Cu2O / Cu modified strontium titanate photocatalytic material and preparation method thereof

Abstract

The invention provides a Cu2O / Cu modified strontium titanate photocatalytic material and a preparation method thereof. A Cu2O / Cu / SrTiO3 ternary p-n heterojunction is successfully constructed through an oxidation-reduction method and an impregnation method. Energy band matching of p-type Cu2O and n-type SrTiO3 is utilized to promote photo-induced electrons to be transferred from a SrTiO3 conduction band to a Cu2O conduction band, holes are reversely migrated, and charge recombination is effectively inhibited; the surface plasma resonance (SPR) effect of the nano Cu particles expands visible light absorption to 600 nm, and the nano Cu particles serve as electron transmission channels to accelerate carrier migration. The material has a liquid-phase formaldehyde removal rate of 91.6% under visible light, which is 6.5 times of that of pure SrTiO3 and 2.4 times of that of Cu2O / Cu, the formaldehyde purification rate still exceeds 85% after circulation for 4 times, a green and environment-friendly redox-impregnation method is adopted in the preparation process, no toxic reagent is needed, the raw material cost is low, the preparation process is green and simple, and the material has efficient and stable photocatalytic performance.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic materials, and in particular to a Cu2O / Cu modified strontium titanate photocatalytic material and a preparation method thereof. Background Art

[0002] As the global energy crisis and environmental problems intensify, the development of efficient and stable photocatalytic materials has become a key approach to solving energy conversion and pollutant degradation. Strontium titanate (SrTiO3), a typical perovskite semiconductor, has attracted much attention in the field of photocatalysis due to its suitable band gap (~3.2eV), excellent chemical stability, and ability to separate photogenerated carriers. However, its wide bandgap means that it can only respond to ultraviolet light (accounting for 4% of the solar spectrum), which seriously limits its practical application efficiency.

[0003] To expand the visible light response range, researchers generally adopt a metal / semiconductor composite strategy. Among them, the introduction of Cu2O (band gap ~2.0eV) and metal Cu has a band synergistic effect, which can promote the spatial separation of photogenerated electron-hole pairs, and nano-Cu particles can enhance visible light absorption and accelerate electron transfer. However, in the existing technology, how to efficiently construct a composite system of Cu2O / Cu and SrTiO3 to achieve a synergistic improvement in photocatalytic performance remains an urgent problem to be solved. To this end, a Cu2O / Cu modified strontium titanate photocatalytic material and its preparation method are proposed. Summary of the Invention

[0004] In view of this, the embodiments of the present invention hope to provide a Cu2O / Cu modified strontium titanate photocatalytic material and a preparation method thereof to solve or alleviate the technical problems existing in the prior art and at least provide a beneficial option.

[0005] To solve the above technical problems, a technical solution adopted in this application is: a Cu2O / Cu modified strontium titanate photocatalytic material, the raw materials comprising by weight: 0.1-10% Cu2O / Cu catalyst, 0.1-10% strontium titanate, and 80-95% photocatalytic material solvent;

[0006] The Cu2O / Cu catalyst is prepared from the following raw materials by weight: 1-10% of copper salt, 1-20% of alkali, 1-10% of reducing agent and 80-95% of catalyst solvent.

[0007] As a further preferred embodiment of the present technical solution, the strontium titanate is spherical with a particle size of 20-40 nm.

[0008] As a further preferred embodiment of the present technical solution, the photocatalytic material solvent is a mixture of ethylene glycol and water in a volume ratio of 2:1.

[0009] As a further preferred embodiment of the present technical solution, the copper salt is a soluble crystalline copper salt, specifically CuSO4·5H2O.

[0010] As a further preferred embodiment of the present technical solution, the base is an inorganic soluble strong base, specifically one or more of KOH and NaOH.

[0011] As a further preferred embodiment of the present invention, the reducing agent is a reducing sugar, specifically D-glucose.

[0012] As a further preferred embodiment of the present technical solution, the catalyst solvent is a mixture of ethylene glycol and deionized water in a volume ratio of 2:1.

[0013] To solve the above technical problems, another technical solution adopted in this application is: a method for preparing a Cu2O / Cu modified strontium titanate photocatalytic material, comprising the following steps:

[0014] Step 1: adding strontium titanate to a photocatalytic material solvent and placing the solution in an ultrasonic cleaning machine to disperse the solution uniformly to form a suspension;

[0015] Step 2: adding Cu2O / Cu catalyst to the suspension, stirring at 20-50°C for 60-100 minutes to obtain a reaction product;

[0016] Step 3: Filter the reaction product to remove the solvent used to prepare the photocatalytic material to obtain a solid product;

[0017] Step 4: washing the solid product obtained by filtration with deionized water and ethanol;

[0018] Step 5: Place the washed product in an oven for drying to obtain a Cu2O / Cu modified strontium titanate photocatalytic material.

