A photocatalytic system based on CoP-regulated electron migration pathway of TiVO2 / g-C3N4Z heterojunction, its preparation method and application

Abstract

The application discloses a kind of based on CoP regulation Ti V A photocatalytic system based on O2 / g-C3N4 Z-type heterojunction electronic migration path, a preparation method and application thereof are disclosed.The photocatalytic system comprises Ti V O2 / g-C3N4 Z-type heterojunction material as a substrate and CoP nanostructured material as a regulation component loaded on the Ti V O2 / g-C3N4 Z-type heterojunction material, wherein Ti V O2 is TiO2 with Ti defects.The photocatalytic system can reduce CO2 to CO, CH4 and other hydrocarbons and simultaneously oxidize and degrade tetracycline, metronidazole and other organic pollutants in aqueous solution under visible light irradiation, realizing the synergistic effect of pollutant removal and CO2 resource utilization.In addition, there is no need to add any sacrificial agent in the reaction system, which not only avoids the waste of photo-generated hole energy, but also realizes the full use of photo-generated carriers, thereby improving the overall reaction efficiency.

Description

Technical Field

[0001] This invention relates to the field of photocatalysis, and more particularly to a method based on CoP-regulated Ti V Photocatalytic systems with O2 / g-C3N4Z heterojunction electron migration pathways, their preparation methods, and applications. Background Technology

[0002] With the increasing severity of global energy and environmental problems, photocatalytic CO2 reduction technology has attracted widespread attention due to its ability to convert greenhouse gases into high-value-added chemicals. Meanwhile, the residues of organic pollutants (such as antibiotics) in water bodies also pose a threat to the ecological environment and human health. Therefore, developing a highly efficient photocatalytic system capable of coupling CO2 reduction and organic pollutant degradation is of great significance.

[0003] Z-type heterojunctions have shown great potential in photocatalysis due to their ability to retain strong redox capabilities while achieving effective charge separation. Among them, traditional TiO2 / g-C3N4 Z-type heterojunction materials, with their matched band structure, have been widely studied for CO2 reduction and pollutant degradation. However, their charge transfer efficiency is limited by interfacial contact quality and electron migration pathways, leading to instability. Currently, no systematic research has explored the regulatory role of electron migration pathways in TiO2 / g-C3N4 Z-type heterojunctions. Summary of the Invention

[0004] The main objective of this invention is to provide a method for regulating Ti based on CoP. V The photocatalytic system of O2 / g-C3N4Z heterojunction electron migration pathway, its preparation method and application, can use CoP nanostructure materials with different morphologies as electron migration bridges to optimize the electron transport path in the heterojunction, thereby improving the separation efficiency and catalytic activity of photogenerated carriers.

[0005] To achieve the above objectives, this invention provides a method based on CoP-regulated Ti V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, characterized in that it includes Ti as a matrix. V O2 / g-C3N4Z type heterojunction material and Ti V CoP nanostructures serving as modulating components on O2 / g-C3N4Z type heterojunction materials, wherein Ti V O2 is TiO2 with Ti defects.

[0006] Furthermore, the morphology of the CoP nanostructure material is selected from any one of nanorods, nanosheets, and hollow spheres. The photocatalytic system can regulate the distribution of active sites and the direction of electron migration by using CoP nanostructure materials with different morphologies.

[0007] Furthermore, the CoP nanostructure material is loaded on the Ti V The surface or heterojunction interface of O2 / g-C3N4Z type heterojunction materials.

[0008] Furthermore, by using g-C3N4 and Ti V O2 and CoP nanostructure materials were prepared using an electrostatic self-assembly method.

[0009] The present invention also provides the above-mentioned method for regulating Ti based on CoP. V A method for preparing a photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway includes the following steps:

[0010] (1) Ti V O2 preparation

[0011] Tetrabutyl titanate was added to a mixed solution of glycerol and ethanol under stirring conditions, followed by heating. After the reaction was complete, the resulting solid product was collected, washed, dried, and finally calcined in air to obtain Ti. V O2;

[0012] (2) Synthesis of CoP nanostructured materials

[0013] First, a solvothermal method was used to prepare a sheet-like precursor, a hollow spherical precursor, or a rod-like precursor of Co. Then, the precursor and NaH2PO2 were placed at the downstream and upstream positions of the same quartz boat, respectively, and calcined in a nitrogen atmosphere to obtain sheet-like, hollow spherical, or rod-like CoP nanostructured materials.

