Preparation of a kind of NiZrOx nano catalyst and its application in photo-thermal catalytic ethanol dry reforming to syngas

Abstract

The application discloses a kind of preparation of NiZrOx Nano catalyst and its application in photo-thermal catalytic ethanol dry gas reforming for synthesis gas. ZrO2 nanorods are prepared by hydrothermal synthesis technology, and the active metal Ni with a content of 5-15wt% is carried by precipitation method. The catalyst shows excellent activity and stability in the photo-thermal catalytic ethanol dry reforming reaction, and no obvious deactivation is found after 40h continuous reaction. The unique morphology of the catalyst and the strong interaction between the transition metal and the carrier enhance the ability of the catalyst to activate inert CO2 and prevent the sintering of active metal and the ability to resist carbon deposition in the reaction. The catalyst prepared by the application has the advantages of simple process flow, low energy consumption and no noble metal, which meets the development trend of green and sustainable chemical industry; and shows high application potential in the field of photo-thermal catalytic conversion of greenhouse gas CO2, and promotes the high-value utilization of CO2.

Description

Technical Field

[0001] This invention belongs to the field of greenhouse gas control and catalytic chemistry technology, involving the intersection and integration of environmental protection, nanomaterials and catalytic chemistry, specifically the preparation of a NiZrOx nanocatalyst and its application in photothermal catalytic reforming of ethanol dry gas to syngas. Background Technology

[0002] The large-scale use of fossil fuels has led to massive carbon dioxide emissions, causing environmental problems such as the greenhouse effect and seriously threatening human health and survival. Meanwhile, with socio-economic development and continuous population growth, the demand for carbon-based fuels and products is increasing. Whether addressing environmental problems or responding to the energy crisis, carbon dioxide resource utilization technology is one of the most promising solutions. In recent years, methane dry reforming technology has received considerable attention, as its product, syngas, can be used as a feedstock for downstream chemical production to meet energy demands. However, methane, as a major component of fossil fuel natural gas, does not align with the requirements of green and sustainable development strategies. Utilizing renewable resources is key to sustainable development. Among various renewable biomass-derived feedstock alternatives, ethanol appears to be a promising feedstock for syngas production due to its relatively high hydrogen content, ease of availability, non-toxicity, and ease of handling and storage. Furthermore, biomass-derived ethanol can be readily obtained on a large scale from lignocellulosic biomass through hydrolysis and fermentation, or extracted from existing biomass feedstocks derived from energy plants, agricultural and industrial waste, forestry residues, and the organic components of municipal solid waste. However, traditional thermocatalytic dry reforming of ethanol is not only kinetic and thermodynamically unfavorable, but also highly susceptible to coke deposition and accompanying catalyst deactivation.

[0003] In recent years, photothermal catalysis has attracted widespread attention in processes such as Fischer-Tropsch synthesis, CO2 conversion, and NH3 synthesis. In photothermal catalysis, the catalyst strongly absorbs light in the UV-Vis-near-infrared (NIR) region, leading to rapid local heating and reaching the temperature range where thermocatalytic reactions may occur. Photothermal catalysis combines the advantages of traditional thermocatalysis and photocatalysis; the synergistic effect of these two catalytic processes typically improves performance. Therefore, constructing a coupled system of photocatalysis and thermocatalysis (photothermal synergy) can effectively address the technical limitations of single catalytic technologies and open up a new and widely applicable catalytic pathway.

[0004] There are few literature reports on the catalytic reforming of ethanol dry gas by metal catalysts with special morphologies, both domestically and internationally. Moreover, there are no patent reports on the application of nickel-based catalysts with specific morphologies in the field of photothermal synergistic catalytic CO2 reduction. Summary of the Invention

[0005] To address the aforementioned bottlenecks in existing technologies, this invention aims to synthesize uniformly morphological ZrO2 nanorod catalysts using hydrothermal technology; and to synthesize NiZrO2 with a nanorod structure using a precipitation method. x Supported metal catalysts. Ni is uniformly distributed on the surface of ZrO2 nanorods, forming a strongly interacting interfacial structure. Through optimized design of the interfacial structure, the electronic structure of the Ni active sites, as well as the size and dispersion state of Ni particles, are controlled, inhibiting the sintering of the active component Ni during the reaction process and improving catalyst stability.