[0019] As a further preferred embodiment of the present invention, the preparation steps of the Cu2O / Cu catalyst are as follows:

[0020] Step 1: Dissolve the copper salt in a catalyst solvent and heat in a water bath to 60°C while stirring for 20 minutes;

[0021] Step 2: Add the diluted alkaline solution, stir at a constant speed for 5 minutes, and add the reducing agent dropwise;

[0022] Step 3: Maintain the reaction system temperature at 60°C and continue the reaction for 40-60 minutes to fully reduce the copper ions to form Cu2O / Cu composite particles;

[0023] Step 4: After the reaction is completed, the product is centrifuged to obtain a separated solid product;

[0024] Step 5: Wash the separated solid product with deionized water and ethanol multiple times to remove residual reaction reagents;

[0025] Step 6: Dry the washed solid product in an oven at 60° C. for 12 hours to obtain a Cu2O / Cu catalyst.

[0026] As a further preferred embodiment of the present technical solution, the concentration of the diluted alkaline solution is 5 M, and the reducing agent is added dropwise at a rate of 30 s.

[0027] The embodiment of the present invention adopts the above technical solution, which has the following advantages:

[0028] The present invention prepares a Cu2O / Cu catalyst through an oxidation-reduction method, and then uses an impregnation method to compound it with 20-40nm spherical strontium titanate to form a Cu2O / Cu / SrTiO3 ternary pn heterojunction. The energy band matching between p-type Cu2O and n-type SrTiO3 promotes the transfer of photogenerated electrons from the SrTiO3 conduction band to the Cu2O conduction band, and the reverse migration of holes, effectively inhibiting charge recombination. The surface plasmon resonance (SPR) effect of the nano-Cu particles extends visible light absorption to 600nm and serves as an electron transmission channel to accelerate carrier migration. The material has a liquid-phase formaldehyde removal rate of 91.6% under visible light, which is 6.5 times that of pure SrTiO3 and 2.4 times that of Cu2O / Cu. After four cycles, the formaldehyde purification rate still exceeds 85%. The preparation process adopts a green and environmentally friendly oxidation-reduction-impregnation method, does not require toxic reagents, has low raw material costs, and is green and simple to prepare. It has efficient and stable photocatalytic performance.

[0029] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 The SEM images of the Cu2O / Cu sample of the present invention and the samples of various embodiments are shown;

[0032] Figure 2 This is the EDS of Example 2 of the present invention and the corresponding element surface scan. DETAILED DESCRIPTION

[0033] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0034] It should be clear that the following embodiments of the present disclosure are described through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other in the absence of conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present disclosure.

[0035] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0036] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0037] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details.

[0038] Example 1

[0039] This embodiment provides a 0.5% Cu2O / Cu modified strontium titanate photocatalytic material and a preparation process;

[0040] First, the raw materials were weighed according to weight percentage to prepare the Cu2O / Cu catalyst; the raw material weighing and proportioning were as follows:

[0041] Copper salt: 5% CuSO4·5H2O (soluble crystalline copper salt);

[0042] Solvent: a mixture of 60% ethylene glycol and water (volume ratio 2:1);

[0043] Alkali solution: 17.5% 5M NaOH solution (inorganic soluble strong base);

[0044] Reducing agent: 17.5% D-glucose solution (reducing sugar);

[0045] Then, the Cu2O / Cu catalyst is prepared using the above raw materials, and the specific steps are as follows:

[0046] Step 1: Add 5% CuSO4·5H2O to 60% mixed solvent (ethylene glycol: water = 2:1) and place in a three-necked flask;

[0047] Turn on magnetic stirring (speed 300-500 r / min) and place the reaction system in a water bath, heat to 60°C, and maintain for 20 min until the copper salt is completely dissolved to form a blue transparent solution;

[0048] Step 2: Slowly add 17.5% 5M NaOH solution dropwise (at a rate of about 1 drop / second) while stirring continuously during the addition process;

[0049] After the addition was complete, the solution was stirred at a constant speed for 5 minutes, and the solution gradually changed from blue to dark blue suspension;

[0050] Step 3: Rapidly add 17.5% D-glucose solution dropwise within 30 seconds while keeping the stirring rate constant;

[0051] Step 4: After the addition is completed, the water bath temperature is maintained at 60°C and the reaction is carried out at this temperature for 40 minutes. During this period, the color of the solution gradually changes from dark blue to brownish red, indicating that Cu2O / Cu particles begin to form;

[0052] Step 5: After the reaction is completed, the mixture is transferred to a centrifuge tube and centrifuged at 8000-10000 rpm for 10 min to collect the brown-red precipitate at the bottom;

[0053] Deionized water was added to the precipitate until the solid was submerged, and the mixture was dispersed ultrasonically and centrifuged again, and the washing was repeated three times;

[0054] Replace deionized water with anhydrous ethanol and wash three more times according to the above steps to remove residual organic matter and ionic impurities;

[0055] Step 6: Transfer the washed precipitate to a Petri dish and place it in a 60°C forced air drying oven for 12 hours;

[0056] After drying, the product is ground into powder to obtain Cu2O / Cu catalyst.

