Near-infrared photoresponsive Cu2O powder photothermal material and its preparation method

Abstract

This invention discloses a near-infrared photoresponsive Cu2O powder photothermal material and its preparation method. Specifically, copper compound powder is added to deionized water and ultrasonically dissolved to form a copper ion aqueous solution. Ethanol is then added and mixed to obtain solution A. Sodium hydroxide powder is added to deionized water and ultrasonically dissolved to form a sodium hydroxide aqueous solution. Ethanol is then added and mixed to obtain solution B. Solution A is stirred and heated, followed by the addition of p-benzoquinone powder to react. Solution B is then added, and the reaction continues. After centrifugation, washing, and drying, the near-infrared photoresponsive Cu2O powder photothermal material is obtained. This invention uses a simple liquid-phase reduction method to prepare Cu2O powder photothermal materials with excellent photothermal performance under near-infrared light irradiation at low temperatures. This preparation method has advantages such as wide availability of raw materials, mild reaction conditions, simple operation, short process flow, and suitability for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of photothermal material preparation technology, specifically relating to a method for preparing near-infrared light-responsive Cu2O powder photothermal material, and also relating to the Cu2O powder photothermal material and its potential application in the field of solar-driven water evaporation. Background Technology

[0002] The core component of solar water purification technology is a photothermal material that facilitates water vapor evaporation. Common photothermal materials are mainly divided into: inorganic semiconductor materials, carbon materials, and nanomaterials with plasmon resonance effects. Although inorganic oxide semiconductor materials are low in cost and widely available, they typically have a wide bandgap and poor absorption capacity for sunlight. This means they require the absorption of high-energy incident light, such as ultraviolet and visible light, to excite electrons and release heat during the return to the ground state. However, based on the energy distribution of the solar spectrum (ultraviolet light wavelengths 10–400 nm, accounting for approximately 5%; visible light wavelengths 400–700 nm, accounting for approximately 43%; near-infrared light wavelengths 700–2500 nm, accounting for approximately 52%), near-infrared light response is a prerequisite and foundation for metal oxides to achieve efficient solar photothermal conversion.

[0003] Cu₂O, as a low-cost, narrow-bandgap p-type semiconductor photocatalyst, has a bandgap of approximately 2.17 eV, exhibiting good photothermal stability, a high conduction band potential, and the ability to absorb sunlight to generate electrons with strong reducing power. This allows it to convert O₂ into highly oxidizing free radicals and non-free radicals, achieving efficient oxidative degradation of organic pollutant molecules. Therefore, this material can be used not only for sunlight-driven water evaporation but also for the elimination of organic pollutants. However, traditional Cu₂O only absorbs ultraviolet-visible light, resulting in limited photothermal performance. Although modification methods such as doping with non-energetic elements and controlling microstructure can induce a redshift in the absorption spectrum of monocomponent Cu₂O, the absorption spectrum of the modified Cu₂O remains confined to the visible light region. Therefore, there is an urgent need to develop a safe, energy-efficient, and near-infrared photoresponsive Cu₂O photothermal material preparation process. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing near-infrared light-responsive Cu2O powder photothermal material, which exhibits excellent photothermal properties under near-infrared light irradiation.

[0005] Another object of the present invention is to provide near-infrared light-responsive Cu2O powder photothermal materials.

[0006] The first technical solution adopted in this invention is a method for preparing near-infrared light-responsive Cu2O powder photothermal material, which is implemented according to the following steps:

[0007] Step 1: Add copper compound powder to deionized water, sonicate to dissolve, form copper ion aqueous solution, then add ethanol and mix to obtain solution A;

[0008] Step 2: Add sodium hydroxide powder to deionized water, sonicate to dissolve, forming sodium hydroxide aqueous solution, then add ethanol and mix to obtain solution B;

[0009] Step 3: Stir and heat the solution A obtained in Step 1, then add p-benzoquinone powder to react, then add solution B and continue the reaction. After centrifugation, washing and drying, near-infrared light-responsive Cu2O powder photothermal material can be obtained.

[0010] The invention is further characterized in that,

[0011] In step 1, the copper compound powder is specifically any one of copper nitrate powder, copper chloride powder, copper acetate powder, and copper sulfate powder.

[0012] In step 1, the concentration of the copper ion aqueous solution is 0.3–1 mol / L; the volume ratio of the copper ion aqueous solution to ethanol is 1:20–25.

