阅读说明：本技术 一种用于高效二氧化碳还原的多孔电催化剂的制备方法 (Preparation method of porous electrocatalyst for efficient carbon dioxide reduction ) 是由 王凯耀 张顺 于 2020-12-16 设计创作，主要内容包括：本发明为一种用于高效二氧化碳还原的多孔电催化剂的制备方法。该方法包括以下步骤：将锡粉、硒粉、氯化胆碱/尿素混合物、水合肼加入到反应釜中,在140-160℃条件下反应15-24小时,获得晶体前驱物；再将上步得到的单晶前驱物升温至600-800℃,再降温得到多孔电催化剂。得到的催化剂用于电催化二氧化碳还原中电解池的负极。本发明得到的产品产率高、比表面积大,作为催化剂,对二氧化碳还原具有高的催化选择性和稳定性。(The invention relates to a preparation method of a porous electrocatalyst for efficient carbon dioxide reduction. The method comprises the following steps: adding tin powder, selenium powder, choline chloride/urea mixture and hydrazine hydrate into a reaction kettle, and reacting for 15-24 hours at the temperature of 140-; and then heating the single crystal precursor obtained in the previous step to 600-800 ℃, and then cooling to obtain the porous electrocatalyst. The obtained catalyst is used for a negative electrode of an electrolytic cell in electrocatalytic carbon dioxide reduction. The product obtained by the method has high yield and large specific surface area, and has high catalytic selectivity and stability for carbon dioxide reduction when used as a catalyst.)

1. A method for preparing a porous electrocatalyst for efficient carbon dioxide reduction, characterized in that the method comprises the steps of:

(1) preparation of organic-oriented tin selenide precursor: adding tin powder, selenium powder, choline chloride/urea mixture and hydrazine hydrate into a reaction kettle, reacting for 10-24 hours at the temperature of 100-180 ℃, naturally cooling, washing and naturally drying the obtained product to obtain a crystal precursor [ (CH)₃)₃N(CH₂)₂OH]₂[Sn₃Se₇]·H₂O(Choline-Sn₃Se₇)；

Wherein, the mol ratio is that choline chloride: 1:1.5-2.5 of urea; urea: hydrazine hydrate 1: 0.5-2; tin powder: selenium powder is 1: 1-5; tin powder: choline chloride 1: 3-15;

(2) porous SnO₂Preparation of electrocatalytic material: the single crystal Choline-Sn obtained in the previous step₃Se₇The precursor is placed in a tubular reaction furnace and is heated at 1-30 ℃ for min in air atmosphere^-1The temperature is raised to 600-800 ℃, then the temperature is kept for 0-30min, and finally the temperature is lowered to obtain the porous electrodeCatalyst, noted as P-SnO₂。

2. The method for preparing a porous electrocatalyst for high efficiency carbon dioxide reduction according to claim 1, characterized in that the specific surface area of the porous electrocatalyst is 20-40m² g^-1。

3. The method of claim 1, wherein the constant temperature in step (2) is preferably immediately lowered or maintained for 0.1-30 min.

4. Use of the porous electrocatalyst for high efficiency carbon dioxide reduction prepared according to the method of claim 1, characterized as negative electrode for electrolytic cell in electrocatalytic carbon dioxide reduction.

5. Use of a porous electrocatalyst for high efficiency carbon dioxide reduction prepared according to the method of claim 4, characterized by comprising the steps of:

(1) preparation of electrode dispersion liquid: weighing a porous electrocatalyst and a conductive agent, dispersing in the mixed solution, and performing ultrasonic treatment for 2-6h to obtain an electrode dispersion solution;

wherein the mixed solution comprises Nafion, alcohol and water, and the volume ratio is Nafion: alcohol: 2:7:1 of water, and 5-15mg mL of conductive agent^-1(ii) a The mass concentration of the catalyst is 10-30mg mL^-1；

(2) Preparation of catalyst electrode: dropwise coating the electrode dispersion liquid on a carbon paper electrode, and airing to obtain a negative electrode of the electrolytic cell; wherein, 10-80 μ L of the carbon paper electrode is dripped into each 1 square centimeter.

6. Use of a porous electrocatalyst for efficient carbon dioxide reduction prepared according to claim 5 wherein the conducting agent comprises ketjen black, acetylene black or XC-72.

7. Use of the porous electrocatalyst for high efficiency carbon dioxide reduction prepared according to the method of claim 5, wherein in step (1), the alcohol is preferably ethanol or isopropanol.