[0057] Next, raw materials were weighed according to weight percentage to prepare a 0.5% Cu2O / Cu modified strontium titanate photocatalytic material; the raw material weighing and proportioning were as follows:

[0058] Strontium titanate: Weigh 10% (by weight) of spherical SrTiO3 powder (particle size 20-40 nm) and pass it through a 200-mesh sieve to remove agglomerated particles before use;

[0059] Cu2O / Cu catalyst: weigh 0.5 wt% Cu2O / Cu catalyst and grind it into fine powder for later use;

[0060] Solvent: Weigh 89.5% (by weight) of a mixture of ethylene glycol and water (volume ratio 2:1), where ethylene glycol must be analytical grade and water must be deionized;

[0061] Finally, the above raw materials were used to prepare 0.5% Cu2O / Cu modified strontium titanate photocatalytic material, and the specific steps were as follows:

[0062] Step 1: Slowly add 10% strontium titanate powder to 89.5% solvent in the order of "powder to solvent" to avoid agglomeration;

[0063] The mixed solution was transferred to a 500 mL beaker and placed in a KQ-500DE ultrasonic cleaning machine (power 300 W). Ultrasonic treatment was performed for 30 min until a uniform suspension with no obvious precipitation was formed (the beaker should be covered during the ultrasonic process to prevent solvent evaporation);

[0064] Step 2: Add 0.5% Cu2O / Cu catalyst powder to the suspension and stir with a glass rod until the powder is dispersed;

[0065] Place the beaker on a constant temperature magnetic stirrer, set the temperature to 25°C, the stirring speed to 400 r / min, and react for 60 min (the system must be kept airtight during stirring to avoid temperature fluctuations);

[0066] Step 3: After the reaction is completed, use a Buchner funnel and quantitative filter paper to filter and collect the filter cake (before filtration, the filter paper must be moistened with deionized water to ensure that it fits the funnel);

[0067] Add 50 mL of deionized water to the filter cake, stir gently with a glass rod to redisperse the solid, filter again, and repeat the washing process three times;

[0068] Replace deionized water with 50 mL of anhydrous ethanol and wash three times according to the above steps (ethanol washing can remove residual ethylene glycol and organic matter);

[0069] Step 4: Transfer the washed filter cake to a clean surface dish, spread it flat to a thickness of no more than 5mm, and place it in a DHG-9070A type blast drying oven;

[0070] Set the temperature to 60°C and dry for 12 hours (turn the solids over every 4 hours during the drying process to ensure uniform drying);

[0071] Step 5: Grind the dried product into powder, and pass it through a 200-mesh sieve to obtain a 0.5% Cu2O / Cu modified strontium titanate photocatalytic material.

[0072] Example 2

[0073] This embodiment provides a 1% Cu2O / Cu modified strontium titanate photocatalytic material and a preparation process;

[0074] First, the raw materials were weighed according to weight percentage to prepare the Cu2O / Cu catalyst; the raw material weighing and proportioning were as follows:

[0075] Copper salt: 5% CuSO4·5H2O (soluble crystalline copper salt);

[0076] Solvent: a mixture of 60% ethylene glycol and water (volume ratio 2:1);

[0077] Alkali solution: 17.5% 5M NaOH solution (inorganic soluble strong base);

[0078] Reducing agent: 17.5% D-glucose solution (reducing sugar);

[0079] Then, the Cu2O / Cu catalyst is prepared using the above raw materials, and the specific steps are as follows:

[0080] Step 1: Add 5% CuSO4·5H2O to 60% mixed solvent (ethylene glycol: water = 2:1) and place in a three-necked flask;

[0081] Turn on magnetic stirring (speed 300-500 r / min) and place the reaction system in a water bath, heat to 60°C, and maintain for 20 min until the copper salt is completely dissolved to form a blue transparent solution;

[0082] Step 2: Slowly add 17.5% 5M NaOH solution dropwise (at a rate of about 1 drop / second) while stirring continuously during the addition process;

[0083] Step 3: After the addition is complete, stir at a constant speed for 5 minutes, and the solution gradually changes from blue to dark blue suspension;

[0084] Step 4: Rapidly add 17.5% D-glucose solution dropwise within 30 seconds while maintaining the stirring rate constant;

[0085] After the addition was completed, the water bath temperature was maintained at 60°C and the reaction was carried out at this temperature for 40 minutes. During this period, the color of the solution gradually changed from dark blue to brown-red, indicating that Cu2O / Cu particles began to form.

[0086] Step 5: After the reaction is completed, the mixture is transferred to a centrifuge tube and centrifuged at 8000-10000 rpm for 10 min to collect the brown-red precipitate at the bottom;

[0087] Deionized water was added to the precipitate until the solid was submerged, and the mixture was dispersed ultrasonically and centrifuged again, and the washing was repeated three times;

[0088] Replace deionized water with anhydrous ethanol and wash three more times according to the above steps to remove residual organic matter and ionic impurities;

[0089] Step 6: Transfer the washed precipitate to a Petri dish and place it in a 60°C forced air drying oven for 12 hours;

[0090] After drying, the product is ground into powder to obtain Cu2O / Cu catalyst.