[0013] In step 2, the concentration of the sodium hydroxide aqueous solution is 3–12 mol / L; the volume ratio of the sodium hydroxide aqueous solution to ethanol is 1:1–5.

[0014] In step 3, the stirring and heating temperature is 40-70℃, the stirring speed is 200-800 r / min, and the stirring and heating time is 5-20 min; the first reaction time is 1-5 min, the second reaction time is 5-60 min; the drying temperature is 60-120℃, and the drying time is 12-24 h.

[0015] In step 3, the mass ratio of p-benzoquinone powder to copper compound powder in solution A is 1-10:1-10.

[0016] Another technical solution adopted in this invention is the potential application of near-infrared light-responsive Cu2O powder photothermal material in the fields of solar-driven water evaporation and photocatalysis.

[0017] The beneficial effects of this invention are:

[0018] (1) This invention can prepare Cu2O powder photothermal material with excellent photothermal performance under near-infrared light irradiation at low temperature by a simple liquid phase reduction method. The preparation method has the advantages of wide availability of raw materials, mild reaction conditions, simple operation, short process flow and suitability for industrial production.

[0019] (2) The Cu2O powder photothermal material prepared by the present invention can exhibit excellent photothermal performance under near-infrared light without loading any photosensitizer or other active components;

[0020] (3) The Cu2O powder photothermal material prepared by this invention can break the traditional limitation of cuprous oxide only responding to visible light, and provide new ideas for the design and development of new oxide photothermal materials. Attached Figure Description

[0021] Figure 1 This is the XRD pattern of the Cu2O powder photothermal material prepared in Example 1 of this invention;

[0022] Figure 2 This is a macroscopic photograph of the Cu2O powder photothermal material prepared in Example 1 of this invention;

[0023] Figure 3 This is the ultraviolet-visible-near-infrared diffuse reflectance spectrum of the Cu2O powder photothermal material prepared in Example 1 of this invention;

[0024] Figure 4 It is a photothermal curve of an aqueous solution containing Cu2O powder photothermal material prepared in Example 1 of the present invention and commercial Cu2O powder under near-infrared light irradiation. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0026] The present invention discloses a method for preparing near-infrared photoresponsive Cu2O powder photothermal material, which uses copper compound as copper source, sodium hydroxide as precipitant, deionized water and ethanol as solvent, and p-benzoquinone as reducing agent. The near-infrared photoresponsive Cu2O powder photothermal material with excellent photothermal performance can be prepared by liquid-phase reduction method.

[0027] The specific steps are as follows:

[0028] Step 1: Add copper compound powder to deionized water, sonicate to dissolve, form copper ion aqueous solution, then add ethanol and mix to obtain solution A;

[0029] The copper compound powder is specifically any one of copper nitrate powder, copper chloride powder, copper acetate powder, and copper sulfate powder;

[0030] The concentration of the copper ion aqueous solution is 0.3–1 mol / L; the volume ratio of the copper ion aqueous solution to ethanol is 1:20–25.

[0031] Step 2: Add sodium hydroxide powder to deionized water, sonicate to dissolve, forming sodium hydroxide aqueous solution, then add ethanol and mix to obtain solution B;

[0032] The concentration of the sodium hydroxide aqueous solution is 3–12 mol / L; the volume ratio of sodium hydroxide aqueous solution to ethanol is 1:1–5.

[0033] Step 3: Stir and heat the solution A obtained in Step 1, then add p-benzoquinone powder to react, then add solution B and continue the reaction. After centrifugation, washing and drying, near-infrared light-responsive Cu2O powder photothermal material can be obtained.

[0034] The stirring and heating temperature is 40–70℃, the stirring speed is 200–800 r / min, and the stirring and heating time is 5–20 min;

[0035] The mass ratio of p-benzoquinone powder to copper compound powder in solution A is 1-10:1-10, the first reaction time is 1-5 min, and the second reaction time is 5-60 min;

[0036] The washing process involves rinsing with anhydrous ethanol 3 to 4 times.

[0037] The drying temperature is 60-120℃, and the drying time is 12-24 hours.

