Preparation method and application of gold phosphorus modified ZnS / ZnIn2S4 photocatalytic material

Abstract

The invention discloses a preparation method and application of a gold phosphorus modified ZnS / ZnIn2S4 photocatalytic material, and relates to a preparation method and application of a photocatalytic material. The method comprises the following steps: 1, preparing ZnS / ZnIn2S4; 2, preparing AuP; and 3, preparing the gold phosphorus modified ZnS / ZnIn2S4 photocatalytic material. The invention discloses a ZnS / ZnIn2S4 photocatalytic material modified by gold and phosphorus. The ZnS / ZnIn2S4 photocatalytic material is used for photocatalytic reduction of CO2 into CO and CH3OH. According to the method, the CO2 reduction hydrogenation is co-catalyzed by cooperation of gold and phosphorus and sulfide for the first time, the CO2 reduction performance is remarkably improved compared with that of an original sulfide heterojunction, the selectivity of a high-added-value hydrocarbon product CH3OH reaches up to 98%, the yield of CH3OH obtained by photocatalytic reduction of CO2 is superior to that of a reported 90% photocatalyst, and the method is suitable for industrial production. The problem of low selectivity of most of photocatalytic reduction of CO2 into hydrocarbon products at present is solved.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a photocatalytic material. Background Art

[0002] With the acceleration of industrial modernization, CO 2 Continued emissions of CO have seriously disrupted the natural carbon balance and exacerbated global warming. To reverse this effect, CO 2 Photocatalytic reduction has attracted increasing attention. 2 Among the various value-added products converted, methanol is considered to be an excellent fuel substitute and an ideal form of energy storage. 2 Photocatalytic reduction to methanol not only saves fossil fuels but also captures green greenhouse gases. It is a very promising and attractive method. However, existing photocatalysts have problems such as low light absorption efficiency, severe carrier recombination, and few active sites, resulting in CO 2 The photoreduction efficiency is low.

[0003] ZnS photocatalyst has a wide band gap, low light absorption efficiency, few photogenerated carriers, and CO 2 Fewer electrons and active sites are required for activation. ZnIn 2 S 4 The photocatalyst has a suitable band gap, but the photogenerated carriers recombine seriously, which seriously inhibits CO 2 Photoreduction. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a gold-phosphorus modified ZnS / ZnIn 2 S 4 Preparation method and application of photocatalytic materials.

[0005] The photocatalyst prepared by the present invention can be mainly prepared by loading gold as CO 2 The introduction of Au into P will inhibit photocatalytic hydrogen production and reduce CO 2 The reduction-competing reaction simultaneously promotes the CO* hydrogenation.

[0006] A gold-phosphorus modified ZnS / ZnIn 2 S 4 The preparation method of the photocatalytic material is specifically completed according to the following steps:

[0007] 1. Preparation of ZnS / ZnIn 2 S 4 :

[0008] ①, Zn(OH) 2 、InCI 3 ·4H 2O and C 2 H 5 NS was dissolved in a mixed solution of deionized water and anhydrous ethanol and stirred for a period of time to obtain a mixed solution I;

[0009] ②, transfer the mixed solution I to a polytetrafluoroethylene-lined reactor, heat it to 180°C, and perform hydrothermal reaction at 180°C for a period of time to obtain reaction product I; wash and dry the reaction product I to obtain ZnS / ZnIn 2 S 4 ;

[0010] 2. Preparation of AuP:

[0011] Disperse red phosphorus into deionized water to obtain deionized water dispersed with P; 4 The solution is added dropwise to deionized water in which P is dispersed, and the temperature is raised and stirred for a period of time to obtain a reaction product II; the reaction product II is washed and then vacuum dried to obtain AuP;

[0012] 3. Preparation of gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials:

[0013] ZnS / ZnIn 2 S 4 and AuP were dispersed in anhydrous ethanol, ultrasonically treated, and then vacuum dried to obtain gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials.

[0014] A gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials for photocatalytic CO 2 Reduction to CO and CH 3 OH.

[0015] The present invention mainly improves the carrier separation efficiency by constructing a heterojunction, and successfully transfers the electron cloud through the Au load to provide a CO 2 Reduction provides more active sites.