[0091] Next, raw materials were weighed according to weight percentage to prepare a 1% Cu2O / Cu modified strontium titanate photocatalytic material; the raw material weighing and proportioning were as follows:

[0092] Strontium titanate: Weigh 10% (by weight) of spherical SrTiO3 powder (particle size 20-40 nm) and pass it through a 200-mesh sieve to remove agglomerated particles before use;

[0093] Cu2O / Cu catalyst: weigh 1% (by weight) Cu2O / Cu catalyst and grind it into fine powder for later use;

[0094] Solvent: Weigh 89% (by weight) of a mixture of ethylene glycol and water (volume ratio 2:1), where ethylene glycol must be analytical grade and water must be deionized;

[0095] Finally, the above raw materials were used to prepare 1% Cu2O / Cu modified strontium titanate photocatalytic material, and the specific steps were as follows:

[0096] Step 1: Slowly add 10% strontium titanate powder to 89% solvent in the order of "powder adding solvent one by one" to avoid agglomeration;

[0097] The mixed solution was transferred to a 500 mL beaker and placed in a KQ-500DE ultrasonic cleaning machine (power 300 W). Ultrasonic treatment was performed for 30 min until a uniform suspension with no obvious precipitation was formed (the beaker should be covered during the ultrasonic process to prevent solvent evaporation);

[0098] Step 2: Add 1% Cu2O / Cu catalyst powder to the suspension and stir with a glass rod until the powder is dispersed;

[0099] Place the beaker on a constant temperature magnetic stirrer, set the temperature to 25°C, the stirring speed to 400 r / min, and react for 60 min (the system must be kept airtight during stirring to avoid temperature fluctuations);

[0100] Step 3: After the reaction is completed, use a Buchner funnel and quantitative filter paper to filter and collect the filter cake (before filtration, the filter paper must be moistened with deionized water to ensure that it fits the funnel);

[0101] Add 50 mL of deionized water to the filter cake, stir gently with a glass rod to redisperse the solid, filter again, and repeat the washing process three times;

[0102] Replace deionized water with 50 mL of anhydrous ethanol and wash three times according to the above steps (ethanol washing can remove residual ethylene glycol and organic matter);

[0103] Step 4: Transfer the washed filter cake to a clean surface dish, spread it flat to a thickness of no more than 5mm, and place it in a DHG-9070A type blast drying oven;

[0104] Set the temperature to 60°C and dry for 12 hours (turn the solids over every 4 hours during the drying process to ensure uniform drying);

[0105] Step 5: Grind the dried product into powder, and pass it through a 200-mesh sieve to obtain a 1% Cu2O / Cu modified strontium titanate photocatalytic material.

[0106] Example 3

[0107] This embodiment provides a 1.5% Cu2O / Cu modified strontium titanate photocatalytic material and a preparation process;

[0108] First, the raw materials were weighed according to weight percentage to prepare the Cu2O / Cu catalyst; the raw material weighing and proportioning were as follows:

[0109] Copper salt: 5% CuSO4·5H2O (soluble crystalline copper salt);

[0110] Solvent: a mixture of 60% ethylene glycol and water (volume ratio 2:1);

[0111] Alkali solution: 17.5% 5M NaOH solution (inorganic soluble strong base);

[0112] Reducing agent: 17.5% D-glucose solution (reducing sugar);

[0113] Then, the Cu2O / Cu catalyst is prepared using the above raw materials, and the specific steps are as follows:

[0114] Step 1: Add 5% CuSO4·5H2O to 60% mixed solvent (ethylene glycol: water = 2:1) and place in a three-necked flask;

[0115] Turn on magnetic stirring (speed 300-500 r / min) and place the reaction system in a water bath, heat to 60°C, and maintain for 20 min until the copper salt is completely dissolved to form a blue transparent solution;

[0116] Step 2: Slowly add 17.5% 5M NaOH solution dropwise (at a rate of about 1 drop / second) while stirring continuously during the addition process;

[0117] Step 3: After the addition is complete, stir at a constant speed for 5 minutes, and the solution gradually changes from blue to dark blue suspension;

[0118] Step 4: Rapidly add 17.5% D-glucose solution dropwise within 30 seconds while maintaining the stirring rate constant;

[0119] After the addition was completed, the water bath temperature was maintained at 60°C and the reaction was carried out at this temperature for 40 minutes. During this period, the color of the solution gradually changed from dark blue to brown-red, indicating that Cu2O / Cu particles began to form.

[0120] Step 5: After the reaction is completed, the mixture is transferred to a centrifuge tube and centrifuged at 8000-10000 rpm for 10 min to collect the brown-red precipitate at the bottom;

[0121] Deionized water was added to the precipitate until the solid was submerged, and the mixture was dispersed ultrasonically and centrifuged again, and the washing was repeated three times;

[0122] Replace deionized water with anhydrous ethanol and wash three more times according to the above steps to remove residual organic matter and ionic impurities;

[0123] Step 6: Transfer the washed precipitate to a Petri dish and place it in a 60°C forced air drying oven for 12 hours;

[0124] After drying, the product is ground into powder to obtain Cu2O / Cu catalyst.

[0125] Next, raw materials were weighed according to weight percentage to prepare a 1.5% Cu2O / Cu modified strontium titanate photocatalytic material; the raw material weighing and proportioning were as follows:

[0126] Strontium titanate: Weigh 10% (by weight) of spherical SrTiO3 powder (particle size 20-40 nm) and pass it through a 200-mesh sieve to remove agglomerated particles before use;

[0127] Cu2O / Cu catalyst: weigh 1.5 wt% Cu2O / Cu catalyst and grind it into fine powder for later use;

[0128] Solvent: Weigh 88.5% (by weight) of a mixture of ethylene glycol and water (volume ratio 2:1), where ethylene glycol must be analytical grade and water must be deionized;

[0129] Finally, the above raw materials were used to prepare 1.5% Cu2O / Cu modified strontium titanate photocatalytic material, and the specific steps were as follows:

[0130] Step 1: Slowly add 10% strontium titanate powder to 88.5% solvent in the order of "powder adding solvent one by one" to avoid agglomeration;

[0131] The mixed solution was transferred to a 500 mL beaker and placed in a KQ-500DE ultrasonic cleaning machine (power 300 W). Ultrasonic treatment was performed for 30 min until a uniform suspension with no obvious precipitation was formed (the beaker should be covered during the ultrasonic process to prevent solvent evaporation);

[0132] Step 2: Add 1.5% Cu2O / Cu catalyst powder to the suspension and stir with a glass rod until the powder is dispersed;

[0133] Place the beaker on a constant temperature magnetic stirrer, set the temperature to 25°C, the stirring speed to 400 r / min, and react for 60 min (the system must be kept airtight during stirring to avoid temperature fluctuations);

[0134] Step 3: After the reaction is completed, use a Buchner funnel and quantitative filter paper to filter and collect the filter cake (before filtration, the filter paper must be moistened with deionized water to ensure that it fits the funnel);

[0135] Add 50 mL of deionized water to the filter cake, stir gently with a glass rod to redisperse the solid, filter again, and repeat the washing process three times;

[0136] Replace deionized water with 50 mL of anhydrous ethanol and wash three times according to the above steps (ethanol washing can remove residual ethylene glycol and organic matter);

[0137] Step 4: Transfer the washed filter cake to a clean surface dish, spread it flat to a thickness of no more than 5mm, and place it in a DHG-9070A type blast drying oven;

[0138] Set the temperature to 60°C and dry for 12 hours (turn the solids over every 4 hours during the drying process to ensure uniform drying);

[0139] Step 5: Grind the dried product into powder, and pass it through a 200-mesh sieve to obtain a 1.5% Cu2O / Cu modified strontium titanate photocatalytic material.

[0140] Example 4

[0141] This embodiment provides a 2% Cu2O / Cu modified strontium titanate photocatalytic material and a preparation process;

[0142] First, the raw materials were weighed according to weight percentage to prepare the Cu2O / Cu catalyst; the raw material weighing and proportioning were as follows:

[0143] Copper salt: 5% CuSO4·5H2O (soluble crystalline copper salt);

[0144] Solvent: a mixture of 60% ethylene glycol and water (volume ratio 2:1);

[0145] Alkali solution: 17.5% 5M NaOH solution (inorganic soluble strong base);

[0146] Reducing agent: 17.5% D-glucose solution (reducing sugar);

[0147] Then, the Cu2O / Cu catalyst is prepared using the above raw materials, and the specific steps are as follows:

[0148] Step 1: Add 5% CuSO4·5H2O to 60% mixed solvent (ethylene glycol: water = 2:1) and place in a three-necked flask;

[0149] Turn on magnetic stirring (speed 300-500 r / min) and place the reaction system in a water bath, heat to 60°C, and maintain for 20 min until the copper salt is completely dissolved to form a blue transparent solution;

[0150] Step 2: Slowly add 17.5% 5M NaOH solution dropwise (at a rate of about 1 drop / second) while stirring continuously during the addition process;

[0151] Step 3: After the addition is complete, stir at a constant speed for 5 minutes, and the solution gradually changes from blue to dark blue suspension;

[0152] Step 4: Rapidly add 17.5% D-glucose solution dropwise within 30 seconds while maintaining the stirring rate constant;

[0153] After the addition was completed, the water bath temperature was maintained at 60°C and the reaction was carried out at this temperature for 40 minutes. During this period, the color of the solution gradually changed from dark blue to brown-red, indicating that Cu2O / Cu particles began to form.

[0154] Step 5: After the reaction is completed, the mixture is transferred to a centrifuge tube and centrifuged at 8000-10000 rpm for 10 min to collect the brown-red precipitate at the bottom;

[0155] Deionized water was added to the precipitate until the solid was submerged, and the mixture was dispersed ultrasonically and centrifuged again, and the washing was repeated three times;

[0156] Replace deionized water with anhydrous ethanol and wash three more times according to the above steps to remove residual organic matter and ionic impurities;

[0157] Step 6: Transfer the washed precipitate to a Petri dish and place it in a 60°C forced air drying oven for 12 hours;

[0158] After drying, the product is ground into powder to obtain Cu2O / Cu catalyst.

[0159] Next, raw materials were weighed according to weight percentage to prepare a 2% Cu2O / Cu modified strontium titanate photocatalytic material; the raw material weighing and proportioning were as follows:

[0160] Strontium titanate: Weigh 10% (by weight) of spherical SrTiO3 powder (particle size 20-40 nm) and pass it through a 200-mesh sieve to remove agglomerated particles before use;

[0161] Cu2O / Cu catalyst: weigh 2% (by weight) Cu2O / Cu catalyst and grind it into fine powder for later use;

[0162] Solvent: Weigh 88% (by weight) of a mixture of ethylene glycol and water (volume ratio 2:1), where ethylene glycol must be analytical grade and water must be deionized;

[0163] Finally, the above raw materials were used to prepare a 2% Cu2O / Cu modified strontium titanate photocatalytic material, and the specific steps were as follows:

[0164] Step 1: Slowly add 10% strontium titanate powder to 88% solvent in the order of "powder to solvent" to avoid agglomeration;

[0165] The mixed solution was transferred to a 500 mL beaker and placed in a KQ-500DE ultrasonic cleaning machine (power 300 W). Ultrasonic treatment was performed for 30 min until a uniform suspension with no obvious precipitation was formed (the beaker should be covered during the ultrasonic process to prevent solvent evaporation);

[0166] Step 2: Add 2% Cu2O / Cu catalyst powder to the suspension and stir with a glass rod until the powder is dispersed;

[0167] Place the beaker on a constant temperature magnetic stirrer, set the temperature to 25°C, the stirring speed to 400 r / min, and react for 60 min (the system must be kept airtight during stirring to avoid temperature fluctuations);

[0168] Step 3: After the reaction is completed, use a Buchner funnel and quantitative filter paper to filter and collect the filter cake (before filtration, the filter paper must be moistened with deionized water to ensure that it fits the funnel);

[0169] Add 50 mL of deionized water to the filter cake, stir gently with a glass rod to redisperse the solid, filter again, and repeat the washing process three times;

[0170] Replace deionized water with 50 mL of anhydrous ethanol and wash three times according to the above steps (ethanol washing can remove residual ethylene glycol and organic matter);

[0171] Step 4: Transfer the washed filter cake to a clean surface dish, spread it flat to a thickness of no more than 5mm, and place it in a DHG-9070A type blast drying oven;

[0172] Set the temperature to 60°C and dry for 12 hours (turn the solids over every 4 hours during the drying process to ensure uniform drying);

[0173] Step 5: Grind the dried product into powder, and pass it through a 200-mesh sieve to obtain a 2% Cu2O / Cu modified strontium titanate photocatalytic material.

[0174] Example 5

[0175] This embodiment provides a 2.5% Cu2O / Cu modified strontium titanate photocatalytic material and a preparation process;

[0176] First, the raw materials were weighed according to weight percentage to prepare the Cu2O / Cu catalyst; the raw material weighing and proportioning were as follows:

[0177] Copper salt: 5% CuSO4·5H2O (soluble crystalline copper salt);

[0178] Solvent: a mixture of 60% ethylene glycol and water (volume ratio 2:1);

[0179] Alkali solution: 17.5% 5M NaOH solution (inorganic soluble strong base);

[0180] Reducing agent: 17.5% D-glucose solution (reducing sugar);

[0181] Then, the Cu2O / Cu catalyst is prepared using the above raw materials, and the specific steps are as follows:

[0182] Step 1: Add 5% CuSO4·5H2O to 60% mixed solvent (ethylene glycol: water = 2:1) and place in a three-necked flask;

[0183] Turn on magnetic stirring (speed 300-500 r / min) and place the reaction system in a water bath, heat to 60°C, and maintain for 20 min until the copper salt is completely dissolved to form a blue transparent solution;

[0184] Step 2: Slowly add 17.5% 5M NaOH solution dropwise (at a rate of about 1 drop / second) while stirring continuously during the addition process;

[0185] Step 3: After the addition is complete, stir at a constant speed for 5 minutes, and the solution gradually changes from blue to dark blue suspension;

[0186] Step 4: Rapidly add 17.5% D-glucose solution dropwise within 30 seconds while maintaining the stirring rate constant;

[0187] After the addition was completed, the water bath temperature was maintained at 60°C and the reaction was carried out at this temperature for 40 minutes. During this period, the color of the solution gradually changed from dark blue to brown-red, indicating that Cu2O / Cu particles began to form.

[0188] Step 5: After the reaction is completed, the mixture is transferred to a centrifuge tube and centrifuged at 8000-10000 rpm for 10 min to collect the brown-red precipitate at the bottom;

[0189] Deionized water was added to the precipitate until the solid was submerged, and the mixture was dispersed ultrasonically and centrifuged again, and the washing was repeated three times;

[0190] Replace deionized water with anhydrous ethanol and wash three more times according to the above steps to remove residual organic matter and ionic impurities;

[0191] Step 6: Transfer the washed precipitate to a Petri dish and place it in a 60°C forced air drying oven for 12 hours;

[0192] After drying, the product is ground into powder to obtain Cu2O / Cu catalyst.

[0193] Next, raw materials were weighed according to weight percentage to prepare a 2.5% Cu2O / Cu modified strontium titanate photocatalytic material; the raw material weighing and proportioning were as follows:

[0194] Strontium titanate: Weigh 10% (by weight) of spherical SrTiO3 powder (particle size 20-40 nm) and pass it through a 200-mesh sieve to remove agglomerated particles before use;

[0195] Cu2O / Cu catalyst: weigh 2.5 wt% Cu2O / Cu catalyst and grind it into fine powder for later use;

[0196] Solvent: Weigh 87.5% (by weight) of a mixture of ethylene glycol and water (volume ratio 2:1), where ethylene glycol must be analytical grade and water must be deionized;

[0197] Finally, the above raw materials were used to prepare a 2.5% Cu2O / Cu modified strontium titanate photocatalytic material, and the specific steps were as follows:

[0198] Step 1: Slowly add 10% strontium titanate powder to 87.5% solvent in the order of "powder to solvent" to avoid agglomeration;

