A copper supported catalyst with space confinement effect for water-gas shift reaction and a preparation method thereof

Abstract

The application discloses a copper supported catalyst with space confinement effect for water-gas shift reaction and a preparation method thereof, and the copper-based catalyst comprises Cu as an active component, an assistant g-C3N4 providing an anchoring site, and mesoporous SBA-15 as a carrier. The g-C3N4 can effectively anchor copper nanoparticles due to defect sites of a network structure, limit the copper nanoparticles in the mesoporous inner wall of the SBA-15, play an anchoring and space confinement role, and prevent copper particles from sintering and growing in the catalytic process. Meanwhile, due to the aforementioned chemical (anchoring) and physical (space) confinement effects, the prepared active component copper particles are small in size, expose more active sites, create a large number of space-limited micro-reaction environments, and thus improve the activity and stability of the catalyst in the water-gas shift reaction.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation and heterogeneous catalysis, specifically relating to a copper-supported catalyst with confinement effect for water-gas shift reaction and its preparation method. Background Technology

[0002] Hydrogen energy, characterized by its cleanliness, high efficiency, and wide availability, is considered a crucial energy source for achieving environmentally friendly and sustainable development. Fossil fuels are a significant source of hydrogen, primarily produced through chemical processes such as coal gasification and natural gas reforming. These processes mainly involve two steps: the gasification or reforming reaction that converts fossil fuels into carbon monoxide, and the water-gas shift reaction that converts carbon monoxide into carbon dioxide and produces hydrogen. Therefore, the water-gas shift reaction (WGS, CO + H₂O → CO₂ + H₂, ΔH = -41.1 kJ / mol) is one of the most important catalytic processes in industrial hydrogen production. In this process, the catalyst is key to improving reaction efficiency and economic benefits.

[0003] The WGS process is exothermic, and low temperatures favor the reaction; however, the WGS reaction rate is low at low temperatures. To improve the efficiency of the WGS reaction, current research mainly focuses on the development of high-performance supported metal catalysts. Therefore, Cu-based catalysts with good water-gas shift reaction performance at low temperatures have been extensively studied. Chinese patent CN111389399B discloses a Cu / SiO2 catalyst prepared by ammonia stripping-hydrothermal method, which yields stable small-sized Cu nanoparticles and Cu... + The species enhance the catalyst's ability to dissociate water and adsorb CO, exhibiting high catalytic activity in the water-gas shift reaction. Chen et al. (Chen, et al. ACSCatal. 2013, 3, 4, 667–677) reported the use of SBA-15 supported Cu nanoparticles with carboxylic acid groups. The synthesized catalyst has highly dispersed Cu, providing abundant active sites and effectively improving reaction selectivity and activity. Chinese patent CN105107513A proposes a method for preparing Cu-based water-gas shift catalysts using mesoporous silica as a template. By controlling the preparation process parameters, the catalyst can be uniformly dispersed in the channels and surface of the organic structure directing agent, significantly improving the dispersibility of the metal active component while effectively avoiding catalyst sintering at high temperatures. It has the characteristics of good thermal stability, high shift activity, large specific surface area, and high dispersion of active components. Chen et al. (Chen, et al. ChemCatChem. 2020, 12, 18) successfully prepared CuO using a hydrothermal method with ammonia stripping. x / SiO2 precursor, Cu was found 0 and Cu +It exhibits activity in both CO adsorption and water dissociation, especially Cu. 0 and Cu + The particle size is relatively small, CO in Cu + The adsorption ratio on Cu 0 Strong adsorption on Cu 0 The dissociation ratio of Cu to water + More active. However, Cu / SiO2 catalysts suffer from problems such as short lifespan and poor stability. Currently reported Cu / SBA-15 catalysts, as mentioned in the above article, have copper species that are prone to agglomeration and sintering, which seriously restricts their practical production applications. Summary of the Invention

[0004] To address the current problems of poor lifetime and stability of Cu / SiO2 catalysts, and the tendency of Cu / SBA-15 to agglomerate and sinter, the present invention aims to anchor Cu nanoparticles at their defect sites through a g-C3N4 anchoring strategy, forming smaller Cu nanoparticles that are loaded into the mesopores of the SBA-15 support. Through physical and chemical confinement, the migration of copper nanoparticles is restricted, the dispersion of Cu nanoparticles is improved, and excellent catalytic activity and stability in water-gas shift reaction are exhibited.

[0005] To achieve the above objectives, the present invention employs the following technical steps:

[0006] A method for preparing a copper-supported catalyst with spatial confinement effect for water-gas shift reaction involves anchoring active component Cu nanoparticles on defect sites of graphite-like carbides (g-C3N4) and confining them within the pores of an SBA-15 support to obtain a supported Cu-NC / SBA-15 catalyst.