[0014] (3) Electrostatic self-assembly

[0015] g-C3N4, Ti V O2 and CoP were mixed and then ultrasonically treated to obtain CoP-regulated Ti. V Photocatalytic system with O2 / g-C3N4Z heterojunction electron migration pathway.

[0016] Furthermore, the preparation process of the sheet-like precursor is as follows: CoCl2·6H2O and hexamethylenetetramine are dissolved in deionized water and stirred at 60-120℃ for 1 hour. The product is then collected, washed, and dried to obtain the sheet-like precursor.

[0017] Furthermore, the preparation process of the hollow spherical precursor is as follows: Co(NO3)2·6H2O is dispersed in a mixed solvent composed of isopropanol and glycerol, and reacted at 180℃ for 6h. The product is then collected, washed, dried, and redispersed in deionized water, and reacted at 180℃ for another 6h. Finally, the product is collected, washed, and dried to obtain the hollow spherical precursor.

[0018] Furthermore, the preparation process of the rod-shaped precursor is as follows: Co(NO3)2·6H2O and urea are dispersed in deionized water and reacted at 120℃ for 12h. The product is then collected, washed, and dried to obtain the rod-shaped precursor.

[0019] The present invention also provides an application of the above-mentioned photocatalytic system in the coupled reaction of photocatalytic CO2 reduction and organic pollutant oxidation.

[0020] Furthermore, no sacrificial agent is added during the application reaction process.

[0021] The design principle of this invention is as follows:

[0022] Transition metal phosphides (CoPs) possess excellent electrical conductivity, noble metal-like catalytic activity, and good stability, making them suitable as co-catalysts and electron migration bridges. Furthermore, the morphology of CoPs significantly influences their conductivity, active site distribution, and electron migration pathways. CoPs and Ti... V A tight interfacial contact is formed between O2 / g-C3N4, which can regulate the electron migration path and enhance charge separation efficiency.

[0023] Introducing electron migration bridges into Z-type heterojunction systems is an effective strategy. To date, various materials have been widely used as electron bridges, including noble metals (such as platinum, gold, and silver), transition metals (such as cadmium and copper), and non-metallic materials (such as carbon dots, reduced graphene oxide, oxygen vacancies, and multi-walled carbon nanotubes). However, these materials generally suffer from resource scarcity or high cost, limiting their large-scale application. This application selects CoP, a typical representative of TMPs (transition metal phosphides), which possesses low overpotential, high stability, low cost, and excellent conductivity. It can be used as an electron bridge to effectively reduce electron migration resistance at the heterojunction interface and can also serve as a non-noble metal co-catalyst. Therefore, introducing CoP, which also functions as an electron bridge, into the Z-type system is an ideal strategy for constructing efficient Z-type heterojunction structures.

[0024] Currently, no studies have systematically explored the regulatory role of CoP electron bridges with different morphologies on electron migration pathways in Z-type heterojunctions, nor their application in the photocatalytic coupling reaction of CO2 reduction and pollutant oxidation. Based on the unique properties of CoP and the aforementioned improvement strategies, this invention introduces CoP electron migration bridges with different morphologies into Ti... V In the O2 / g-C3N4Z heterojunction system, the effects of different CoP morphologies (e.g., nanosheets, nanorods, hollow spheres) on Ti were investigated. V The regulatory role of electron migration pathways in O2 / g-C3N4Z heterojunctions. This invention provides a new approach for constructing efficient photocatalytic systems using transition metal phosphides (TMPs) to achieve synergistic CO2 reduction and organic pollutant degradation.

[0025] The beneficial effects of this invention are reflected in:

[0026] The photocatalytic system of this invention can reduce CO2 to hydrocarbons such as CO and CH4 under visible light irradiation, and simultaneously oxidize and degrade organic pollutants such as tetracycline and metronidazole, achieving a synergistic effect of pollutant removal and CO2 resource utilization. Furthermore, no sacrificial agent is added to the reaction system, which not only avoids the waste of photogenerated hole energy but also achieves full utilization of photogenerated charge carriers, thereby improving the overall reaction efficiency. It has the following advantages:

[0027] I. CoP, as an electron migration bridge, not only effectively reduces interfacial migration resistance, but also significantly improves charge separation efficiency and interfacial charge transport rate.

