Preparation method and application of ultraviolet light induced cubic Cu2O surface reconstruction catalytic material

Abstract

The invention discloses a preparation method and application of an ultraviolet light-induced cubic Cu2O surface reconstruction catalytic material, belongs to the field of preparation of high-performance catalytic materials, and mainly relates to preparation and modification of a catalytic material for electrocatalytic carbon dioxide reaction. According to the method, the Cu2O surface is reconstructed in a simple ultraviolet light induction mode, a large number of mixed valence active sites are exposed, and therefore the electro-catalytic performance and stability of the Cu2O material are improved, and the method is safe and mild in preparation process, rapid and efficient in proportion adjustment mode, simple in step and easy to operate.

Description

Technical Field

[0001] The invention belongs to the field of high-performance catalytic material preparation, and mainly relates to the preparation and modification of catalytic materials for electrocatalytic carbon dioxide reaction. Background Art

[0002] The rapid development of human society has led to excessive consumption of fossil energy and an increase in atmospheric carbon dioxide (CO 2 ) content increases rapidly. Excess CO 2 Emissions lead to a series of environmental problems, such as global warming and ocean acidification. Electrocatalytic reduction is a mild and efficient means to convert CO 2 Converting it into chemical products with economic and use value can not only reduce CO 2 emissions and can also promote large-scale storage of renewable energy.

[0003] Electrocatalytic CO 2 The reduction reaction involves different electron transfer processes corresponding to a variety of products. Among them, high value-added ethanol and ethylene (abbreviated as C 2 The electroreduction of CO is a focus of attention and has great commercial application value. At present, the synthesis of ethanol and ethylene mainly relies on fossil fuels and biomass carbon, which consumes a large amount of fossil energy and causes serious damage to the environment. 2 C 2 The product has been widely studied as a green and pollution-free synthesis route.

[0004] Copper-based catalysts are currently the only metal catalytic materials that can promote CC coupling and have considerable Faradaic efficiency and kinetic driving force. Among them, the valence change of copper is the key to efficient C production. 2 The multivalent mixed structure is more conducive to the reduction of the reaction thermodynamic energy barrier and the CC coupling of the intermediate products, thereby promoting the C 2 Production of products. Existing modification technologies make it difficult to form a stable structure with multiple mixed valence states (such as Cu0, Cu1+), and it is difficult to maintain long-term dynamic equilibrium, which is not conducive to the continuous production of products. In addition, most modification synthesis methods have cumbersome and complicated steps.

[0005] To solve the above problems, we used UV-induced cubic Cu 2 O method to reconstruct its surface, under the induction of ultraviolet light, part of the Cu+ is reduced to Cu0, which improves the surface roughness and fully exposes the active sites of mixed valence, thereby increasing the C 2 Product selectivity. Using cubic Cu 2 O is irradiated under a high-pressure mercury lamp for a long time to adjust the mixing ratio of Cu+ / Cu0 and thus control the catalytic effect. 2A simple and effective modification method is provided. Summary of the invention

[0006] The primary purpose of the present invention is to use a fast and effective modification method to prepare a simple and controllable high-efficiency oxide-derived catalytic material for electrocatalytic CO 2 Reduction product C 2 The product is induced by ultraviolet light. 2 O surface, in situ reconstruction of the surface, and improvement of Cu 2 Stability and electrocatalytic performance of O materials.

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

[0008] Step 1: Cubic Copper Oxide (Cu 2 Preparation of O)

[0009] Add 20.0 mL of 2.0 mol / L NaOH aqueous solution to 250 mL of 0.1 mol / L CuCl 2 ·2H 2 After stirring for 10 min, 1.5 g of glucose powder was added to the dark brown solution and the reaction was continued for 2 h. All the above reactions were carried out under continuous stirring and the temperature was maintained at 60 °C in an oil bath. ～ 80℃. The brick-red precipitate was collected by centrifugation and washed three times with distilled water and anhydrous ethanol respectively. Finally, brick-red cubic cuprous oxide was obtained after vacuum drying at 60℃ for 6h.

[0010] Step 2: Reconstruction of cuprous oxide (Cu 2 Preparation of Ox

[0011] Take 4 mL of isopropanol and 2 mL of H 2 O 2 and 34 mL of deionized water to prepare a reducing solution, then 0.1 g of brick-red Cu 2 O powder was put into the above reducing solution and placed in a tubular quartz photoreactor for 20 minutes of ultrasonic treatment to fully dissolve it. Then, it was placed under a 300W high-pressure mercury lamp for 0-18 minutes under the condition of continuous bubbling with pure Ar. Finally, the precipitate was collected by centrifugation and washed with ethanol and deionized water three times respectively, and dried in vacuum at 60°C for 6 hours. The obtained material was named Cu 2 Ox, where x represents the irradiation time.

