Nickel-copper ion double-doped modified bismuth tungstate self-supporting photoelectric catalytic material as well as preparation method and application thereof
By modifying bismuth tungstate self-supporting photocatalytic material with nickel-copper ion dual doping, the problem of low separation efficiency of photogenerated carriers was solved, and high-efficiency photocatalytic performance in alkaline electrolyte was achieved.
Patent Information
- Application Number
- CN202510953660.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-11-25
AI Technical Summary
Existing bismuth tungstate photocatalysts have low efficiency in the separation and transport of photogenerated carriers, resulting in poor photoelectrocatalytic performance, especially in alkaline electrolytes.
A NiCu-BWO/NF composite material was prepared by using nickel-copper ion-doped modified bismuth tungstate self-supporting photoelectrocatalytic material and liquid-phase thermal impregnation method to control the band structure and optimize the surface active sites. At the same time, the material morphology was controlled by the soft template method to form ultrathin nanosheets, increasing the specific surface area, and the three-dimensional porous structure of nickel foam was used to accelerate charge transport.
The carrier separation efficiency was enhanced, the surface active sites were optimized, and the photoelectrocatalytic performance of the material in alkaline electrolyte was improved.
Smart Images
Figure CN121006572A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of functional materials, and relates to a photoelectrocatalytic material, in particular to a nickel-copper ion double-doped modified bismuth tungstate self-supporting photoelectrocatalytic material and a preparation method and application thereof. BACKGROUND
[0002] Photoelectrocatalytic water splitting technology drives water splitting to produce hydrogen by directly utilizing solar energy, avoids the intermediate energy conversion loss of traditional water electrolysis hydrogen production, and is an ideal path for green hydrogen production, but faces many challenges in practical application. For example, the photoabsorption range of the catalytic material is limited, the stability is insufficient, the carrier recombination is serious, the overpotential of the hydrogen evolution and oxygen evolution reaction is high, and the active sites are insufficient.
[0003] Bismuth tungstate (Bi2WO6) is a typical Aurivillius oxide. Due to its unique "sandwich" crystal structure, it has a natural two-dimensional electronic potential barrier. Due to its suitable band gap (2.6-2.8 eV) and strong piezoelectricity, it has been proved to be an excellent photocatalyst. Bi2WO6 is composed of bismuth (Bi), tungsten (W) and oxygen (O), and its unique structure and physical and chemical properties have attracted great interest, and its dimensional morphology is closely related to the physical structure and shape. At room temperature, it has an orthorhombic structure, called L phase, which is composed of alternating [Bi2O2] 2+ layers and [WO4] 2- layers. Bi2WO6 is a medium-temperature orthorhombic phase with high symmetry, and the space group is B2cb, but the connectivity is similar to that of the low-temperature orthorhombic phase. However, the efficient separation and transport of photo-generated carriers (electron-hole pairs) are the key to achieving high-efficiency photoelectrocatalysis, and the performance of pure Bi2WO6 is not satisfactory due to the recombination of electrons and holes. SUMMARY
[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a nickel-copper ion double-doped modified bismuth tungstate self-supporting photoelectrocatalytic material and a preparation method and application thereof. The catalytic material enhances the carrier separation efficiency while optimizing the surface active sites, and exhibits good photoelectrocatalytic performance in an alkaline electrolyte.
[0005] In order to achieve the above-mentioned purpose, the following technical solutions are adopted:
[0006] A preparation method of a nickel-copper ion double-doped modified bismuth tungstate self-supporting photoelectrocatalytic material, comprising the following steps:
[0007] Step one, weigh 0.1-2 mol of bismuth nitrate pentahydrate, 0.1-2 mmol of copper chloride and 0.1-2 mmol of nickel chloride into 50 mL of deionized water, and stir uniformly to form a solution A;
[0008] Step two, adjust the pH to 3-5 by adding dilute hydrochloric acid to solution A, then add 0.1-0.5g polyvinylpyrrolidone and stir to form solution B;
[0009] Step three, weigh 0.1-2mol sodium tungstate and add to 50mL of deionized water and stir to form solution C;
[0010] Step four, mix equal volumes of solution B and solution C into a polytetrafluoroethylene-lined high-pressure reaction kettle, place the sealed reaction kettle into a homogeneous hydrothermal reactor, set the temperature parameter to 150-220℃, and the reaction time to 10-20h, after the reaction is completed, cool to room temperature, and then filter, wash and dry the final reaction product, and then grind to obtain nickel-copper ion double-doped modified bismuth tungstate powder;
[0011] Step five, disperse 1-5g of nickel-copper ion double-doped modified bismuth tungstate powder in 120mL of isopropanol solution to obtain a NiCu-BWO-containing isopropanol solution, then heat to 100-150℃ in a muffle furnace, completely immerse the nickel foam into the NiCu-BWO-containing isopropanol solution for 10s, then take it out and dry, repeat the immersion ten times, and then dry to form a NiCu-BWO photoanode self-supporting catalyst stably on the surface of the nickel foam.
