Niobium pentoxide photocatalyst as well as preparation method and application thereof

Abstract

The invention relates to a niobium pentoxide photocatalyst as well as a preparation method and application thereof, and belongs to the field of environmental functional materials. According to the preparation method of the niobium pentoxide photocatalyst, Nb2O5 powder is subjected to neutron ray irradiation treatment to obtain the NI-Nb2O5 photocatalyst, the dose of the neutron ray irradiation treatment is 0.5 * 10 < 12 >-5 * 10 < 13 > n / cm < 2 >, and the NI-Nb2O5 photocatalyst is Nb2O5 powder with oxygen vacancies on the surface. According to the invention, Nb2O5 is treated by neutron irradiation from Nb2O5, and the neutron irradiation initiates the change of material element composition, so that the NI-Nb2O5 photocatalyst is prepared. The surface of the prepared NI-Nb2O5 photocatalyst has abundant vacancies, charge separation and electron localization can be promoted, the light response capability is enhanced, and the photocatalytic activity is effectively enhanced.

Description

Technical Field

[0001] The invention relates to a niobium pentoxide photocatalyst and a preparation method and application thereof, belonging to the field of environmental functional materials. Background Art

[0002] Volatile organic compounds (VOCs) are a significant source of indoor and outdoor air pollution, and their anthropogenic emissions can significantly deteriorate air quality and human health. Photocatalytic degradation of VOCs is considered a promising purification technology due to its low cost, high efficiency, and environmental friendliness.

[0003] Photocatalytic technology uses light energy to excite semiconductor materials to produce active free radicals, which oxidize and decompose VOCs into CO2 and H2O. It has the advantages of being green and environmentally friendly, and having mild reaction conditions. Nb2O5 is a VOCs degradation photocatalyst with good application prospects. Currently, the effectiveness of Nb2O5 photocatalytic treatment of VOCs is still far from practical application, and constructing defects in it is an effective modification method. Invention patent CN117563583A prepares an amorphous Nb2O5 photocatalyst rich in oxygen vacancies by calcining under a protective gas atmosphere, thereby improving the photocatalytic activity.

[0004] Neutron irradiation technology uses thermal neutrons to irradiate materials, causing changes in their properties. Among the various catalyst modification methods currently under investigation, neutron irradiation is a relatively unique approach, capable of altering catalytic activity by creating defects and other structures through collisions with catalyst atoms. Summary of the Invention

[0005] The present invention aims to provide a method for improving the photocatalytic degradation of VOCs using niobium pentoxide through neutron irradiation. The present photocatalyst preparation method utilizes a non-contact process to avoid chemical contamination. Neutron irradiation generates a large number of oxygen vacancies in the Nb2O5 photocatalyst, enhancing the separation efficiency of photogenerated electron-hole pairs. This results in a high conversion rate for photocatalytic removal of VOCs and has promising application prospects in the field of gaseous pollutant treatment. By rationally designing the Nb2O5 photocatalyst and utilizing neutron irradiation to alter its elemental composition and energy band structure, the present invention enhances contact between the catalytically active sites and reactants, promotes the separation of photogenerated electrons and holes, and improves the photocatalytic removal of VOCs.

[0006] A method for preparing a niobium pentoxide photocatalyst comprises subjecting Nb2O5 powder to neutron ray irradiation treatment to obtain a NI-Nb2O5 photocatalyst.

[0007] The "neutron ray irradiation" mentioned in the present invention is carried out in a neutron ray irradiation device provided by the prior art, which is commercially available.

[0008] Preferably, the dose of the neutron irradiation treatment is 0.5*10 12 ~5*10 13 n / cm 2 .

[0009] The NI-Nb2O5 photocatalyst of the present invention is Nb2O5 powder with oxygen vacancies on the surface.

