Au@SnO 2-X A SiO2 photocatalyst, a preparation method and applications

Abstract

This invention proposes an Au@SnO 2‑x -SiO2 photocatalyst, preparation method and application. This method uses SiO2 nanospheres as a support and employs an adsorption method to enable Sn... 2+ Adsorbed on SiO2 nanospheres, utilizing Sn 2+ The reducing property of Au@SnO reduces chloroauric acid to gold particles, making Au@SnO 2‑x Au@SnO was obtained by growing on the surface of SiO2 nanospheres. 2‑x -SiO2 composite material. The Au@SnO prepared in this invention... 2‑x The Au@SnO composite material has a larger specific surface area than SiO2 nanomaterials, thus reactants are more easily adsorbed, and electron-hole recombination is effectively suppressed, thereby improving its photocatalytic performance. 2‑x The SiO2 composite material exhibits excellent photocatalytic water splitting and hydrogen production performance under simulated sunlight conditions.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of photocatalysis, and particularly relates to an Au@SnO 2-X -SiO2 photocatalyst, a preparation method and application. BACKGROUND

[0002] Solar energy is a new type of energy that can be taken without exhaustion and used without depletion. The semiconductor photocatalysis technology uses semiconductor oxides as catalysts, can directly use solar energy as driving force to activate the catalysts, and can be used for photocatalytic degradation of pollutants and photocatalytic hydrogen production at room temperature, thereby attracting extensive attention and research of people.

[0003] SnO2 is an environmentally friendly and cheap stable semiconductor metal oxide, has excellent photocatalytic activity, and has wide application prospects in the fields of environmental science and energy. However, the traditional SnO2 photocatalytic efficiency far fails to meet the actual requirements, and the main bottleneck is that the energy conversion efficiency is not high in the photocatalytic process. A key factor restricting the energy conversion efficiency is the separation efficiency of photo-generated carriers. In order to improve the activity of the photocatalyst, the energy band width of the photocatalyst can be regulated and the separation efficiency of the carriers can be improved by means such as loading of noble metals and construction of heterojunction, so as to improve the photocatalytic activity. SUMMARY

[0004] In view of the above situation, the main purpose of the present application is to provide an Au@SnO 2-X -SiO2 photocatalyst, a preparation method and application, to solve the above technical problems.

[0005] The present application provides an Au@SnO 2-X -SiO2 photocatalyst preparation method, the method comprises the following steps:

[0006] Step 1, dissolving SiO2 nanospheres in the first pure water to form a SiO2 nanosphere solution;

[0007] Step 2, dissolving SnF2 with the second pure water to form a SnF2 solution, adding the SnF2 solution into the SiO2 nanosphere solution, and obtaining a first suspension liquid by magnetic stirring, and centrifugal washing the first suspension liquid to obtain a first precipitate;

[0008] Step 3, dispersing the first precipitate into the third pure water to obtain a dispersion liquid, adding a HAuCl4 solution into the dispersion liquid for magnetic stirring to obtain a second suspension liquid;

[0009] Step 4, pouring the second suspension liquid into a centrifuge tube for centrifugal separation to obtain a second precipitate.

[0010] Step 5, the second precipitate is washed with pure water, and then centrifugal washing is carried out, and after washing is completed, drying is carried out, and Au@SnO 2-X -SiO2 composite material is obtained.

[0011] The application provides an Au@SnO 2-X -SiO2 photocatalyst, and the photocatalyst is prepared by the method. 2-X -SiO2 photocatalyst.

[0012] The application further provides an application of the Au@SnO 2-X -SiO2 photocatalyst. 2-X -SiO2 photocatalyst prepared by the method, and the photocatalyst is used for photocatalytic hydrogen evolution.

[0013] Compared with the prior art, the application has the following beneficial effects:

[0014] 1. The application uses SiO2 nanospheres as carriers, and Sn 2+ is adsorbed on the SiO2 nanospheres by using an adsorption method, then the reducibility of Sn 2+ is used to promote the redox reaction between chloroauric acid and Sn 2+ , so that Au@SnO 2-X is grown on the surface of the SiO2 nanospheres, and finally, the Au@SnO 2-X -SiO2 composite material is obtained. The in-situ redox synthesis method used in the application does not need organic solvents or surfactants, the synthesis method is simple, the environment is friendly, the specific surface area of the material is increased, the interface between Au and SnO 2-X is combined closely, the separation of photo-generated carriers is facilitated, and therefore the photocatalytic performance of the material is improved.

[0015] 2. The specific surface area of the Au@SnO 2-X -SiO2 composite material prepared by the application is larger than that of SiO2 nanomaterial, so that reactants are more easily adsorbed, and the recombination of electrons and holes can be well inhibited, and the photocatalytic performance is effectively improved.