[0012] Preferably, the stirring in steps one, two and three is performed using a magnetic stirrer for 10-30min.
[0013] Preferably, the concentration of the dilute hydrochloric acid in step two is 1-3M.
[0014] Preferably, the volume filling ratio of the lining of the high-pressure reaction kettle in step four is 40%-60%.
[0015] Preferably, the filter washing in step four is performed using deionized water for 3-5 times.
[0016] Preferably, the drying in steps four and five is performed by placing in a 40-70℃ vacuum oven or freeze-drying oven for 12-24h.
[0017] Preferably, the grinding in step four is performed in a mortar for 15-30min.
[0018] The application also protects a nickel-copper ion double-doped modified bismuth tungstate self-supporting photoelectrocatalytic material prepared using the above method and its application as a photoelectrocatalytic photoanode in an alkaline electrolyte.
[0019] Compared with the prior art, the application has the following technical effects:
[0020] This invention first prepares a NiCu-BWO material with good crystallinity, and then prepares a NiCu-BWO / NF composite material by liquid-phase hot impregnation method; Ni 2+ and Cu 2+ Doping is incorporated into the Bi2WO6 (BWO) lattice, replacing Bi. 3+ Doping creates impurity energy levels, modulates the band structure of the BWO (Block Wire Oxide), narrows the band gap, thereby enhancing carrier separation efficiency. Simultaneously, it optimizes surface active sites, promoting visible light absorption. The defect states introduced by doping can act as electron traps, suppressing electrons. - -h + Furthermore, the microstructure of BWO was controlled using PVP via a soft template method. PVP selectively adsorbed onto specific crystal planes of BWO, inducing anisotropic growth to form ultrathin nanosheets, increasing the specific surface area. By controlling the content of each precursor, reaction temperature, and reaction time, the size of the product and the content of oxygen vacancies in the product could be well controlled. Finally, NiCu-BWO material was loaded onto NF. The three-dimensional porous structure of NF provided a highly conductive substrate, accelerating charge transport. The resulting NiCu-BWO / NF photocatalyst exhibited good photocatalytic performance in alkaline electrolyte. Attached Figure Description
[0021] Figure 1 The XRD pattern of NiCu-BWO prepared in Example 1;
[0022] Figure 2 SEM image of NiCu-BWO prepared in Example 1;
[0023] Figure 3 The image shows the photoelectrocatalytic performance of NiCu-BWO prepared in Example 1. Detailed Implementation
[0024] The specific content of the present invention will be further explained in detail below with reference to the embodiments.
[0025] The polyvinylpyrrolidone (PVP) used in the following examples is produced by Aladdin, CAS No.: 9003-39-8, catalog number P110607-100g, average molecular weight 58000, K29-32.
[0026] Example 1:
[0027] This embodiment provides a method for preparing a nickel-copper ion-doped modified bismuth tungstate self-supporting photocatalytic material, including the following steps:
[0028] Step 1: Weigh 1 mol of bismuth nitrate pentahydrate, 0.5 mmol of copper chloride and 0.5 mmol of nickel chloride and add them to 50 mL of deionized water. Stir with a magnetic stirrer for 30 min until a homogeneous solution A is formed.
[0029] Step 2: Add 2M dilute hydrochloric acid to solution A to adjust the pH to 4, then add 0.25g of polyvinylpyrrolidone and stir with a magnetic stirrer for 30 minutes until a homogeneous solution B is formed.
