Functionalized graphene modulated nanocomposite photocatalyst and preparation method thereof

Abstract

This invention discloses a novel method for preparing a functionalized graphene-modified nanocomposite photocatalyst, comprising the following steps: Sodium tungstate dihydrate and PVP are selected and treated to obtain layered WO3. Then, graphene is subjected to specific treatment to obtain partially functionalized graphene. Subsequently, it is ultrasonically treated in deionized water, and a measured amount of layered WO3 is added and stirred. The mixture is then placed in a Teflon-lined autoclave and heated for a period of time. After cooling, it is repeatedly purified with deionized water and dried. Finally, it is calcined at high temperature in a nitrogen atmosphere to obtain graphene-functionalized layered WO3. This WO3 is dissolved with a measured amount of ZnPc in anhydrous ethanol and stirred for a period of time, followed by water bath drying to obtain the final functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst. The composite photocatalyst obtained by this preparation method has the characteristics of high efficiency in separating photogenerated electron and hole pairs, strong visible light capture ability, and good photoelectron transport performance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor photocatalysis, specifically to a functionalized graphene-modulated ZnPc / WO3 nanocomposite photocatalyst and its preparation method. Background Technology

[0002] Van der Waals heterojunctions play a crucial role in applications such as water splitting, pollutant degradation, and photocatalytic CO2 conversion. They are typically prepared through in-situ growth or ex-situ self-assembly, each technique possessing distinct characteristics and limitations. In-situ grown van der Waals heterojunctions are characterized by a certain gap between the two components. However, through the Coulomb field effect and ultrafast mechanisms, the interaction between the two elements is strengthened, which can, to a limited extent, improve electron transport efficiency. [1] Non-in-situ self-assembled photocatalytic heterojunctions exhibit a considerable interfacial gap due to uncontrolled element growth. This gap, coupled with inefficient quantum tunneling, reduces coupling forces, hinders electron transfer, and consequently lowers electron transport efficiency. [2] Therefore, there is an urgent need to develop practical methods to increase charge transfer in the vast majority of van der Waals heterojunctions, thereby ultimately improving the photocatalytic efficiency of CO2 conversion.

[0003] The addition of an electron mediator is of paramount importance in promoting the movement of photogenerated electrons in heterojunctions and plays a crucial role in this regard. The functionalized graphene (G) designed in this invention can serve as an electron-mediated medium, enabling efficient electron transfer and separation between the two components of a Z-type van der Waals heterojunction. Compared to systems lacking electron channels, the presence of functionalized graphene (G)-based channels significantly improves electron separation / transfer efficiency. Essentially, this invention designs and synthesizes a functionalized G-mediated Z-type van der Waals heterojunction composed of ZnPc and G-WO3. Due to the presence of the central metal unit, ZnPc possesses potential catalytic functionality. The selective absorption of ZnPc in the 550–800 nm wavelength range can offset the relatively low light absorption of WO3 in the near-infrared region. This property enhances the heterojunction's ability to capture visible light. Functionalized graphene can establish a robust connection between the ZnPc and WO3 interface, making it an effective electron mediator. This interaction enhances electron transport, establishes photoelectron transport pathways, and ultimately improves the separation and utilization of photoelectrons. Therefore, it can significantly improve the photocatalytic performance of CO2 reduction. This invention establishes a design framework for the efficient photocatalytic conversion of CO2 in Z-type van der Waals heterojunctions. This provides a new perspective for the development and use of advanced photocatalysts with better performance.

[0004] Source: [1] a)MMFurchi,F. L.Dobusch,DKPolyushkin,S.Schuler,T.Mueller,npj 2D Materials and Applications 2018,2,3;b)PMIsmail,S.Ali,S.Ali,J.Li,M.Liu,D.Yan,F.Raziq,F.Wahid,G.Li,S.Yuan, X.Wu,J.Yi,JSchen,Q.Wang,L.Zhong,Y.Yang,P.Xia,L.Qiao,Adv.Mater.2023,35,2303047.