[0006] To achieve the above-mentioned objectives, the present invention provides a NiZrO x The preparation method of the nanocatalyst includes the following steps:

[0007] ①Preparation of ZrO2 nanorods

[0008] At room temperature, soluble Zr salts were dissolved in deionized water, and ammonia was added dropwise until the pH reached 8-10 to form solution A. A certain amount of NaOH was dissolved in deionized water to form solution B. Solution B was poured into solution A, and the mixture was transferred to a hydrothermal reactor and reacted at 180-250℃ for 24-48 hours. After cooling to room temperature, the precipitate obtained by vacuum filtration was calcined to obtain ZrO2 nanorods.

[0009] Furthermore, the soluble Zr salt mentioned in step ① is one of ZrOCl·8H2O and ZrCl4.

[0010] Further, dissolve 2-3g of ZrOCl·8H2O in 80-100mL of deionized water, and then add 7-10 drops of ammonia (NH3·H2O) to form solution A. Simultaneously, dissolve 8-10g of NaOH in 20-30mL of deionized water to form solution B. Stir each solution for 1-1.5h, then pour solution B into solution A; continue stirring for 2-2.5h, then transfer to a hydrothermal reactor and react at 180-250℃ for 24-48h. After cooling to room temperature, filter, wash several times with deionized water and ethanol, and dry the precipitate at 60-90℃ overnight; then calcine in a muffle furnace at 400-600℃ for 3-5h.

[0011] ②NiZrO x Catalyst preparation

[0012] Under room temperature conditions, the ZrO2 nanorods obtained in step ① were dissolved in deionized water with soluble Ni salt, and sodium carbonate was added before reacting for 4-5 hours. The resulting precipitate was washed, dried, and then calcined to obtain NiZrO2. x catalyst.

[0013] Furthermore, the soluble Ni salt mentioned in step ② is one of Ni(CH3COO)2·4H2O and Ni(NO3)2·6H2O. The calcination process mentioned in step ② is carried out in a muffle furnace at 400-600℃ for 4-6 hours.

[0014] Furthermore, at room temperature, 0.9-1 g of ZrO2 nanorods and 0.4-0.5 g of Ni(NO3)2·6H2O were dissolved in 100 mL of deionized water, and then 0.1-0.2 g of sodium carbonate was added and stirred for 4-5 h. The mixture was then filtered, washed several times with ethanol and water, and the precipitate was dried overnight at 60-90 °C; subsequently, it was calcined in a Maverick oven at 400-600 °C for 4-5 h.

[0015] NiZrO prepared by the above method x The catalyst has a nanorod structure, wherein the surface of the ZrO2 nanorods is uniformly loaded with active metal Ni, and the loading of active metal is 5-15%.

[0016] A NiZrO x Application of nanocatalysts in the photothermal synergistic catalytic reduction of CO2 to produce high-value-added syngas. A conventional fixed-bed reactor was used, with the catalyst added to a quartz reaction tube; the reaction temperature was 350-550℃, the reaction pressure was atmospheric pressure, and the xenon lamp light source power was 50-300W. 0.05-0.3g of the catalyst was added to the quartz reaction tube; the reactants were a C2H5OH / CO2 / N2 mixture with a molar ratio of 1 / 1 / 3, and the reaction space velocity was 30000-85000 mLg. -1 h -1 .

[0017] Furthermore, the reaction is carried out in a fixed-bed reactor, with 0.05-0.1 g of the catalyst, sieved (40-60 mesh), placed in a quartz reaction tube with an inner diameter of 8 mm. Before the reaction, the catalyst is reduced online at 400-600 °C in 5 vol% H2 / N2 (flow rate 30-60 mL / min) for 0.5-2 h. After purging with nitrogen and allowing the temperature to drop to the reaction temperature, an ethanol dry gas reforming reaction is carried out at 350-550 °C under 50-300 W xenon lamp illumination. Inert nitrogen is used as the dilution gas, and the reactants are a C2H5OH / CO2 / N2 mixture with a molar ratio of 1 / 1 / 3, with a reaction space velocity of 30000-80000 mLg. -1 h -1 .