[0028] II. By introducing CoP structures with different morphologies, it is possible to achieve the desired effect on Ti. V Precise regulation of electron migration pathways in O2 / g-C3N4Z heterojunctions; CoPs with different morphologies can regulate the distribution of active sites and the direction of electron migration, thereby enhancing catalytic selectivity and reaction efficiency.

[0029] Third, it achieves efficient coupling of CO2 reduction and organic pollutant oxidation, resulting in significant environmental and energy benefits. Attached Figure Description

[0030] Figure 1 For different morphologies of CoP and Ti V SEM images of O2@CoP@g-C3N4;

[0031] Figure 2 For Ti V O2 and Ti V EPR plot of O2@SCoP@g-C3N4;

[0032] Figure 3 For Ti V Performance of O2@SCoP@g-C3N4 catalyst under visible light for CO2 reduction coupled with tetracycline (TC) oxidation;

[0033] Figure 4 Ti regulated by CoP with different morphologies V Photocatalytic redox performance of O2@CoP@g-C3N4 catalyst;

[0034] Figure 5 For Ti V Photocatalytic redox performance of O2@5SCoP@g-C3N4 catalyst in different reaction systems. Detailed Implementation

[0035] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0036] Unless otherwise specified, the raw materials, reagents or devices used in the following embodiments can be obtained from conventional commercial sources or by existing known methods; unless otherwise specified, the methods used in the embodiments of the present invention are methods mastered by those skilled in the art.

[0037] Example 1

[0038] Ti V Preparation of O2@1SCoP@g-C3N4” photocatalyst

[0039] The preparation method includes the following steps:

[0040] (1) Preparation of g-C3N4 nanosheets

[0041] 5.04 g of melamine and 5.16 g of cyanuric acid were thoroughly ground and mixed, and then ultrasonically dispersed in 200 mL of deionized water. After stirring continuously for 12 h, the melamine-cyanuric acid complex was obtained by centrifugation and dried at 60 °C for 12 h. Subsequently, the dried product was ground into a fine powder, transferred to a covered crucible, and finally, heated in air at 5 °C·min. -1 The temperature was increased to 550℃ and calcined for 4 hours to obtain g-C3N4 nanosheets.

[0042] (2) Ti V O2 preparation

[0043] Under magnetic stirring, 1.5 g of tetrabutyl titanate (Ti(OC4H9)4, TBT) was slowly added to a mixed solution of 15 mL glycerol and 45 mL ethanol. The resulting mixture was then transferred to an 80 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 180 °C for 24 h. After the reaction, the resulting solid product (glycerate ester) was collected and washed repeatedly with anhydrous ethanol and deionized water, followed by drying at 60 °C for 12 h. Finally, the dried white powder product was dried in air at 5 °C·min. -1 The temperature was increased to 470℃ and calcined for 1 hour at a heating rate of [missing information] to obtain titanium dioxide powder rich in Ti defects, labeled as Ti [missing information]. V O2.

[0044] (3) Preparation of sheet-like CoP nanostructured materials

[0045] 1.43 g CoCl2·6H2O and 10.0 g hexamethylenetetramine (HMT) were dissolved in 200 mL of deionized water, and then heated to react at 90 °C under magnetic stirring for 1 h to obtain a suspension containing green particles. After filtration, the product was washed several times with deionized water and anhydrous ethanol, and finally dried at 60 °C for 12 h to obtain a sheet-like precursor.

[0046] A sheet-like precursor and NaH₂PO₂ (in a Co:P mass ratio of 1:10) were placed in two separate regions of the same quartz boat, with NaH₂PO₂ in the upstream region and the sheet-like precursor in the downstream region. The mixture was then calcined at 350 °C for 2 h under a N₂ atmosphere at a heating rate of 1 °C / min. After the reaction was complete, the product in the downstream quartz boat was collected, yielding sheet-like cobalt phosphide nanostructured material, labeled SCoP.

[0047] (4) Ti V Assembly of O2@1SCoP@g-C3N4

[0048] 100 mg g-C3N4 nanosheets, 1 mg SCoP and 1 mg Ti were added. V O2 powder was added to a 100 mL beaker, followed by ultrasonic treatment (100 W) for 1 h. The mixture was then washed multiple times with deionized water and centrifuged. The collected powder was vacuum dried at 60 °C for 12 h to obtain a Ti-based product regulated by CoP. V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@1SCoP@g-C3N4.