[0010] Furthermore, the Nb2O5 powder is prepared by the following method: ammonium niobium oxalate hydrate, oleic acid, and trioctylamine are prepared into a mixture in a molar ratio of 5 to 8:18:61, transferred to a polytetrafluoroethylene liner, reacted at 100 to 200°C for 2 to 6 hours, washed, and dried; heated to 500 to 700°C at a rate of 1 to 20°C / min, treated at high temperature in a dry air atmosphere for 1 to 6 hours, and cooled to room temperature to obtain Nb2O5 powder.

[0011] Another object of the present invention is to provide a niobium pentoxide photocatalyst prepared by the above method.

[0012] The oxygen content in the NI-Nb2O5 photocatalyst of the present invention is reduced by 1 to 15%; the band gap of the NI-Nb2O5 photocatalyst is reduced by 0.16 to 0.30 eV compared with untreated Nb2O5 powder.

[0013] Furthermore, the oxygen content in the NI-Nb2O5 photocatalyst is reduced by 5 to 10%.

[0014] Another object of the present invention is to provide use of the niobium pentoxide photocatalyst in photocatalytic removal of volatile organic compounds.

[0015] Furthermore, the volatile organic compound is acetone.

[0016] The oxygen-vacancy-rich NI-Nb2O5 photocatalyst prepared by the present invention removes some oxygen atoms by neutron irradiation through collision of high-energy particles with the material surface, thereby improving the efficiency of photocatalytic removal of VOCs.

[0017] The present invention has the following beneficial effects: Starting from Nb2O5, the present invention utilizes neutron irradiation to treat Nb2O5, where neutron irradiation induces changes in the elemental composition of the material to prepare a Ni-Nb2O5 photocatalyst. The resulting Ni-Nb2O5 photocatalyst has abundant vacancies on its surface, which promotes charge separation and electron localization, enhancing light response and effectively increasing photocatalytic activity. Furthermore, the optimized defects form a highly active surface, enhancing the adsorption and activation of VOCs, further improving the efficiency of photocatalytic VOC removal. The preparation method of the present invention utilizes neutron irradiation, is simple and easy to operate, has low energy consumption, and employs non-contact processing, thus avoiding chemical contamination. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a scanning electron microscope photograph of the Ni-Nb2O5 photocatalyst prepared in Example 4 of the present invention. Its morphology is a micron-sized powder material.

[0019] Figure 2 This is the X-ray diffraction pattern of the Ni-Nb2O5 photocatalyst prepared in Example 4 of the present invention. After irradiation treatment, the Nb2O5 crystal form is still maintained, indicating that the crystal structure has not changed significantly.

[0020] Figure 3 This is the energy dispersion spectrum of the NI-Nb2O5 photocatalyst prepared in Example 4 of the present invention. After neutron irradiation, the oxygen content in Example 4 decreased by 7.48% compared with that in Comparative Example 1.

[0021] Figure 4 Graph showing the band gap width of the Ni-Nb2O5 photocatalyst prepared in Example 4 of the present invention and in Comparative Example 1. After neutron irradiation, the band gap of Example 4 is reduced by 0.30 eV compared to Comparative Example 1. DETAILED DESCRIPTION

[0022] The following non-limiting examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0023] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are all commercially available unless otherwise specified.

[0024] A method for preparing a niobium pentoxide photocatalyst comprises the following steps:

[0025] (1) Preparation of Nb2O5: A mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 5:18:61 to 8:18:61 is transferred to a polytetrafluoroethylene liner and reacted at 100 to 200°C for 2 to 6 hours. After hydrothermal treatment, the mixture is removed and washed with ethanol and acetone, dried, and annealed at 500 to 700°C in a dry air atmosphere for 1 to 6 hours. The mixture is cooled to room temperature to obtain Nb2O5.

[0026] (2) Preparation of NI-Nb2O5 photocatalyst: Nb2O5 was placed on a sample holder and irradiated with neutron radiation at a dose of 0.5*10 12 ~5*10 13 n / cm 2 , obtaining NI-Nb2O5.

