A nickel-rare earth oxide composite nano-island catalyst for hydrogen production by ethanol steam reforming and a preparation method thereof

Abstract

This invention discloses a nickel-rare earth oxide composite nanoisland catalyst for hydrogen production from ethanol steam reforming, wherein the catalyst is composed of metallic Ni and rare earth oxide ReO. x The composite nanoisland structure is the active component, and its general chemical formula can be expressed as Ni / ReO. x / S; where ReO x The catalyst is composed of one or more of CeO2, Sm2O3, or La2O3, and the support S is composed of one or more of Al2O3, SiO2, MgO, ZnO, silicalite-1, ZSM-5, activated carbon, C3N4, or BN. The catalyst contains 1%–10% Ni by weight, 0%–50% ReOx by weight, and the remainder is the support S. This invention also discloses a method for preparing a nickel-rare earth oxide composite nanoisland catalyst for hydrogen production via ethanol steam reforming. The nickel-rare earth oxide composite nanoisland catalyst provided by this invention exhibits not only good stability but also excellent performance in ethanol steam reforming for hydrogen production when applied to the ethanol steam reforming hydrogen production reaction.

Description

Technical Field

[0001] This invention belongs to the field of catalysis technology, specifically relating to a nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol, its preparation method and application. Background Technology

[0002] With the deepening of the "dual carbon" goal, my country is accelerating the construction of a clean, low-carbon, safe, and efficient modern energy system. Bioethanol, as an important renewable energy source, plays a crucial role in promoting energy structure transformation. After 2020, ethanol synthesis entered a diversified development stage, with raw materials expanding from food crops to non-food resources such as agricultural and forestry waste and algae. Among these, with the rapid development of cellulosic ethanol large-scale technology, bioethanol production is no longer limited to starch-based raw materials. Currently, bioethanol reforming can leverage existing industrial achievements in hydrogen production and bioethanol to achieve rapid integration with the existing hydrogen energy industry. Because bioethanol has a high hydrogen content (13%), the hydrogen in water can be further activated through ethanol steam reforming (C2H5OH+3H2O→2CO2+6H2), achieving both renewable and sustainable development goals and forming a closed-loop CO2 system (without new CO2 generation), thus achieving environmentally friendly objectives.

[0003] Current research on ethanol reforming for hydrogen production mainly focuses on reactions at temperatures above 500 °C. This is because higher reaction temperatures are beneficial for enhancing the further reaction between the intermediate product methane and water vapor, thus improving hydrogen production efficiency. Currently, a wide variety of active metals are used in catalysts for ethanol reforming for hydrogen production. Noble metals such as rhodium, ruthenium, gold, palladium, platinum, and iridium, as well as non-noble metals such as copper, nickel, and cobalt, can all be used as active components. The noble metal Rh exhibits the highest activity, but its high price limits its large-scale application. Among commonly used non-noble metals, Ni is not only inexpensive but also has better C / C bond breaking ability compared to Cu and Co. However, at high temperatures, its metal particles are prone to sintering, and carbon deposition on the metal surface leads to poor catalyst stability. In addition, rare earth oxides are widely used in ethanol steam reforming research due to their strong ability to activate water. However, the abundance of acidic and basic sites on their surfaces leads to the formation of large amounts of ethylene and acetone (Matteo Compagnoni, Antonio Tripodi, Ilenia Rossetti, et al., Parametric study and kinetic testing for ethanol steam reforming [J]. Applied Catalysis B: Environmental, 2017, 203: 899-909; Isabela Dancini-Pontes, Marcos DeSouza, Fernando Alves Silva, et al., Influence of the CeO2 and Nb2O5 supports and the inert gas in ethanol steamreforming for H2 production [J]. Chemical Engineering Journal, 2015, 273: 66-74), severely limiting hydrogen yield. Furthermore, studies have reported that excessively large Ni metal particles are prone to carbon deposition on their surface, leading to the occupation of metal sites and subsequent catalyst deactivation (Daniela Zanchet, Joao Batista O. Santos Sonia, Damyanova, et al. Toward understanding metal-catalyzed ethanol reforming [J]. ACS Catalysis, 2015, 5: 3841-3863). Therefore, controlling the Ni metal particles to a suitable size can effectively improve the catalytic activity and reaction stability of the catalyst.In addition, water, as a weak oxidant, can effectively help remove carbon deposits on metal surfaces. Meanwhile, CO, as an important reaction intermediate, can be converted into CO2 through water-gas shift reaction, which can further extract hydrogen from water and thus improve hydrogen production efficiency. Therefore, it is particularly important to improve the catalyst's ability to activate water. Some literature suggests that reducing the particle size of CeO2 can increase the concentration of oxygen vacancy sites on the surface, and oxygen vacancy sites on the CeO2 surface are important sites for the efficient activation and dissociation of water (Dan Yu, Yanyan, Jia Zhou Yang, et al., Solar photocatalytic oxidation of methane to methanol with water over RuO). x / ZnO / CeO2 nanorods [J].ACS Sustainable Chemistry & Engineering, 2022, 10: 16-22), therefore, reducing the CeO2 particle size can effectively improve the activation ability of water and effectively inhibit the formation of ethylene and acetone.