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] The catalyst prepared by this invention exhibits excellent performance, demonstrating superior catalytic activity and stability in the photothermal synergistic CO2 reduction reaction. The strong interaction and interfacial structure between the active metal Ni and the support ZrO2 effectively inhibit the sintering of the active component Ni during the reaction process, while simultaneously enhancing the activation capacity of CO2, providing active oxygen species, and achieving dynamic elimination of carbon deposits, thus preventing carbon buildup. This invention is beneficial for promoting the reduction and high-value utilization of greenhouse gas CO2 emissions. Attached Figure Description

[0020] Figure 1 NiZrO prepared in Example 1 x Transmission electron microscopy images of nanocatalysts;

[0021] Figure 2 The graph shows the catalytic reaction activity test results for Application Example 1;

[0022] Figure 3 The graph shows the stability test results of the catalytic reaction in Application Example 4. Detailed Implementation

[0023] The present invention will be further described below with reference to specific embodiments, but this does not limit the invention in any way. To avoid redundancy, unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and the methods used are all conventional methods unless otherwise specified.

[0024] Example 1

[0025] A NiZrO x The preparation method of the nanocatalyst includes the following steps:

[0026] ①Preparation of ZrO2 nanorods

[0027] At room temperature, 2.5 g of ZrOCl·8H2O was dissolved in 80 mL of deionized water, and then 7 drops of ammonia (NH3·H2O) were added dropwise to form solution A. Simultaneously, 8.1 g of NaOH was dissolved in 25 mL of deionized water to form solution B. After stirring each solution for 30 min, solution B was poured into solution A. Stirring continued for 1 h. The mixed solution was then transferred to a reaction vessel and maintained at 180 °C for 24 h. After cooling to room temperature, the solution was filtered, washed several times with deionized water and ethanol, and then dried overnight at 60 °C. Finally, it was calcined in a muffle furnace at 450 °C for 4 h.

[0028] ②NiZrO x Preparation of nanocatalysts

[0029] At room temperature, 0.9 g of ZrO2 nanorods prepared in step ① were dissolved in 100 mL of deionized water along with 0.5 g of Ni(NO3)2·6H2O. Then, 0.2 g of sodium carbonate was added, and the mixture was stirred for 4 h. The mixture was then filtered and washed several times with ethanol and water. It was then dried overnight at 60 °C. Finally, it was calcined in a Maverick atmosphere at 450 °C for 4 h. The resulting catalyst was named P-NiZrO2. x The prepared P-NiZrO x Transmission electron microscopy images of the catalyst are as follows: Figure 1 As shown, the catalyst has a uniform nanorod morphology with a diameter of 100-300 nm; active nickel oxide particles are uniformly dispersed on the surface with a particle size of 10-20 nm.

[0030] Comparative Example 1

[0031] ZrO2 nanorods were prepared using the same method as in Example 1, and the active metal Ni was supported using a conventional impregnation method. The resulting catalyst was named I-NiZrO. x The active metal Ni loading is 5-15%.

[0032] Application Example 1

[0033] 0.10g of NiZrO prepared in Example 1 x The catalyst was added to the quartz reaction tube, with an ethanol / carbon dioxide / nitrogen ratio of 1 / 1 / 3 and a space velocity of 34000 mLg. -1 h -1 The reaction was carried out at atmospheric pressure. The reaction was conducted at 450°C under xenon lamp irradiation (50W power) (photothermal synergy) and without a light source (thermal catalysis). The reaction results are as follows. Figure 2 As shown, under xenon lamp irradiation (photothermal synergy), P-NiZrO x The ethanol conversion rate on the catalyst was 71%; while under no light source (thermal catalysis), the ethanol conversion rate was only 30%, and more byproducts were generated. This indicates that under photothermal synergistic catalysis, P-NiZrO₂... x Nanorod catalysts exhibit superior catalytic activity.

[0034] Application Comparative Example 1

[0035] 0.10 g of P-NiZrO x and I-NiZrO x The catalyst was added to quartz reaction tubes to test its catalytic performance. The molar ratio of ethanol / carbon dioxide / nitrogen was 1 / 1 / 3, and the space velocity was 34000 mL / g. -1 h -1The reaction was carried out at atmospheric pressure under xenon lamp irradiation (50W) at 450℃. The results are shown in Table 1. At 450℃, the molar ratio of ethanol / carbon dioxide / nitrogen was 1 / 1 / 3, and the space velocity was 34000 mL / g. -1 h -1 Under a xenon lamp power of 50W, I-NiZrO x The ethanol conversion rate of the catalyst is only 40%, far lower than that of P-NiZrO. x 70% of the catalyst. And I-NiZrO x The catalyst generates more methane as a byproduct (6.5 mol%).

