CN102320657A - Method for preparing gamma-phase bismuth oxide - Google Patents

Abstract

The invention provides a method for synthesizing gamma-phase (body-centered cubic structure) bismuth oxide (Bi2O3). The method is characterized by comprising the following steps of: placing a certain amount of raw materials into a reaction kettle with polytetrafluoroethylene lining, wherein the raw materials comprise commercialized alpha-phase or beta-phase Bi2O3; adding deionized water to ensure that a reactor has a certain filling degree; adding a certain amount of NaOH or KOH solution; adjusting the pH value of a system; placing the reaction into a drying oven; performing hydrothermal reaction at a certain reaction temperature; after the reaction is finished, performing solid liquid separation; washing by using the deionized water; and drying in the air to obtain the gamma-phase Bi2O3. By the method, the raw materials are readily available; the equipment and the process are simple; the used ionic solution can be recycled; zero emission is realized; and the environment is not polluted.

Description

A kind of preparation method of γ phase oxidation bismuth

Technical field

The present invention relates to a kind of hydrothermal preparation γ phase Bi ₂O ₃Novel method, belong to technical field of inorganic chemical industry.

Background technology

Bismuth oxide is a kind of important functional material, has α, β, γ and four kinds of crystal formations of σ, belongs to monocline, tetragonal, body-centered cubic structure and face-centred cubic structure respectively.The performance of bismuth oxide and Application Areas and its crystalline structure are closely related.Such as, the Bi of δ phase ₂O ₃Be the highest ionophore of electric conductivity up to now, its electric conductivity is about 1Scm ^-1, than the high several magnitude of bismuth oxide of other crystal formations; Zou Wen etc. have compared different crystal forms Bi ₂O ₃Visible light photocatalysis active, find Bi under radiation of visible light ₂O ₃The activity of photocatalytic degradation rhodamine B be: γ-Bi ₂O ₃＞β-Bi ₂O ₃＞α-Bi ₂O ₃(Chinese Journal of Inorganic Chemistry 2009,25,1971).Therefore, how controllable preparation has great scientific research value and application prospect with the bismuth oxide of producing different crystalline phases, and producing special crystal formation powder also is the important directions of manufacturer's development from now on.

The Bi of produced in conventional processes ₂O ₃All be α phase oxidation bismuth (Chinese patent ZL03151466.9; CN1850621A; CN101811732A).This mainly is because α phase Bi ₂O ₃Be the Thermodynamically stable crystal habit, at stable existence below 727 ℃.With α phase Bi ₂O ₃Be warming up to 727 ℃, the crystal transition that α arrives the δ phase mutually will take place; δ with stable existence to Bi ₂O ₃Fusing point (824 ℃); In temperature-fall period, control different cooling rates, respectively at 650 ℃ or 639 ℃, the Bi of δ phase ₂O ₃To change β phase or γ phase into, and further reduce temperature, β will change the thermodynamically stable α of room temperature into mutually again with γ phase oxidation bismuth mutually.This shows, except α phase Bi ₂O ₃, the Bi of other crystalline phases ₂O ₃All only in certain TR, exist, though great deal of research results is illustrated in Bi ₂O ₃Middle some other elements that mix can enlarge metastable state Bi ₂O ₃The stable existence TR.Such as, at Bi ₂O ₃In go into elements such as a spot of Al, B, Ga, Si disastrously after, can at room temperature obtain the Bi of γ phase ₂O ₃, but other elements that mix, can remarkably influenced Bi ₂O ₃Distinctive character.Therefore, how at room temperature to prepare pure metastable state Bi ₂O ₃It is a great challenge.

In recent years, international and domesticly all have breakthrough, reported preparation γ phase Bi under Action of Surfactant like Tseng T K etc. in this field ₂O ₃Method (ACS Appl.Mater.Inter.2010,2,943.), Zheng Bo etc. have utilized electrochemical production γ phase Bi ₂O ₃(SCI 2005,26,628).Yet the comparatively use of complex apparatus and technical process and tensio-active agent has increased preparation cost in these methods, is difficult to realize large-scale industrial production.Therefore, research prepares γ Bi mutually with exploration technology process method simple, that cost is cheap relatively ₂O ₃Be of great immediate significance.

The invention provides a kind of novel green chemical process, through the control reaction conditions, based on Bi ₂O ₃Phase transition process under hydrothermal condition prepares γ phase Bi ₂O ₃

Summary of the invention

The preparation method who the purpose of this invention is to provide a kind of γ phase oxidation bismuth, this method can adopt raw material cheap and easy to get under lower temperature condition, preparation γ phase Bi ₂O ₃, fill up γ phase Bi ₂O ₃The blank of scale preparation aspect.

Technical solution of the present invention is:

With business-like α phase or β phase Bi ₂O ₃Be raw material.A certain amount of raw material is packed in the band teflon-lined reaction kettle, add deionized water again and make reactor drum have certain compactedness, and add a certain amount of NaOH or KOH solution, the pH value of regulation system.Then reaction kettle is put into baking oven, under the certain reaction temperature, carry out hydro-thermal reaction, after reaction finishes, carry out solid-liquid separation, use deionized water wash again, in air, carry out drying treatment then, can obtain γ phase Bi ₂O ₃This method is very responsive to the pH value, and the pH value of initial reaction system should be controlled between 12.5～14.Embodiment is following:

(1) be raw material with α phase or β phase oxidation bismuth, solvent is a deionized water, and after adding deionized water, α phase or β phase oxidation bismuth raw material concentration are 0.01M～3M;

(2) described raw material is uniformly dispersed in deionized water after, adding concentration is the pH regulator agent of 1M～10M, regulates pH value to 12.5～14, packs into and is with in the teflon-lined reaction kettle;

(3) reaction kettle is put into baking oven, in 120 ℃～220 ℃ TR, be incubated 1～48 hour, be cooled to room temperature,, behind deionized water wash, obtain xanchromatic γ phase Bi with the funnel suction filtration ₂O ₃

Described pH regulator agent can be selected NaOH, KOH for use, also can adopt other can regulator solution the pH value other pH regulator agent of 12.5～14.