[0007] Furthermore, the loading of Cu, the active component, in the Cu-supported catalyst is 12-32 wt.%.

[0008] The preparation method of the Cu-supported catalyst includes the following steps:

[0009] (1) Preparation of carrier SBA-15: Organic structure directing agent P123 was dissolved in hydrochloric acid, and then silicon salt precursor was slowly added under vigorous stirring. The mixed solution was stirred for 24 h, and then transferred to a stainless steel autoclave for hydrothermal reaction for 24 h. The product was filtered, washed, dried and calcined to finally obtain SBA-15.

[0010] (2) Metal support: The polymer and copper salt were dissolved in deionized water, and SBA-15 support was added for impregnation to obtain Cu-NC / SBA-15 wet sample. Then, after drying, grinding and calcination, Cu-NC / SBA-15 catalyst precursor was obtained.

[0011] (3) The Cu-NC / SBA-15 catalyst precursor obtained in step (2) is reduced to obtain a copper-supported catalyst.

[0012] Further, in step (1), the ratio of organic structure directing agent P123, silicon salt precursor and hydrochloric acid is 1g:2g:37.5mL.

[0013] Further, the silicon salt precursor mentioned in step (1) is tetraethyl orthosilicate.

[0014] Furthermore, the stirring and heating temperature in step (1) is 35-40 ℃;

[0015] Furthermore, the temperature of the hydrothermal treatment in step (1) is 100-150 ℃;

[0016] Furthermore, the calcination described in step (1) is carried out under static air, with the temperature increased to 500-600 ℃ at a rate of 4-5 ℃ / min and held for 2-3 h.

[0017] Furthermore, the copper salt mentioned in step (2) includes one or more of copper nitrate, copper carbonate, copper chloride, and copper sulfate.

[0018] Further, the polymer mentioned in step (2) includes one or more of melamine, urea, cyanamide, and dicyandiamide, and the mass ratio of the polymer to the carrier SBA-15 is 1:1.

[0019] Furthermore, the soaking time in step (2) is 12-24 h;

[0020] Furthermore, the calcination conditions described in step (2) are as follows: heating to 500-600 °C at a rate of 4 °C / min under hydrogen, nitrogen, and air, and holding for 1-2 h.

[0021] Furthermore, the reduction in step (3) is carried out in an atmosphere of 5 vol.% H2 / N2 at 300-400 °C for 2-4 hours.

[0022] A copper-supported catalyst with spatial confinement effect for water-gas shift reaction, prepared by the above method.

[0023] The application of the copper-supported catalyst with spatial confinement effect in the water-gas shift reaction.

[0024] The technical solution of the present invention has the following advantages:

[0025] This invention provides a Cu-based water-gas shift catalyst with a confinement effect. By selecting SBA-15, an organic mesoporous silica material with a large specific surface area, tunable pore size, and hydrothermal stability, as a support, and introducing g-C3N4 to provide defect sites, the highly dispersed copper species are assembled into the pores of the SBA-15 support through the confinement effect of the SBA-15 mesoporous channels and the anchoring effect of the pore walls. This produces small, stable copper particles with a large number of exposed active edges. Specifically, modifying the support with N-doped carbon material (g-C3N4) is beneficial for the dispersion of copper nanoparticles. Simultaneously, SBA-15, as a mesoporous molecular sieve, can spatially restrict the growth of copper nanoparticles, creating numerous spatially confined micro-reaction environments, thereby improving the activity and stability of the catalyst in the water-gas shift reaction. Attached Figure Description

[0026] Figure 1 The small-angle XRD patterns are those of the support SBA-15 and the catalyst precursor obtained in Example 2.

[0027] Figure 2 The XRD patterns are of the catalysts obtained from commercial SiO2 support, SBA-15 support, Example 2, and Comparative Examples 1-2 after reduction at 350 °C.

[0028] Figure 3 The above are H2-TPR diagrams of the catalyst precursors obtained in Example 2 and Comparative Examples 1 and 2.

[0029] Figure 4 Comparison diagrams of the activities of the catalysts obtained in Examples 1-12 and Comparative Examples 1-2; (a) Activity of Example 2 and Comparative Examples 1-2; (b) Activity of Examples 1, 2, 8-10; (c) Activity of Examples 2, 11 and 12; (d) Activity of Examples 2-7.

[0030] Figure 5 The stability graphs are for the catalysts obtained in Example 2 and Comparative Examples 1-2.