[0005] [2]a)Y.Deng,Z.Luo,NJConrad,H.Liu,Y.Gong,S.Najmaei,PMAjayan,J.Lou,X.Xu,PDYe,ACS Nano 2014,8,8292;b)X.Yu,X.Wang,F.Zhou,J.Qu,J.Song,Adv.FunctMater.2021,31,2104260. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the primary objective of this invention is to provide a novel functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst and its preparation method. This preparation method uses a certain amount of sodium tungstate dihydrate and PVP, dissolved in appropriate amounts of deionized water and acetic acid. After ultrasonic and hydrothermal treatment for a period of time, layered WO3 is obtained. Then, the graphene is acid-treated, followed by ultrasonication and reflux. The entire process is repeated multiple times. Solid separation and washing are then performed until the pH reaches approximately 7. The separated solid is then cooled to room temperature and subsequently dehydrated under vacuum for a certain time to obtain partially functionalized graphene. This is then ultrasonically treated in deionized water, and a measured amount of layered WO3 is added, followed by stirring for a period of time. The mixture was then placed in a Teflon-lined autoclave and heated for a period of time. After cooling, it was repeatedly purified with deionized water and then dehydrated. Finally, it was calcined at high temperature under nitrogen purging for a period of time to obtain graphene-functionalized layered WO3. This WO3 was dissolved with a quantitative amount of ZnPc in anhydrous ethanol and stirred for a period of time, followed by water bath drying to obtain the final functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst. This preparation method is easy to operate; on the other hand, it improves the separation efficiency of photogenerated electron and hole pairs and the photoelectron transport performance, and enhances the ability to capture visible light. The performance of the prepared composite photocatalyst is significantly improved compared with that of the pure WO3 photocatalyst.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A novel method for preparing a functionalized graphene-modulated ZnPc / WO3 nanocomposite photocatalyst includes the following steps:

[0009] A certain amount of sodium tungstate dihydrate and PVP were selected and dissolved in an appropriate amount of deionized water and acetic acid. After ultrasonic and hydrothermal treatment for a period of time, layered WO3 was obtained. Then, the graphene was acid-treated, ultrasonicated and refluxed. The treatment process was repeated multiple times. The solid was then separated and washed with water. The separated solid was then cooled to room temperature and then heated and dehydrated in a vacuum for a certain period of time to obtain partially functionalized graphene.

[0010] The mixture was ultrasonically treated in deionized water, and a fixed amount of layered WO3 was added. After stirring for a period of time, the mixture was placed in a Teflon-lined autoclave and heated for a period of time. After cooling, it was repeatedly purified with deionized water and then dehydrated. Finally, it was calcined at high temperature under nitrogen atmosphere for a period of time to obtain graphene-functionalized layered WO3. This WO3 was then dissolved with a fixed amount of ZnPc in anhydrous ethanol and stirred for a period of time. Finally, it was dried in a water bath to obtain the final functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst.

[0011] Further, the mass ratio of PVP to sodium tungstate dihydrate is (1:6) to (1:60), and the volume ratio of acetic acid to deionized water is 1:6; preferably, the mass ratio of PVP to sodium tungstate dihydrate is 1:6.

[0012] Furthermore, the ultrasonic treatment time is 30 minutes, the hydrothermal temperature is 220°C, and the hydrothermal time is 8 hours.

[0013] Furthermore, the acids used in the mixed acid treatment of graphene are nitric acid and sulfuric acid in a volume ratio of 1:3, and the mass of the graphene is 0.1 to 1 g.

[0014] Furthermore, the ultrasonic treatment time is 20-60 minutes, the reflux temperature is 50-100°C, the reflux time is 20-60 minutes, and the process is repeated 3-8 times.

[0015] Furthermore, the vacuum dehydration temperature is 30–80°C, and the dehydration time is 12–48 hours.

[0016] Furthermore, the amount of deionized water is 60 mL, and the ultrasonic time is 60 min.

[0017] Furthermore, the mass of the layered WO3 is 0.1–1 g, and the stirring time is 30–80 min.

[0018] Furthermore, the heating temperature of the autoclave is 100-200℃, the heating time is 2-6 hours, and the temperature used for dehydration is 30-80℃.

[0019] Furthermore, the anhydrous ethanol is 30-60 mL, the stirring time is 1 h, and the water bath temperature is 30-80 °C.