[0049] Example 2

[0050] Ti V Preparation of O2@1SCoP@g-C3N4” photocatalyst

[0051] The preparation method includes the following steps:

[0052] (1) Preparation of g-C3N4 nanosheets

[0053] 5.04 g of melamine and 5.16 g of cyanuric acid were thoroughly ground and mixed, and then ultrasonically dispersed in 200 mL of deionized water. After stirring continuously for 12 h, the melamine-cyanuric acid complex was obtained by centrifugation and dried at 60 °C for 12 h. Subsequently, the dried product was ground into a fine powder, transferred to a covered crucible, and finally, heated in air at 2.5 °C·min. -1 The temperature was increased to 500℃ and calcined for 2 hours to obtain g-C3N4 nanosheets.

[0054] (2) TiV O2 preparation

[0055] Under magnetic stirring, 1.5 g of tetrabutyl titanate (Ti(OC4H9)4, TBT) was slowly added to a mixed solution of 15 mL glycerol and 45 mL ethanol. The resulting mixture was then transferred to an 80 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 120 °C for 12 h. After the reaction, the resulting solid product (glycerate ester) was collected and washed repeatedly with anhydrous ethanol and deionized water, followed by drying at 60 °C for 12 h. Finally, the dried white powder product was dried in air at 2.5 °C·min. -1 The temperature was increased to 400℃ and calcined for 0.5 h at a heating rate to obtain titanium dioxide powder rich in Ti defects, labeled as Ti V O2.

[0056] (3) Preparation of sheet-like CoP nanostructured materials

[0057] 1.43 g CoCl2·6H2O and 10.0 g hexamethylenetetramine (HMT) were dissolved in 200 mL of deionized water, and then heated to react at 60 °C under magnetic stirring for 1 h to obtain a suspension containing green particles. After filtration, the product was washed several times with deionized water and anhydrous ethanol, and finally dried at 60 °C for 12 h to obtain a sheet-like precursor.

[0058] A sheet-like precursor and NaH₂PO₂ (in a Co:P mass ratio of 1:10) were placed in two separate regions of the same quartz boat, with NaH₂PO₂ in the upstream region and the sheet-like precursor in the downstream region. The mixture was calcined at 350 °C for 2 hours under a N₂ atmosphere at a heating rate of 1 °C / min. After the reaction was complete, the product in the downstream quartz boat was collected, yielding sheet-like cobalt phosphide nanostructured material, labeled SCoP.

[0059] (4) Ti V Assembly of O2@1SCoP@g-C3N4

[0060] 100 mg g-C3N4 nanosheets, 1 mg SCoP and 1 mg Ti were added. V O2 powder was added to a 100 mL beaker, followed by ultrasonic treatment (100 W) for 0.5 h. After washing several times with deionized water and centrifuging, the resulting powder was collected and vacuum-dried at 60 °C for 12 h to obtain a Ti-based product based on CoP regulation. V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@1SCoP@g-C3N4.

[0061] Example 3

[0062] Ti V Preparation of O2@1SCoP@g-C3N4” photocatalyst

[0063] The preparation method includes the following steps:

[0064] (1) Preparation of g-C3N4 nanosheets

[0065] 5.04 g of melamine and 5.16 g of cyanuric acid were thoroughly ground and mixed, and then ultrasonically dispersed in 200 mL of deionized water. After stirring continuously for 12 h, the melamine-cyanuric acid complex was obtained by centrifugation and dried at 60 °C for 12 h. Subsequently, the dried product was ground into a fine powder, transferred to a covered crucible, and finally, heated in air at 10 °C·min. -1 The temperature was increased to 600℃ and calcined for 6 hours to obtain g-C3N4 nanosheets.

[0066] (2) Ti V O2 preparation

[0067] Under magnetic stirring, 1.5 g of tetrabutyl titanate (Ti(OC4H9)4, TBT) was slowly added to a mixed solution of 15 mL glycerol and 45 mL ethanol. The resulting mixture was then transferred to an 80 mL high-pressure reactor lined with polytetrafluoroethylene and reacted at 200 °C for 36 h. After the reaction, the resulting solid product (glycerate ester) was collected and washed repeatedly with anhydrous ethanol and deionized water, followed by drying at 60 °C for 12 h. Finally, the dried white powder product was dried in air at 10 °C·min. -1 The temperature was increased to 500℃ and calcined for 2 hours to obtain titanium dioxide powder rich in Ti defects, labeled as Ti. V O2.