[0004] As can be seen from the above research progress, the control of the particle size and composite degree of the active components of metal and rare earth oxides in the catalyst is crucial for developing practical high-performance Ni-based ethanol steam reforming hydrogen production catalysts. This is expected to effectively suppress the formation of methane, ethylene, and carbon deposits while improving the efficiency of ethanol reforming hydrogen production. Therefore, this patent application is hereby filed. Summary of the Invention

[0005] To address the shortcomings of existing technologies and overcome the drawbacks of low hydrogen selectivity, poor stability, and easy carbon deposition in current catalysts, this invention aims to provide a method for preparing a nickel-rare earth oxide composite nanoisland supported catalyst. This catalyst can be widely applied to hydrogen production via steam reforming of lower alcohols, such as ethanol, as well as CO and CH4 steam reforming. This invention preferentially utilizes bioethanol reforming for hydrogen production.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A nickel-rare earth oxide composite nanoisland catalyst for hydrogen production from ethanol steam reforming, the catalyst being composed of metallic Ni and rare earth oxide ReO x The composite nanoisland structure is the active component, and its general chemical formula can be expressed as Ni / ReO. x / S; where ReO xThe catalyst is composed of one or more of CeO2, Sm2O3 or La2O3, and the support S is composed of one or more of Al2O3, SiO2, MgO, ZnO, silicalite-1, ZSM-5, activated carbon, C3N4 or BN. The weight ratio of metallic Ni in the catalyst is 1% to 10%, the weight ratio of ReOx is 0% to 50%, and the balance is the support S.

[0007] Preferably, the rare earth oxide ReOx loaded on the support S has a size of 1 to 15 nm and is uniformly distributed on the support S.

[0008] The specific steps of the aforementioned preparation method for the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol are as follows: (1) Add carrier S to solvent and disperse evenly to obtain a suspension containing carrier S; (2) Add rare earth oxide precursor salt to the suspension containing carrier S obtained in step (1), stir evenly, and then prepare a mixture containing rare earth oxide precursor salt. (3) Add a precipitant to the mixture of rare earth oxide precursor salts obtained in step (2), stir and react, then centrifuge and separate. The resulting solid is washed, dried and calcined to obtain a composite carrier containing rare earth oxides. (4) The composite support containing rare earth oxides obtained in step (3) is added to the precursor solution containing metallic Ni. The resulting mixture is dispersed evenly and then stirred vigorously. The solvent is then evaporated, and the resulting solid is dried and calcined to obtain the catalyst.

[0009] Preferably, the solvent in step (1) is composed of one or more of water, methanol, ethanol, acetone or acetonitrile.

[0010] Preferably, the rare earth oxide precursor salt described in step (2) is composed of one or more of lanthanum nitrate, cerium nitrate, or samarium nitrate.

[0011] Preferably, the precipitant in step (3) is composed of one or more of ammonia, urea, sodium hydroxide, potassium hydroxide or hexamethylenetetramine.

[0012] Preferably, the solvent in step (4) is one or a combination of water, methanol, ethanol, acetone, acetonitrile or tetrahydrofuran.