[0020] In another aspect, the present invention provides a novel functionalized graphene-modulated ZnPc / WO3 nanocomposite photocatalyst, wherein the photocatalyst is obtained by the above-described preparation method.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention utilizes a wet chemical growth method to obtain graphene-functionalized layered WO3, which is then used as a substrate for assembling ZnPc, successfully preparing a functionalized graphene-modulated ZnPc / WO3 nanocomposite photocatalyst. Functionalized graphene (G) can act as an electron-mediated medium, enabling efficient electron transfer and separation between the two components of a Z-type van der Waals (vdW) heterojunction. Compared to systems lacking electron channels, the presence of functionalized G-based channels significantly improves electron separation / transfer efficiency. Essentially, this invention successfully synthesizes a functionalized G-mediated Z-type vdW heterojunction composed of ZnPc and G-WO3. Due to the presence of the central metal unit, ZnPc possesses potential catalytic functionality. The selective absorption of ZnPc in the 550–800 nm wavelength range can offset the relatively low light absorption of WO3 in the near-infrared region. This characteristic enhances the heterojunction's ability to capture visible light. Furthermore, the functionalized graphene of this invention can act as an electron-mediated medium, enabling efficient electron transfer and separation between the two components of the Z-type vdW heterojunction. Compared to systems lacking electron channels, the presence of functionalized graphene channels significantly improves electron separation efficiency and mobility. Functionalized graphene can establish robust connections between the ZnPc and WO3 interface, making it an effective electron medium. This interaction enhances electron transport, establishes photoelectron transport pathways, and ultimately improves the separation and utilization of photoelectrons. Therefore, it can significantly improve the photocatalytic performance of carbon dioxide reduction. This invention designs a framework for the efficient photocatalytic conversion of CO2 in Z-type van der Waals heterostructures, providing valuable guidance for the development and use of advanced photocatalysts with better performance. Attached Figure Description

[0023] Figure 1 These are schematic diagrams, transmission electron microscope images, and elemental distribution diagrams of the van der Waals heterostructure of the composite photocatalyst prepared in Example 1 of this invention.

[0024] Figure 2 These are X-ray diffraction patterns of composite photocatalysts with different proportions prepared in Example 1 of this invention.

[0025] Figure 3 These are the UV-Vis absorption spectra of composite photocatalysts with different proportions prepared in Example 1 of this invention.

[0026] Figure 4 These are steady-state and transient fluorescence spectra of composite photocatalysts with different proportions prepared in Example 1 of this invention.

[0027] Figure 5 The graph shows the photocatalytic CO2 reduction performance of composite photocatalysts with different proportions prepared in Example 1 of this invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are merely some, not all, of the embodiments of the present invention. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; the reagents and materials, unless otherwise specified, can be obtained from publicly available commercial channels.

[0029] Example 1

[0030] Dissolve 300 mg of sodium tungstate dihydrate (Na2WO4·2H2O) and 50 mg of PVP in 6 mL of deionized water and 1 mL of acetic acid (CHCOOH). Sonicate the solution for 40 minutes, and then hydrothermally treat it at 220 °C for 8 hours in a sealed Teflon-lined stainless steel autoclave (12 mL).

[0031] Next, acid-treated graphene (G) was prepared. Graphene of varying mass ratios was weighed, and 10 mL of HNO3 and 30 mL of H2SO4 were mixed and added to a flask. The mixture was then vigorously shaken in the flask. The flask was then subjected to 30 min of sonication followed by 30 min of reflux at 80°C. This process was repeated six times. The solid was then separated and washed with deionized water until the pH reached approximately 7. The separated solid was then cooled to room temperature and subsequently dehydrated under vacuum at 60°C for 24 hours. The partially functionalized G was then sonicated in 60 mL of deionized water for 60 min. Immediately afterward, 0.5 g of layered WO3 was added to the reaction solution, and the mixture was stirred continuously for 60 min. The mixture was then sealed and heated at 150°C for 4 h in a Teflon-lined autoclave (50 mL). After the system was cooled to ambient temperature, the product was repeatedly purified with deionized water and dehydrated at 60°C. Finally, the obtained sample was calcined at 250°C in a N2 atmosphere for 4 hours to obtain graphene-functionalized layered WO3.