[0199] The mixed solution was transferred to a 500 mL beaker and placed in a KQ-500DE ultrasonic cleaning machine (power 300 W). Ultrasonic treatment was performed for 30 min until a uniform suspension with no obvious precipitation was formed (the beaker should be covered during the ultrasonic process to prevent solvent evaporation);

[0200] Step 2: Add 2.5% Cu2O / Cu catalyst powder to the suspension and stir with a glass rod until the powder is dispersed;

[0201] Place the beaker on a constant temperature magnetic stirrer, set the temperature to 25°C, the stirring speed to 400 r / min, and react for 60 min (the system must be kept airtight during stirring to avoid temperature fluctuations);

[0202] Step 3: After the reaction is completed, use a Buchner funnel and quantitative filter paper to filter and collect the filter cake (before filtration, the filter paper must be moistened with deionized water to ensure that it fits the funnel);

[0203] Add 50 mL of deionized water to the filter cake, stir gently with a glass rod to redisperse the solid, filter again, and repeat the washing process three times;

[0204] Replace deionized water with 50 mL of anhydrous ethanol and wash three times according to the above steps (ethanol washing can remove residual ethylene glycol and organic matter);

[0205] Step 4: Transfer the washed filter cake to a clean surface dish, spread it flat to a thickness of no more than 5mm, and place it in a DHG-9070A type blast drying oven;

[0206] Set the temperature to 60°C and dry for 12 hours (turn the solids over every 4 hours during the drying process to ensure uniform drying);

[0207] Step 5: Grind the dried product into powder, and pass it through a 200-mesh sieve to obtain a 2.5% Cu2O / Cu modified strontium titanate photocatalytic material.

[0208] like Figure 1 Shown: According to Figure 1 From the SEM image of the Cu2O / Cu sample, it can be observed that smaller metallic Cu nanoparticles are dispersed on the surface of the micron-sized spherical Cu2O, and the metallic Cu nanoparticles are evenly dispersed and have uniform size and shape. This indicates that part of the Cu2+ in the solution is reduced to form Cu2O microspheres, and part of the Cu2+ is further reduced to Cu nanoparticles on the Cu2O surface. The nucleation energy of the Cu nanoparticles deposited on the Cu2O surface is lower than that of the Cu particles spontaneously formed in the solution. Therefore, Cu preferentially grows on the Cu2O surface rather than independently nucleating. In Examples 1 to 5, the Cu2O / Cu is uniformly and tightly combined with the SrTiO3 to form a Cu2O / Cu / SrTiO3 heterojunction.

[0209] Through the gradient experiments of Example 1 to Example 5, the effect of the amount of Cu2O / Cu catalyst (0.5% to 2.5%) on the performance of SrTiO3 photocatalytic materials was systematically studied. The key data are shown in Table 1:

[0210]

[0211] By analyzing the Cu2O / Cu catalyst dosage and formaldehyde degradation rate in Table 1, the degradation rate of Example 2 (1% Cu2O / Cu catalyst dosage) reached 91.6%, the highest among the five groups of experiments, confirming that 1% Cu2O / Cu catalyst loading is the optimal loading; at this time, the pn heterojunction density formed by Cu2O / Cu and SrTiO3 is moderate, the photogenerated carrier separation efficiency is the highest, and the surface plasmon resonance (SPR) effect of metallic Cu enhances visible light absorption; when the catalyst dosage exceeds 1% (Examples 3 to 5), the degradation rate shows a downward trend, which may be due to the agglomeration of Cu2O / Cu particles on the SrTiO3 surface, resulting in overlapping active sites, which in turn hinders the transmission of photogenerated electrons.

[0212] like Figure 1 As shown in Figure 2, the Cu2O / Cu particles of Example 2 are uniformly dispersed on the SrTiO3 surface through SEM observation, forming a spherical composite structure with a diameter of 20-40 nm, without obvious agglomeration; while the Cu2O / Cu particles of Example 5 are locally accumulated, confirming the adverse effects of excessive loading;

[0213] like Figure 2 As shown: The EDS spectrum shows that the Sr, Ti, O, and Cu elements are evenly distributed in the composite material of Example 2, confirming that Cu2O / Cu and SrTiO3 are successfully composited to form a Cu2O / Cu / SrTiO3 ternary system.

[0214] Four cycles of degradation experiments were conducted on Example 2. The results are shown in Table 2:

[0215]

[0216] After analyzing Table 2, the purification rate remains at 87.7% after 4 cycles, indicating that the material has good stability, which is mainly attributed to:

[0217] The chemical bonding force between Cu2O / Cu and SrTiO3 is strong and not easy to fall off;

[0218] The oxidation resistance of metallic Cu inhibits the photocorrosion of Cu2O and prolongs the catalytic life.

