CN114014360B - Sillin-Aurivillius layered structure material Bi 4 SbO 8 Cl and synthesis method - Google Patents

Abstract

The invention discloses a Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl and a synthesis method thereof. Its microstructure is: —Cl—Bi ₂ O ₂ —SbO ₄ —Bi ₂ O ₂ —Cl—. The synthesis steps are as follows: mix Sb ₂ O ₄ with Bi and Cl-containing compounds in a certain proportion and grind them thoroughly; further obtain the Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl through high-temperature solid-state reaction, which can absorb wavelengths less than 500 nm Visible light and ultraviolet light, and the conduction band position meets the H ₂ /H ⁺ potential requirement. The material can be used in dyes, carbon dioxide reduction, hydrogen production from water splitting, nitrogen fixation and other fields.

Description

A Sillen-Aurivillius layered structure material Bi4SbO8Cl and its synthesis method

technical field

The invention relates to a layered structure narrow band gap semiconductor material, which belongs to the field of preparation of nanometer materials.

Background technique

Sillen-Aurivillius layered structure material is a kind of composite bismuth oxide layered material, composed of -Bi ₂ O ₂ -layer and -MO _x -type perovskite layer (where M is other metal elements), with excellent Photoelectric properties, wide application fields, have significant economic and social benefits. Sillen-Aurivillius layered structure materials that have been successfully synthesized include Bi ₄ NbO ₈ Cl, Bi ₄ TaO ₈ Cl, etc., among which the M elements in the -MO _x -type perovskite layer include Nb, Ta, V, W, Pb, etc. However, these materials mainly have problems such as wide band gap, high electron-hole recombination rate, conduction band position that does not meet the requirements of H ₂ /H ⁺ reduction potential, or expensive M element, etc., which need to be solved urgently.

Contents of the invention

The purpose of the present invention is to overcome the shortcomings of the above technical problems, and propose a Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl and a synthesis method thereof.

In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions:

A Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl, whose microstructure is —Cl—Bi ₂ O ₂ —SbO ₄ —Bi ₂ O ₂ —Cl—, can absorb visible light and ultraviolet light with a wavelength less than 500 nm, And the conduction band position meets the H ₂ /H ⁺ potential requirement.

The present invention also proposes a synthesis method of Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl, comprising the following steps:

(1) Sb ₂ O ₄ and oxides containing Bi and Cl or their salts are ground, and the resulting mixture is subjected to high-temperature solid-state reaction;

(2) Continue to grind the reactants obtained in step (1) for a period of time, and carry out high-temperature solid-phase reaction again.

Preferably, in step (1), Sb ₂ O ₄ is prepared by a high-temperature solid-phase method, the steps of which are: grinding Sb ₂ O ₅ for a period of time, and then performing a high-temperature solid-state reaction to obtain Sb ₂ O ₄ .

Specifically, grind for 5 minutes to 30 minutes.

Specifically, the high-temperature solid-state reaction conditions are as follows: the calcination temperature is 700-1000°C, the reaction time is 1h-6h, and the heating rate is 3-7°C/min.

Preferably, in step (1), Sb ₂ O ₄ is prepared by hydrothermal method, the steps are: dissolving SbCl ₃ and urea in water, adjusting the pH to 10, and hydrothermally reacting for a period of time to obtain Sb ₂ O ₄ .

Specifically, the molar ratio of SbCl ₃ and urea is 1:1.

Specifically, the hydrothermal reaction temperature is 150°C, and the hydrothermal reaction time is 18h.

Preferably, in step (1), grind for 5 minutes to 30 minutes.

Preferably, in step (1), the oxides of Bi and Cl or their salts include Bi ₂ O ₃ , NH ₄ Cl, BiOCl and BiCl ₃ .

Preferably, in step (1), the high-temperature solid-state reaction conditions are: the calcination temperature is 700-900ºC, the reaction time is 1h-20h, and the heating rate is 3-7ºC/min.

Preferably, in step (2), grind for 5 minutes to 30 minutes.