[0027] (3) 0.2 g of NI-Nb2O5 photocatalyst was dispersed in 10 mL of anhydrous ethanol to form a suspension. The suspension was evenly drop-coated on a 10 cm × 10 cm test piece. After drying at room temperature, the test piece was placed in a continuous flow photocatalytic reactor and treated with 50 ppm acetone in a dry air atmosphere using a 1000 W UV lamp as the light source.

[0028] Example 1

[0029] (1) A mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 6:18:61 was transferred to a 45 ml polytetrafluoroethylene liner and reacted at 180°C for 6 h. After the hydrothermal reaction, the mixture was taken out and washed with ethanol and acetone, dried, and annealed at 580°C for 1 h in a dry air atmosphere. The mixture was cooled to room temperature to obtain Nb2O5.

[0030] (2) Place Nb2O5 on a sample holder and irradiate it with neutron radiation at a dose of 2.5*10 12 n / cm 2 After cooling to room temperature, NI-Nb2O5 was obtained. SEM-EDS analysis showed that the oxygen content in the material decreased by 4.18% after neutron irradiation. Tests also revealed that the band gap of the photocatalyst decreased by 0.20 eV.

[0031] (3) 0.2 g of NI-Nb2O5 photocatalyst was dispersed in 10 mL of anhydrous ethanol to form a suspension. The suspension was evenly drop-coated onto a 10 cm × 10 cm test piece. After drying at room temperature, the test piece was placed in a continuous flow photocatalytic reactor and treated with a 1000 W UV lamp in a dry air atmosphere to remove 50 ppm of acetone. The acetone removal rate reached 36.2%.

[0032] Example 2

[0033] (1) A mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 6:18:61 was transferred to a 45 ml polytetrafluoroethylene liner and reacted at 80°C for 6 h. After the hydrothermal reaction, the mixture was taken out and washed with ethanol and acetone, dried, and annealed at 580°C for 1 h in a dry air atmosphere. The mixture was cooled to room temperature to obtain Nb2O5.

[0034] (2) Place Nb2O5 on a sample holder and irradiate it with neutron radiation at a dose of 2.5*10 12 n / cm 2 After cooling to room temperature, NI-Nb2O5 was obtained. SEM-EDS analysis showed that the oxygen content in the material decreased by 3.37% after neutron irradiation. Tests also revealed that the band gap of the photocatalyst decreased by 0.16 eV.

[0035] (3) 0.2 g of NI-Nb2O5 photocatalyst was dispersed in 10 mL of anhydrous ethanol to form a suspension. The suspension was evenly drop-coated onto a 10 cm × 10 cm test piece. After drying at room temperature, the test piece was placed in a continuous flow photocatalytic reactor and treated with a 1000 W UV lamp in a dry air atmosphere to remove 50 ppm of acetone. The acetone removal rate reached 32.6%.

[0036] Example 3

[0037] (1) A mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 6:18:61 was transferred to a 45 ml polytetrafluoroethylene liner and reacted at 180°C for 6 h. After the hydrothermal reaction, the mixture was taken out and washed with ethanol and acetone, dried, and annealed at 480°C for 1 h in a dry air atmosphere. The mixture was cooled to room temperature to obtain Nb2O5.

[0038] (2) Place Nb2O5 on a sample holder and irradiate it with neutron radiation at a dose of 2.5*10 12 n / cm 2 After cooling to room temperature, NI-Nb2O5 was obtained. SEM-EDS analysis showed that the oxygen content in the material decreased by 1.21% after neutron irradiation. Tests also revealed that the band gap of the photocatalyst decreased by 0.12 eV.

[0039] (3) 0.2 g of NI-Nb2O5 photocatalyst was dispersed in 10 mL of anhydrous ethanol to form a suspension. The suspension was evenly drop-coated onto a 10 cm × 10 cm test piece. After drying at room temperature, the test piece was placed in a continuous flow photocatalytic reactor and treated with a 1000 W UV lamp in a dry air atmosphere to remove 50 ppm of acetone. The acetone removal rate reached 37.5%.

