Methods and applications for improving the photocatalytic CO2 reduction performance of lead titanate nanoparticles by rare earth element doping

Abstract

The application discloses a method for improving the photocatalytic CO2 reduction performance of lead titanate nanoparticles by doping rare earth elements and application thereof. Perovskite lead titanate nanoparticles are prepared by a hydrothermal method: taking lead nitrate as a lead source, different types of rare earth elements are added and dissolved into a sodium hydroxide solution; tetrabutyl titanate is taken as a titanium source; after the two solutions are fully mixed, perovskite lead titanate nanoparticles are obtained through a hydrothermal reaction. In the photocatalytic CO2 reduction reaction, the sample doped with the rare earth elements has higher reducibility and better product stability compared with the lead titanate nanoparticles without doping, and has stronger CO2 adsorption capacity, so that the conversion of CO2 gas can be effectively realized.

Description

Technical Field

[0001] This invention belongs to the field of photocatalytic CO2 reduction, specifically relating to a method and application of rare earth element doping to improve the photocatalytic CO2 reduction performance of lead titanate nanoparticles. Background Technology

[0002] Climate change is a universal problem for humankind. Currently, high concentrations of CO2 in the atmosphere mainly accumulate in the troposphere, which is one of the main causes of global warming and climate change. Therefore, people have begun to search for methods to reduce atmospheric CO2 concentrations, including CO2 capture and conversion, sequestration, and conversion into valuable substances.

[0003] Currently, a variety of photocatalysts have been developed for solar energy conversion, including metal oxides (TiO2, ZnO, SnO2, etc.), metal sulfides (CdS, ZnS, MoS2, etc.), metal-organic frameworks (MOFs), two-dimensional materials (MXene), and novel nanomaterials such as ABX3-type perovskite photocatalysts.

[0004] Rare earth doping is a commonly used method for catalyst modification. Rare earth elements have abundant electronic energy levels and 4f electron transition characteristics. As dopants, they can introduce electron trap energy levels, reduce electron-hole recombination rate, and enhance light absorption capacity, thereby significantly improving photocatalytic activity. Therefore, rare earth elements have received increasing attention in the modification of photocatalysts.

[0005] Currently, carbon dioxide conversion mainly relies on photocatalysis, electrocatalysis, and thermocatalysis. Among these, photocatalytic carbon dioxide reduction consumes the least energy and is therefore highly favored by researchers. For photocatalytic carbon dioxide reduction technology, developing a photocatalyst with high efficiency, high stability, and controllable products is a key step in achieving efficient carbon dioxide conversion. Summary of the Invention

[0006] The purpose of this invention is to provide a method and application for improving the photocatalytic CO2 reduction performance of lead titanate nanoparticles by rare earth element doping. The prepared product exhibits higher reducibility and better stability, and has a stronger ability to adsorb CO2, thus effectively achieving efficient CO2 conversion.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] 1) Take 4-6g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4700-1.4755g of lead nitrate to obtain solution A.

[0009] 2) Add 0.015-0.1g of rare earth elements and 0.003-0.005mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0010] 3) Place the polytetrafluoroethylene liner containing solution B into an ultrasonic machine for ultrasonic treatment, stir, and then place it in a reaction vessel to react at 180-200℃ and cool it with the furnace.

[0011] 4) Wash the cooled precipitate with deionized water until neutral, and then dry it in an oven;

[0012] 5) The dried product was placed in a muffle furnace and calcined at 800-900℃ to obtain surface-treated lead titanate nanoparticles doped with rare earth elements.

[0013] The rare earth element in step 2) is lanthanum nitrate hexahydrate, praseodymium nitrate hexahydrate, samarium nitrate hexahydrate, dysprosium nitrate hexahydrate, or thulium nitrate pentahydrate.

[0014] In step 3), the polytetrafluoroethylene liner containing solution B is placed in a 100W ultrasonic machine for ultrasonic treatment for 15-25 minutes, stirred for 2 hours, and then placed in a reaction vessel.

[0015] The reaction time for step 3) is 12 to 24 hours.

[0016] Step 4) involves placing the item in an oven and drying it at 60-65℃.

[0017] The calcination time in step 5) is 10-12 hours.

[0018] The rare earth element-doped lead titanate nanoparticles obtained by the above method are used for photocatalytic CO2 reduction reaction.

[0019] This invention involves doping PbTiO3 nanoparticles with different rare earth elements, significantly enhancing the photocatalytic CO2 reduction performance of PbTiO3 as a catalyst. By incorporating rare earth elements into PbTiO3 nanoparticles, the catalyst can generate both CO and CH4, with improved yields of both reduction products. Applying this technology to solar-driven CO2 resource recovery can reduce atmospheric CO2 concentrations and alleviate dependence on fossil fuels.