[0016] Principle of the present invention:

[0017] The present invention regulates CO by regulating the types of active sites on the surface of photocatalytic materials. 2Reduction product. P is an abundant and low-cost non-metallic element on earth, and has good economic benefits. Amorphous phosphorus can inhibit photocatalytic hydrogen production, while gold nanoparticles are active sites for photocatalytic hydrogen production and Au-S bonds have natural affinity. However, the research on composite materials of Au, P and sulfide is still blank. Therefore, the present invention first deposits Au on amorphous P by impregnation, and then uses ultrasound to bond the Au-loaded P with ZnS / ZnIn 2 S 4 Heterojunction recombination makes CO 2 The molecules are effectively activated and * CO provides more H to favor the generation of CH 3 OH direction, thus achieving efficient photocatalytic CO 2 Pathways to reduction into high value-added chemical fuels.

[0018] Beneficial effects of the present invention:

[0019] This invention is the first to use gold and phosphorus to catalyze CO 2 Reduction hydrogenation, compared with the original sulfide heterojunction CO 2 The reduction performance is significantly improved, and the high value-added hydrocarbon product CH 3 The selectivity of OH is as high as 98%, and its photocatalytic CO 2 Reduction to CH 3 The OH production is better than 90% of the reported photocatalysts, which solves the current problem of most photocatalytic CO 2 The problem of low selectivity of reduction to hydrocarbon products. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 XRD patterns of P, AP, ZS / ZIS, 40-AP / ZS / ZIS and A / ZS / ZIS;

[0021] Figure 2 SEM images and element mapping images, (a) is the SEM image of P, (b) is the SEM image of ZS / ZIS, (c) is the SEM image of 40-AP / ZS / ZIS, (d)-(i) are the element mapping images of 40-AP / ZS / ZIS;

[0022] Figure 3 Photocatalytic CO catalysis for ZS / ZIS, 40-AP / ZS / ZIS, A / ZS / ZIS and 40-P / ZS / ZIS photocatalysts 2 Restore performance graphs. DETAILED DESCRIPTION

[0023] Specific embodiment 1: This embodiment is a gold-phosphorus modified ZnS / ZnIn 2 S 4The preparation method of the photocatalytic material is specifically completed according to the following steps:

[0024] 1. Preparation of ZnS / ZnIn 2 S 4 :

[0025] ①, Zn(OH) 2 、InCI 3 ·4H 2 O and C 2 H 5 NS was dissolved in a mixed solution of deionized water and anhydrous ethanol and stirred for a period of time to obtain a mixed solution I;

[0026] ②, transfer the mixed solution I to a polytetrafluoroethylene-lined reactor, heat it to 180°C, and perform hydrothermal reaction at 180°C for a period of time to obtain reaction product I; wash and dry the reaction product I to obtain ZnS / ZnIn 2 S 4 ;

[0027] 2. Preparation of AuP:

[0028] Disperse red phosphorus into deionized water to obtain deionized water dispersed with P; 4 The solution is added dropwise to deionized water in which P is dispersed, and the temperature is raised and stirred for a period of time to obtain a reaction product II; the reaction product II is washed and then vacuum dried to obtain AuP;

[0029] 3. Preparation of gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials:

[0030] ZnS / ZnIn 2 S 4 and AuP were dispersed in anhydrous ethanol, ultrasonically treated, and then vacuum dried to obtain gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials.

[0031] Specific embodiment 2: This embodiment differs from the specific embodiment 1 in that: the Zn(OH) described in step 1① 2 、InCI 3 ·4H 2 O and C 2 H 5 The molar ratio of NS is 0.497 mmol:0.8 mmol:3.2 mmol. The other steps are the same as those in the first embodiment.

[0032] Specific implementation method three: The difference between this implementation method and specific implementation method one or two is that the volume ratio of deionized water to anhydrous ethanol in the mixed solution of deionized water and anhydrous ethanol described in step 1① is 1:1; the Zn(OH) 2 The volume ratio of the substance to the mixed solution of deionized water and anhydrous ethanol is 0.497mmol:15mL. The other steps are the same as those in the first or second specific implementation.

[0033] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the stirring time in step 1① is 10 min to 20 min, and the stirring speed is 40 r / min to 60 r / min. The other steps are the same as those of specific embodiments 1 to 3.