[0068] (3) Preparation of sheet-like CoP nanostructured materials

[0069] 1.43 g CoCl2·6H2O and 10.0 g hexamethylenetetramine (HMT) were dissolved in 200 mL of deionized water, and then heated at 120 °C with magnetic stirring for 1 h to obtain a suspension containing green particles. After filtration, the product was washed several times with deionized water and anhydrous ethanol, and finally dried at 60 °C for 12 h to obtain a sheet-like precursor.

[0070] A sheet-like precursor and NaH₂PO₂ (mixed at a Co:P mass ratio of 1:10) were placed in two separate regions of the same quartz boat, with NaH₂PO₂ in the upstream region and the sheet-like precursor in the downstream region. The mixture was calcined at 350 °C for 2 hours under a N₂ atmosphere at a heating rate of 1 °C / min. After the reaction was complete, the product in the downstream quartz boat was collected, yielding sheet-like cobalt phosphide nanostructured material, labeled SCoP.

[0071] (4) Ti V Assembly of O2@1SCoP@g-C3N4

[0072] 100 mg g-C3N4 nanosheets, 1 mg SCoP and 1 mg Ti were added. V O2 powder was added to a 100 mL beaker, followed by ultrasonic treatment (100 W) for 2 h. The mixture was then washed multiple times with deionized water and centrifuged. The collected powder was vacuum dried at 60 °C for 12 h to obtain a Ti-based product regulated by CoP. V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@1SCoP@g-C3N4.

[0073] Example 4

[0074] Ti V Preparation of O2@2.5SCoP@g-C3N4” photocatalyst

[0075] The preparation method is basically the same as in Example 1, except that in step (4), the amount of raw materials is adjusted to 100 mg g-C3N4 nanosheets, 2.5 mg SCoP and 1 mg Ti V O2 powder. The Ti-based powder obtained in this embodiment is based on CoP regulation. V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@2.5SCoP@g-C3N4.

[0076] Example 5

[0077] Ti V Preparation of O2@5SCoP@g-C3N4” photocatalyst

[0078] The preparation method is basically the same as in Example 1, except that in step (4), the amount of raw materials is adjusted to 100 mg g-C3N4 nanosheets, 5 mg SCoP and 1 mg Ti V O2 powder. The Ti-based powder obtained in this embodiment is based on CoP regulation. VA photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@5SCoP@g-C3N4.

[0079] Example 6

[0080] Ti V Preparation of the O2@7.5SCoP@g-C3N4” photocatalytic system

[0081] The preparation method is basically the same as in Example 1, except that in step (4), the amount of raw materials is adjusted to 100 mg g-C3N4 nanosheets, 7.5 mg SCoP and 1 mg Ti V O2 powder. The Ti-based powder obtained in this embodiment is based on CoP regulation. V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@7.5SCoP@g-C3N4.

[0082] Example 7

[0083] Ti V Preparation of O2@10SCoP@g-C3N4” photocatalyst

[0084] The preparation method is basically the same as in Example 1, except that in step (4), the amount of raw materials is adjusted to 100 mg g-C3N4 nanosheets, 10 mg SCoP and 1 mg Ti V O2 powder. The Ti-based powder obtained in this embodiment is based on CoP regulation. V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@10SCoP@g-C3N4.

[0085] Example 8

[0086] Ti V Preparation of O2@5HCoP@g-C3N4” photocatalyst

[0087] The preparation method is basically the same as in Example 5, except that the sheet-like CoP nanostructure material SCoP is replaced with the hollow spherical nanostructure material HCoP. The Ti-based CoP-regulated material obtained in this example... V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@5HCoP@g-C3N4.