[0030] Step 3: Weigh 1 mol of sodium tungstate and add it to 50 mL of deionized water, and stir with a magnetic stirrer for 30 min until a homogeneous solution C is formed;
[0031] Step 4: Mix equal volumes of solutions B and C and load them into a polytetrafluoroethylene-lined high-pressure reactor with a filling ratio of 50%. Place the sealed reactor into a homogeneous hydrothermal reactor, set the temperature parameters to 190℃, and the reaction time to 12h. After the reaction is completed, cool to room temperature, filter and wash the final reactant with deionized water 5 times, dry it in a freeze dryer for 24h, and then grind it to obtain nickel-copper ion-doped modified bismuth tungstate powder.
[0032] Step 5: Disperse 3g of nickel-copper ion-doped modified bismuth tungstate powder in 120mL of isopropanol solution to obtain an isopropanol solution containing NiCu-BWO. Then heat it to 120℃ in a muffle furnace, completely immerse the nickel foam in the isopropanol solution containing NiCu-BWO for 10s, remove it and air dry it. Repeat the immersion ten times and then put it in a vacuum oven at 40℃ to dry for 24h to form a stable NiCu-BWO photoanode self-supporting catalyst on the surface of the nickel foam.
[0033] Figure 1 The XRD pattern of NiCu-BWO prepared in Example 1 is shown below; Figure 1 As shown, the XRD pattern of NiCu-BWO powder corresponds to the standard diffraction data of BiWO in PDF#39-0256, indicating that nickel-copper co-doped bismuth tungstate (NiCu-BWO) was successfully prepared.
[0034] Figure 2 SEM images of NiCu-BWO prepared in Example 1; from Figure 2As can be seen in the image, NiCu-BWO exhibits a distinct lamellar, flower-like, or hierarchical structure, with the lamellar layers interlacing and assembling. This morphology is beneficial for increasing the specific surface area. The image scale bar is 1.00 μm, indicating that the lamellar structures constituting the material are at the submicron scale. The material as a whole is a micron-sized aggregate, but composed of nano- or submicron-sized basic units. A large specific surface area can provide more active sites in catalytic applications, promoting the reaction. The co-doping of Ni and Cu did not induce significant macroscopic phase separation (no obvious independent particles of other phases were observed in the image), suggesting that the dopant elements may be well integrated into the bismuth tungstate lattice or uniformly distributed in the material system, playing a role in the construction of the microstructure and possibly influencing the crystal growth habit, thus promoting the formation and assembly of lamellar structures. This multi-level, lamellar stacked structure, with its large specific surface area, is beneficial for substrate adsorption and photogenerated carrier separation during photoelectrocatalysis.
[0035] Figure 3 The image shows the photoelectrocatalytic performance of NiCu-BWO prepared in Example 1. In a conventional three-electrode system (nickel-copper double-doped bismuth tungstate / nickel foam electrode as the working electrode, mercury / mercuric oxide electrode as the reference electrode, and platinum sheet electrode as the counter electrode), the electrolyte was a buffer solution prepared with sodium tetraborate (pH = 9.5). The photocurrent density-voltage (JV) curve was measured using a photoelectrochemical testing system (PEC2000, Pofilai). Figure 3 As shown, the current density first increases and then decreases as the potential increases from 0.6V to 1.2V (vs. RHE). In the low potential range (around 0.6-1.0V), the current density gradually increases, indicating that the electrode reactivity is enhanced with the increase of the applied potential, and more charges participate in the redox process. As the potential continues to rise (after about 1.0V), the current density reaches its peak and then falls back, which may be due to changes in reaction kinetics or electrode surface state (such as oxidation of active sites or changes in the adsorption / desorption balance of intermediate products).
[0036] Example 2
[0037] This embodiment provides a method for preparing a nickel-copper ion-doped modified bismuth tungstate self-supporting photocatalytic material, including the following steps:
[0038] Step 1: Weigh 2 mol of bismuth nitrate pentahydrate, 0.2 mmol of copper chloride and 0.2 mmol of nickel chloride and add them to 50 mL of deionized water. Stir with a magnetic stirrer for 20 min until a homogeneous solution A is formed.
[0039] Step 2: Add 3M dilute hydrochloric acid to solution A to adjust the pH to 3, then add 0.1g of polyvinylpyrrolidone and stir with a magnetic stirrer for 20 minutes until a homogeneous solution B is formed.
