Preparation method and application of ultrathin metal vanadate nanobelt with in-plane microcell heterogeneity

Abstract

The invention provides a preparation method and application of an ultrathin vanadate nanobelt with in-plane microcell heterogeneity, a hydrothermal synthesis method is utilized, Na3VO4 or NH4VO3 and metal chlorides with different molar ratios are used as precursors, different vanadates exist on the same nanobelt, and microcell heterogeneity regulation on the same nanobelt is realized. The method is simple, has general applicability, and has wide application prospects in the aspects of photocatalytic carbon dioxide reduction, benzyl alcohol oxidation, benzylamine coupling and the like.

Description

Technical Field

[0001] The present invention relates to the field of nanomaterials with nanomorphology and controlled synthesis, in particular to nanomaterials with heterostructures, and specifically to a preparation method and application of ultrathin metal vanadate nanoribbons with in-plane heterogeneity. The nanomaterials can be applied in fields such as photocatalytic carbon dioxide reduction. Background Art

[0002] Metal vanadate nanomaterials are promising nanomaterials and have shown high application potential in fields such as heterogeneous catalysis, catalytic organic synthesis, degradation of organic dyes, and electrochemical cells. In recent years, metal vanadate semiconductor photocatalysts such as BiVO4, InVO4, and FeVO4 have been considered potential photocatalytic materials due to their excellent light absorption performance, suitable band gap width, and unique electronic structure, and have been widely studied in aspects such as photocatalytic carbon dioxide reduction, oxidation of benzyl alcohol, and coupling of benzylamine.

[0003] Metal vanadate nanomaterials have rich morphologies, including rod-shaped, cubic, nanotubes, nanoribbons, nanoparticles, nanosheets, etc. The morphology of metal vanadates can be precisely regulated by adjusting factors such as the molar ratio of precursors, concentration of surfactants, pH, hydrothermal reaction temperature, and time. Among them, by precisely regulating the synthesis to construct two-dimensional nanostructures, the specific surface area of the catalyst can be improved, the exposure of catalytic reaction surface active sites can be increased, the adsorption of substrates and the transfer efficiency of carriers can be enhanced, and at the same time, charge migration can be promoted and charge recombination can be inhibited, thereby improving its catalytic performance.

[0004] Constructing heterojunctions and utilizing the energy level differences between multiple components can not only effectively improve the separation and utilization efficiency of carriers, but also provide more suitable active sites for catalytic reactions, which is an important method to enhance catalytic activity. By constructing heterojunctions on two-dimensional metal vanadate nanostructures, not only can the active sites exposed on the catalyst surface be increased, but also the carrier transport pathway can be changed, improving the selectivity of catalytic reactions.

[0005] In the current stage of research, the synthesis methods for constructing heterojunctions in two-dimensional metal vanadate structures are mainly in-situ growth of metal particles or metal oxides directly on two-dimensional metal vanadate structures, or depositing metals on two-dimensional metal vanadate structures at high temperatures by means of metal deposition. The synthesis processes of these methods are relatively complex and cannot achieve precise regulation of heterostructures. Developing a new and universal method for preparing metal vanadates with micro-region heterojunctions has important application value. Summary of the Invention

[0006] In view of the defects existing in the prior art, the present invention provides an ultrathin vanadate nanobelt with in-plane micro-region heterogeneity and a general preparation method thereof. By adjusting the feeding ratio of the precursors, ultrathin vanadate nanobelts with different combinations and adjustable structures and in-plane micro-region heterogeneity can be obtained.