[0088] The preparation method of HCoP is as follows:

[0089] 2 mmol of Co(NO3)2·6H2O was dispersed in 32 mL of a mixed solvent consisting of isopropanol and glycerol in a volume ratio of 25:7. The solution was then transferred to a 50 mL polytetrafluoroethylene (PTFE) liner and placed in a stainless steel autoclave. The reaction was carried out at 180 °C for 6 h. The resulting solid product was centrifuged, thoroughly washed with ethanol, and dried at 60 °C for 12 h. The dried powder was redispersed in 32 mL of deionized water, transferred again to a 50 mL PTFE liner, and placed in a stainless steel autoclave. The reaction was carried out at 180 °C for 6 h. The resulting product was centrifuged, washed with deionized water, and dried at 60 °C for 12 h to obtain a hollow spherical precursor. The hollow spherical precursor and NaH2PO2 (prepared at a Co:P mass ratio of 1:10) were placed in two separate regions of the same quartz boat, with NaH2PO2 in the upstream position and the hollow spherical precursor in the downstream position. Under a nitrogen atmosphere, the temperature was increased to 350℃ at a heating rate of 1℃ / min and held for 2 hours. After the reaction was completed, the product in the downstream quartz boat was collected, which was the hollow spherical cobalt phosphide nanostructure material, labeled as HCoP.

[0090] Example 9

[0091] Ti V Preparation of O2@5RCoP@g-C3N4” photocatalyst

[0092] The preparation method is basically the same as in Example 5, except that the sheet-like CoP nanostructure material SCoP is replaced with the rod-like nanostructure material RCoP. The Ti-based CoP-regulated material obtained in this example... V A photocatalytic system with an O2 / g-C3N4Z heterojunction electron migration pathway, labeled as Ti V O2@5RCoP@g-C3N4.

[0093] The preparation method of RCoP is as follows: 1 mmol Co(NO3)2·6H2O and 3 mmol urea were added to 40 mL of deionized water, stirred for 30 minutes, and then transferred to a 100 mL polytetrafluoroethylene liner. The mixture was placed in a stainless steel autoclave and reacted at 120 °C for 12 h. After the reaction, the mixture was naturally cooled to room temperature to obtain a purple product. The product was centrifuged, washed multiple times with deionized water and anhydrous ethanol, and dried at 60 °C for 12 h to obtain a rod-shaped precursor. The rod-shaped precursor and NaH2PO2 (mixed at a Co:P mass ratio of 1:10) were placed in two separate regions of the same quartz boat, with NaH2PO2 in the upstream position and the rod-shaped precursor in the downstream position. The mixture was calcined at 350 °C for 2 h under a N2 atmosphere at a heating rate of 1 °C / min. After the reaction, the product in the downstream quartz boat was collected, which is the rod-shaped cobalt phosphide nanostructure material, labeled RCoP.

[0094] Experimental Example 1

[0095] Structural characteristics analysis of photocatalytic systems

[0096] The HCoP, SCoP, RCoP, and Ti prepared in Examples 1, 5, 8, and 9 V O2@5HCoP@g-C3N4、Ti V O2@5SCoP@g-C3N4 and Ti V Taking O2@5RCoP@g-C3N4 as an example, we observe its microstructure.

[0097] The results are as follows Figure 1 As shown in the figure. Figure A is an electron microscope image of HCoP, Figure B is an electron microscope image of SCoP, Figure C is an electron microscope image of RCoP, and Figure D is an electron microscope image of Ti. V Electron micrograph of O2@5HCoP@g-C3N4, E figure is Ti V Electron micrograph of O2@5SCoP@g-C3N4, F figure shows Ti V Electron microscopy images of O2@5RCoP@g-C3N4. It can be seen that HCoP exhibits a hollow spherical structure composed of nanosheets, SCoP is composed of stacked nanosheets, and RCoP presents a rod-like structure. When HCoP, SCoP, and RCoP are introduced into Ti... V After entering the O2@g-C3N4 heterojunction system, hollow spherical HCoP, sheet-like SCoP, and rod-like RCoP can be clearly observed distributed in Ti. V The O2 and g-C3N4 interface or its composite structure surface. The above results further demonstrate that the introduction of CoP with different morphologies can not only [benefit] Ti V O2 acts as an electron transport bridge between itself and g-C3N4, promoting the directional migration of charges. It can also serve as a co-catalyst, attaching to the surface of the heterojunction and providing more catalytically active sites. Therefore, this invention effectively optimizes the electron transport path in the heterojunction by introducing CoP nanomaterials with different morphologies as electron transport bridges, improving the separation efficiency of photogenerated carriers and the catalytic activity, thereby achieving highly efficient synergistic catalysis for CO2 reduction and the oxidation of organic pollutants (such as tetracycline).

[0098] Experiment Example 2

[0099] Structural analysis of Ti defects

[0100] Ti prepared according to Examples 1 and 5 V O2 and Ti V Taking the O2@5SCoP@g-C3N4 photocatalyst as an example, we analyze the existence of its defects.