The technical field is as follows:

the invention belongs to the field of electrochemical catalyst preparation, and particularly relates to a method for converting carbon dioxide into C by electrocatalytic reduction₁Process for the preparation of a tin-based catalyst of the product (formic acid + carbon monoxide).

Background art:

in the current society, consumption of fossil energy such as petroleum and coal is accompanied by a large amount of carbon dioxide (CO)₂) The generation of the organic fertilizer causes serious greenhouse effect and environmental damage. At the same time, the limited storage of fossil resources is facing the foreseeable futureThe survival pressure for resource exhaustion. The clean electric energy obtained by solar energy, wind energy, tidal energy and the like is utilized to further convert CO into CO₂Reduction to chemicals or chemical fuels with high added values to achieve carbon recycling is one of the important methods to solve the above two problems. C represented by formic acid (HCOOH) and carbon monoxide (CO)₁The substances are important chemical raw materials in the fields of medicine, hydrogen storage, rubber, fuel cells, synthesis gas and the like, and have higher commercial value than other substances such as methanol, methane, ethanol and the like (Chem,2018,4(11): 2571-2586). However, due to CO₂The self has stronger chemical inertia, and in addition, a complex multi-electron transfer process is involved in the reduction reaction, the electrocatalysis technology often faces adverse factors such as high overpotential, low current density, product diversification and the like, and finally the development of the energy industry is hindered. Therefore, it is very critical to develop efficient and inexpensive electrocatalytic materials.

Nanoporous tin dioxide (SnO)₂) To CO₂The reduction reaction has high catalytic activity and C₁The product selectivity is a potential catalyst, and the material also has the advantages of no toxicity, easy raw material acquisition and the like, and is widely researched and reported in recent years. The porous structural characteristic not only endows SnO₂Better mass transfer capability, more active sites and abundant grain boundaries, and can increase CO₂The adsorption capacity of the catalyst can also enhance the adsorption effect of the material on the reduction reaction intermediate, thereby improving the catalytic efficiency and the selectivity of the product. With dense SnO₂Compared with the bulk material, the porous material catalyzes CO in electrochemistry₂To produce C represented by HCOOH and CO₁The product process exhibited significantly higher current density and faraday efficiency. Therefore, it is a challenge for the scientists to design and prepare catalysts with an open framework structure and uniform pore size distribution, and the design and preparation of the catalysts are dependent on the development and innovation of the synthesis technology.

Currently, porous SnO is prepared₂The main methods for materials are hard template method and soft template method (chem. Soc. Rev.2013,42(7), 2610-2653). The hard template method uses solid particles, porous membrane or patterned solid surface as template agent and makes the template agent pass throughThe method comprises the steps of coating or filling the template with raw materials by chemical impregnation, precipitation or vapor deposition and the like, generating corresponding species through crystallization, polymerization and the like, and finally removing the template selectively to obtain the porous material which is in a reverse phase structure with the template. The hard template method is simple and convenient to operate and widely applied to the construction of nano materials, but the method has the following obvious defects: (1) the one-time use of the template causes a serious waste of materials; (2) the process of removing the template usually involves the use of strong acid or strong base, which is harmful to the environment and is not in accordance with the green development concept. The soft template method uses molecules with specific functional groups as a template agent, and uses intermolecular forces (e.g., hydrogen bonds, electrostatic forces) to form aggregates with certain structural orientations. By using the template as a template, a guest material is deposited and grown in the template and on the surface of the template with orientation, and finally a particle product with a certain configuration is obtained. The material with rich configuration, high dispersity and uniform pore diameter can be obtained by a soft template method, but the operation flow is often more complicated, the synthesis parameters are difficult to control, the yield is lower, and the application of the material in actual production is greatly hindered. Therefore, there is an urgent need to develop new template synthesis technology from the design and assembly of template and precursor, the synthesis process conditions of porous material to CO₂Reaction mechanism of reduction and method for improving performance of porous SnO₂The materials were subjected to intensive research and exploration.

The invention content is as follows:

the invention aims to overcome the defects of the prior template technology and provides a novel method for preparing a high-efficiency carbon dioxide reduction porous electrocatalyst. The method uses the Choline-Sn which is uniformly distributed and arranged by an organic template₃Se₇The crystal material is a precursor, the template agent is removed to construct a porous structure by simple one-step heating treatment in the air atmosphere, phase transformation from selenide to oxide is realized, and the nano-porous SnO is obtained₂Electrocatalytic material (P-SnO)₂). The product obtained by the method has high yield and large specific surface area, and has high catalytic selectivity and stability for carbon dioxide reduction when used as a catalyst.