Preferably, in step (2), the high-temperature solid-state reaction conditions are: calcination temperature 800-1000ºC, reaction time 1h-20h, heating rate 3-7ºC/min.

Preferably, in step (2), the high-temperature solid-state reaction is carried out again for 1 to 3 times.

Compared with the prior art, the present invention has the following beneficial effects:

The microstructure of the Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl provided by the present invention is —Cl—Bi ₂ O ₂ —SbO ₄ —Bi ₂ O ₂ —Cl—, which can absorb visible light and ultraviolet light with a wavelength less than 500 nm light, and the conduction band position meets the H ₂ /H ⁺ potential requirements. The material can be used in dyes, carbon dioxide reduction, hydrogen production from water splitting, nitrogen fixation and other fields.

Description of drawings

Fig. 1 is a microstructure diagram of Bi ₄ SbO ₈ Cl of the present invention.

Fig. 2 is an X-ray diffraction pattern of Sb ₂ O ₄ prepared in the present invention.

Fig. 3 is an X-ray diffraction pattern of Bi ₄ SbO ₈ Cl prepared in the present invention.

Fig. 4 is the ultraviolet-visible light absorption spectrum of Bi ₄ SbO ₈ Cl prepared in the present invention.

Fig. 5 is a graph showing the water splitting hydrogen production performance of Bi ₄ SbO ₈ Cl prepared in the present invention.

Detailed ways

The present invention will be further elaborated below in conjunction with the accompanying drawings and embodiments.

The innovations of the present invention are as follows: 1) In terms of energy band structure, Sb is used to replace Nb, and the conduction band position of Bi ₄ SbO ₈ Cl satisfies the requirement of H ₂ /H ⁺ reduction potential. 2) In terms of synthesis, the Sb source must use Sb ₂ O ₄ , such as Sb ₂ O ₅ undergoing a high-temperature solid-state reaction at 950°C for 4 hours or converting SbCl ₃ into Sb ₂ O by hydrothermal reaction at 150°C for 18 hours under alkaline conditions After ₄ , the Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl can be further mixed and reacted with compounds containing Bi and Cl.

Example 1

The process of preparing photocatalyst Bi ₄ SbO ₈ Cl by high temperature solid phase synthesis of Sb ₂ O ₄ is as follows:

(1) Weigh 2 g of Sb ₂ O ₅ and grind for 10 min, then undergo a high-temperature solid-state reaction at 950°C for 4 hours to obtain Sb ₂ O ₄ , the X-ray diffraction diagram is shown in Figure 2.

(2) Measure and grind Sb ₂ O ₄ (0.312 g), Bi ₂ O ₃ (0.932 g), and NH ₄ Cl (0.108 g) for 10 min, and react in a muffle furnace at 800 °C for 6 h at high temperature for solid-state reaction.

(3) Grind the obtained mixture again for 10 minutes, and then undergo a high-temperature solid-state reaction at 850°C for 6 hours in a muffle furnace to obtain the final product Bi ₄ SbO ₈ Cl. The microstructure is shown in Figure 1, and the X-ray diffraction diagram is shown in Figure 1. 3. The ultraviolet-visible light absorption spectrum of the obtained Bi ₄ SbO ₈ Cl is shown in Fig. 4 , and the hydrogen production performance of photocatalytic water splitting is shown in Fig. 5 .

Example 2

The process of synthesizing Sb ₂ O ₄ by hydrothermal method and then preparing photocatalyst Bi ₄ SbO ₈ Cl is as follows:

(1) Weigh 0.005 mol of SbCl ₃ and 0.005 mol of urea and dissolve them in 50 mL of water, adjust the pH to 10 with ammonia water, move the mixed solution to the reaction kettle, the reaction temperature is 150 ℃, the reaction time is 18 hours, and the reaction is completed , washed with deionized water, centrifuged and dried to obtain Sb ₂ O ₄ , and the X-ray diffraction diagram is shown in FIG. 2 .

(2) Measure and grind Sb ₂ O ₄ (0.312 g), Bi ₂ O ₃ (1.864 g), NH ₄ Cl (0.108 g) for 10 min, and react in a muffle furnace at 800 °C for 6 h at high temperature for solid-state reaction.