[0034] Specific embodiment 5: The difference between this embodiment and specific embodiments 1 to 4 is that the heating rate described in step 1 ② is 10°C / min; the hydrothermal reaction time described in step 1 ② is 24h; in step 1 ②, the reaction product I is washed 3 to 5 times with deionized water and anhydrous ethanol respectively, and then dried at 60°C for 10h to 12h to obtain ZnS / ZnIn 2 S 4 The other steps are the same as those in Specific Embodiments 1 to 4.

[0035] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the mass ratio of red phosphorus in the deionized water dispersed with P to the volume ratio of deionized water in step 2 is 100 mg:30 mL; the HAuCl in step 2 4 The concentration of the solution is 5 mg / mL. The other steps are the same as those in Specific Embodiments 1 to 5.

[0036] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that: the HAuCl in step 2 4 The volume ratio of the solution to the deionized water in which P is dispersed is 200 μL:30 mL; the temperature of the heating and stirring in step 2 is 70° C. to 80° C., and the heating and stirring time is 5 h to 7 h; in step 2, the reaction product II is washed 3 to 5 times with deionized water and anhydrous ethanol respectively, and then vacuum dried at 50° C. to 60° C. for 10 h to 12 h to obtain AuP. The other steps are the same as those in specific embodiments 1 to 6.

[0037] Specific embodiment eight: This embodiment differs from specific embodiments one to seven in that: the ZnS / ZnIn described in step three 2 S 4The mass volume ratio of AuP and anhydrous ethanol is 60 mg:40 mg:20 mL. The other steps are the same as those in the first to seventh embodiments.

[0038] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that: the ultrasonic treatment time in step 3 is 2 hours; the vacuum drying temperature in step 3 is 50°C to 60°C, and the vacuum drying time is 10 hours to 12 hours. The other steps are the same as those in specific embodiments 1 to 8.

[0039] Specific embodiment 10: This embodiment is a gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials for photocatalytic CO 2 Reduction to CO and CH 3 OH.

[0040] The following examples are used to verify the beneficial effects of the present invention:

[0041] Example 1: A gold-phosphorus modified ZnS / ZnIn 2 S 4 The preparation method of the photocatalytic material is specifically completed according to the following steps:

[0042] 1. Preparation of ZnS / ZnIn 2 S 4 :

[0043] ①, 0.497mmol Zn(OH) 2 、0.8mmol InCl 3 ·4H 2 O and 3.2 mmol C 2 H 5 NS was dissolved in a mixed solution of 15 mL of deionized water and 15 mL of anhydrous ethanol, and stirred at a stirring speed of 60 r / min for 15 min to obtain a mixed solution I;

[0044] ②, the mixed solution I was transferred to a polytetrafluoroethylene-lined reactor, the temperature was raised to 180°C, and the reaction was hydrothermally reacted at 180°C for 24 hours to obtain the reaction product I; the reaction product I was washed three times with deionized water and anhydrous ethanol respectively, and then dried at 60°C for 12 hours to obtain ZnS / ZnIn 2 S 4 (denoted as ZS / ZIS);

[0045] The heating rate described in step 1② is 10℃ / min;

[0046] 2. Preparation of AuP:

[0047] 100 mg of red phosphorus (denoted as P) was dispersed in 30 mL of deionized water to obtain deionized water dispersed with P; 200 μL of HAuCl with a concentration of 5 mg / mL was added. 4 The solution was added dropwise to the deionized water in which P was dispersed, and stirred at 70°C for 6 hours to obtain the reaction product II; the reaction product II was washed three times with deionized water and anhydrous ethanol respectively, and then vacuum dried at 50°C for 12 hours to obtain AuP (denoted as AP);

[0048] 3. Preparation of gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials:

[0049] 60mg ZnS / ZnIn 2 S 4 and 40 mg AuP were dispersed in 20 mL anhydrous ethanol and ultrasonically treated for 2 h to obtain gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic material (denoted as 40-AP / ZS / ZIS).

