CN104495932A - Method for solid-phase chemical reaction synthesis of nano molybdenum trioxide - Google Patents

Abstract

The object of the present invention is to provide a preparation method for synthesizing nano-molybdenum oxide by solid-phase chemical reaction. Nanoscale molybdenum trioxide material. The invention is based on the solid-phase chemical reaction, adopts common and easy-to-obtain raw materials, obtains a nano-sized precursor through a simple solid-solid chemical reaction, and calcines the precursor to obtain nano-molybdenum trioxide. Due to the characteristics of simple preparation method, convenient operation, high product yield, short process flow, simple equipment, and easy realization of mass production, the present invention has very broad practical application prospects.

Description

A method for synthesizing nanomolybdenum trioxide by solid phase chemical reaction

technical field

The invention relates to a method for synthesizing nanomolybdenum trioxide by solid phase chemical reaction.

Background technique

Molybdenum trioxide (MoO ₃ ) is a white or pale yellow orthorhombic crystal. There are three common crystal structures: monoclinic phase (p-MoO ₃ ), hexagonal phase (h-MoO ₃ ) and orthorhombic phase (a-MoO ₃ ). The former two are thermodynamic metastable phases, and the latter is a thermodynamically stable phase at room temperature. However, the basic units of the above three phase structures are distorted [MoO ₆ ] octahedra. The crystal structure of stable MoO ₃ (a-MoO ₃ ) belongs to the orthorhombic system, and the lattice parameters a=0.395nrn, b=l.381nm, c=0.369nm. Each [MoO ₆ ] unit in the crystal is connected with a common edge in one direction and a common vertex in another direction, forming a two-dimensional infinitely stretched planar layer, which is double-wave-shaped and extends perpendicular to the b-axis. The unique layered structure of orthorhombic MoO ₃ can increase active sites and facilitate the entry and desorption of gas molecules, and this layered structure is rare in metal oxides.

Nanomaterials have special physical effects such as small size effect, quantum size effect, macroscopic quantum tunneling effect, surface effect, etc. These special effects make nanomaterials have different physical and chemical properties from conventional size materials, making nanomaterials in optical materials, gas Sensitive materials, electrode materials, catalytic materials, magnetic materials and other fields have broad application prospects. Nano-scale molybdenum trioxide, as an oxide of transition metal, has stronger catalytic activity, photoelectric properties, corrosion resistance, etc. In addition, nano-scale molybdenum trioxide has attracted more and more attention because of its attractive application value in information display and storage, intelligent camouflage and other fields.

At present, the synthesis methods of nanomolybdenum trioxide mainly include hydrothermal method, solvothermal method, sol-gel method, vapor deposition method, template method, chemical precipitation method, ion exchange method and other methods. Most of these methods have complicated synthesis process, high cost, harsh experimental conditions, and great difficulties in realizing large-scale industrial production; and the traditional high-temperature solid-phase method requires high equipment requirements due to high energy consumption, which is also difficult for large-scale industrial production. Bring a lot of inconvenience and difficulty. Therefore, it is of great significance to choose a simple, reliable, short process flow, and green and environmentally friendly preparation method to prepare nano-molybdenum trioxide. The solid-phase chemical synthesis method has the advantages of simple steps, short reaction cycle, high selectivity, high yield, and little environmental pollution. It has become a simple method to obtain nanomaterials.

Contents of the invention

The object of the present invention is to provide a method for synthesizing nano-molybdenum trioxide by solid-phase chemical reaction, which is synthesized by solid-phase chemical reaction by using simple and easy-to-obtain raw materials, adopting a simple and feasible operation method, and mild and controllable reaction conditions. Nanomolybdenum trioxide.

In the invention, ammonium molybdate and organic acid are used as reactants to synthesize a nano-precursor through solid-phase chemical reaction at room temperature, and then the precursor is calcined to obtain nano-molybdenum trioxide.

The organic acid of the present invention is oxalic acid, benzoic acid, glycine and citric acid. Compared with the prior art, the present invention has the following advantages: the nanometer molybdenum trioxide can be obtained through simple grinding and calcination processes by using cheap and easy-to-obtain raw materials. Due to the outstanding features of the present invention, such as simple preparation method, mild and controllable reaction conditions, high product yield, environmental friendliness, and easy realization of mass production, the present invention has extremely broad application prospects.