[0031] Figure 6 The images show TEM images of the catalysts obtained in Example 2 and Comparative Example 2. Detailed Implementation

[0032] A Cu-based catalyst with confinement effect for water-gas shift reaction is prepared by the following steps:

[0033] (1) Preparation of carrier SBA-15: The mixture of organic structure directing agent and hydrochloric acid was heated at 38 °C and continuously stirred until the organic structure directing agent was completely dissolved. Then, the silicon salt precursor was slowly added under vigorous stirring, and the mixture was stirred at this temperature for 24 h. Subsequently, it was transferred to a stainless steel autoclave and hydrothermally heated at 100 °C for 24 h. After filtration, washing, and drying, the mixture was calcined at 600 °C for 2 h under a static atmosphere at a rate of 4-5 °C / min to finally obtain SBA-15. The ratio of organic structure directing agent P123, silicon salt precursor and hydrochloric acid used was 1 g:2 g:37.5 mL.

[0034] (2) Metal loading: The polymer and copper salt were dissolved in deionized water using the traditional impregnation method. The SBA-15 support prepared in step (1) was impregnated with the above mixed solution for 24 h to obtain Cu-NC / SBA-15 wet sample. Then, after drying and grinding, the sample was heated to 500-600 ℃ at a rate of 4 ℃ / min under an atmosphere and calcined for 1-2 h to obtain Cu-NC / SBA-15 catalyst precursor.

[0035] (3) The Cu-NC / SBA-15 precursor obtained in step (2) is reduced at 300-400℃ for 2-4 h in an atmosphere of 5 vol.% H2 / N2 to obtain a copper-supported catalyst, wherein the proportion of Cu in the catalyst is 12-32 wt.%.

[0036] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0037] Preparation of carrier SBA-15:

[0038] Weigh 8 g of P123 and 300 mL of 1.6 M HCl aqueous solution, and stir continuously at 38 °C until completely dissolved. Add 16 g of tetraethyl orthosilicate (TEOS) under vigorous stirring, and stir for another 24 h. Transfer to a hydrothermal reactor and hydrothermally heat at 100 °C for 24 h. Wash several times with water and ethanol alternately, dry at 60 °C overnight, and then calcine at 600 °C for 2 h in a muffle furnace (heating rate 4 °C / min) to obtain the SBA-15 support.

[0039] Example 1

[0040] 1.68 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of deionized water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 12 wt% by ICP.

[0041] Example 2

[0042] 2.44 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of deionized water. 3.5 g of support SBA-15 was added and impregnated for 24 h. Then, the mixture was dried at 60 °C overnight and lightly ground. Finally, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0043] Example 3

[0044] 2.44 g of Cu(NO3)2·3H2O and 3.5 g of melamine were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0045] Example 4

[0046] 2.44 g Cu(NO3)2·3H2O and 3.5 g dicyandiamine were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0047] Example 5

[0048] 1.62 g CuSO4 and 3.5 g urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added and allowed to stand for 24 h. Then, the mixture was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 600 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0049] Example 6

[0050] 1.25 g CuCO3 and 3.5 g urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added and allowed to stand for 24 h. Then, the mixture was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0051] Example 7

[0052] 2.44 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 600 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0053] Example 8

[0054] 3.31 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 22 wt% by ICP.

[0055] Example 9

[0056] 4.28 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 27 wt% by ICP.

[0057] Example 10

[0058] 5.40 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 32 wt% by ICP.

[0059] Example 11

[0060] 2.44 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a nitrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0061] Example 12

[0062] 2.44 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in air atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0063] Comparative Example 1

[0064] 2.44 g of Cu(NO3)2·3H2O and 3.5 g of urea were weighed and dissolved in 12 mL of water. 3.5 g of commercial SiO2 support was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SiO2 catalyst precursor. The Cu content was determined to be approximately 17 wt% by ICP.

[0065] Comparative Example 2

[0066] 2.44 g of Cu(NO3)2·3H2O was weighed and dissolved in 12 mL of water. 3.5 g of support SBA-15 was added, and the mixture was allowed to stand for 24 h. Then, it was dried at 60 °C overnight. After slight grinding, it was calcined in a tube furnace at 500 °C for 1 h in a hydrogen atmosphere (heating rate 4 °C / min) to obtain the Cu-NC / SBA-15 catalyst precursor, in which the Cu content was 17 wt%.

[0067] Weigh 0.5 g (40-60 mesh) of each of the catalyst precursors prepared in the examples and comparative examples, and reduce them in a fixed-bed reactor (reduction temperature 350℃, reduction time 3 h, reduction atmosphere 5 vol.% H2 / N2) to obtain the copper-supported catalyst.