[0050] Comparative Example 1: The preparation method of A / ZS / ZIS photocatalyst is specifically completed according to the following steps:

[0051] 1. Preparation of ZnS / ZnIn 2 S 4 :

[0052] ①, 0.497mmol Zn(OH) 2 、0.8mmol InCl 3 ·4H 2 O and 3.2 mmol C 2 H 5 NS was dissolved in a mixed solution of 15 mL of deionized water and 15 mL of anhydrous ethanol, and stirred at a stirring speed of 60 r / min for 15 min to obtain a mixed solution I;

[0053] ②, the mixed solution I was transferred to a polytetrafluoroethylene-lined reactor, the temperature was raised to 180°C, and the reaction was hydrothermally reacted at 180°C for 24 hours to obtain the reaction product I; the reaction product I was washed three times with deionized water and anhydrous ethanol respectively, and then dried at 60°C for 12 hours to obtain ZnS / ZnIn 2 S 4 (denoted as ZS / ZIS);

[0054] The heating rate described in step 1② is 10℃ / min;

[0055] 2. 60mg ZnS / ZnIn 2 S 4and 40 mg Au powder were dispersed in 20 mL anhydrous ethanol and ultrasonically treated for 2 h to obtain gold-phosphorus modified ZnS / ZnIn 2 S 4 Photocatalytic materials (denoted as A / ZS / ZIS).

[0056] Comparative Example 2: The preparation method of 40-P / ZS / ZIS photocatalyst is specifically completed according to the following steps:

[0057] 1. Preparation of ZnS / ZnIn 2 S 4 :

[0058] ①, 0.497mmol Zn(OH) 2 、0.8mmol InCl 3 ·4H 2 O and 3.2 mmol C 2 H 5 NS was dissolved in a mixed solution of 15 mL of deionized water and 15 mL of anhydrous ethanol, and stirred at a stirring speed of 60 r / min for 15 min to obtain a mixed solution I;

[0059] ②, the mixed solution I was transferred to a polytetrafluoroethylene-lined reactor, the temperature was raised to 180°C, and the reaction was hydrothermally reacted at 180°C for 24 hours to obtain the reaction product I; the reaction product I was washed three times with deionized water and anhydrous ethanol respectively, and then dried at 60°C for 12 hours to obtain ZnS / ZnIn 2 S 4 (denoted as ZS / ZIS);

[0060] The heating rate described in step 1② is 10℃ / min;

[0061] 2. 60mg ZnS / ZnIn 2 S 4 and 40 mg of red phosphorus (denoted as P) were dispersed in 20 mL of anhydrous ethanol and ultrasonically treated for 2 h to obtain a 40-P / ZS / ZIS photocatalyst.

[0062] Figure 1 XRD patterns of P, AP, ZS / ZIS, 40-AP / ZS / ZIS and A / ZS / ZIS;

[0063] from Figure 1 It can be seen that the ZS / ZIS sample is cubic ZnS and hexagonal ZnIn 2 S 4 The heterojunction photocatalytic material composed of ZS / ZIS is amorphous. The 40-AP / ZS / ZIS sample has characteristic peaks of P and sulfide, indicating that the sample was successfully prepared.

[0064] Figure 2 SEM images and element mapping images, (a) is the SEM image of P, (b) is the SEM image of ZS / ZIS, (c) is the SEM image of 40-AP / ZS / ZIS, (d)-(i) are the element mapping images of 40-AP / ZS / ZIS;

[0065] from Figure 2 The morphology and elemental analysis test show that red phosphorus is a large porous bulk particle, while ZS / ZIS is a nanoflower material with a size of about 5μm. After the two are combined, the sulfide is mainly accumulated on the large block of red phosphorus. Mapping tests show that Zn, In and S elements are evenly distributed in the sulfide, while P is mainly loaded on Au and Au serves as a connecting bridge between ZS / ZIS and P, indicating the successful preparation of gold-phosphorus synergistic sulfide photocatalytic materials.

[0066] Photocatalytic method: Disperse 20 mg of photocatalyst in a reactor and pour 45 mL of CH 3 CN and 5 mL of TEOA were ultrasonically dispersed for 10 min. The mixture was sealed and vacuumed, and CO was introduced. 2 Gas. Irradiate with a 300W xenon lamp, collect gas during illumination with a Labsolar-6A system (once every half an hour, 8 times in total), and check the product by gas chromatography.