[0007] The present invention provides a new method for preparing an ultrathin vanadate nanobelt with in-plane micro-region heterogeneity. This method has general applicability in the synthesis field of such vanadate two-dimensional nanocomposites. The ultrathin vanadate nanobelt with in-plane micro-region heterogeneity has been widely applied in aspects such as photocatalytic water splitting, carbon dioxide reduction, organic pollutant degradation, and nitrogen reduction.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A preparation method of an ultrathin metal vanadate nanobelt with in-plane micro-region heterogeneity, the preparation method comprising:

[0010] Step 1), adjusting the pH of an aqueous solution of Na3VO4 or NH4VO3 to acidic with nitric acid to obtain a bright orange transparent solution;

[0011] Step 2), adding aqueous solutions of different metal chlorides with a certain molar ratio to the bright orange solution to obtain a transparent solution;

[0012] Step 3), subjecting the transparent solution to a hydrothermal reaction;

[0013] Step 4), cooling the hydrothermal reaction solution to room temperature, centrifuging, and drying to obtain an ultrathin metal vanadate nanobelt with in-plane micro-region heterogeneity.

[0014] Preferably, the concentration of the nitric acid is 1-3 mol / L.

[0015] Preferably, the concentration of the aqueous solution of Na3VO4 or NH4VO3 is 1-2 mmol / L.

[0016] Preferably, the pH is 0.5-7.

[0017] Preferably, the different metal chlorides with a certain molar ratio are two of ErCl3, InCl3, BiCl3, FeCl3, MnCl2, and CuCl2.

[0018] More preferably, the different metal chlorides with a certain molar ratio are ErCl3 / InCl3, BiCl3 / FeCl3, or MnCl2 / CuCl2.

[0019] In the present invention, the addition amounts of Na3VO4 or NH4VO3 and different metal chlorides are based on VO4 of Na3VO4 3-VO3 of NH4VO3 - It is determined with vanadates formed by the valence states of metal ions in different metal chlorides.

[0020] Preferably, the molar ratio of the different metal chlorides in the certain molar ratio is 1:3 to 3:1.

[0021] Preferably, the hydrothermal reaction conditions are as follows: a polytetrafluoroethylene autoclave, the reaction temperature is 180°C, and the reaction time is 18 hours. The reaction temperature and reaction time in the hydrothermal reaction conditions of the present invention can be adjusted as needed.

[0022] Preferably, the centrifugation conditions are: centrifuging for 5 minutes at a rotation speed of 7000 revolutions per minute.

[0023] Preferably, the drying conditions are: freeze-drying for 48 hours.

[0024] The nitric acid in the present invention is used to adjust the pH of the Na3VO4 or NH4VO3 aqueous solution, and its concentration can be selected as needed.

[0025] The length of the ultrathin metal vanadate nanobelt with in-plane micro-region heterogeneity in the present invention is 100 nm - 1000 nm, and the thickness is 0.5 nm - 5 nm.

[0026] A preparation method of an ultrathin metal vanadate nanobelt with in-plane micro-region heterogeneity, the preparation method comprising the following steps:

[0027] Step 1), using an appropriate amount of nitric acid to adjust the pH of the Na3VO4 or NH4VO3 aqueous solution to be acidic to obtain a bright orange transparent solution; adding an aqueous solution of ErCl3 / InCl3 in a certain molar ratio to the bright orange solution to obtain a yellow transparent solution; transferring the yellow solution to a polytetrafluoroethylene autoclave, adjusting the temperature and time; after reacting for a period of time, obtaining an ErVO4 / InVO4 nanobelt with in-plane micro-region heterogeneity.

[0028] Among them, the concentration of the nitric acid is 1 mol / L, and the different molar ratios of ErCl3 / InCl3 can also be other different combinations of metal chlorides, such as metal chlorides such as BiCl3 / FeCl3, MnCl2 / CuCl2, etc. The aqueous solution of ErCl3 / InCl3 with a molar ratio of 3:1 is added to the bright orange solution to obtain a yellow transparent solution, transferred to a polytetrafluoroethylene autoclave at a temperature of 180°C and reacted for 18 hours. After the solution is cooled to room temperature, it is centrifuged for 5 minutes at a rotation speed of 7000 revolutions per minute, and the lower layer precipitate is dried with a freeze dryer for 48 hours to obtain an ErVO4 / InVO4 nanobelt with in-plane micro-region heterogeneity.