[0032] Next, G-functionalized layered WO3 was used as a substrate for assembling ZnPc. The optimized functionalized G-WO3 and ZnPc in different proportions were dissolved in 50 mL of anhydrous ethanol after magnetic stirring for 1 h. The resulting slurry was then dried in a water bath at 60 °C. Finally, functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalysts with different proportions were obtained.

[0033] Example 2

[0034] Dissolve 330 mg of sodium tungstate dihydrate (Na2WO4·2H2O) and 50 mg of PVP in 10 mL of deionized water and 2 mL of acetic acid (CHCOOH). Sonicate the solution for 30 minutes, and then hydrothermally treat it at 250 °C for 8 hours in a sealed Teflon-lined stainless steel autoclave (12 mL).

[0035] Next, the graphene (G) was acid-treated. 0.5 g of graphene was weighed and mixed with 10 mL of HNO3 and 30 mL of H2SO4, then added to a flask. The mixture was vigorously shaken in the flask. The flask was then subjected to 30 min of sonication followed by 30 min of reflux at 90°C. This process was repeated six times. The solid was then separated and washed with deionized water until the pH reached approximately 7. The separated solid was then cooled to room temperature and subsequently dehydrated under vacuum at 60°C for 24 hours. The partially functionalized G was then sonicated in 60 mL of deionized water for 60 min. Immediately afterward, 0.5 g of layered WO3 was added to the reaction solution, and the mixture was stirred continuously for 60 min. The mixture was then sealed and heated at 150°C for 4 h in a Teflon-lined autoclave (50 mL). After the system was cooled to ambient temperature, the product was repeatedly purified with deionized water and dehydrated at 65°C. Finally, the obtained sample was calcined at 250°C in a N2 atmosphere for 4 hours to obtain graphene-functionalized layered WO3.

[0036] Next, G-functionalized layered WO3 was used as a substrate for assembling ZnPc. The optimized functionalized G-WO3 and a measured amount of ZnPc were dissolved in 50 mL of anhydrous ethanol after magnetic stirring for 1 h. The resulting slurry was then dried in a water bath at 60 °C. The functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst was finally obtained.

[0037] Example 3

[0038] Dissolve 330 mg of sodium tungstate dihydrate (Na2WO4·2H2O) and 50 mg of PVP in 8 mL of deionized water and 1 mL of acetic acid (CHCOOH). Sonicate the solution for 40 minutes, and then hydrothermally treat it at 220 °C for 6 hours in a sealed Teflon-lined stainless steel autoclave (12 mL).

[0039] Next, the graphene (G) was acid-treated. 0.8 g of graphene was weighed and mixed with 15 mL of HNO3 and 30 mL of H2SO4, then added to a flask. The mixture was vigorously shaken in the flask. The flask was then subjected to ultrasonic treatment for 30 min followed by reflux at 60°C for 30 min. This process was repeated five times. The solid was then separated and washed with deionized water until the pH reached approximately 7. The separated solid was then cooled to room temperature and subsequently dehydrated under vacuum at 60°C for 24 hours. The partially functionalized G was then ultrasonicated in 60 mL of deionized water for 60 min. Immediately afterward, 0.7 g of layered WO3 was added to the reaction solution, and the mixture was stirred continuously for 60 min. The mixture was then sealed and heated at 150°C for 4 h in a Teflon-lined autoclave (50 mL). After the system was cooled to ambient temperature, the product was repeatedly purified with deionized water and dehydrated at 60°C. Finally, the obtained sample was calcined at 240°C in a N2 atmosphere for 4 hours to obtain graphene-functionalized layered WO3.

[0040] Next, G-functionalized layered WO3 was used as a substrate for assembling ZnPc. The optimized functionalized G-WO3 and a measured amount of ZnPc were dissolved in 50 mL of anhydrous ethanol after magnetic stirring for 1 h. The resulting slurry was then dried in a water bath at 60 °C. The functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst was finally obtained.

[0041] Example 4

[0042] Dissolve 330 mg of sodium tungstate dihydrate (Na2WO4·2H2O) and 50 mg of PVP in 6 mL of deionized water and 1 mL of acetic acid (CHCOOH). Sonicate the solution for 30 minutes, and then hydrothermally treat it at 220 °C for 8 hours in a sealed Teflon-lined stainless steel autoclave (12 mL).

