Bi/Bi2SiO5Preparation method and application of photocatalyst
阅读说明：本技术 一种Bi/Bi2SiO5光催化剂的制备方法及其应用 (Bi/Bi2SiO5Preparation method and application of photocatalyst ) 是由 张小超 官修帅 任广敏 张长明 李�瑞 王韵芳 樊彩梅 于 2019-09-20 设计创作，主要内容包括：一种Bi/Bi_2SiO_5光催化剂的制备方法及其应用,属于Bi/Bi基光催化材料复合体系的可控制备、CO_2还原资源化转化利用、人工光合成领域,可解决Bi_2SiO_5光响应范围较窄和光生电子-空穴复合率较高等问题,以Bi(NO_3)_3·5H_2O和Na_2SiO_3·9H_2O为铋源和硅源,乙二醇和去离子水为溶剂,NaOH溶液为pH值调节剂,利用一步水热法,通过调控NaOH溶液浓度调节反应溶液的pH值在9～14,均可得到高纯度Bi/Bi_2SiO_5光催化剂,最终提高Bi_2SiO_5光催化还原CO_2活性、选择性和稳定性,为高效新型单质Bi/Bi基光催化材料复合体系的制备提供新方法和新应用。(Bi/Bi 2 SiO 5 A preparation method and application of a photocatalyst, belonging to the controllable preparation of a Bi/Bi-based photocatalytic material composite system and CO 2 The field of reduction resource conversion utilization and artificial photosynthesis, and can solve the problem of Bi 2 SiO 5 The problems of narrow photoresponse range, high photogenerated electron-hole recombination rate and the like are solved by using Bi (NO) 3 ) 3 ·5H 2 O and Na 2 SiO 3 ·9H 2 O is a bismuth source and a silicon source, ethylene glycol and deionized water are used as solvents, a NaOH solution is a pH value regulator, a one-step hydrothermal method is utilized, the concentration of the NaOH solution is regulated to regulate the pH value of the reaction solution to 9-14, and high-purity Bi/Bi can be obtained 2 SiO 5 Photocatalyst for finally increasing Bi 2 SiO 5 Photocatalytic reduction of CO 2 Activity, selectivity and stability, and provides preparation of a novel high-efficiency simple substance Bi/Bi-based photocatalytic material composite systemNovel methods and novel applications.)
1. Bi/Bi2SiO5The preparation method of the photocatalyst is characterized by comprising the following steps: with Bi (NO)3)3·5H2O and Na2SiO3·9H2O is a bismuth source and a silicon source, ethylene glycol and deionized water are used as solvents, a NaOH solution is a pH value regulator, a one-step hydrothermal method is utilized, the concentration of the NaOH solution is regulated to regulate the pH value of the reaction solution to 9-14, and high-purity Bi/Bi can be obtained2SiO5A photocatalyst.
2. The Bi/Bi composition of claim 12SiO5The preparation method of the photocatalyst is characterized by comprising the following steps: the method comprises the following steps:
firstly, weighing Bi (NO) according to the molar ratio of 2: 1-4: 13)3·5H2O and Na2SiO3 ·9H2Dissolving O in ethylene glycol and deionized water with equal volumes respectively, stirring for 0.5-2 h to form solutions A and B respectively, mixing the solutions A and B with equal volumes, and stirring for 1-3 h to form a white suspension C;
and secondly, dripping 1 mol/L NaOH solution into the suspension C to adjust the pH of the solution to be = 9-14, transferring the reaction solution into a 100-500 mL reaction kettle, reacting for 6-12 h at 150-200 ℃, taking out the reaction kettle, cooling to room temperature, performing centrifugal separation, washing the precipitate for 3 times with deionized water and absolute ethyl alcohol respectively, collecting the precipitate, and drying in an oven at 80 ℃ for 12 h to obtain the Bi/Bi2SiO5A photocatalyst.
3. The Bi/Bi composition of claim 22SiO5The preparation method of the photocatalyst is characterized in that the volumes of the ethylene glycol and the deionized water in the first step are both 50 ~ 200 mL.
4. The Bi/Bi composition of claim 22SiO5The preparation method of the photocatalyst is characterized in that the volumes of the solution A and the solution B in the first step are both 20 ~ 200 mL.