[0029] The present invention adjusts the pH of an aqueous solution of Na3VO4 or NH4VO3 to acidic with nitric acid, preferably pH = 1.5. The molar ratio of the aqueous solution of ErCl3 / InCl3 with different molar ratios is preferably ErCl3:InCl3 = 1:3, and the concentration is 0.05 - 0.2 mmol / L. Among them, adjusting the pH of the Na3VO4 aqueous solution to acidic can control the morphology into ultra-thin layered nanoribbons.

[0030] Step 1) of the present invention is to perform micro-region heterojunction regulation on vanadate nanoribbons to obtain ultra-thin metal vanadate nanoribbons with in-plane micro-region heterogeneity.

[0031] Specifically, step 1) includes the following steps:

[0032] Dissolve Na3VO4 or NH4VO3 in water and stir magnetically until clear and transparent to obtain solution a. Then add an appropriate amount of 1 mol / L nitric acid to adjust the pH of solution a to 0.5 - 3 to obtain a bright orange solution b. Dissolve ErCl3 / InCl3 with a molar ratio of 1:3 in 10 mL of water to obtain solution c. Under continuous stirring, add solution c dropwise to solution b to obtain a yellow solution d. Transfer solution d to a polytetrafluoroethylene autoclave, and adjust the reaction temperature and time to 180 °C and 18 hours. After the reaction is completed, wait for the solution temperature to drop to room temperature, centrifuge at a speed of 7000 revolutions per minute for 5 minutes, and dry the lower precipitate in a freeze dryer for 48 hours to obtain ErVO4 / InVO4 nanoribbons with in-plane micro-region heterogeneity.

[0033] In another preferred embodiment of the present invention, an aqueous solution with different molar ratios of BiCl3 / FeCl3 is used, and its preparation includes the following steps:

[0034] Step 1), dissolve Na3VO4 or NH4VO3 in water and stir magnetically until clear and transparent to obtain solution e. Then add an appropriate amount of 1 mol / L nitric acid to adjust the pH of solution a to 1.5 to obtain a bright orange solution f.

[0035] Step 2), dissolve BiCl3 / FeCl3 with a molar ratio of 1:3 in 10 mL of water to obtain solution g.

[0036] Step 3), under continuous stirring, add solution g dropwise to solution f to obtain solution h.

[0037] Step 4), transfer solution h to a polytetrafluoroethylene autoclave, and adjust the reaction temperature and time to 180 °C and 18 h.

[0038] Step 5): After the reaction is completed, wait for the solution temperature to drop to room temperature, centrifuge at a speed of 7000 revolutions per minute for 5 minutes, and dry the lower layer precipitate in a freeze dryer for 48 h to obtain BiVO4 / FeVO4 nanoribbons with in-plane micro-region heterogeneity.

[0039] The ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity prepared by the preparation method described in the present invention have a micro-region heterogeneous structure on the ultrathin metal vanadate nanoribbons. Such micro-region heterogeneous structure semiconductors are preferably ErVO4 / InVO4, BiVO4 / FeVO4, Mn3(VO4)2 / Cu3(VO4)2.

[0040] The length of the ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity described in the present invention is 100 nm - 1000 nm, preferably 200 - 300 nm; the thickness is 0.5 nm - 5 nm, preferably 1.5 nm - 3 nm.

[0041] The ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity described in the present invention have wide application values in photocatalytic water splitting, carbon dioxide reduction, organic pollutant degradation, nitrogen reduction, etc. Moreover, the preparation method described in the present invention is simple to operate, has universal applicability in preparing ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity, is of great significance for synthesizing in-plane heterogeneous nanomaterials, and provides an important basis and material foundation for synthesizing semiconductor-based heterogeneous nanocrystals with in-plane heterogeneous structures.

[0042] The beneficial effects of the present invention are mainly reflected in the following aspects:

[0043] (1) By using Na3VO4 or NH4VO3 and metal chlorides with different molar ratio combinations as precursors and utilizing hydrothermal reactions, ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity are obtained, providing a new choice for the preparation of novel in-plane heterogeneous structure nanocrystals and their applications.