[0068] Figure 1 The figures show the small-angle XRD patterns of the support SBA-15 and the catalyst precursor obtained in Example 2. As can be seen from the figures, Example 2 has three distinct diffraction peaks at 1.3°, 2.2°, and 2.4°, which are attributed to the (100), (110), and (200) diffraction peaks of the ordered two-dimensional (2D) hexagonal mesoscopic structure SBA-15, respectively. This indicates that the loading of metallic Cu and the modification with g-C3N4 have no significant effect on the symmetry of the mesoporous framework.

[0069] Figure 2 The XRD patterns of the catalysts obtained from commercial SiO2 support, SBA-15 support, Example 2, and Comparative Examples 1-2 after reduction at 350 °C are shown in the figures. As can be seen from the figures, the peak intensities of Cu and Cu2O in Example 2 are both low, indicating that the Cu and Cu2O crystallites in the catalyst bulk phase are small in size and highly dispersed.

[0070] Figure 3 The figures show the H2-TPR diagrams of the catalyst precursors obtained in Example 2 and Comparative Examples 1 and 2. As can be seen from the figures, compared with Comparative Examples 1 and 2, the catalyst sample obtained in Example 2 has a lower reduction temperature, indicating a better synergistic effect between the metal and the support.

[0071] Figure 4This is a comparison of the activity of the catalyst precursors obtained in Examples 1-12 and Comparative Examples 1-2 after reduction at 350 °C. Figure 4 As can be seen from Figure a, by comparing with Comparative Examples 1 and 2, the CO conversion rates of the catalyst sample in Example 2 at 200 °C, 240 °C, 280 °C, 320 °C, and 360 °C were 91.0%, 95.0%, 92.2%, 91.8%, and 91.4%, respectively. The catalyst sample in Example 2 has higher catalytic activity than the comparative examples, indicating that the catalyst with SBA-15 as a support and under the action of polymers has more advantages. Figure 4 b indicates that the optimal Cu loading is 17%. Figure 4 c and Figure 4 As can be seen, different calcination atmospheres, different polymers, different copper salts, and different calcination temperatures also have a significant impact on the activity. Among them, Example 2 has the best CO conversion rate, and the optimal calcination temperature is 500 °C.

[0072] Figure 5 The figure shows the WGS stability of the catalysts obtained in Example 2 and Comparative Examples 1-2 at 240 °C. As can be seen from the figure, during the 50-hour test, the CO conversion rate of Example 2 remained relatively stable with almost no loss, while the CO conversion rates of Comparative Examples 1 and 2 both showed varying degrees of loss. Specifically, the CO conversion rate of Comparative Example 1 decreased by approximately 15% within 50 hours, and the CO conversion rate of Comparative Example 2 decreased by approximately 5% within 50 hours. This indicates that using SBA-15 as a support and the polymer can effectively improve the stability of the catalyst.

[0073] Figure 6 The images show TEM images of the catalysts obtained in Example 2 and Comparative Example 2. As can be seen from the images, Cu particles with a diameter of 2-6 nm are dispersed in the SBA-15 channels in Example 2, while larger particles with a diameter of 4-8 nm are dispersed on the surface of SBA-15 in Comparative Example 2. This indicates that the polymer-formed g-C3N4 anchors Cu to form smaller nanoparticles, fixing them at defect sites and thus dispersing them in the SBA-15 channels.

[0074] Table 1 compares the process parameters and structural parameters of the catalyst precursors prepared in the examples and comparative examples.

[0075] Table 1. Process parameters and structural parameters of different catalyst precursors

[0076]

[0077] As shown in Table 1, comparing Examples 1-12 and Comparative Example 2 with Comparative Example 1, the catalyst precursor with SBA-15 as the support has a larger specific surface area than the catalyst precursor with SiO2 as the support, indicating that SBA-15 as a support can significantly increase the specific surface area of ​​the catalyst precursor. Comparing Example 2 and Comparative Example 2, it was found that the specific surface area and pore volume of the catalyst precursor with added polymers were significantly increased. This is because dispersing Cu particles within the pores by limiting their size provides more specific surface area and molecular diffusion channels. Comparing Examples 1, 2, 8, 9, and 10, it was seen that the specific surface area of ​​the catalyst precursors with different loading amounts varied. This is due to the different degrees to which the metal occupies the SBA-15 pores, indicating that the metal loading amount affects the specific surface area of ​​the catalyst precursor. Meanwhile, through comparisons of Example 2 with Examples 3 and 4, Example 2 with Examples 5 and 6, Example 2 with Examples 11 and 12, and Example 2 with Example 7, it can be seen that polymers, copper salts, calcination atmosphere, and calcination temperature also affect the specific surface area and pore volume of the catalyst precursor.