The technical scheme of the invention is as follows:

a method of preparing a porous electrocatalyst for efficient carbon dioxide reduction, the method comprising the steps of:

(1) preparation of organic-oriented tin selenide precursor: adding tin powder, selenium powder, choline chloride/urea mixture and hydrazine hydrate into a reaction kettle, reacting for 10-24h at the temperature of 100-180 ℃, naturally cooling, washing and naturally drying the obtained product to obtain a crystal precursor [ (CH)₃)₃N(CH₂)₂OH]₂[Sn₃Se₇]·H₂O(Choline-Sn₃Se₇)；

Wherein, the mol ratio is that choline chloride: 1:1.5-2.5 of urea; urea: hydrazine hydrate 1: 0.5-2; tin powder: selenium powder is 1: 1-5; tin powder: choline chloride 1: 3-15;

(2) porous SnO₂Preparation of electrocatalytic material: the single crystal Choline-Sn obtained in the previous step₃Se₇The precursor is placed in a tubular reaction furnace and is heated at 1-30 ℃ for min in air atmosphere^-1The temperature is raised to 800 ℃ at the speed of 600-₂；

The specific surface area of the porous electrocatalyst is 20-40m² g^-1。

The constant temperature time in the step (2) is preferably immediately reduced or kept for 0.1-30 min.

The preparation method of the porous electrocatalyst for efficient carbon dioxide reduction is applied to a negative electrode of an electrolytic cell in electrocatalytic carbon dioxide reduction.

The preparation method of the porous electrocatalyst for efficient carbon dioxide reduction comprises the following steps:

(1) preparation of electrode dispersion liquid: weighing a porous electrocatalyst and a conductive agent, dispersing in the mixed solution, and performing ultrasonic treatment for 2-6h to obtain an electrode dispersion solution;

wherein the mixed solution comprises Nafion, alcohol and water, and the volume ratio is Nafion: alcohol: 2:7:1 of water, and 5-15mg mL of conductive agent^-1(ii) a Mass concentration of catalyst10-30mg mL^-1；

(2) Preparation of catalyst electrode: dropwise coating the electrode dispersion liquid on a carbon paper electrode, and airing to obtain a negative electrode of the electrolytic cell; wherein, 10-80 μ L of the carbon paper electrode is dripped into each 1 square centimeter.

The conductive agent comprises Ketjen black, acetylene black or XC-72.

In the step (1), the alcohol is preferably ethanol or isopropanol.

The invention has the substantive characteristics that:

firstly, a solvent thermal technology is utilized to prepare a tin selenide crystal material Choline-Sn with a lamellar molecular structure, wherein the interlayer contains a removable Choline cation template agent which is regularly arranged₃Se₇. Then with Choline-Sn₃Se₇As a precursor, the template agent is removed to construct a porous structure by simple one-step heating treatment in the air atmosphere, phase transformation from selenide to oxide is realized, and finally the nano-porous SnO with high yield and large specific surface area is obtained₂Electrocatalytic material (P-SnO)₂). The catalyst is used for CO₂The reduction has high catalytic selectivity and stability.

The invention has the beneficial effects that:

1. the method abandons the complicated preparation process of the traditional template method, utilizes the organic-oriented tin selenide crystal material as a reaction precursor, and realizes template removal and porous SnO through simple one-step heating treatment₂The product is formed, the operation is simple, the yield is high, the preparation is controllable, and the repeatability is strong;

2. P-SnO prepared by the invention₂The porous material has good pore canal dispersibility, large specific surface area, high mass transfer and high surface active site number, and can effectively improve the electrocatalytic CO₂The activity and efficiency of the reduction reaction;

3. P-SnO prepared by the invention₂The porous material exhibits excellent electrocatalytic reduction of CO₂System C of₁The properties of the product: CO at-1.06V vs RHE (reversible Hydrogen electrode, RHE) potential₂Conversion to C₁The faradaic conversion efficiency of the product reaches 94.5 percent, andc within the interval of-0.96 to-1.26V vs RHE₁The Faraday efficiency can be kept above 90%. Can continuously obtain 11.8 +/-2.1 mA cm for 100 hours at the potential of-1.06V vs RHE^-2Current density of 90.4. + -. 2.5% C₁Faradaic conversion efficiency of the product.