[0044] (2) The prepared ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity accurately adjust the electron transfer path and improve the carrier efficiency, providing a new synthesis path for the preparation of novel heterogeneous structure composite nanomaterials.

[0045] (3) The prepared ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity have controllable morphologies and good crystallinity, and have good application prospects in water splitting, carbon dioxide reduction, environmental remediation, organic synthesis, etc. in the field of heterogeneous photocatalysis. The thickness and micro-region electron tunability of the vanadate nanoribbons enable the present invention to prepare ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity, and the in-plane micro-region heterogeneous metal vanadate semiconductors have good application prospects. Description of the Drawings

[0046] Figure 1 Transmission electron microscope image of ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity prepared in Example 1 of the present invention;

[0047] Figure 2 Corresponding elemental mapping image of ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity prepared in Example 1 of the present invention;

[0048] Figure 3 Transmission electron microscope image of ErVO4 / InVO4 nanobelts prepared in Example 1 of the present invention under the condition of pH = 0.5;

[0049] Figure 4 Transmission electron microscope image of ErVO4 / InVO4 particles prepared in Example 1 of the present invention under the condition of pH = 7;

[0050] Figure 5 Transmission electron microscope image of ultrathin InVO4 nanobelts prepared in Comparative Example 1 of the present invention;

[0051] Figure 6 Transmission electron microscope image of ultrathin ErVO4 nanobelts prepared in Comparative Example 2 of the present invention;

[0052] Figure 7 Photocatalytic carbon dioxide reduction yield diagram of ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity prepared in Example 1 of the present invention;

[0053] Figure 8 Photocatalytic selective oxidation of benzyl alcohol conversion rate diagram of ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity prepared in Example 1 of the present invention;

[0054] Figure 9 Photocatalytic coupling of benzylamine conversion rate diagram of ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity prepared in Example 1 of the present invention. Detailed implementation manners

[0055] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and examples.

[0056] The reagents used in the implementation manners are as follows:

[0057] Sodium orthovanadate (Na3VO4, 99%) was purchased from Beijing MRD Technology Co., Ltd., ammonium metavanadate (NH4VO3, 99%) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., nitric acid (HNO3, 65 - 68%) was purchased from Beijing Tongguang Fine Chemical Co., Ltd., indium chloride (InCl3, 99%) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., erbium chloride (ErCl3, 99%) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., bismuth chloride (BiCl3, 99%) was purchased from Shanghai Merck Chemical Technology Co., Ltd., ferric chloride (FeCl3, 99%) was purchased from Shanghai Merck Chemical Technology Co., Ltd., manganese chloride (MnCl2, 99%) was purchased from Shanghai Merck Chemical Technology Co., Ltd., and copper chloride (CuCl2, 99%) was purchased from Shanghai Merck Chemical Technology Co., Ltd. All reagents were not further purified before use. The above reagents are only raw material reagents used to further illustrate the examples and do not further limit the scope of protection.

[0058] Example 1 Preparation of ErVO4 / InVO4 Nanoribbons with In - plane Micro - region Heterogeneity

[0059] A preparation method of ultrathin metal vanadate nanoribbons with in - plane micro - region heterogeneity, the preparation method comprising:

[0060] Step 1): Dissolve Na3VO4 or NH4VO3 in water, stir with a magnetic stirrer until clear and transparent to obtain solution a, and then add an appropriate amount of 1 mol / L nitric acid to adjust the pH of solution a to 1.5 to obtain a bright orange solution b.

[0061] Step 2): Dissolve 1 mmol of ErCl3 / InCl3 with a molar ratio of 1:3 in 10 mL of water to obtain solution c.

[0062] Step 3): Under continuous stirring, dropwise add solution c into solution b to obtain a yellow solution d.

[0063] Step 4): Transfer solution d to a polytetrafluoroethylene autoclave for reaction, and the reaction temperature and time are 180 °C and 18 hours.

[0064] Step 5): After the reaction is completed, wait for the solution temperature to drop to room temperature, centrifuge at a speed of 7000 revolutions per minute for 5 minutes, and dry the lower - layer precipitate with a freeze - dryer for 48 hours to obtain ErVO4 / InVO4 nanoribbons with in - plane micro - region heterogeneity.