5. Bi/Bi2SiO5Application of photocatalyst to light-driven CO2Reducing to CO.
Technical Field
The invention belongs to controllable preparation of a Bi/Bi-based photocatalytic material composite system and CO2The fields of reduction resource conversion utilization and artificial photosynthesis, in particular to Bi/Bi2SiO5A preparation method of the photocatalyst and application thereof.
Background
Since the 21 st century, urgent calls for CO control have been made in spite of united nations and global climate specialists2Discharge of, but global CO2The emission amount still creates historical new height in 2018, and the use amount of the global fossil fuel is predicted to be increased by 2.7% in 2019 compared with 2018. Visible, CO2The emission amount is gradually increased, and the generated energy crisis, environmental problems and the like are more and more emphasized. Among them, how to efficiently utilize renewable energy solar energy to realize CO2Resource green is converted into high value-added solar fuel (such as CO and CH)4Or CH3OH, etc.) has become one of the hot spots of interest to researchers.
In recent years, Bi-based semiconductor materials have exhibited advantages such as unique electronic structures and excellent photo-corrosion resistance photocatalytic performance. Wherein, Bi2SiO5Belongs to the Aurivillius family of compounds consisting of [ Bi2O2］2+ Layer and SiO3 2-The layer structure formed by the layers alternately growing along the C-axis direction has good chemical stability, dielectricity and voltage property, and is favored by researchers. At present, to solve Bi2SiO5The problems of narrow photoresponse range, high photogenerated electron-hole recombination rate and the like are solved, and the visible light response and the catalytic performance of the material are improved by adopting methods such as element doping, precious metal deposition, heterojunction construction and the like. For example, silicon [Appl. Surf. Sci., 2011, 257(13): 5571-5575"carbon quantum dots" [Chem. Eng. J., 2016, 302: 334-343Semiconductor [ 1 ]Appl. Cataly. B: Environ., 2018, 236: 205-211Bi modified2SiO5Effective liftingSeparation effect of high charge, broadening of Bi2SiO5Spectral response range. Wherein the deposition of noble metals (Au, Pt, etc.) is to improve Bi2SiO5A range of photoresponse and an efficient method of transferring the ability of photogenerated electrons. It has been found that when noble metals are added to the material, free electrons in the conductive material vibrate collectively under illumination to produce a plasmon resonance effect. The plasma resonance effect can widen the spectral response range and increase the separation efficiency of photo-generated electrons and holes. However, the introduction of the hetero-elements makes the reaction process complicated, the structure, morphology, properties, etc. of the material may be greatly changed, the stability of the sample may be greatly affected, and the noble metal has high cost, which is greatly limited in practical application.
The invention provides a self-doping method to construct Bi/Bi2SiO5The system not only solves the complex problem of the hetero-group elements, but also enables Bi and Bi to be equivalent to noble metal2SiO5The surface plasma resonance effect is formed, and the 'one stone two birds' effect is achieved, so that the method has obvious innovation significance and practical value.
Disclosure of Invention
The present invention is directed to Bi2SiO5The problems of narrow photoresponse range, high photoproduction electron-hole recombination rate and the like are solved, and the Bi/Bi is provided2SiO5Preparation method and application of photocatalyst prepared from Bi (NO)3)3·5H2O and Na2SiO3·9H2O is a bismuth source and a silicon source, ethylene glycol and deionized water are used as solvents, a NaOH solution is a pH value regulator, a one-step hydrothermal method is utilized, the concentration of the NaOH solution is regulated to regulate the pH value of the reaction solution to 9-14, and high-purity Bi/Bi can be obtained2SiO5The photocatalyst has different Bi simple substance precipitation amount along with the change of pH value. Combined with photocatalytic CO2In the application field of green conversion, the Bi simple substance plays a 'one stone two birds' effect, is equivalent to the formation of plasma resonance effect of noble metal so as to widen the spectral response range, increases the reduction potential, improves the photoproduction electron-hole separation efficiency and finally improves the Bi2SiO5Photocatalytic reduction of CO2Activity, selectivity and stabilityProvides a new method and a new application for the preparation of a high-efficiency novel elementary substance Bi/Bi-based photocatalytic material composite system.
The invention adopts the following technical scheme:
Bi/Bi2SiO5Method for preparing photocatalyst from Bi (NO)3)3·5H2O and Na2SiO3·9H2O is a bismuth source and a silicon source, ethylene glycol and deionized water are used as solvents, a NaOH solution is a pH value regulator, a one-step hydrothermal method is utilized, the concentration of the NaOH solution is regulated to regulate the pH value of the reaction solution to 9-14, and high-purity Bi/Bi can be obtained2SiO5A photocatalyst.