[0012] The catalytic material prepared by the method of the present invention has excellent electrocatalytic activity and stability. Ultraviolet light induces the reduction of Cu+ to form a mixed valence state, and the ratio of Cu+ / Cu0 is effectively adjusted by the duration of light exposure, accelerating the C 2The CC coupling process of the product intermediate reduces the chemical reaction energy barrier and thus improves the product selectivity.

[0013] The method of the present invention is used to adjust the prepared Cu 2 The Ox catalytic material has a high C of 65.03% (ethylene = 33.23%, ethanol = 31.8%) 2 Selectivity. After maintaining a constant current of 15 mA for 10 hours, it still exhibits a high stability of 65%. It exhibits excellent electrocatalytic activity in tests such as electrochemical active area (ECSA) and current density (J). BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The prepared material Cu 2 O, Cu 2 SEM and TEM images of O-12min: ac is Cu 2 SEM and TEM images of O, df is Cu 2 SEM and TEM images of O-12min.

[0015] Figure 2 The prepared material Cu 2 O, Cu 2 O-6min, Cu 2 O-12min, Cu 2 LSV curve and electrochemical activity area curve of O-18min: a is the LSV curve of each material, b is the electrochemical activity area curve of each material.

[0016] Figure 3 Where ad is the prepared material Cu 2 O, Cu 2 O-6min, Cu 2 O-12min, Cu 2 The Faradaic efficiency and C of each product corresponding to 0-18min 2 Product partial current density curve, e is the C corresponding to each catalytic material at -1.3V voltage 2 Faradaic efficiency, f is Cu at -1.3V 2 Stability test curve of O-12.

[0017] Figure 4 The prepared material Cu 2 The Faradaic efficiency and C of each product from 0 to 0 min 2 Product partial current density curve. DETAILED DESCRIPTION

[0018] The specific implementation method adopted according to the technical solution of the present invention is described as follows:

[0019] Example 1

[0020] (1) Cubic copper oxide (Cu 2 O) is prepared as shown in step 1 above.

[0021] (2) Reconstruction of cuprous oxide (Cu 2 Preparation of 2-6min

[0022] Take 4 mL of isopropanol and 2 mL of H 2 O 2 and 34 mL of deionized water to prepare a reducing solution, then 0.1 g of brick-red Cu 2 O powder was put into the above reducing solution and placed in a tubular quartz photoreactor for 20 minutes of ultrasonic treatment to fully dissolve it. Then, it was placed under a 300W high-pressure mercury lamp for 6 minutes under continuous bubbling with pure Ar. Finally, the precipitate was collected by centrifugation and washed with ethanol and deionized water three times respectively, and dried in vacuum at 60°C for 6 hours. The obtained material was named Cu 2 O-6min.

[0023] The reconstructed cuprous oxide (Cu 2 0-6min) performance evaluation is as follows: Cu 2 The average double layer capacitance of O-6min is 0.081mF / cm 2 , C 2 The Faradaic efficiency is 58.51%.

[0024] Example 2

[0025] (1) Cubic copper oxide (Cu 2 O) is prepared as shown in step 1 above.

[0026] (2) Reconstruction of cuprous oxide (Cu 2 Preparation of

[0027] Take 4 mL of isopropanol and 2 mL of H 2 O 2 and 34 mL of deionized water to prepare a reducing solution, then 0.1 g of brick-red Cu 2 O powder was put into the above reducing solution and placed in a tubular quartz photoreactor for 20 minutes of ultrasonic treatment to fully dissolve it. Then, it was placed under a 300W high-pressure mercury lamp for 12 minutes under continuous bubbling with pure Ar. Finally, the precipitate was collected by centrifugation and washed with ethanol and deionized water three times respectively, and dried in vacuum at 60°C for 6 hours. The obtained material was named Cu 2 O-12min.

[0028] The reconstructed cuprous oxide (Cu2 0-12min) performance evaluation is as follows: Cu 2 The average double layer capacitance of O-12min is 0.380mF / cm 2 , C 2 The Faradaic efficiency is 65.03%.

[0029] Example 3

[0030] (1) Cubic copper oxide (Cu 2 O) is prepared as shown in step 1 above.