[0040] Example 4

[0041] (1) A mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 6:18:61 was transferred to a 45 ml polytetrafluoroethylene liner and reacted at 180°C for 6 h. After the hydrothermal reaction, the mixture was taken out and washed with ethanol and acetone, dried, and annealed at 580°C for 1 h in a dry air atmosphere. The mixture was cooled to room temperature to obtain Nb2O5.

[0042] (2) Place Nb2O5 on a sample holder and irradiate it with neutron radiation at a dose of 2.5*10 13 n / cm 2 After cooling to room temperature, NI-Nb2O5 was obtained. SEM-EDS analysis showed that the oxygen content in the material decreased by 7.48% after neutron irradiation. Tests also revealed that the band gap of the photocatalyst decreased by 0.30 eV.

[0043] (3) 0.2 g of NI-Nb2O5 photocatalyst was dispersed in 10 mL of anhydrous ethanol to form a suspension. The suspension was evenly drop-coated onto a 10 cm × 10 cm test piece. After drying at room temperature, the test piece was placed in a continuous flow photocatalytic reactor and treated with a 1000 W UV lamp in a dry air atmosphere to remove 50 ppm of acetone. The acetone removal rate reached 48.2%.

[0044] Comparative Example 1

[0045] (1) A mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 6:18:61 was transferred to a 45 ml polytetrafluoroethylene liner and reacted at 180°C for 6 h. After the hydrothermal reaction, the mixture was taken out and washed with ethanol and acetone, dried, and annealed at 580°C for 1 h in a dry air atmosphere. The mixture was cooled to room temperature to obtain Nb2O5.

[0046] (2) 0.2 g of Nb2O5 photocatalyst was dispersed in 10 mL of anhydrous ethanol to form a suspension. The suspension was evenly drop-coated onto a 10 cm × 10 cm test piece. After drying at room temperature, the test piece was placed in a continuous flow photocatalytic reactor and treated with a 1000 W UV lamp in a dry air atmosphere to remove 50 ppm of acetone. The acetone removal rate was 32.0%.

Claims

1. A method for preparing a niobium pentoxide photocatalyst, characterized in that: The Nb2O5 powder is irradiated with neutron rays to obtain NI-Nb2O5 photocatalyst.

2. The method according to claim 1, characterized in that The dose of the neutron ray irradiation treatment is 0.5*10 12 ~5*10 13 n / cm 2 .

3. The method according to claim 1, characterized in that The NI-Nb2O5 photocatalyst is Nb2O5 powder with oxygen vacancies on the surface.

4. The method according to claim 1, wherein The Nb2O5 powder is prepared by the following method: transferring a mixture of ammonium niobium oxalate hydrate, oleic acid, and trioctylamine in a molar ratio of 5 to 8:18:61 to a polytetrafluoroethylene liner, reacting at 100 to 200°C for 2 to 6 hours, washing, and drying; heating to 500 to 700°C at a rate of 1 to 20°C / min, high-temperature treating in a dry air atmosphere for 1 to 6 hours, and cooling to room temperature to obtain Nb2O5 powder.

5. Niobium pentoxide photocatalyst prepared by the method according to any one of claims 1 to 4.

6. The niobium pentoxide photocatalyst according to claim 5, characterized in that The oxygen content in the NI-Nb2O5 photocatalyst decreases by 1 to 15%; the band gap of the NI-Nb2O5 photocatalyst decreases by 0.16 to 0.30 eV compared with untreated Nb2O5 powder.

7. Use of the niobium pentoxide photocatalyst according to claim 5 in photocatalytic removal of volatile organic compounds.

8. The application according to claim 7, characterized in that: The volatile organic compound is acetone.

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