[0040] Step 3: Weigh 2 mol of sodium tungstate and add it to 50 mL of deionized water, and stir with a magnetic stirrer for 20 min until a homogeneous solution C is formed;
[0041] Step 4: Mix equal volumes of solutions B and C and load them into a polytetrafluoroethylene-lined high-pressure reactor with a filling ratio of 60%. Place the sealed reactor into a homogeneous hydrothermal reactor, set the temperature parameters to 220℃, and the reaction time to 10h. After the reaction is completed, cool to room temperature, filter and wash the final reactant with deionized water 4 times, dry it in a 40℃ vacuum oven for 24h, and then grind it to obtain nickel-copper ion-doped modified bismuth tungstate powder.
[0042] Step 5: Disperse 1g of nickel-copper ion-doped modified bismuth tungstate powder in 120mL of isopropanol solution to obtain an isopropanol solution containing NiCu-BWO. Then heat it to 150℃ in a muffle furnace, completely immerse the nickel foam in the isopropanol solution containing NiCu-BWO for 10s, remove it and air dry it. Repeat the immersion ten times and then put it in a vacuum oven at 70℃ for 12h to form a stable NiCu-BWO photoanode self-supporting catalyst on the surface of the nickel foam.
[0043] Example 3:
[0044] This embodiment provides a method for preparing a nickel-copper ion-doped modified bismuth tungstate self-supporting photocatalytic material, including the following steps:
[0045] Step 1: Weigh 0.1 mol bismuth nitrate pentahydrate, 0.1 mmol copper chloride and 0.1 mmol nickel chloride and add them to 50 mL of deionized water. Stir with a magnetic stirrer for 10 min until a homogeneous solution A is formed.
[0046] Step 2: Add 1M dilute hydrochloric acid to solution A to adjust the pH to 5, then add 0.5g of polyvinylpyrrolidone and stir with a magnetic stirrer for 10 minutes until a homogeneous solution B is formed.
[0047] Step 3: Weigh 0.1 mol of sodium tungstate and add it to 50 mL of deionized water, and stir with a magnetic stirrer for 10 min until a homogeneous solution C is formed;
[0048] Step 4: Mix equal volumes of solutions B and C and load them into a polytetrafluoroethylene-lined high-pressure reactor with a filling ratio of 40%. Place the sealed reactor into a homogeneous hydrothermal reactor, set the temperature parameters to 150℃, and the reaction time to 20h. After the reaction is completed, cool to room temperature, filter and wash the final reactant three times with deionized water, dry it in a 70℃ vacuum oven for 12h, and then grind it to obtain nickel-copper ion-doped modified bismuth tungstate powder.
[0049] Step 5: Disperse 5g of nickel-copper ion-doped modified bismuth tungstate powder in 120mL of isopropanol solution to obtain an isopropanol solution containing NiCu-BWO. Then heat it to 100℃ in a muffle furnace, completely immerse the nickel foam in the isopropanol solution containing NiCu-BWO for 10s, remove it and air dry it. Repeat the immersion ten times and then put it in a vacuum oven at 60℃ to dry for 15h to form a stable NiCu-BWO photoanode self-supporting catalyst on the surface of the nickel foam.
[0050] Example 4:
[0051] This embodiment provides a method for preparing a nickel-copper ion-doped modified bismuth tungstate self-supporting photocatalytic material, including the following steps:
[0052] Step 1: Weigh 2 mol of bismuth nitrate pentahydrate, 2 mmol of copper chloride and 2 mmol of nickel chloride and add them to 50 mL of deionized water. Stir with a magnetic stirrer for 30 min until a homogeneous solution A is formed.
[0053] Step 2: Add 3M dilute hydrochloric acid to solution A to adjust the pH to 5, then add 0.4g of polyvinylpyrrolidone and stir with a magnetic stirrer for 30 minutes until a homogeneous solution B is formed.
[0054] Step 3: Weigh 0.5 mol of sodium tungstate and add it to 50 mL of deionized water, and stir with a magnetic stirrer for 30 min until a homogeneous solution C is formed;
[0055] Step 4: Mix equal volumes of solutions B and C and load them into a polytetrafluoroethylene-lined high-pressure reactor with a filling ratio of 60%. Place the sealed reactor into a homogeneous hydrothermal reactor, set the temperature parameters to 180℃, and the reaction time to 16h. After the reaction is completed, cool to room temperature, filter and wash the final reactant five times with deionized water, dry it in a 40℃ vacuum oven for 15h, and then grind it to obtain nickel-copper ion-doped modified bismuth tungstate powder.