[0020] This invention uses photocatalysis to convert CO2. Compared with other methods, the photocatalytic reduction of CO2 to methane (CH4), carbon monoxide (CO), methanol (CH3OH), formic acid (HCOOH), ethanol (C2H5OH), formaldehyde (HCHO), etc. can be carried out under ambient temperature and pressure conditions and has a large amount of sustainable energy. It is a favorable choice for mitigating and deciphering the problems related to global warming caused by atmospheric CO2.

[0021] This invention involves doping PbTiO3 nanoparticles with different rare earth elements, significantly enhancing the photocatalytic CO2 reduction performance of PbTiO3 as a catalyst. By incorporating rare earth elements into PbTiO3 nanoparticles, the catalyst can generate both CO and CH4, with improved yields of both reduction products. Applying this technology to solar-driven CO2 resource recovery can reduce atmospheric CO2 concentrations and alleviate dependence on fossil fuels. Attached Figure Description

[0022] Figure 1 X-ray diffraction patterns of the photocatalysts in comparative examples and Examples 1-5;

[0023] Figure 2 X-ray diffraction patterns of photocatalysts in comparative examples and Examples 2, 6-8;

[0024] Figure 3 The graphs show the yields of photocatalytic CO2 reduction products from Examples 1-5.

[0025] Figure 4 The graphs show the yields of photocatalytic CO2 reduction products in Examples 2, 6-8. Detailed Implementation

[0026] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0027] Comparative example:

[0028] 1) Take 30 mL of sodium hydroxide solution and add 0.0045 mol of lead nitrate to it to obtain solution A;

[0029] 2) Add 0.003 mol of tetrabutyl titanate to solution A in step 1) and mix to obtain solution B;

[0030] 3) Place the mixture in an ultrasonic chamber for 15 minutes and stir for 2 hours to obtain solution C;

[0031] 4) Place solution C into a reaction vessel and react at 200℃ for 2 hours, then cool with the furnace. Wash the precipitate with deionized water until neutral and dry it in an oven.

[0032] 5) The sample from step 4) was placed in a muffle furnace and calcined at 900°C for 10 h to obtain lead titanate nanoparticles, which were named PTO.

[0033] Example 1:

[0034] 1) Take 4g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4755g of lead nitrate to obtain solution A.

[0035] 2) Add 0.0195 g of lanthanum nitrate hexahydrate and 0.003 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0036] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine and sonicate for 15 minutes. After stirring for 2 hours, place it in a reaction vessel and react at 200℃ for 12 hours, then cool it with the furnace.

[0037] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 60°C;

[0038] 5) The dried product was placed in a muffle furnace and calcined at 900℃ for 10h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named La-PTO-0.01.

[0039] Example 2:

[0040] 1) Take 5g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4700g of lead nitrate to it to obtain solution A;

[0041] 2) Add 0.015 g of praseodymium nitrate hexahydrate and 0.003 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0042] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine for ultrasonic treatment for 15 minutes, stir for 2 hours, then place it in a reaction vessel and react at 180℃ for 24 hours, and then cool it with the furnace.

[0043] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 65°C;

[0044] 5) The dried product was placed in a muffle furnace and calcined at 800℃ for 12h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Pr-PTO-0.01.

[0045] Example 3:

[0046] 1) Take 6g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4710g of lead nitrate to obtain solution A.

[0047] 2) Add 0.0200 g of samarium hexahydrate and 0.003 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0048] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine for ultrasonic treatment for 15 minutes, stir for 2 hours, then place it in a reaction vessel and react at 190℃ for 18 hours, and then cool it with the furnace.

[0049] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 63°C;

[0050] 5) The dried product was placed in a muffle furnace and calcined at 850°C for 11 h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Sm-PTO-0.01.

[0051] Example 4:

[0052] 1) Take 4.5g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4730g of lead nitrate to it to obtain solution A;

[0053] 2) Add 0.0205 g of dysprosium hexahydrate and 0.003 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0054] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine and sonicate for 15 minutes. After stirring for 2 hours, place it in a reaction vessel and react at 185℃ for 20 hours, then cool it with the furnace.

[0055] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 61°C;

[0056] 5) The dried product was placed in a muffle furnace and calcined at 830℃ for 12h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Dy-PTO-0.01.