[0101] The results are as follows Figure 2As shown in the figure. It can be seen from the figure that Ti V O2 and Ti V The O2@5SCoP@g-C3N4 catalysts both exhibited obvious EPR signal peaks, further indicating that Ti defects have been successfully introduced into these two catalysts.

[0102] Experimental Example 3

[0103] Activity analysis of photocatalytic CO2 reduction coupled with tetracycline (TC) oxidation in photocatalyst system

[0104] A series of CoP-modified Ti samples with different morphologies prepared in the above embodiments were used. V The photocatalytic system with the electron migration pathway of the O2 / g-C3N4Z heterojunction was used in the coupled reaction system of photocatalytic CO2 reduction coupled with TC oxidation decomposition. The specific process is as follows:

[0105] After adding 50 mg of photocatalyst to the photocatalytic reactor, 50 mL of TC aqueous solution (20 mg / L) was added and ultrasonically dispersed for 5 min. Then, the reactor was vacuumed, and 50 mL of CO2 (purity 99.999%) reaction gas was introduced into the reactor. Subsequently, the reaction was carried out under 300 W xenon lamp irradiation. Every 1 h, the gaseous products of the photocatalytic reaction (mainly CO and CH4) were measured using a gas chromatograph. After 5 h of reaction, the reaction liquid was collected, the catalyst powder was removed by centrifugation, and finally the absorbance of the TC supernatant after the catalytic reaction was measured using a UV-Vis spectrophotometer.

[0106] Figure 3 This invention relates to a series of photocatalyst systems (Ti in Example 1). V O2@1SCoP@g-C3N4, Ti in Example 4 V O2@2.5SCoP@g-C3N4, Ti in Example 5 V O2@5SCoP@g-C3N4, Ti in Example 6 V O2@7.5SCoP@g-C3N4, Ti in Example 7 V The photocatalytic CO2 reduction coupled TC oxidation activity results of O2@10SCoP@g-C3N4 (using the Ti in Example 1) V O2, g-C3N4 and Ti V O2@g-C3N4 served as the control, and Ti V O2@g-C3N4 is obtained by omitting SCoP from Example 1. Figure 3 It can be seen that Ti V The photocatalytic performance of O2@g-C3N4 is significantly superior to that of single-component Ti. VO2 and g-C3N4 indicate that the construction of heterojunctions can effectively improve photocatalytic redox performance;

[0107] Once sheet-like SCoP is introduced, Ti V O2@SCoP@g-C3N4 was significantly improved, and Ti increased with increasing SCoP deposition. V The photocatalytic CO2 reduction coupled with TC oxidation activity of O2@SCoP@g-C3N4 increases accordingly, reaching its maximum at 5 wt%. However, with further increases in SCoP deposition, Ti... V However, the photocatalytic redox performance of O2@SCoP@g-C3N4 gradually decreased.

[0108] Experiment Example 4

[0109] Effects of different CoP morphologies on the photocatalytic activity of the photocatalyst system

[0110] Ti prepared according to Examples 5, 8 and 9 V O2@5HCoP@g-C3N4、Ti V O2@5SCoP@g-C3N4 and Ti V Taking the O2@5RCoP@g-C3N4 photocatalyst as an example, its corresponding photocatalytic CO2 reduction coupled TC oxidation activity was measured (the measurement method is the same as in Experiment 2).

[0111] The results are as follows Figure 4 As shown. By Figure 4 It can be seen that Ti V O2@5SCoP@g-C3N4 photocatalyst is superior to Ti V O2@5HCoP@g-C3N4 and Ti V The O2@5RCoP@g-C3N4 catalyst exhibits excellent photocatalytic redox performance, mainly attributed to the fact that the plate-like SCoP can effectively improve the photocatalytic redox performance.

[0112] Experimental Example 5

[0113] Effects of different reaction systems on the catalytic activity of the photocatalyst system of this invention

[0114] Following the method in Experimental Example 2, different reaction systems were constructed (a single TC oxidation system, a coupled reaction system of CO2 reduction coupled with TC oxidation, and a single CO2 reduction system), and Ti was added. VThe O2@5SCoP@g-C3N4 photocatalysts were tested for catalytic activity in the above systems. The coupled reaction system corresponds to the coupled reaction system of photocatalytic CO2 reduction coupled with TC oxidation in Experimental Example 2; the single TC oxidation system is the same as Experimental Example 2 without the addition of CO2; and the single CO2 reduction system is the same as Experimental Example 2 without the addition of TC aqueous solution.