[0056] Step 5: Disperse 4g of nickel-copper ion-doped modified bismuth tungstate powder in 120mL of isopropanol solution to obtain an isopropanol solution containing NiCu-BWO. Then heat it to 150℃ in a muffle furnace, completely immerse the nickel foam in the isopropanol solution containing NiCu-BWO for 10s, remove it and air dry it. Repeat the immersion ten times and then put it in a vacuum oven at 60℃ for 15h to form a stable NiCu-BWO photoanode self-supporting catalyst on the surface of the nickel foam.
Claims
1. A method for preparing a nickel-copper ion-doped modified bismuth tungstate self-supporting photocatalytic material, characterized in that, Includes the following steps: Step 1: Weigh 0.1–2 mol of bismuth nitrate pentahydrate, 0.1–2 mmol of copper chloride and 0.1–2 mmol of nickel chloride and add them to 50 mL of deionized water, and stir well to form solution A; Step 2: Add dilute hydrochloric acid to solution A to adjust the pH to 3-5, then add 0.1-0.5g of polyvinylpyrrolidone and stir well to form solution B; Step 3: Weigh 0.1–2 mol of sodium tungstate and add it to 50 mL of deionized water, and stir until homogeneous to form solution C; Step 4: Mix equal volumes of solutions B and C and load them into a polytetrafluoroethylene-lined high-pressure reactor. Place the sealed reactor into a homogeneous hydrothermal reactor and set the temperature parameters to 150–220°C and the reaction time to 10–20 h. After the reaction is completed, cool to room temperature, filter, wash, dry, and grind the final reactant to obtain nickel-copper ion-doped modified bismuth tungstate powder. Step 5: Disperse 1-5g of nickel-copper ion-doped modified bismuth tungstate powder in 120mL of isopropanol solution to obtain an isopropanol solution containing NiCu-BWO. Then heat it to 100-150℃ in a muffle furnace, completely immerse the nickel foam in the isopropanol solution containing NiCu-BWO for 10s, remove it and air dry. Repeat the immersion ten times and then dry it to form a NiCu-BWO photoanode self-supporting catalyst stable on the surface of the nickel foam.
2. The preparation method of the nickel-copper ion dual-doped modified bismuth tungstate self-supporting photocatalytic material as described in claim 1, characterized in that, The stirring described in steps one, two, and three involves stirring with a magnetic stirrer for 10–30 minutes.
3. The preparation method of the nickel-copper ion dual-doped modified bismuth tungstate self-supporting photocatalytic material as described in claim 1, characterized in that, The concentration of the dilute hydrochloric acid mentioned in step two is 1-3M.
4. The preparation method of the nickel-copper ion dual-doped modified bismuth tungstate self-supporting photocatalytic material as described in claim 1, characterized in that, The volumetric filling ratio of the high-pressure reactor liner described in step four is 40% to 60%.
5. The preparation method of the nickel-copper ion dual-doped modified bismuth tungstate self-supporting photocatalytic material as described in claim 1, characterized in that, The filtration and washing described in step four involves filtration and washing with deionized water 3 to 5 times.
6. The preparation method of the nickel-copper ion dual-doped modified bismuth tungstate self-supporting photocatalytic material as described in claim 1, characterized in that, The drying process described in steps four and five involves placing the food in a vacuum oven or freeze dryer at 40–70°C for 12–24 hours.
7. The preparation method of the nickel-copper ion dual-doped modified bismuth tungstate self-supporting photocatalytic material as described in claim 1, characterized in that, The grinding described in step four involves grinding in a mortar for 15 to 30 minutes.
8. A nickel-copper ion-doped modified bismuth tungstate self-supporting photocatalytic material prepared by the method described in any one of claims 1 to 7.
9. The application of the nickel-copper ion-doped modified bismuth tungstate self-supporting photoelectrocatalytic material as described in claim 8 as a photoelectrocatalytic photoanode in an alkaline electrolyte.