[0065] The transmission electron microscope of the ErVO4 / InVO4 nanoribbons with in - plane micro - region heterogeneity prepared in Example 1 of the present invention is as Figure 1 shown, and the morphology and internal microstructure of the ErVO4 / InVO4 heterojunction can be observed, showing an ultrathin nanoribbon structure;

[0066] The corresponding elemental mapping of the ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity prepared in Example 1 of the present invention is as Figure 2 shown; observing the elemental distribution of the 25% ErVO4 / InVO4 heterojunction clearly shows the uniform dispersion of Er, In, V, and O on the nanobelts;

[0067] Adjust the pH of Example 1 to 0.5 and 7. The transmission electron microscope images of the ErVO4 / InVO4 nanobelts prepared in an environment with pH = 0.5 are as Figure 3 shown. ErVO4 / InVO4 presents the morphology of nanobelts; the transmission electron microscope images of the ErVO4 / InVO4 particles prepared in an environment with pH = 7 show that ErVO4 / InVO4 presents the morphology of nanoparticles;

[0068] Preparation of BiVO4 / FeVO4 nanobelts with in-plane micro-region heterogeneity in Example 2

[0069] A preparation method of ultrathin metal vanadate nanobelts with in-plane micro-region heterogeneity, the preparation method comprising:

[0070] Step 1), Dissolve Na3VO4 or NH4VO3 in water, stir with a magnetic stirrer until clear and transparent to obtain solution a, and then add an appropriate amount of 3 mol / L nitric acid to adjust the pH of solution a to 1.5 to obtain a bright orange solution b.

[0071] Step 2), Dissolve 1 mmol of BiCl3 / FeCl3 with a molar ratio of 1:3 in 10 mL of water to obtain solution c.

[0072] Step 3), Under continuous stirring, dropwise add solution c into solution b to obtain solution d.

[0073] Step 4), Transfer solution d to a polytetrafluoroethylene autoclave for reaction, and the reaction temperature and time are 180 °C and 18 hours.

[0074] Step 5), After the reaction is completed, wait for the solution temperature to drop to room temperature, centrifuge at a speed of 7000 revolutions per minute for 5 minutes, and dry the lower precipitate with a freeze dryer for 48 hours to obtain BiVO4 / FeVO4 nanobelts with in-plane micro-region heterogeneity.

[0075] Preparation of Mn3(VO4)2 / Cu3(VO4)2 nanobelts with in-plane micro-region heterogeneity in Example 3

[0076] A preparation method of ultrathin metal vanadate nanobelts with in-plane micro-region heterogeneity, the preparation method comprising:

[0077] Step 1): Dissolve Na3VO4 or NH4VO3 in water and stir magnetically until clear and transparent to obtain solution a. Then add an appropriate amount of 2 mol / L nitric acid to adjust the pH of solution a to 1.5 to obtain a bright orange solution b.

[0078] Step 2): Dissolve 1 mmol of MnCl2 / CuCl2 with a molar ratio of 1:3 in 10 mL of water to obtain solution c.

[0079] Step 3): While continuously stirring, slowly add solution c dropwise to solution b to obtain solution d.

[0080] Step 4): Transfer solution d to a polytetrafluoroethylene autoclave for reaction, with the reaction temperature and time being 180 °C and 18 hours.

[0081] Step 5): After the reaction is completed, wait for the solution temperature to drop to room temperature, centrifuge at a speed of 7000 revolutions per minute for 5 minutes, and dry the lower layer precipitate in a freeze dryer for 48 hours to obtain Mn3(VO4)2 / Cu3(VO4)2 nanobelts with in-plane micro-region heterogeneity.