The present invention compared with prior art has the following advantages and the high-lighting effect: the present invention adopts business-like α phase or β phase Bi ₂O ₃Powder is a raw material, utilizes hydro-thermal reaction, prepares γ phase Bi ₂O ₃, its degree of purity of production can be through α phase or β phase Bi ₂O ₃The purity of presoma is controlled; Employed solion can be recycled, and realizes zero release, environmentally safe; Equipment and preparation technology are simple, and operational safety is reliable, are easy to suitability for industrialized production, have good industrialization prospect.

Description of drawings

Fig. 1 is embodiment 1 obtained γ-Bi ₂O ₃And α-Bi ₂O ₃The x-ray diffraction pattern of raw material.

Fig. 2 is used α-Bi ₂O ₃The sem photograph of raw material.

Fig. 3 is embodiment 1 obtained γ-Bi ₂O ₃Sem photograph.

Embodiment

With the mode of specific embodiment the present invention is described below, but is confined to following examples incessantly.

Embodiment 1:

Take by weighing 1mmol α-Bi ₂O ₃Powder adds the 6mL deionized water as in the withstand voltage reaction kettle of the stainless steel of 23mL, stirs it is uniformly dispersed, and adds 8M KOH solution again, and the pH value of regulation system is 13.5.Sealed reactor behind 160 ℃ of reaction 24h, is cooled to room temperature, with the funnel suction filtration, behind deionized water wash, obtains yellow powder.Product is accredited as γ-Bi through X-ray powder diffraction ₂O ₃(Fig. 1).ESEM shows irregular α-Bi ₂O ₃Powder (Fig. 2) after embodiment 1 said method is handled, can obtain the micron order cube γ-Bi of rule ₂O ₃Particle (Fig. 3).

Embodiment 2:

Take by weighing 0.2mmol β-Bi ₂O ₃Powder adds the 9mL deionized water as in the withstand voltage reaction kettle of the stainless steel of 23mL, stirs it is uniformly dispersed, and adds 8M KOH solution again, and the pH value of regulation system is 12.6.Sealed reactor behind 160 ℃ of reaction 24h, is cooled to room temperature, with the funnel suction filtration, behind deionized water wash, obtains pale yellow powder.Product is accredited as γ-Bi through X-ray powder diffraction ₂O ₃

Embodiment 3:

Take by weighing 5mmol β-Bi ₂O ₃Powder adds the 30mL deionized water as in the withstand voltage reaction kettle of the stainless steel of 100mL, stirs it is uniformly dispersed, and adds 8M NaOH solution again, and the pH value of regulation system is 13.2.Sealed reactor behind 180 ℃ of reaction 5h, is cooled to room temperature, with the funnel suction filtration, behind deionized water wash, obtains yellow powder.Product is accredited as γ-Bi through X-ray powder diffraction ₂O ₃

Embodiment 4:

Take by weighing 0.1mmol α-Bi ₂O ₃Powder adds the 8mL deionized water as in the withstand voltage reaction kettle of the stainless steel of 23mL, stirs it is uniformly dispersed, and adds 4MNaOH solution again, and the pH value of regulation system is 13.5.Sealed reactor behind 120 ℃ of reaction 24h, is cooled to room temperature, with the funnel suction filtration, behind deionized water wash, obtains yellow powder.Product is accredited as γ-Bi through X-ray powder diffraction ₂O ₃

Embodiment 5:

Take by weighing 0.2mmol β-Bi ₂O ₃Powder adds the 8mL deionized water as in the withstand voltage reaction kettle of the stainless steel of 23mL, stirs it is uniformly dispersed, and adds 10M KOH solution again, and the pH value of regulation system is 13.8.Sealed reactor behind 160 ℃ of reaction 3h, is cooled to room temperature, with the funnel suction filtration, behind deionized water wash, obtains yellow powder.Product is accredited as γ-Bi through X-ray powder diffraction ₂O ₃

Claims (2)

1. the preparation method of a γ phase oxidation bismuth is characterized in that this method comprises the following steps:

(1) be raw material with α phase or β phase oxidation bismuth, solvent is a deionized water, and after adding deionized water, α phase or β phase oxidation bismuth raw material concentration are 0.01M～3M;

(2) described raw material is uniformly dispersed in deionized water after, adding concentration is the pH regulator agent of 1M～10M, regulates pH value to 12.5～14, packs into and is with in the teflon-lined reaction kettle;

(3) reaction kettle is put into baking oven, in 120 ℃～220 ℃ TR, be incubated 1～48 hour, be cooled to room temperature,, behind deionized water wash, obtain xanchromatic γ phase Bi with the funnel suction filtration ₂O ₃

2. γ phase Bi according to claim 1 ₂O ₃The preparation method, it is characterized in that: described pH regulator agent is NaOH, KOH, also comprise other can regulator solution the pH value other pH regulator agent of 12.5～14.

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