Description of the drawings:

FIG. 1 shows P-SnO of the present invention₂Preparation process of porous material and application of porous material in CO₂Schematic representation of electrocatalytic reduction.

FIG. 2 shows Choline-Sn₃Se₇Crystal structure resolution of the precursor.

FIG. 3 shows Choline-Sn₃Se₇XRD pattern of the precursor.

FIG. 4 shows Choline-Sn₃Se₇P-SnO obtained by roasting precursors for different times in air atmosphere₂XRD pattern of (a).

FIG. 5 shows P-SnO prepared by the present invention₂SEM and TEM images of; wherein, FIG. 5a is P-SnO₂SEM image of-0 min solid surface, FIG. 5b is P-SnO₂SEM image of-0 min internal morphology, FIG. 5c is P-SnO₂TEM image at-0 min, FIG. 5d is P-SnO₂SEM image of-15 min solid surface, FIG. 5e is P-SnO₂SEM image of internal morphology at-15 min, and FIG. 5f is P-SnO₂TEM image at-15 min, FIG. 5g is P-SnO₂SEM image of solid surface at-30 min, FIG. 5h is P-SnO₂SEM image of internal morphology at-30 min, and P-SnO in FIG. 5i₂TEM image at 30 min.

FIG. 6 shows P-SnO prepared by the present invention₂To N₂The absorption and desorption performance diagram; wherein, FIG. 6a shows a material pair N₂Fig. 6b is a graph of pore size distribution and cumulative pore volume of the material.

FIG. 7 shows P-SnO prepared by the present invention₂Electrode in Ar and CO₂Current density-voltage curve in saturated solution; wherein, FIG. 7a shows P-SnO₂Electrode made of-0 min material in Ar and CO₂Current density-Voltage curves in saturated solution, FIG. 7b is P-SnO₂Electrode made of-15 min material in Ar and CO₂Current density-Voltage curves in saturated solution, FIG. 7c is P-SnO₂Electrode made of-30 min material in Ar and CO₂Current density-voltage curve in saturated solution.

FIG. 8 shows P-SnO prepared by the present invention₂-0min current density versus time curve of the electrode at different potentials;

FIG. 9 shows P-SnO prepared by the present invention₂Catalysis of CO by-0 min electrode pair₂Conversion to C₁Faradaic efficiency versus voltage curve for the product.

FIG. 10 shows P-SnO prepared by the present invention₂Current density and faraday efficiency plot of-0 min electrode run at-1.06V vs RHE for 100 h.

FIG. 11 shows Choline-Sn₃Se₇The thermal weight loss curve of the precursor in the air atmosphere and the heating rate of 10 ℃ for min^-1。

FIG. 12 shows Choline-Sn₃Se₇XRD patterns of products of the precursors after heating treatment at 300 ℃ and 550 ℃ respectively.

FIG. 13 shows Choline-Sn₃Se₇SEM images of products of the precursors after heating treatment at 300 ℃ and 550 ℃ respectively; wherein FIG. 13a shows Choline-Sn₃Se₇SEM image of-300, FIG. 13b is Choline-Sn₃Se₇SEM picture of 550.

The specific implementation mode is as follows:

the invention is further explained below with reference to examples and figures, which are intended to assist the reader in better understanding the technical solutions of the invention, but the scope of protection of the invention is not limited thereto.

Example 1

The method comprises the following steps: putting 1.0mmol of tin powder, 2.67mmol of selenium powder, 8.0mmol of Choline chloride, 16.0mmol of urea and 20.6mmol of hydrazine hydrate serving as an auxiliary solvent into a reaction kettle with a 20mL polytetrafluoroethylene lining, stirring for 30min, transferring the reaction kettle into a drying oven, heating to react for 24h at 150 ℃, naturally cooling to room temperature after the reaction is finished, washing the product with 5 times of 20mL of water and 5 times of 20mL of ethanol, and naturally drying to obtain single crystal Choline-Sn₃Se₇A precursor. (said Choline-Sn₃Se₇The precursor is a known material, and can be referred to as the following documents: chem.Commun.2018,54(38),4806 obtained by one of ordinary skill in the art through 4809)

Step two: drying the single crystal Choline-Sn obtained in the step one₃Se₇Placing in a quartz tube in the central temperature region of the tubular reaction furnace in a porcelain boat at 10 deg.C for 10min^-1Heating to 800 deg.C at a heating rate, naturally cooling to room temperature (i.e. keeping the temperature for 0 min), and grinding for 10min to obtain porous SnO₂Material, marked as P-SnO₂-0min。

Step three: 10mg of P-SnO obtained in step two₂0min, 5mg Ketjen black and 0.5mL of Nafion solution (volume ratio, Nafion: isopropanol: water: 2:7:1) were mixed thoroughly and placed in an ultrasonic machine for ultrasonic treatment for 4h to form a uniform catalyst dispersion.