[0038] Compared to other strong reducing agents, p-benzoquinone has weaker reducing properties and is less likely to cause excessive reduction of cuprous oxide to copper. Under certain conditions, it is more stable than reducing agents such as ascorbic acid and can maintain its reducing properties within a certain range. Furthermore, p-benzoquinone has a unique conjugated structure, which results in a distinctive electron distribution, making it more receptive to or donating electrons, thus giving it high reactivity. Secondly, its molecular structure is relatively unstable, readily undergoing redox reactions to reach a more stable state, resulting in high reactivity and rapid participation in redox reactions.

[0039] The Cu2O powder photothermal material prepared by the method of this invention has more oxygen vacancies, resulting in a large number of lattice distortions, which leads to a shortened band gap and thus better absorption capacity under near-infrared light. Furthermore, the narrower band gap makes it easier for electrons to jump from the valence band to the conduction band, and the generation of excited-state electrons and holes is easier, which further increases the efficiency of energy transfer and conversion into heat, giving it excellent photothermal effect.

[0040] The specific method for determining the photothermal effect of the prepared Cu2O powder photothermal material under near-infrared light in this invention is as follows: 20 mg of sample is ultrasonically dispersed in 50 mL of aqueous solution, and a photothermal experiment is carried out under a 300 W xenon lamp light source equipped with a cutoff filter (λ>700 nm). The surface temperature of the aqueous solution is measured with an infrared thermal imager, and the temperature change trend is recorded.

[0041] Example 1

[0042] The preparation method of the near-infrared light-responsive Cu2O powder photothermal material of the present invention is as follows:

[0043] Step 1: Mix 1 mL of 0.6 mol / L copper nitrate aqueous solution with 25 mL of ethanol to obtain solution A.

[0044] Step 2: Mix 1 mL of 3 mol / L sodium hydroxide aqueous solution with 5 mL of ethanol to obtain solution B.

[0045] Step 3: Stir solution A at 600 r / min for 10 min in an oil bath at 60℃. Then, add 0.3 g of p-benzoquinone powder and react for 5 min. Then add solution B and continue the reaction for 20 min. Centrifuge while hot and wash the product 4 times with anhydrous ethanol. Then dry in an oven at 60℃ for 24 h to obtain Cu2O powder photothermal material.

[0046] XRD pattern of the prepared Cu2O powder photothermal material ( Figure 1 This indicates that the product prepared in Example 1 is pure-phase Cu₂O. Its macroscopic photograph is shown below. Figure 2 As shown, it is a black powder, indicating a wider light absorption range, as shown by the ultraviolet-visible-near-infrared diffuse reflectance spectrum (UV-Vis-NIR). Figure 3 As can be seen, the prepared sample can generate a response in the near-infrared region.

[0047] The photothermal curve test results show that, under the above experimental conditions, after 75 minutes of near-infrared light irradiation, the temperature of the aqueous solution containing the Cu2O powder photothermal material prepared in Example 1 (62.1℃) is 1.46 times higher than the temperature of the aqueous solution containing commercial Cu2O powder (42.3℃). Figure 4 Both remained stable within this temperature range. The reason for this is that the Cu2O powder photothermal material prepared in Example 1 has more oxygen vacancies compared to commercial Cu2O powder, resulting in significant lattice distortion and a shortened bandgap. This makes it easier for electrons to absorb lower photon energy and be excited, thus exhibiting better absorption under near-infrared light. Furthermore, the narrower bandgap makes it easier for electrons to transition from the valence band to the conduction band, facilitating the generation of excited-state electrons and holes, further increasing the efficiency of energy transfer and heat conversion. This better drives the water evaporation process, enabling the utilization of clean energy.

[0048] Example 2

[0049] The preparation method of the near-infrared light-responsive Cu2O powder photothermal material of the present invention is as follows:

[0050] Step 1: Mix 1 mL of 0.3 mol / L copper nitrate aqueous solution with 20 mL of ethanol to obtain solution A.

[0051] Step 2: Mix 1 mL of 6 mol / L sodium hydroxide aqueous solution with 4 mL of ethanol to obtain solution B.

[0052] Step 3: Stir solution A at 200 r / min for 20 min in an oil bath at 65℃. Then, add 0.7 g of p-benzoquinone powder and react for 3 min. Then add solution B and continue the reaction for 40 min. Centrifuge while hot and wash the product 4 times with anhydrous ethanol. Then dry in an oven at 90℃ for 12 h to obtain Cu2O powder photothermal material with excellent photothermal properties.