Description of drawings

Fig. 1 is the powder X-ray diffraction spectrum of the nanomolybdenum trioxide of the orthorhombic phase that the first embodiment of the present invention prepares. (PDF#35-0609 in the figure is the X-ray diffraction data of orthorhombic molybdenum trioxide).

Fig. 2 is a field emission scanning electron micrograph of the orthorhombic nanomolybdenum trioxide prepared in the first embodiment of the present invention.

Detailed ways

The present invention will be further elaborated below in conjunction with specific examples. These examples should be understood as only for illustrating the present invention but not for limiting the protection scope of the present invention. After reading the contents of the present invention, various changes or modifications made to the present invention based on the principles of the present invention also fall within the scope defined by the claims of the present invention.

Embodiment one:

Accurately weigh 0.01 mol of ammonium molybdate and grind it in an agate mortar, then add 0.03 mol of finely ground oxalic acid, grind the solid phase reaction system for 30 minutes, let it stand at room temperature for 3 days, and then calcinate two Nano-molybdenum trioxide in metastable monoclinic phase and hexagonal phase can be obtained within 1 hour; and nano-molybdenum trioxide in stable orthorhombic phase can be obtained after calcination at 500°C for two hours.

Embodiment two:

Accurately weigh 0.01 mol of ammonium molybdate and grind it in an agate mortar, then add 0.06 mol of finely ground benzoic acid, grind the solid phase reaction system for 40 minutes, let it stand at room temperature for 4 days, and then calcinate it at 300°C for two Nano-molybdenum trioxide in metastable monoclinic phase and hexagonal phase can be obtained within one hour; and stable orthorhombic nano-molybdenum trioxide can be obtained after calcination at 500°C for two hours.

Embodiment three:

Accurately weigh 0.01 mol ammonium molybdate and grind it in an agate mortar, then add 0.02 mol ground citric acid, grind the solid phase reaction system for 50 minutes, let it stand at room temperature for 5 days, and then calcinate two Nano-molybdenum trioxide in metastable monoclinic phase and hexagonal phase can be obtained within one hour; and stable orthorhombic nano-molybdenum trioxide can be obtained after calcination at 500°C for two hours.

Embodiment four:

Accurately weigh 0.01 mol ammonium molybdate and grind it in an agate mortar, then add 0.03 mol ground glycine, grind the solid phase reaction system for 50 minutes, let it stand at room temperature for 5 days, and calcinate two Nano-molybdenum trioxide in metastable monoclinic phase and hexagonal phase can be obtained within one hour; and stable orthorhombic nano-molybdenum trioxide can be obtained after calcination at 500°C for two hours.

Claims (4)

1. A method for synthesizing nanometer molybdenum trioxide by solid-phase chemical reaction, which comprises the following steps: after ammonium molybdate and organic acid are weighed according to a certain stoichiometric ratio, carry out solid phase under room temperature conditions and in an agate mortar Nano-sized precursors are obtained through chemical reactions, and then the precursors are calcined at a certain temperature in a muffle furnace to obtain nano-molybdenum trioxide. 2. The method for synthesizing nanomolybdenum trioxide according to a kind of solid phase chemical reaction according to claim 1, is characterized in that: the organic acid used is one of oxalic acid, benzoic acid, citric acid and glycine. 3. according to the method for a kind of solid phase chemical reaction synthesis nano molybdenum trioxide described in claim 1, it is characterized in that: the stoichiometric ratio of ammonium molybdate and organic acid is that ammonium molybdate and oxalic acid are 1:3, molybdate Ammonium and Benzoic Acid 1:6, Ammonium Molybdate and Citric Acid 1:2, Ammonium Molybdate and Glycine 1:3. 4. The method for synthesizing nanomolybdenum trioxide by solid-phase chemical reaction according to claim 1, characterized in that: the solid-phase reaction product is calcined in a muffle furnace at 300°C for two hours to obtain a metastable monoclinic phase and hexagonal phase of nano-molybdenum trioxide, and calcined at 500°C for two hours in a muffle furnace to obtain stable orthorhombic nano-molybdenum trioxide.