(3) The obtained mixture was ground again for 10 minutes, and then subjected to a high-temperature solid-state reaction at 850°C for 6 hours in a muffle furnace to obtain the final product Bi ₄ SbO ₈ Cl, whose X-ray diffraction pattern is shown in Figure 3. Photocatalytic water splitting Hydrogen properties are shown in Figure 5. It can be seen from Figure 5 that the photocatalytic water splitting hydrogen production performance of Bi ₄ SbO ₈ Cl prepared in Example 1 is more than ten times higher than that in Example 2, which may be due to the microscopic characteristics of Sb ₂ O ₄ synthesized by the two methods (particle size , surface defects, etc.) are different, resulting in different microscopic properties of the final synthesized Bi ₄ SbO ₈ Cl.

Comparative example 1

Sb ₂ O ₅ reacts directly with compounds containing Bi and Cl without high-temperature calcination.

(1) Measure and grind Sb ₂ O ₅ (0.167 g), Bi ₂ O ₃ (0.932 g), NH ₄ Cl (0.054 g) for 10 min, and react in a muffle furnace at 800 °C for 6 h at high temperature for solid-state reaction.

(2) The obtained mixture was ground again for 10 minutes, and then subjected to a high-temperature solid-state reaction at 850°C for 6 hours in a muffle furnace. The main component of the obtained product was BiSbO ₄ . 2 The comparison shows that the Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl could not be obtained by directly mixing and reacting Sb ₂ O ₅ with compounds containing Bi and Cl without high-temperature calcination. Under the same photocatalytic water splitting hydrogen production test conditions as in Examples 1 and 2, no hydrogen generation was detected.

Claims (10)

1. A Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl, characterized in that its microstructure is —Cl—Bi ₂ O ₂ —SbO ₄ —Bi ₂ O ₂ —Cl—, capable of absorbing wavelengths less than 500 nm Visible light and ultraviolet light, and the conduction band position meets the H ₂ /H ⁺ potential requirement. 2. a synthetic method of Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl as claimed in claim 1, is characterized in that, comprises the following steps: (1) Sb ₂ O ₄ and oxides containing Bi and Cl or their salts are ground, and the resulting mixture is subjected to high-temperature solid-state reaction; (2) Continue to grind the reactants obtained in step (1) for a period of time, and carry out high-temperature solid-phase reaction again. 3. The method according to claim 2, characterized in that Sb ₂ O ₄ is prepared by a high-temperature solid-phase method, the steps of which are: grinding Sb ₂ O ₅ for a period of time, and then performing a high-temperature solid-phase reaction to obtain Sb ₂ O ₄ . 4. The method according to claim 3, characterized in that the high-temperature solid-phase reaction conditions are: the calcination temperature is 700-1000ºC, the reaction time is 1h-6h, and the heating rate is 3-7ºC/min. 5. The method as claimed in claim 2, characterized in that, Sb ₂ O ₄ is prepared by hydrothermal method, the steps are: dissolving SbCl ₃ and urea in water, adjusting the pH to 10, and hydrothermally reacting for a period of time to obtain Sb ₂ O ₄ . 6. the method for claim 5, is characterized in that, hydrothermal reaction temperature is 150 ℃, and hydrothermal reaction time is 18h. 7. The method according to claim 2, characterized in that, in step (1), the high-temperature solid-state reaction conditions are: the calcination temperature is 700-900ºC, the reaction time is 1h-20h, and the heating rate is 3-7ºC/ min. 8. The method according to claim 2, characterized in that, in step (2), the high-temperature solid-state reaction conditions are: calcination temperature 800-1000ºC, reaction time 1h-20h, heating rate 3-7 ºC/min . 9 . The method according to claim 2 , characterized in that, in step (2), the high-temperature solid-state reaction is carried out again for 1 to 3 times. 10. Use of the Sillen-Aurivillius layered structure material Bi ₄ SbO ₈ Cl as claimed in claim 1 in splitting water to produce hydrogen.

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