[0115] Test results as follows Figure 5 As shown. By Figure 5 It can be seen that Ti V The O2@5SCoP@g-C3N4 photocatalyst exhibits optimal photocatalytic redox performance in the "coupled reaction system of photocatalytic CO2 reduction coupled with TC oxidation," significantly outperforming other "single reaction systems." This confirms that the coupled reaction system achieves full utilization of charge carriers, thus demonstrating remarkable photocatalytic oxidation performance. Therefore, the Ti prepared in this invention... V The O2@5SCoP@g-C3N4 photocatalyst has potential applications in synergistically alleviating the energy crisis and treating industrial wastewater.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating Ti based on CoP V The photocatalytic system with an O2 / g-C3N4 Z-type heterojunction electron migration pathway is characterized by... Ti as a base V O2 / g-C3N4 Z-type heterojunction material and CoP nanostructure material as a regulation component loaded on Ti V O2 / g-C3N4 Z-type heterojunction material and CoP nanostructure material as a regulation component loaded on Ti V O2 is TiO2 with Ti defects; The morphology of the CoP nanostructure material is selected from any one of nanorods, nanosheets and hollow spheres. The photocatalytic system can regulate the distribution of active sites and the direction of electron migration by CoP nanostructure materials with different morphologies. The CoP-based Ti regulation V A method for preparing a photocatalytic system with an O2 / g-C3N4 Z-type heterojunction electron migration pathway includes the following steps: (1) Ti V O2 preparation Tetrabutyl titanate was added to a mixed solution of glycerol and ethanol under stirring conditions, followed by heating. After the reaction was complete, the resulting solid product was collected, washed, dried, and finally calcined in air to obtain Ti. V O2; (2) Synthesis of CoP nanostructured materials First, a sheet-like, hollow spherical, or rod-like precursor of Co is prepared by a solvothermal method. Then, the precursor and NaH2PO2 are placed in two regions of the same quartz boat and calcined in a nitrogen atmosphere to obtain sheet-like, hollow spherical, or rod-like CoP nanostructured materials. (3) Electrostatic self-assembly g-C3N4, Ti V O2 and CoP were mixed and then ultrasonically treated to obtain CoP-regulated Ti. V Photocatalytic system with O2 / g-C3N4 Z-type heterojunction electron migration pathway.

2. The CoP-based Ti regulation method as described in claim 1 V The photocatalytic system with an O2 / g-C3N4 Z-type heterojunction electron migration pathway is characterized by... CoP nanostructure material loaded on Ti V The surface or heterojunction interface of O2 / g-C3N4 Z-type heterojunction material.

3. The CoP-based Ti regulation method as described in claim 1 V The photocatalytic system with an O2 / g-C3N4 Z-type heterojunction electron migration pathway is characterized by... The preparation process of the sheet-like precursor is as follows: CoCl2·6H2O and hexamethylenetetramine are dissolved in deionized water and stirred at 60-120℃ for 1 h. The product is then collected, washed, and dried to obtain the sheet-like precursor.

4. The CoP-based Ti regulation method as described in claim 1 V The photocatalytic system with an O2 / g-C3N4 Z-type heterojunction electron migration pathway is characterized by... The preparation process of the hollow spherical precursor is as follows: Co(NO3)2·6H2O is dispersed in a mixed solvent composed of isopropanol and glycerol, and reacted at 180℃ for 6h. The product is then collected, washed, dried, and redispersed in deionized water. The reaction is then carried out at 180℃ for 6h. Finally, the product is collected, washed, and dried to obtain the hollow spherical precursor.

5. The CoP-based Ti regulation method as described in claim 1 V The photocatalytic system with an O2 / g-C3N4 Z-type heterojunction electron migration pathway is characterized by... The preparation process of the rod-shaped precursor is as follows: Co(NO3)2·6H2O and urea are dispersed in deionized water and reacted at 120℃ for 12h. The product is then collected, washed, and dried to obtain the rod-shaped precursor.

6. The application of the photocatalytic system as described in any one of claims 1 to 5 in the coupled reaction of photocatalytic CO2 reduction and organic pollutant oxidation.

7. The application as described in claim 6, characterized in that, No sacrificial agents are added during the reaction.

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