[0043] Next, the graphene (G) was acid-treated. 0.5 g of graphene was weighed and mixed with 10 mL of HNO3 and 30 mL of H2SO4, then added to a flask. The mixture was vigorously shaken in the flask. The flask was then subjected to 30 min of sonication followed by 30 min of reflux at 80°C. This process was repeated six times. The solid was then separated and washed with deionized water until the pH reached approximately 7. The separated solid was then cooled to room temperature and subsequently dehydrated under vacuum at 70°C for 24 hours. The partially functionalized G was then sonicated in 50 mL of deionized water for 60 min. Immediately afterward, 0.6 g of layered WO3 was added to the reaction solution, and the mixture was stirred continuously for 60 min. The mixture was then sealed and heated at 180°C for 5 h in a Teflon-lined autoclave (50 mL). After the system was cooled to ambient temperature, the product was repeatedly purified with deionized water and dehydrated at 60°C. Finally, the obtained sample was calcined at 250°C in a N2 atmosphere for 3 hours to obtain graphene-functionalized layered WO3.

[0044] Next, G-functionalized layered WO3 was used as a substrate for assembling ZnPc. The optimized functionalized G-WO3 and a measured amount of ZnPc were dissolved in 60 mL of anhydrous ethanol after magnetic stirring for 1 h. The resulting slurry was then dried in a water bath at 55 °C. The functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst was finally obtained.

[0045] The functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst prepared in Example 1 was subjected to morphology and performance tests, such as... Figure 1 The diagram shows (a) a schematic of the VdW heterojunction with electron transfer, prepared by in-situ growth and ex-situ assembly methods. The insertion of functionalized graphene acts as an electron "bridge" at the heterojunction interface, significantly reducing the interfacial potential difference and increasing the efficiency of the photocatalytic process. (bd) are transmission electron microscope images of the sample, showing that the basic morphology of WO3 is layered. The functionalized graphene modification of the sample increases the degree of aggregation. The elemental mapping diagram in (ej) clearly shows the uniform distribution of W, O, C, N, and Zn elements, indicating the successful synthesis of a graphene-modulated ZnPc / WO3 heterojunction photocatalyst.

[0046] Figure 2 These are X-ray diffraction patterns of the composite photocatalysts with different proportions prepared in Example 1 of this invention. The purity of the pure WO3 catalyst structure was analyzed using X-ray diffraction (XRD), and the effect of functionalized graphene (G) modulation on ZnPc anchoring was investigated. Figure 2As shown, the XRD peaks were accurately attributed to WO3 (JCPDS 32-1395). Notably, no distinct peaks corresponding to ZnPc were observed in the xZnPc / WO3 and 2ZnPc / yG-WO3 modes. Figure 2 ) or as a modified functionalized graphene ( Figure 2 This is attributed to the high dispersion of ZnPc (x = 0.5-3 wt% and y = 0.3-1.2 wt%). The presence of ZnPc effectively alters the light absorption of WO3.

[0047] Figure 3 These are the UV-Vis absorption spectra of the composite photocatalysts with different proportions prepared in Example 1 of this invention. The presence of ZnPc effectively alters the light absorption of WO3. For example... Figure 3 As shown, the absorption intensity increases after the addition of ZnPc. Furthermore, no broad-shoulder absorption was observed in pure WO3 between approximately 500 and 750 nm.

[0048] Figure 4 These are the steady-state and transient fluorescence spectra of the composite photocatalysts with different proportions prepared in Example 1 of this invention. To explain the charge separation promoted by adding functionalized graphene (G) to 2ZnPc / WO3, we measured the photoluminescence (PL) spectrum of WO3 using a 420 nm excitation wavelength. Figure 4 Compared to 2ZnPc / 0.9G-WO3, the photoluminescence (PL) intensity of 2ZnPc / 0.9G-WO3 decreased, indicating that the integrated functionalized graphene (G) effectively suppressed carrier recombination. PL confirms that the optimized 2ZnPc / 0.9G-WO3 sample exhibits good photoexcited carrier separation and transfer capabilities under solar irradiation.