[0057] Example 5:

[0058] 1) Take 5.5g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4720g of lead nitrate to it to obtain solution A;

[0059] 2) Add 0.0200 g of thulium nitrate pentahydrate and 0.003 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0060] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine and sonicate for 15 minutes. After stirring for 2 hours, place it in a reaction vessel and react at 195℃ for 15 hours, then cool it with the furnace.

[0061] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 64°C;

[0062] 5) The dried product was placed in a muffle furnace and calcined at 880℃ for 11h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Tm-PTO-0.01.

[0063] Depend on Figure 1 It can be seen that the crystallinity of lead titanate photocatalyst changes after being doped with rare earth ions;

[0064] Depend on Figure 3 It can be seen that the efficiency of photocatalytic CO2 reduction to CO and CH4 is improved after doping with rare earth ions.

[0065] Example 6:

[0066] 1) Take 4g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4740g of lead nitrate to it to obtain solution A;

[0067] 2) Add 0.0587 g of praseodymium nitrate hexahydrate and 0.004 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0068] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine for ultrasonic treatment for 20 minutes, stir for 2 hours, then place it in a reaction vessel and react at 200℃ for 12 hours, and then cool it with the furnace.

[0069] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 62°C;

[0070] 5) The dried product was placed in a muffle furnace and calcined at 820°C for 12 hours to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Pr-PTO-0.03.

[0071] Example 7:

[0072] 1) Take 5g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4750g of lead nitrate to it to obtain solution A;

[0073] 2) Add 0.0978 g of praseodymium nitrate hexahydrate and 0.005 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0074] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine for ultrasonic treatment for 25 minutes, stir for 2 hours, then place it in a reaction vessel and react at 200℃ for 20 hours, and then cool it with the furnace.

[0075] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 65°C;

[0076] 5) The dried product was placed in a muffle furnace and calcined at 860℃ for 12h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Pr-PTO-0.05.

[0077] Example 8:

[0078] 1) Take 6g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4735g of lead nitrate to it to obtain solution A;

[0079] 2) Add 0.1 g of praseodymium nitrate hexahydrate and 0.0035 mol of tetrabutyl titanate to solution A in sequence to obtain solution B;

[0080] 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine for ultrasonic treatment for 23 minutes, stir for 2 hours, then place it in a reaction vessel and react at 190℃ for 18 hours, and then cool it with the furnace.

[0081] 4) Wash the cooled precipitate with deionized water until neutral, and dry it in an oven at 60°C;

[0082] 5) The dried product was placed in a muffle furnace and calcined at 900℃ for 10h to obtain surface-treated lead titanate nanoparticles doped with rare earth elements, named Pr-PTO-0.07.

[0083] Depend on Figure 2 It can be seen that doping with different proportions of rare earth ions will also change its crystallinity.

[0084] Depend on Figure 4 It can be seen that the efficiency of photocatalytic CO2 reduction to CO and CH4 is improved after doping with different proportions of rare earth ions.

[0085] Implementation Results: Based on the yield analysis of photocatalytic CO2 reduction products, barium titanate photocatalysis, after Pr doping, produces more CO, reaching 3.13 μmol·g. -1 It is more conducive to the photocatalytic reduction of CO2.

Claims

1. A rare earth element-doped lead titanate nanoparticle for photocatalytic CO2 reduction reaction, characterized in that, The preparation method of the nanoparticles includes the following steps: 1) Take 4-6g of sodium hydroxide to prepare 30mL of sodium hydroxide solution and place it in a polytetrafluoroethylene liner. Add 1.4700-1.4755g of lead nitrate to obtain solution A. 2) Add 0.015-0.1 g of praseodymium nitrate hexahydrate and 0.003-0.005 mol of tetrabutyl titanate to solution A to obtain solution B; 3) Place the polytetrafluoroethylene liner containing solution B into a 100W ultrasonic machine and sonicate for 15-25 minutes. Then stir for 2 hours and place it in a reaction vessel to react at 180-200℃. After that, cool it with the furnace. 4) Wash the cooled precipitate with deionized water until neutral, and then dry it in an oven; 5) The dried product was placed in a muffle furnace and calcined at 800-900 ℃ to obtain surface-treated lead titanate nanoparticles doped with rare earth elements.

2. The reduction reaction according to claim 1, characterized in that, The reaction time for step 3) is 12 to 24 hours.

3. The reduction reaction according to claim 1, characterized in that, Step 4) involves placing the item in an oven and drying it at 60-65°C.

4. The reduction reaction according to claim 1, characterized in that, The calcination time in step 5) is 10-12 hours.

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