[0078] Catalyst performance evaluation

[0079] Weigh 0.5 g of each of the catalysts prepared in the examples and comparative examples. Activity testing conditions: dry feed gas composition: 15% CO, 55% H2, 7% CO2, 23% N2 (volume fraction); water vapor to dry feed gas molar ratio: 1:1; space velocity: 4500 mL·g⁻¹. -1 ·h -1 The test temperature range was 200~360 ℃. The catalyst activity was expressed as CO conversion rate, CO conversion rate = (1-V) / (200-360-300-400℃). CO ′ / V CO ) / (1+V CO ′)×100%, where V CO and V CO ′ represents the volume fraction of CO in the dry feed gas and the outlet gas, respectively. The activity evaluation results of the catalysts obtained in the examples and comparative examples are shown in Table 2.

[0080] Table 2. Activity evaluation results of copper-supported catalysts obtained in the examples and comparative examples.

[0081]

[0082] As shown in Table 2, compared with Comparative Example 1, Examples 1-12 demonstrate that the SBA-15 catalyst with SBA-15 as the support exhibits superior performance compared to the traditional Cu / SiO2 catalyst; the addition of polymers to form g-C3N4 effectively improves the reaction activity. Compared with Examples 1, 8, 9, and 10, the catalyst prepared in Example 2 shows better performance in the water-gas shift reaction, indicating that the Cu loading has a significant impact on the reaction activity. Furthermore, a comparison of the results of Example 2 with Examples 11 and 12 shows that an H2 activation atmosphere is beneficial to improving the catalyst activity. This is attributed to the promoting effect of the activation atmosphere on the interaction between the active component and the support. Compared with other atmospheres such as N2 and Air, the H2 atmosphere can significantly improve the catalytic activity of copper-based catalysts in the water-gas shift reaction. Through Examples 2 and 3, 4, 5, 6, and 7, it can be seen that the selection of polymers, copper salts, and calcination temperature all affect the performance of the Cu-NC / SBA-15 catalyst in the water-gas shift reaction.

[0083] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. Use of a copper supported catalyst having a spatial confinement effect in the water gas shift reaction, characterized in that: The copper supported catalyst is a supported Cu-NC / SBA-15 catalyst prepared by anchoring active component Cu nanoparticles with a particle size of 2-6 nm on defect sites of g-C3N4 and confining and loading the Cu nanoparticles in channels of an SBA-15 carrier; The preparation method of the copper supported catalyst comprises the following steps: (1) Preparation of the carrier SBA-15: dissolving an organic structure directing agent P123 in hydrochloric acid, then slowly adding a silicon salt precursor under vigorous stirring, stirring the mixed solution for 24 h, and then transferring the mixed solution into a stainless steel autoclave for hydrothermal reaction for 24 h; after filtration, washing, drying and calcination, the SBA-15 is prepared; (2) Metal loading: dissolving a polymer and a copper salt in deionized water, adding the SBA-15 carrier for impregnation to prepare a Cu-NC / SBA-15 wet sample; then drying, grinding and calcining to obtain a Cu-NC / SBA-15 catalyst precursor; (3) Reducing the Cu-NC / SBA-15 catalyst precursor obtained in step (2) to obtain a copper-based catalyst; In step (2), the impregnation time is 12-24 h; and the calcination condition is heating to 500-600 ℃ at a rate of 4 ℃ / min under hydrogen, nitrogen or air, and maintaining for 1-2 h.

2. Use according to claim 1 : characterized in that, In step (1), the amount ratio of the organic structure directing agent P123, the silicon salt precursor and hydrochloric acid is 1 g:2 g:37.5 mL; and the silicon salt precursor is tetraethyl orthosilicate.

3. Use according to claim 1, characterized in that: In step (1), the stirring temperature is 35-40 ℃; the hydrothermal reaction temperature is 100-150 ℃; and the calcination is heating to 500-600 ℃ at a rate of 4-5 ℃ / min under static air, and maintaining for 2-3 h.

4. Use according to claim 1, characterized in that: In step (2), the copper salt includes one or more of copper nitrate, copper carbonate, copper chloride and copper sulfate; and the loading amount of copper in the catalyst is 12-32 wt.%.

5. The use according to claim 1, characterized in that: In step (2), the polymer includes one or more of melamine, urea, monocyamide and dicyandiamide; and the mass ratio of the polymer to the carrier SBA-15 is 1:

1.

6. Use according to claim 1, characterized in that: In step (3), the reduction is in an atmosphere of 5 vol.% H2 / N2 at 300-400 ℃ for 2-4 h.

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