[0082] Comparative Example 1 Preparation of ultrathin InVO4 nanobelts

[0083] A preparation method of ultrathin metal vanadate nanobelts, the preparation method comprising:

[0084] Step 1): Use 1 mol / L nitric acid to adjust the pH of the Na3VO4 or NH4VO3 aqueous solution to 1.5 to obtain a bright orange transparent solution. Add the InCl3 aqueous solution (1 mmol / L, 10 mL) to the bright orange solution to obtain a yellow transparent solution. Transfer the yellow solution to a polytetrafluoroethylene autoclave, and adjust the temperature and time. React at a certain temperature for a period of time to obtain ultrathin InVO4 nanobelts.

[0085] The transmission electron microscope image of the ultrathin InVO4 nanobelts prepared in Comparative Example 1 is as Figure 5 shown, and InVO4 presents the morphology of ultrathin nanobelts.

[0086] Comparative Example 2 Preparation of ultrathin ErVO4 nanobelts

[0087] A preparation method of ultrathin metal vanadate nanobelts, the preparation method comprising:

[0088] Step 1): Adjust the pH of an aqueous solution of Na3VO4 or NH4VO3 to 1.5 with 1 mol / L nitric acid to obtain a bright orange transparent solution. Add an aqueous solution of ErCl3 (1 mmol / L, 10 mL) to the bright orange solution to obtain a yellow transparent solution. Transfer the yellow solution to a polytetrafluoroethylene autoclave, and adjust the temperature and time. React at a certain temperature for a period of time to obtain ultrathin ErVO4 nanoribbons.

[0089] The transmission electron microscope image of the ultrathin ErVO4 nanoribbons prepared in Comparative Example 2 is as Figure 6 shown. ErVO4 presents the morphology of ultrathin nanoribbons.

[0090] Preparation of ultrathin BiVO4 nanoribbons in Comparative Example 3

[0091] A method for preparing ultrathin metal vanadate nanoribbons, the preparation method comprising:

[0092] Step 1): Adjust the pH of an aqueous solution of Na3VO4 or NH4VO3 to 1.5 with 1 mol / L nitric acid to obtain a bright orange transparent solution. Add an aqueous solution of BiCl3 (1 mmol / L, 10 mL) to the bright orange solution to obtain a yellow transparent solution. Transfer the yellow solution to a polytetrafluoroethylene autoclave, and adjust the temperature and time. React at a certain temperature for a period of time to obtain ultrathin BiVO4 nanoribbons.

[0093] Preparation of ultrathin FeVO4 nanoribbons in Comparative Example 4

[0094] A method for preparing ultrathin metal vanadate nanoribbons, the preparation method comprising:

[0095] Step 1): Adjust the pH of an aqueous solution of Na3VO4 or NH4VO3 to 1.5 with 1 mol / L nitric acid to obtain a bright orange transparent solution. Add an aqueous solution of FeCl3 (1 mmol / L, 10 mL) to the bright orange solution to obtain a yellow transparent solution. Transfer the yellow solution to a polytetrafluoroethylene autoclave, and adjust the temperature and time. React at a certain temperature for a period of time to obtain ultrathin FeVO4 nanoribbons.

[0096] Preparation of ultrathin Mn3(VO4)2 nanoribbons in Comparative Example 5

[0097] A method for preparing ultrathin metal vanadate nanoribbons, the preparation method comprising:

[0098] Step 1): Adjust the pH of an aqueous solution of Na3VO4 or NH4VO3 to 1.5 with 1 mol / L nitric acid to obtain a bright orange transparent solution. Add an aqueous solution of MnCl2 (1 mmol / L, 10 mL) to the bright orange solution to obtain a yellow transparent solution. Transfer the yellow solution to a polytetrafluoroethylene autoclave, and adjust the temperature and time. React at a certain temperature for a period of time to obtain ultrathin Mn3(VO4)2 nanobelts.

[0099] Comparative Example 6 Preparation of ultrathin Cu3(VO4)2 nanobelts

[0100] A method for preparing ultrathin metal vanadate nanobelts, the preparation method comprising:

[0101] Step 1): Adjust the pH of an aqueous solution of Na3VO4 or NH4VO3 to 1.5 with 1 mol / L nitric acid to obtain a bright orange transparent solution. Add an aqueous solution of CuCl2 (1 mmol / L, 10 mL) to the bright orange solution to obtain a yellow transparent solution. Transfer the yellow solution to a polytetrafluoroethylene autoclave, and adjust the temperature and time. React at a certain temperature for a period of time to obtain ultrathin Cu3(VO4)2 nanobelts.