[0031] (2) Reconstruction of cuprous oxide (Cu 2 Preparation of

[0032] Take 4 mL of isopropanol and 2 mL of H 2 O 2 and 34 mL of deionized water to prepare a reducing solution, then 0.1 g of brick-red Cu 2 O powder was put into the above reducing solution and placed in a tubular quartz photoreactor for 20 minutes of ultrasonic treatment to fully dissolve it. Then, it was placed under a 300W high-pressure mercury lamp for 18 minutes under continuous bubbling with pure Ar. Finally, the precipitate was collected by centrifugation and washed with ethanol and deionized water three times respectively, and dried in vacuum at 60°C for 6 hours. The obtained material was named Cu 2 O-18min.

[0033] The reconstructed cuprous oxide (Cu 2 O-18min) performance evaluation is as follows: Cu 2 The average double layer capacitance of O-18min is 0.078mF / cm 2 , C 2 The Faradaic efficiency is 53.59%.

[0034] Comparative Example 1

[0035] (1) Cubic copper oxide (Cu 2 O) is prepared as shown in step 1 above.

[0036] (2) Reconstruction of cuprous oxide (Cu 2 Preparation of

[0037] Take 4 mL of isopropanol and 2 mL of H 2 O 2 and 34 mL of deionized water to prepare a reducing solution, then 0.1 g of brick-red Cu 2O powder was put into the above reducing solution and placed in a tubular quartz photoreactor for ultrasonic treatment for 20 minutes to fully dissolve it. Then, it was placed under a 300W high-pressure mercury lamp for 10 minutes under continuous bubbling with pure Ar. Finally, the precipitate was collected by centrifugation and washed with ethanol and deionized water three times respectively, and dried under vacuum at 60°C for 6 hours. The obtained material was named Cu 2 O-0min.

[0038] The reconstructed cuprous oxide (Cu 2 0-0min) performance evaluation is as follows: Cu 2 Catalytic performance FEC of O-0min 2 =50.38%.

[0039] Comparative Example 2

[0040] (1) Cubic copper oxide (Cu 2 O) is prepared as shown in step 1 above.

[0041] Primitive Cu 2 Catalytic performance of O FEC 2 =50.65%. This is almost close to Comparative Example 1.

[0042] From the above results, it can be seen that the order of the effect of preparing the ultraviolet-induced reconstruction of cuprous oxide catalyst is Application Example > Comparative Example 1 = Comparative Example 2, which shows that the reconstruction process of cubic cuprous oxide requires a certain length of ultraviolet light induction to play a reconstruction role, triggering the mixing of Cu+ / Cu0 multivalent states, effectively improving its C in the carbon dioxide electroreduction. 2 Product selectivity.

[0043] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A preparation method and application of ultraviolet light-induced cubic Cu2O surface reconstruction catalytic material, characterized in that: The following steps are involved: Step 1: Preparation of Cubic Copper Oxide (Cu2O) First, 20.0 mL of 2.0 mol / L NaOH aqueous solution was added to 250 mL of 0.1 mol / L CuCl2·2H2O aqueous solution. After stirring for 10 min, 1.5 g of glucose powder was added to the dark brown solution and the reaction continued for 2 h. All the above reactions were carried out under continuous stirring and the temperature was maintained at 60 °C in an oil bath. ～ 80℃. The brick-red precipitate was collected by centrifugation and washed three times with distilled water and anhydrous ethanol respectively. Finally, brick-red cubic cuprous oxide was obtained after vacuum drying at 60℃ for 6h. Step 2: Preparation of reconstructed cuprous oxide (Cu2O-x) First, 4 mL of isopropanol, 2 mL of H2O2 and 34 mL of deionized water were prepared into a reducing solution, and then 0.1 g of brick-red Cu2O powder was put into the reducing solution and placed in a tubular quartz photoreactor for ultrasonication for 20 minutes to fully dissolve it. Then, under continuous bubbling with pure Ar, it was placed under a 300W high-pressure mercury lamp for 0-18 minutes. Finally, the precipitate was collected by centrifugation and washed with ethanol and deionized water three times respectively, and vacuum dried at 60°C for 6 hours. The obtained material was named Cu2O-x, where x represents the irradiation time.

2. The preparation method and application of a UV-induced cubic Cu2O surface reconstruction catalytic material according to claim 1, characterized in that: The optimal exposure time is 12 minutes of UV light.

3. A UV-induced cubic Cu2O surface reconstruction catalytic material prepared according to the method described in any one of claims 1-2.

4. A UV-induced cubic Cu2O surface reconstruction catalytic material prepared according to the method described in any one of claims 1-2, which is used for electrocatalytic CO2 reduction to produce C2.

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