Bi/Bi2SiO5The preparation method of the photocatalyst comprises the following steps:
firstly, weighing Bi (NO) according to the molar ratio of 2: 1-4: 13)3·5H2O and Na2SiO3 ·9H2Dissolving O in ethylene glycol and deionized water with equal volumes respectively, stirring for 0.5-2 h to form solutions A and B respectively, mixing the solutions A and B with equal volumes, and stirring for 1-3 h to form a white suspension C;
and secondly, dripping 1 mol/L NaOH solution into the suspension C to adjust the pH of the solution to be = 9-14, transferring the reaction solution into a 100-500 mL reaction kettle, reacting for 6-12 h at 150-200 ℃, taking out the reaction kettle, cooling to room temperature, performing centrifugal separation, washing the precipitate for 3 times with deionized water and absolute ethyl alcohol respectively, collecting the precipitate, and drying in an oven at 80 ℃ for 12 h to obtain the Bi/Bi2SiO5A photocatalyst.
The volumes of ethylene glycol and deionized water in the first step were 50 ~ 200mL each.
The volumes of solution A and solution B in the first step were both 20 ~ 200 mL.
Bi/Bi2SiO5Application of photocatalyst to light-driven CO2Reducing to CO.
The invention has the following beneficial effects:
1. Bi/Bi2SiO5the preparation method is simple and easy to control,NaOH solution can regulate and control the precipitation amount of Bi simple substance and light-drive CO2The capability is excellent, the process is environment-friendly, and harmful byproducts are not generated;
2. Bi/Bi2SiO5the 'one stone two birds' efficacy characteristic of the Bi simple substance in the system is outstanding, and the activity stability is ensured while the precious metal is replaced;
3. for the first time, the self-doping of Bi into Bi is realized2SiO5System and application for photo-reduction of CO2The method can provide a new method and a new application for preparing a novel elementary substance Bi/Bi-based photocatalytic material composite system with high efficiency, and has potential value for environmental management and green energy utilization. Under the irradiation of different light sources (ultraviolet light, visible light and simulated sunlight), light drives CO2Excellent performance of reducing into CO (CO yield is 21-110.2 mu mol g)-1·h-1) Has good photocatalytic CO2The application prospect of reduction is achieved, and the purpose of realizing CO by utilizing renewable energy sources is achieved2The purpose of resource green conversion.
Drawings
FIG. 1 shows Bi/Bi prepared in example 1 of the present invention2SiO5An X-ray diffraction (XRD) pattern of the photocatalyst;
FIG. 2 shows Bi/Bi prepared in example 1 of the present invention2SiO5An X-ray diffraction (XRD) pattern of the photocatalyst;
FIG. 3 shows Bi/Bi prepared in example 1 of the present invention2SiO5An X-ray diffraction (XRD) pattern of the photocatalyst;
FIG. 4 shows Bi/Bi prepared in examples 1 to 3 of the present invention2SiO5Photocatalyst for photo-reduction of CO2The performance test is carried out on a CO yield histogram under the irradiation of visible light, ultraviolet light and simulated sunlight.
Detailed Description
Bi/Bi2SiO5The preparation method of the photocatalyst comprises the following steps:
firstly, weighing Bi (NO) according to the molar ratio of 2: 1-4: 13)3·5H2O and Na2SiO3 ·9H2O, dissolved in equal volumes of ethylene glycol and deionised, respectivelyStirring in water for 0.5-2 h to form solutions A and B respectively, mixing the solutions A and B with equal volume, and stirring for 1-3 h to form a white suspension C;
and secondly, dripping 1 mol/L NaOH solution into the suspension C to adjust the pH of the solution to be = 9-14, transferring the reaction solution into a 100-500 mL reaction kettle, reacting for 6-12 h at 150-200 ℃, taking out the reaction kettle, cooling to room temperature, performing centrifugal separation, washing the precipitate for 3 times with deionized water and absolute ethyl alcohol respectively, collecting the precipitate, and drying in an oven at 80 ℃ for 12 h to obtain the Bi/Bi2SiO5A photocatalyst.
All the medicine reagents used in the embodiment of the invention are analytically pure.