Step four: measuring 10 mu L of the catalyst dispersion obtained in the step three, and dripping the catalyst dispersion on the cut carbon paper to form a region of 1cm²Then the dropping process was repeated 5 times. After natural drying, the carbon paper is fixed by an electrode clamp and placed in a container containing 0.1M KHCO₃In the H-type electrolytic cell of the solution, the working electrode is used, and the platinum sheet and the saturated calomel electrode are respectively used as a counter electrode and a reference electrode. With CO before testing₂The gas was pre-bubbled to saturate it in the electrolyte solution and continuous aeration was maintained at a constant flow of 20sccm during the test. The current density-voltage curve was tested at a potential of 0.24 to-1.36V vs RHE, and potentiostatic electrolysis was tested at a potential of-0.56 to-1.36V vs RHE. Gas and liquid products after the electrolytic reaction are respectively subjected to gas chromatography and nuclear magnetic resonance spectroscopy (¹H NMR) was performed.

Example 2

The heat preservation time of the second step in the example 1 is changed to 15min, and the obtained product is marked as P-SnO₂15min, the other operations are the same as in example 1.

Example 3

The heat preservation time of the second step in the example 1 is changed to 30min, and the obtained product is marked as P-SnO₂30min, and the other operations are the same as in example 1.

Examples 4 to 5

The temperature raising termination temperature of the second step in example 1 was changed to 300 ℃ and 550 ℃ to obtain products labeled Choline-Sn₃Se₇-300 and Choline-Sn₃Se₇-550。

FIG. 3 shows Choline-Sn synthesized in the present invention₃Se₇XRD spectrum of precursor.

FIG. 4 shows Choline-Sn of the present invention in examples 1-3₃Se₇P-SnO obtained through different roasting time₂XRD pattern of (a). With Choline-Sn₃Se₇The XRD spectrogram (figure 3) shows that Choline-Sn is obtained after roasting₃Se₇Complete conversion of the precursor into SnO₂Phase, and the peak width becomes narrower as the firing time is longer, means SnO constituting the porous material₂The particle size gradually increases.

FIG. 5 shows P-SnO obtained in examples 1 to 3 according to the present invention₂SEM and TEM images of (a). As can be seen from the SEM image, Choline-Sn₃Se₇After firing, a large number of regular pores appear on the surface, and as the firing time is extended from 0min to 30min, the pores become wider and decrease in number. The interior of which is formed by a plurality of SnO connected with each other₂The nanoparticle composition, with a significant increase in particle size over the duration of firing, showed by particle size statistics on TEM that the particle sizes obtained in examples 1-3 were 13.1, 19.5 and 25.8nm, respectively.

FIG. 6 shows P-SnO obtained in examples 1 to 3 according to the present invention₂To N₂And (b) pore size distribution and cumulative pore volume. Warp of N₂The specific surface areas of the three samples obtained by the adsorption and desorption tests are 36.1 m, 27.4 m and 21.6m respectively² g^-1. The pore size distribution and cumulative pore volume plots show that the proportion of mesopores having a pore size in the range of 2 to 20nm is reduced from 60.7% to 29.7% with the increase in firing time, in agreement with the results of the SEM (fig. 5).

FIGS. 7a-c are P-SnO obtained in examples 1-3 according to the present invention₂The current density-voltage curve obtained when the electrode prepared by the sample is subjected to linear voltammetry test. Compared with the results measured under an Ar atmosphere, CO₂The curve under the atmosphere shows significantly greater current density, meaning electrocatalytic CO₂Reduction reaction occurs. In addition, the sample electrodes obtained with longer firing times exhibited significantly lower current values, which illustrates that the samples P-SnO obtained in example 1₂-0min material has higher catalytic CO₂And (4) reducing activity.

FIG. 8 shows a sample P-SnO obtained in example 1 according to the present invention₂Current density-time plot obtained at potentiostatic test for electrodes prepared at 0 min. Under different potentials of-0.56 to-1.36V vs RHE, the current passing through the electrode can quickly reach an equilibrium value and can be kept stable for a long time, which means that P-SnO₂The electrode prepared in-0 min has good catalytic stability.