[0016] 3. The Au@SnO 2-X -SiO2 composite material prepared by the application has more excellent photocatalytic hydrogen production performance, and the photocatalytic hydrogen production rate is about 2 times that of pure SnO2 under a simulated sunlight light source. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The application discloses SiO2, Sn 2+XRD pattern of Au@SnO 2-X XRD pattern of Au@SnO

[0018] Figure 2 XRD pattern of Au@SnO 2-X SEM pattern of Au@SnO

[0019] Figure 3 XRD pattern of Au@SnO 2-X TEM pattern of Au@SnO

[0020] Figure 4 XRD pattern of Au@SnO 2-X EDS pattern of Au@SnO DETAILED DESCRIPTION

[0021] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like component have the same or similar designations throughout the drawing figures and the detailed description. The embodiments described below are presented by way of example only and are not intended to limit the present application as defined by the appended claims and their equivalents.

[0022] These and other aspects of embodiments of the present application will become apparent from the following description and the accompanying drawings, in which:

[0023] Embodiment 1

[0024] This embodiment proposes a method for preparing Au@SnO 2-X The method comprises the following steps:

[0025] Step 1, 0.2501 g of SiO2nanospheres is dissolved in 100 mL of first pure water to form a SiO2nanosphere solution;

[0026] Step 2, 0.07 g of SnF2is dissolved in 20 mL of second pure water to form a SnF2solution, the SnF2solution is added to the SiO2nanosphere solution, and magnetic stirring is performed for 1 h to obtain a first suspension, the first suspension is centrifuged and washed to obtain a first precipitate;

[0027] Step 3, the first precipitate is dispersed in third pure water to obtain a dispersion liquid, 62 μL of HAuCl4solution with a concentration of 0.02 g / mL is added to the dispersion liquid, and magnetic stirring is performed for 12 h to obtain a second suspension;

[0028] Step 4, pour the second suspension into a centrifuge tube for centrifugal separation to obtain a second precipitate;

[0029] Step 5, wash the second precipitate with pure water, and then centrifugal washing is performed, after the washing is completed, drying is performed at 60°C for 12h to obtain 1%-Au@SnO 2-X -SiO2 composite material.

[0030] Example 2

[0031] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 , the embodiment proposes a preparation method of Au@SnO 2-X -SiO2 photocatalyst, and the method comprises the following steps:

[0032] Step 1, dissolve 0.2501g of SiO2 nanospheres in 100mL of first pure water to form a SiO2 nanosphere solution;

[0033] Step 2, dissolve 0.07g of SnF2 in 20mL of second pure water to form a SnF2 solution, add the SnF2 solution into the SiO2 nanosphere solution, and perform magnetic stirring for 1h to obtain a first suspension, centrifugal washing is performed on the first suspension to obtain a first precipitate;

[0034] Step 3, disperse the first precipitate in third pure water to obtain a dispersion liquid, add 309μL of HAuCl4 solution with a concentration of 0.02g / mL into the dispersion liquid, and perform magnetic stirring for 12h to obtain a second suspension;

[0035] Step 4, pour the second suspension into a centrifuge tube for centrifugal separation to obtain a second precipitate;

[0036] Step 5, wash the second precipitate with pure water, and then centrifugal washing is performed, after the washing is completed, drying is performed at 60°C for 12h to obtain 5%-Au@SnO 2-X -SiO2 composite material.

[0037] Example 3

[0038] The embodiment proposes a Au@SnO 2-X -SiO2 photocatalyst, and the photocatalyst is prepared by using the above preparation method of Au@SnO 2-X -SiO2 photocatalyst.

[0039] Example 4

[0040] This embodiment proposes an Au@SnO 2-X The application of SiO2 photocatalysts utilizes one of the aforementioned Au@SnO... 2-X The photocatalyst prepared by the SiO2 photocatalyst preparation method is used for photocatalytic hydrogen evolution.

[0041] from Figure 1 As can be seen from the X-ray powder diffraction (Cu-Kα target, λ=0.15406 nm; working voltage and current: 40 kV and 40 mA, respectively), the results show that 2θ=26.579° and 51.756° correspond to the (110) and (211) crystal planes of SnO2, respectively; 2θ=24.850°, 29.868°, 33.305° and 47.807° correspond to the (111), (101), (110) and (200) crystal planes of SnO, respectively; and 2θ=38.184° and 44.392° correspond to the (111) and (200) crystal planes of Au, respectively.

[0042] from Figure 2 As can be seen from the SEM image at high magnification, fine particles and octahedral-shaped substances can be observed growing on the surface of the SiO2 nanospheres.