[0219] In summary, the mechanism of action of this photocatalytic material lies in the pn heterojunction formed by p-type Cu2O and n-type SrTiO3, which promotes the transfer of photogenerated electrons from the SrTiO3 conduction band to the Cu2O conduction band and the transfer of holes from the Cu2O valence band to the SrTiO3 valence band through energy band matching, effectively inhibiting charge recombination. At the same time, the SPR effect of nano-Cu particles enhances visible light absorption (wavelength extended to 600nm) and acts as an electron transport channel to accelerate carrier migration. When the catalyst dosage is 1%, Cu2O / Cu is dispersed in a monolayer on the SrTiO3 surface, maximizing the exposure of active sites and improving the formaldehyde adsorption and degradation efficiency. In addition, its technical advantages are significant. The formaldehyde degradation rate under visible light reaches 91.6%, which is better than similar materials. The efficiency retention rate exceeds 85% after 4 cycles. It has good stability. It is prepared by a green redox-impregnation method without toxic reagents. The process is simple and easy to scale up. It can be applied to indoor air purification, formaldehyde pollution control and photocatalytic environmental protection.

[0220] The basic principles of the present disclosure have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this disclosure are merely illustrative and not restrictive, and should not be construed as necessarily possessed by each embodiment of the present disclosure. Furthermore, the specific details disclosed above are provided for illustrative purposes and to facilitate understanding, rather than as limitations. These details do not limit the present disclosure to necessarily being implemented using these specific details.

[0221] In the present disclosure, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. The block diagrams of the devices, devices, equipment, and systems involved in the present disclosure are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "including," "comprising," "having," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0222] Additionally, as used herein, "or" used in a list of items beginning with "at least one" indicates a separate list, so that, for example, a list of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not mean that the example described is preferred or better than other examples.

[0223] It should also be noted that in the system and method of the present disclosure, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present disclosure.

[0224] Various changes, substitutions, and modifications may be made to the technology described herein without departing from the teachings defined by the appended claims. Moreover, the scope of the claims of this disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of things, means, methods, and actions described above. Currently existing or later developed processes, machines, manufactures, compositions of things, means, methods, or actions that perform substantially the same function or achieve substantially the same results as the corresponding aspects described herein may be utilized. Accordingly, the appended claims include within their scope such processes, machines, manufactures, compositions of things, means, methods, or actions.

[0225] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0226] The above description has been provided for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A Cu2O / Cu modified strontium titanate photocatalytic material, characterized in that: The raw materials include, by weight, 0.1-10% of Cu2O / Cu catalyst, 0.1-10% of strontium titanate, and 80-95% of photocatalytic material solvent; The Cu2O / Cu catalyst is prepared from the following raw materials by weight: 1-10% of copper salt, 1-20% of alkali, 1-10% of reducing agent and 80-95% of catalyst solvent.

2. The Cu2O / Cu modified strontium titanate photocatalytic material according to claim 1, characterized in that: The strontium titanate is spherical and has a particle size of 20-40 nm.

3. The Cu2O / Cu modified strontium titanate photocatalytic material according to claim 1, characterized in that: The photocatalytic material solvent is a mixture of ethylene glycol and water in a volume ratio of 2:

1.

4. The Cu2O / Cu modified strontium titanate photocatalytic material according to claim 1, characterized in that: The copper salt is a soluble crystalline copper salt, specifically CuSO4·5H2O.

5. The Cu2O / Cu modified strontium titanate photocatalytic material according to claim 1, characterized in that: The base is an inorganic soluble strong base, specifically one or more of KOH and NaOH.

6. The Cu2O / Cu modified strontium titanate photocatalytic material according to claim 1, characterized in that: The reducing agent is a reducing sugar, specifically D-glucose.

7. The Cu2O / Cu modified strontium titanate photocatalytic material according to claim 1, characterized in that: The catalyst solvent is a mixture of ethylene glycol and deionized water in a volume ratio of 2:

1.

8. A method for preparing a Cu2O / Cu modified strontium titanate photocatalytic material, applied to a Cu2O / Cu modified strontium titanate photocatalytic material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step 1: adding strontium titanate to the solvent for preparing the photocatalytic material, placing the solvent in an ultrasonic cleaning machine and dispersing the solvent evenly to form a suspension; Step 2: adding Cu2O / Cu catalyst to the suspension, stirring at 20-50°C for 60-100 minutes to obtain a reaction product; Step 3: Filter the reaction product to remove the solvent used to prepare the photocatalytic material to obtain a solid product; Step 4: washing the solid product obtained by filtration with deionized water and ethanol; Step 5: Place the washed product in an oven for drying to obtain a Cu2O / Cu modified strontium titanate photocatalytic material.

9. The method for preparing a Cu2O / Cu modified strontium titanate photocatalytic material according to claim 8, characterized in that: The preparation steps of the Cu2O / Cu catalyst are as follows: Step 1: Dissolve the copper salt in a catalyst solvent and heat in a water bath to 60°C while stirring for 20 minutes; Step 2: Add the diluted alkaline solution, stir at a constant speed for 5 minutes, and add the reducing agent dropwise; Step 3: Maintain the reaction system temperature at 60°C and continue the reaction for 40-60 minutes to fully reduce the copper ions to form Cu2O / Cu composite particles; Step 4: After the reaction is completed, the product is centrifuged to obtain a separated solid product; Step 5: Wash the separated solid product with deionized water and ethanol multiple times to remove residual reaction reagents; Step 6: Dry the washed solid product in an oven at 60° C. for 12 hours to obtain a Cu2O / Cu catalyst.

10. The method for preparing a Cu2O / Cu modified strontium titanate photocatalytic material according to claim 9, characterized in that: The concentration of the diluted alkaline solution is 5M, and the reducing agent is added dropwise at a rate of 30 seconds.

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