FIG. 9 shows P-SnO obtained in examples 1 to 3 according to the present invention₂Faradaic efficiency versus voltage plot for the prepared electrodes. As can be seen from the figure, the P-SnO obtained as the calcination time was prolonged₂Display of catalytic CO₂Generation of C₁The faraday efficiency of (a) gradually decreases. P-SnO₂The highest catalytic activity (highest C at-1.06V vs RHE) was exhibited at-0 min₁Faraday efficiency of 94.5%), P-SnO₂15min and P-SnO₂The activity was relatively low at-30 min (highest C at-1.26V vs RHE and-1.06V vs RHE)₁Faradaic efficiencies were 88.9% and 79.0%, respectively).

FIG. 10 shows P-SnO obtained in example 1 according to the present invention₂Electrocatalysis of CO at-1.06V vs RHE with electrode prepared at-0 min₂Faradaic efficiency of reduction and current density versus time. As can be seen, P-SnO₂The electrode prepared in-0 min has catalytic efficiency, current density and C in the electrolytic process of 100h₁The product selectivity can be kept at a higher level without obvious attenuation. From the figure, CO can also be observed₂The faradaic efficiency of the conversion to HCOOH gradually increased over the first 15h of electrolysis time and stabilized around 70% after 20 h.

FIG. 11 shows Choline-Sn of the present invention₃Se₇Thermogravimetric curve of precursor in air atmosphere. It can be seen that the thermogravimetric curve is at 300 DEG CTwo weight loss platforms are arranged at about 550 ℃, the corresponding weight loss amounts are respectively 26 percent and 58 percent, and the corresponding weights are respectively corresponding to Choline-Sn₃Se₇Loss of choline ion template and synthesis of SnSe₂Conversion to SnO₂The process of (1).

FIG. 12 shows Choline-Sn obtained in examples 4-5 according to the present invention₃Se₇-300 and Choline-Sn₃Se₇-XRD pattern of 550 product. From the results of phase analysis, Choline-Sn₃Se₇-300 main component SnSe₂And Choline-Sn₃Se₇SnO at-550₂(main phase) and SnSe₂A mixture of (a). Incorporation of P-SnO in example 1₂XRD analysis at-0 min (FIG. 4) showed that Choline-Sn increased with increasing heating temperature₃Se₇The precursor is decomposed and volatilized to form SnSe through a template₂And further heating and oxidizing to form SnO₂The step-by-step transformation process of (1). At the same time, 550 ℃ is not enough for Choline-Sn₃Se₇Complete conversion of the precursor into SnO₂The completion of the conversion reaction can be promoted only by continuously raising the temperature to 600-800 ℃.

FIG. 13 shows Choline-Sn from examples 4-5₃Se₇-300 and Choline-Sn₃Se₇SEM picture of 550 products. As can be seen, Choline-Sn₃Se₇300 exhibited a heterogeneous macroporous morphology due to Choline-Sn heating to 300 deg.C₃Se₇The mesocholine ion template agent is decomposed and volatilized. When the mixture is further heated to 550 ℃, most of SnSe₂Conversion to SnO₂The Choline-Sn is caused to be accompanied with the change of the crystal structure and the lattice contraction₃Se₇-550 presents a much smaller and uniform mesoporous morphology. However, Choline-Sn₃Se₇-550 and P-SnO in example 1₂The morphology still differs from-0 min, since further heating to 800 ℃ promotes SnSe₂Complete conversion to SnO₂And accompanied by nucleation and growth of particles, P-SnO is formed₂-a porous structure assembled from homogeneous particles in 0min (fig. 5a, fig. 5 b).

From the above embodiments we canAs can be seen, for the organically oriented tin selenide crystal precursor (Choline-Sn)₃Se₇) Porous SnO can be prepared by simple heating treatment₂A material. Choline-Sn with increasing reaction temperature₃Se₇SnSe subjected to volatilization of organic template to generate macropores₂Then gradually converted into SnO consisting of uniform nano particles connected through oxidation reaction₂A porous material. At the same time, SnO is generated along with the extension of constant temperature time₂The particle size of the nano particles is gradually increased, so that a larger pore passage size is created. The obtained P-SnO₂The porous material can be used for high-efficiency electrocatalytic reduction of CO₂System C of₁Product exhibiting faradaic conversion efficiency higher than 90% and excellent stability up to 100 h. Therefore, the preparation method has the advantages of simple operation, high yield and adjustable product aperture and has important application value.

The invention is not the best known technology.