[0036] Table 1. Preparation techniques for P-NiZrO x Effect of catalyst performance

[0037]

[0038] Application Example 2

[0039] 0.10 g of P-NiZrO x The catalyst was added to a quartz reaction tube to test its catalytic performance. The molar ratio of ethanol / carbon dioxide / nitrogen was 1 / 1 / 3, and the space velocity was 34000 mL / g. -1 h -1 The reaction was carried out at atmospheric pressure under xenon lamp irradiation (50W). The results are shown in Table 2. With increasing reaction temperature, the ethanol conversion rate gradually increased, which is consistent with the endothermic characteristics of the ethanol dry gas reforming reaction. Hydrogen selectivity increased, accompanied by a decrease in carbon monoxide selectivity. The selectivity of the byproduct methane gradually decreased, because higher reaction temperatures favor the methane dry gas reforming reaction.

[0040] Table 2 Effect of reaction temperature on P-NiZrO x Effect of catalyst performance

[0041]

[0042] Application Example 3

[0043] 0.10 g of P-NiZrO x The catalyst was added to a quartz reaction tube to test its catalytic performance. The molar ratio of ethanol / carbon dioxide / nitrogen was 1 / 1 / 3, the reaction temperature was 450℃, and the reaction pressure was atmospheric pressure. The reaction was carried out under xenon lamp irradiation (50W). The reaction results are shown in Table 3. With increasing space velocity, P-NiZrO... x The ethanol conversion rate decreased while the selectivity for the byproduct methane increased. This is because the increased space velocity leads to a reduction in the contact time between the reactants and the catalytically active sites, resulting in a decrease in catalyst activity.

[0044] Table 3 Reaction space velocity versus P-NiZrO x Effect of catalyst performance

[0045]

[0046] Application Example 4

[0047] 0.10 g of P-NiZrO x The catalyst was added to a quartz reaction tube to test its catalytic performance. The molar ratio of ethanol / carbon dioxide / nitrogen was 1 / 1 / 3, the reaction temperature was 450℃, and the space velocity was 34000 mLg. -1 h -1 The reaction was carried out at atmospheric pressure under xenon lamp irradiation (50W). The reaction results are as follows. Figure 3 As shown, P-NiZrO x After 40 hours of catalytic reaction, the reaction performance showed no significant decrease. During continuous testing, the ethanol conversion rate remained around 70%, and the selectivity for the target products hydrogen and carbon monoxide remained around 48 mol% and 45 mol%, respectively. Meanwhile, the selectivity for byproducts methane, acetone, and acetaldehyde did not increase significantly, remaining below 5 mol%. Stability testing results demonstrate that the catalyst exhibits excellent catalytic stability.

[0048] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention based on the disclosed technical content, or equivalent embodiments can be modified accordingly, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A NiZrO x The application of nanocatalysts in the photothermal synergistic catalytic dry reforming of ethanol is characterized by... Using a fixed-bed reactor, 0.05-0.3 g of the catalyst was added to a quartz reaction tube. The reaction temperature was 350℃-550℃, the reaction pressure was atmospheric pressure, and the xenon lamp light source power was 50-300W. The reactants were a C2H5OH / CO2 / N2 mixture with a molar ratio of 1 / 1 / 3, and the reaction space velocity was 30000-85000 mL·g. -1 ·h -1 ; The NiZrO x The nanocatalyst has a nanorod structure, with active metal Ni uniformly loaded on the surface of the ZrO2 nanorods; The NiZrO x The preparation method of nanocatalysts includes the following steps: ①Preparation of ZrO2 nanorods At room temperature, 2-3g of soluble Zr salt is dissolved in 80-100mL of deionized water, and 7-10 drops of ammonia are added dropwise until the pH is 8-10 to form solution A; 8-10g of NaOH is dissolved in 20-30mL of deionized water to form solution B. Solution B is poured into solution A, and the mixture is transferred to a hydrothermal reactor and reacted at 180℃-250℃ for 24-48h; after cooling to room temperature, the precipitate obtained by suction filtration is calcined in a muffle furnace at 400℃-600℃ for 3-5h to obtain ZrO2 nanorods; The soluble Zr salt is one of ZrOCl·8H2O and ZrCl4; ②NiZrO x Preparation At room temperature, 0.9-1 g of ZrO2 nanorods obtained in step ① were dissolved in 100 mL of deionized water along with 0.4-0.5 g of soluble Ni salt. After adding 0.1-0.2 g of sodium carbonate, the reaction proceeded for 4-5 h. The resulting precipitate was washed, dried, and then calcined at 400℃-600℃ for 4-6 h to obtain NiZrO2 nanorods. x catalyst.

Images