[0067] from Figure 3 It can be found that the original ZS / ZIS samples photocatalyze CO 2 The reduction to CO yield is higher but CH 3 The amount and selectivity of OH generation are very low. When Au is loaded (A / ZS / ZIS), it is found that its photocatalytic hydrogen production performance is 8.12 times higher than that of the original ZS / ZIS, indicating that Au is the active site for photocatalytic water splitting and hydrogen production. 2 The performance of reducing to CO was slightly improved, but the performance of hydrogen production was reduced, indicating that P inhibited the photocatalytic hydrogen evolution. 2 When reduced, the generation of CH 3 OH yield and selectivity of 40-AP / ZS / ZIS compared with pristine ZS / ZIS photocatalytic CO 2 The reduction efficiency was increased by 26.85 times. The data results can intuitively show that the synergistic effect between AuP and ZS / ZIS significantly improves CO 2 Photoreduction to hydrocarbon products.

Claims

1. A method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material, characterized in that The preparation method is specifically completed according to the following steps:

1. Preparation of ZnS / ZnIn2S4: ① Dissolve Zn(OH)2, InCI3·4H2O and C2H5NS in a mixed solution of deionized water and anhydrous ethanol, stir for a period of time to obtain a mixed solution I; ②, transfer the mixed solution I to a polytetrafluoroethylene-lined reactor, raise the temperature to 180°C, and perform hydrothermal reaction at 180°C for a period of time to obtain reaction product I; The reaction product I is washed and dried to obtain ZnS / ZnIn2S4; 2. Preparation of AuP: Dispersing red phosphorus in deionized water to obtain deionized water dispersed with P; dropping HAuCl4 solution into the deionized water dispersed with P, heating and stirring for a period of time to obtain reaction product II; washing reaction product II, and then vacuum drying to obtain AuP; 3. Preparation of gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic materials: The ZnS / ZnIn2S4 and AuP were dispersed in anhydrous ethanol, ultrasonically treated, and then vacuum dried to obtain the gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material.

2. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The molar ratio of Zn(OH)2, InCI3·4H2O and C2H5NS described in step 1① is 0.497mmol:0.8mmol:3.2mmol.

3. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The volume ratio of deionized water to anhydrous ethanol in the mixed solution of deionized water and anhydrous ethanol described in step 1① is 1:1; the volume ratio of the amount of Zn(OH)2 described in step 1① to the mixed solution of deionized water and anhydrous ethanol is (4mmol~0.497mmol):15mL.

4. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The stirring time described in step 1① is 10min~20min, and the stirring speed is 40r / min~60r / min.

5. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The heating rate described in step 1② is 10℃ / min; the time of the hydrothermal reaction described in step 1② is 24h; in step 1②, the reaction product I is washed 3 to 5 times with deionized water and anhydrous ethanol respectively, and then dried at 60℃ for 10h to 12h to obtain ZnS / ZnIn2S4.

6. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The mass ratio of red phosphorus in the deionized water dispersed with P to the volume ratio of deionized water in step 2 is 100 mg:30 mL; the concentration of the HAuCl4 solution in step 2 is 5 mg / mL.

7. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The volume ratio of the HAuCl4 solution described in step 2 to the deionized water dispersed with P is 200μL:30mL; the temperature of the heating and stirring described in step 2 is 70℃~80℃, and the heating and stirring time is 5h~7h; in step 2, the reaction product II is washed 3 times to 5 times with deionized water and anhydrous ethanol respectively, and then vacuum dried at 50℃~60℃ for 10h~12h to obtain AuP.

8. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The mass volume ratio of ZnS / ZnIn2S4, AuP and anhydrous ethanol described in step 3 is 60 mg:40 mg:20 mL.

9. The method for preparing a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material according to claim 1, characterized in that The ultrasonic treatment time in step 3 is 2 hours; the vacuum drying temperature in step 3 is 50° C. to 60° C., and the vacuum drying time is 10 hours to 12 hours.

10. Use of a gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material prepared by the preparation method according to claim 1, characterized in that A gold-phosphorus modified ZnS / ZnIn2S4 photocatalytic material is used for photocatalytic reduction of CO2 to CO and CH3OH.

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