[0049] Figure 5 The graph shows the photocatalytic CO2 reduction performance of composite photocatalysts with different proportions prepared in Example 1 of this invention. Figure 5 The results show that a 2 wt% ZnPc loading produced the highest CO2 to CO and CH4 conversion. However, the photocatalytic activity decreased when the ZnPc loading exceeded 2 wt%. This indicates that a higher ZnPc loading may lead to the self-aggregation of ZnPc molecules on the WO3 catalyst, resulting in a reduction in the number of active sites available for the CO2 photoreduction reaction. To ensure a good distribution of the 2 wt% ZnPc loading, functionalized graphene (G) modulation was employed in this invention. Different loadings of functionalized G (denoted as 2ZnPc / yG-WO3) were investigated, where "y" represents the mass percentage of functionalized G at 0.3, 0.6, 0.9, and 1.2%. Figure 5The results showed that the photocatalytic activity gradually increased to 0.9 wt% of functionalized G (i.e., 2ZnPc / 0.9G-WO3). However, the activity decreased at 1.2 wt% functionalized G loading (2ZnPc / 1.2G-WO3).

[0050] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a functionalized graphene-modulated nanocomposite photocatalyst, characterized in that, Includes the following steps: A certain amount of sodium tungstate dihydrate and PVP were selected and dissolved in an appropriate amount of deionized water and acetic acid. After ultrasonic and hydrothermal treatment for a period of time, layered WO3 was obtained. Then, the graphene was acid-treated, ultrasonicated and refluxed. The whole process was repeated multiple times. Then, solid separation and water washing were performed. The separated solid was cooled to room temperature and then heated and dehydrated in a vacuum for a certain period of time to obtain partially functionalized graphene. The mixture is ultrasonically treated in deionized water, a fixed amount of layered WO3 is added, and the mixture is stirred for a period of time. Then, the mixture is placed in a Teflon-lined autoclave and heated for a period of time. After cooling, it is repeatedly purified with deionized water and then dehydrated. Finally, it is calcined at high temperature for a period of time under nitrogen purging. The high temperature calcination temperature is 240℃ or 250℃ to obtain graphene-functionalized layered WO3. This WO3 is dissolved with a fixed amount of ZnPc in anhydrous ethanol and stirred for a period of time. Then, it is dried in a water bath to obtain the final functionalized graphene-modified ZnPc / WO3 nanocomposite photocatalyst. The mass ratio of PVP to sodium tungstate dihydrate is (1:6) to (1:60), and the volume ratio of acetic acid to deionized water is 1:

6. The acid used for the acid treatment of graphene is nitric acid and sulfuric acid in a volume ratio of 1:3, and the mass of the graphene is 0.1~1 g.

2. The method for preparing functionalized graphene-modulated nanocomposite photocatalysts according to claim 1, characterized in that, The ultrasonic treatment time is 30 min, the hydrothermal temperature is 220 ℃, and the hydrothermal time is 8 h.

3. The method for preparing the functionalized graphene-modulated nanocomposite photocatalyst according to claim 1, characterized in that, The ultrasonic treatment time is 20-60 min, the reflux temperature is 50-100 ℃, the reflux time is 20-60 min, and the process is repeated 3-8 times.

4. The method for preparing the functionalized graphene-modulated nanocomposite photocatalyst according to claim 1, characterized in that, The vacuum dehydration temperature is 30~80 ℃, and the dehydration time is 12~48 h.

5. The method for preparing the functionalized graphene-modulated nanocomposite photocatalyst according to claim 1, characterized in that, The mass of the layered WO3 is 0.1~1 g, and the stirring time is 30~80 min.

6. The method for preparing the functionalized graphene-modulated nanocomposite photocatalyst according to claim 1, characterized in that, The heating temperature of the autoclave is 100~200 ℃, the heating time is 2~6 h, and the temperature used for dehydration is 30~80 ℃.

7. The method for preparing the functionalized graphene-modulated nanocomposite photocatalyst according to claim 1, characterized in that, The anhydrous ethanol is 30-60 mL, the stirring time is 1 h, and the water bath temperature is 30-80 ℃.

8. A functionalized graphene-modulated nanocomposite photocatalyst, characterized in that, The photocatalyst is obtained by the preparation method described in any one of claims 1 to 7.

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