indoor natural weak light conditions.
Compared with the prior art, the invention has the following advantages:
under the conditions of room temperature, normal pressure and weak light, cheap pure water and nitrogen are used as raw materials, high-efficiency hydrated molybdenum trioxide is used as a catalyst, ammonia with high added value can be obtained under the condition of sealed stirring, and the yield is as high as 13.23μmol·g-1·h-1。
The method is simple to operate, low in cost and beneficial to large-scale popularization.
Drawings
FIG. 1 is a Scanning Electron Microscope (SEM) image of a hydrated molybdenum trioxide photocatalyst prepared in example one;
FIG. 2 is an X-ray diffraction (XRD) pattern of a hydrated molybdenum trioxide photocatalyst prepared in example one;
FIG. 3 is a graph showing the activity of a hydrated molybdenum trioxide photocatalyst in ammonia synthesis prepared in example II;
in FIG. 3, the ordinate ppm represents the ammonia concentration in the reaction system, and the abscissa t represents the reaction time.
Detailed Description
The present invention will be described in detail with reference to specific examples.