[0043] from Figure 3 As can be seen from this, Au@SnO 2-X In a high-magnification transmission electron microscope image of SiO2 material, Au@SnO 2-X -The octahedral material in SiO2 is composed of many small particles. Through analysis, it can be found that the octahedral material contains Au, SnO2 and SnO. After measurement and calculation, the interplanar spacing of Au, SnO2 and SnO is 0.2322 nm, 0.3205 nm and 0.33 nm respectively, and the corresponding crystal planes are Au (111), SnO2 (110) and SnO (200).

[0044] from Figure 4 In the middle, Au@SnO 2-X -EDS energy dispersive spectroscopy analysis of SiO2 materials shows that Au@SnO 2-X The SiO2 material mainly contains elements such as O, Au, Si and Sn, and the test results are consistent with those of SEM and TEM.

[0045] By observing SEM, TEM, and EDS images, combined with XRD images, it can be inferred that the Au@SnO prepared in Example 2 of this invention... 2-X -SiO2 composite materials contain Au, SnO2, and SnO substances.

[0046] To verify the effectiveness of the present application, Sn 2+ -SiO2 material and Au@SnO 2-X -SiO2 composite material prepared by the present application were carried out. First, Sn 2+ -SiO2 material was prepared as follows:

[0047] 0.2501 g of SiO2 was weighed and put into a 150 mL beaker with 100 mL of pure water. 0.07 g of SnF2 was weighed and dissolved, and then added to the SiO2 solution. The mixture was stirred on a magnetic stirrer for 1 h. The obtained precipitate was dried at 60°C for 12 h to obtain Sn 2+ -SiO2 material, which was collected and dried by a mortar.

[0048] The process of the photocatalytic experiment is as follows:

[0049] 5 mg of the catalyst was weighed and dispersed in 25 mL of aqueous solution, and then 5 mL of a sacrificial agent was added to the reaction bottle. The reaction solution was ultrasonically cleaned in an ultrasonic cleaner to fully disperse the photocatalyst sample in the solution. Before the reaction, the vacuum pump was turned on to remove all the air in the reactor for 20 min. A xenon lamp full waveband was selected as the simulated sunlight light source of the experiment, and the reaction time was 3 h. The hydrogen production of the reaction sample was detected every 1 h.

[0050] Au@SnO 2-X -SiO2 composite material prepared by the present application, Sn 2+ -SiO2 material and pure SnO2 material were respectively subjected to the above photocatalytic experiment, and the hydrogen production rate of the Au@SnO 2-X -SiO2 composite material prepared in Example 1 was 10.17 mmol / g / h, and the hydrogen production rate of the Au@SnO 2-X -SiO2 composite material prepared in Example 2 was 11.34 mmol / g / h, and the hydrogen production rate of Sn 2+ -SiO2 material was 6.18 mmol / g / h, and the hydrogen production rate of SnO2 material was 3.54 mmol / g / h.

[0051] From the above experiments, it can be seen that the 1%-Au@SnO 2-X -SiO2 composite material prepared by the present application has a hydrogen production rate which is obviously higher than that of Sn 2-X -SiO2 material and SnO2 material. 2+ -SiO2 material and SnO2 material.

[0052] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0053] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but cannot be understood as a limitation on the patent scope of the present application. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. Au@SnO 2-X A method for preparing an Au@SnO The method comprises the following steps: Step 1, 0.2501g of SiO2 nanospheres is dissolved in 100mL of first pure water to form a SiO2 nanosphere solution; Step 2, 0.07g of SnF2 is dissolved in 20mL of second pure water to form a SnF2 solution, the SnF2 solution is added to the SiO2 nanosphere solution, and magnetic stirring is carried out for 1h to obtain a first suspension, the first suspension is centrifuged and washed to obtain a first precipitate; Step 3, the first precipitate is dispersed in third pure water to obtain a dispersion, 309μL of HAuCl4 solution with a concentration of 0.02g / mL is added to the dispersion, and magnetic stirring is carried out for 12h to obtain a second suspension; Step 4, the second suspension is poured into a centrifuge tube and centrifuged to obtain a second precipitate; Step 5, the second precipitate is washed with pure water, and then centrifuged and washed. After washing, the second precipitate is dried at 60°C for 12h to obtain 5%-Au@SnO 2-X -SiO2 composite material; The SiO2 nanospheres have fine particulate matter on the surface, and octahedral-shaped matter is grown on the surface of the SiO2 nanospheres, and the octahedral-shaped matter contains Au, SnO2 and SnO.

2. An Au@SnO 2-X -SiO2 photocatalyst characterized by, The photocatalyst is prepared by the method of claim 1 2-X -SiO2 photocatalyst.

3. Au@SnO 2-X -SiO2 photocatalyst, the Au@SnO 2-X -SiO2 photocatalyst prepared by the method of claim 1, characterized in that, The photocatalyst is used for photocatalytic hydrogen evolution.

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