[0102] Perform photocatalytic carbon dioxide reduction experiments on the products of Example 1, Comparative Example 1, and Comparative Example 2, and their CO production rate diagrams are as Figure 7 shown. It can be seen from the figure that the ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity have a much better CO production rate than ultrathin InVO4 nanobelts and ultrathin ErVO4 nanobelts.

[0103] Perform photocatalytic selective oxidation of benzyl alcohol experiments on the products of Example 1, Comparative Example 1, and Comparative Example 2, and their conversion rates are as Figure 8 shown. It can be seen from the figure that the ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity have a much better conversion rate than ultrathin InVO4 nanobelts and ultrathin ErVO4 nanobelts.

[0104] Perform photocatalytic benzylamine coupling experiments on the products of Example 1, Comparative Example 1, and Comparative Example 2, and their conversion rates are as Figure 9 shown. It can be seen from the figure that the ErVO4 / InVO4 nanobelts with in-plane micro-region heterogeneity have a much better coupling conversion rate than ultrathin InVO4 nanobelts and ultrathin ErVO4 nanobelts.

[0105] Similarly, according to the experimental results of Example 1, Comparative Example 1, and Comparative Example 2, Example 2 and its corresponding Comparative Examples 3-4 were prepared, Example 3 and its corresponding Comparative Examples 5-6 were prepared, and the prepared products were subjected to photocatalytic carbon dioxide reduction experiments, photocatalytic selective oxidation of benzyl alcohol experiments, and photocatalytic benzylamine coupling experiments. The experimental results were similar to those of Example 1, Comparative Example 1, and Comparative Example 2, and all showed that the nanoribbons obtained in Example 2 and Example 3 had far better yields and conversion rates than single vanadate nanoribbons.

[0106] The upper and lower limit values and interval values of the process parameters (such as temperature, time, etc.) of the present invention can all implement this method, and the examples are not listed one by one here.

[0107] The content not detailed in the present invention can all adopt the conventional technical knowledge in the art.

[0108] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A preparation method of ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity, the preparation method comprising: Step 1), adjusting the pH of an aqueous solution of Na3VO4 or NH4VO3 to acidic with nitric acid to obtain a bright orange transparent solution; Step 2), adding aqueous solutions of different metal chlorides in a certain molar ratio to the bright orange solution to obtain a transparent solution; Step 3), subjecting the transparent solution to a hydrothermal reaction; Step 4), cooling the hydrothermal reaction solution to room temperature, centrifuging, and drying to obtain ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity.

2. The preparation method according to claim 1, wherein The concentration of the nitric acid is 1-3 mol / L.

3. The preparation method according to claim 1, characterized in that, The concentration of the aqueous solution of Na3VO4 or NH4VO3 is 1-2 mmol / L.

4. The preparation method according to claim 1, wherein The pH is 0.5-7.

5. The preparation method according to claim 1, characterized in that The different metal chlorides in the certain molar ratio are two of ErCl3, InCl3, BiCl3, FeCl3, MnCl2, and CuCl2.

6. The preparation method according to claim 1, wherein, The molar ratio of the different metal chlorides in the certain molar ratio is 1:3 to 3:

1.

7. The preparation method according to claim 1, wherein The hydrothermal reaction conditions are: a polytetrafluoroethylene autoclave, a reaction temperature of 180 °C, and a reaction time of 18 hours.

8. The preparation method according to claim 1, characterized in that, The length of the ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity is 100-1000 nm, and the thickness is 0.5-5 nm.

9. Use of the ultrathin metal vanadate nanoribbons with in-plane micro-region heterogeneity prepared by the preparation method according to any one of claims 1-8 in photocatalytic carbon dioxide reduction, benzyl alcohol oxidation, and benzylamine coupling.

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