[0053] Example 3

[0054] The preparation method of the near-infrared light-responsive Cu2O powder photothermal material of the present invention is as follows:

[0055] Step 1: Mix 1 mL of 0.3 mol / L copper nitrate aqueous solution with 20 mL of ethanol to obtain solution A.

[0056] Step 2: Mix 1 mL of 3 mol / L sodium hydroxide aqueous solution with 1 mL of ethanol to obtain solution B.

[0057] Step 3: Stir solution A at 800 r / min for 5 min in an oil bath at 50℃. Then, add 0.5 g of p-benzoquinone powder and react for 2 min. Then add solution B and continue to react for 5 min. Centrifuge while hot and wash the product three times with anhydrous ethanol. Then dry in an oven at 120℃ for 12 h to obtain Cu2O powder photothermal material with excellent photothermal properties.

[0058] Example 4

[0059] The preparation method of the near-infrared light-responsive Cu2O powder photothermal material of the present invention is as follows:

[0060] Step 1: Mix 1 mL of 0.9 mol / L copper nitrate aqueous solution with 24 mL of ethanol to obtain solution A.

[0061] Step 2: Mix 1 mL of 12 mol / L sodium hydroxide aqueous solution with 4 mL of ethanol to obtain solution B.

[0062] Step 3: Stir solution A at 500 r / min for 10 min in an oil bath at 60℃. Then, add 0.2 g of p-benzoquinone powder and react for 1 min. Add solution B and continue reacting for 60 min. Centrifuge while hot and wash the product three times with anhydrous ethanol. Then, dry in an oven at 60℃ for 24 h to obtain Cu2O powder photothermal material with excellent photothermal properties.

[0063] Example 5

[0064] The preparation method of the near-infrared light-responsive Cu2O powder photothermal material of the present invention is as follows:

[0065] Step 1: Mix 1 mL of 1 mol / L copper nitrate aqueous solution with 25 mL of ethanol to obtain solution A.

[0066] Step 2: Mix 1 mL of 9 mol / L sodium hydroxide aqueous solution with 3 mL of ethanol to obtain solution B.

[0067] Step 3: Stir solution A at 200 r / min for 20 min in an oil bath at 40℃. Then, add 1 g of p-benzoquinone powder and react for 5 min. Then add solution B and react for 30 min. Centrifuge while hot and wash the product 4 times with anhydrous ethanol. Then dry in an oven at 60℃ for 24 h to obtain Cu2O powder photothermal material with excellent photothermal properties.

[0068] This invention enables the preparation of Cu2O powder photothermal materials with excellent photothermal properties under near-infrared light irradiation via a simple liquid-phase reduction method. This will provide new ideas for other researchers to design and prepare novel, high-efficiency oxide near-infrared photoresponsive photothermal materials.

Claims

1. A method for preparing near-infrared light-responsive Cu2O powder photothermal material, characterized in that, The specific steps are as follows: Step 1: Add copper compound powder to deionized water, sonicate to dissolve, form copper ion aqueous solution, then add ethanol and mix to obtain solution A; The copper compound powder is specifically any one of copper nitrate powder, copper chloride powder, copper acetate powder, and copper sulfate powder; The concentration of the copper ion aqueous solution is 0.3~1mol / L; the volume ratio of the copper ion aqueous solution to ethanol is 1:20~25; Step 2: Add sodium hydroxide powder to deionized water, sonicate to dissolve, forming a sodium hydroxide aqueous solution, then add ethanol and mix to obtain solution B; the concentration of the sodium hydroxide aqueous solution is 3~12 mol / L; the volume ratio of sodium hydroxide aqueous solution to ethanol is 1:1~5; Step 3: Stir and heat the solution A obtained in Step 1, then add p-benzoquinone powder to react, then add solution B and continue the reaction. After centrifugation, washing and drying, near-infrared light-responsive Cu2O powder photothermal material can be obtained. The stirring and heating temperature is 40~70℃, the stirring speed is 200~800r / min, and the stirring and heating time is 5~20min; the first reaction time is 1~5min, and the second reaction time is 5~60min; the drying temperature is 60~120℃, and the drying time is 12h~24h; the mass ratio of p-benzoquinone powder to copper compound powder in solution A is 1~10:1~10.

2. The preparation method of the near-infrared light-responsive Cu2O powder photothermal material as described in claim 1, characterized in that, In step 3, the washing process involves washing with anhydrous ethanol 3 to 4 times.

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