[0013] Preferably, the stirring reaction conditions in step (3) are: stirring temperature of 20-100 °C and stirring time of 0.5-48 h; Preferably, the roasting conditions in step (4) are: the roasting atmosphere is one of air, nitrogen or argon, the roasting temperature is 300 to 1000 °C, and the roasting time is 1 to 12 h.

[0014] The application of the aforementioned nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol involves the following steps: the catalyst is granulated and pretreated, and then the pretreated catalyst is loaded into a fixed-bed reactor. The ethanol steam reforming reaction can be carried out by introducing a feed gas composed of ethanol, water and nitrogen.

[0015] The principle of this invention is as follows: The hydrogen production process using existing Ni-based catalysts in ethanol steam reforming typically involves complex reaction steps. First, rare earth oxide surfaces often possess numerous acid-base sites, and ethanol readily undergoes dehydration at these sites at higher temperatures, producing ethylene, acetone, and long-chain organic compounds, thus reducing hydrogen production efficiency. Second, byproducts such as CH4 are usually generated during ethanol steam reforming. These byproducts can carbonize on the transition metal Ni surface, obscuring the catalyst's active sites or reacting with the active Ni metal to form Ni3C species, leading to catalyst deactivation. The supported nickel-rare earth oxide composite nanoisland catalyst provided by this invention confines metallic Ni within rare earth oxide nanoislands, thereby achieving spatial isolation between metal particles and inhibiting metal sintering of Ni metal particles. Furthermore, the nanoscale rare earth oxide nanoislands can stabilize metallic Ni through metal-support interactions and further enhance its ability to activate water through oxygen vacancy defects. This allows the generated hydroxyl groups to effectively promote the conversion of the intermediate ethoxy group to acetate, thus achieving efficient ethanol vapor reforming for hydrogen production. While generating hydrogen with high selectivity, it also successfully inhibits the carbon surface reaction on the active metal Ni. On the other hand, the rare earth oxide nanoislands can effectively reduce the excessive exposure of acid and base centers on the surface of the rare earth oxides by utilizing a high metal-rare earth oxide interface ratio, thereby avoiding the formation of ethylene, acetone, and higher carbon chain products. This further improves the stability and hydrogen production performance of the Ni-based catalyst.

[0016] Compared to existing methods, the gains of this invention are as follows: 1. The nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol provided by the present invention does not require the use of precious metals. It can achieve efficient hydrogen production by steam reforming of ethanol at 450°C by using inexpensive metals and with a small amount of metal.

[0017] 2. The nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by ethanol steam reforming provided by this invention has more defect sites. Through the regulation of the metal support interface, the active metal Ni and the defect sites of the active rare earth oxide components have a synergistic effect. The designed catalyst not only has higher catalytic activity in actual hydrogen production processes, but also has excellent carbon deposition inhibition ability.

[0018] 3. The nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol provided by this invention also has excellent performance in hydrogen production by steam reforming of ethanol: at 450℃, it can effectively reduce the selectivity of by-products C2H4, CH4 and acetone, improve the purity of hydrogen production, and has the prospect of practical application in the hydrogen energy industry.

[0019] 4. The preparation method of the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol provided by the present invention has the advantages of simple and readily available raw materials and simple preparation process, which can further reduce the production cost of hydrogen production by steam reforming of ethanol. Attached Figure Description

[0020] Figure 1 Transmission electron microscopy (TEM) image of the Ni-CeO2 nanoisland catalyst supported on BN and SiO2 as supports provided by the present invention. Figure 2 Comparison of X-ray powder diffraction (XRD) images of Ni-CeO2 nanoisland catalyst supported by BN and SiO2 as supports provided in this invention and Ni / CeO2 catalyst prepared by ordinary impregnation method; Figure 3 Comparison of hydrogen temperature programmed reduction (H2-TPR) of Ni-CeO2 nanoisland catalysts with different Ni particle sizes supported by BN as a support, as provided in this invention. Figure 4 A comparison of thermogravimetric analysis of the Ni / CeO2 / BN catalyst provided by this invention and the Ni / CeO2 catalyst prepared by the conventional impregnation method after 50 hours of reaction; Figure 5 The stability diagram of the catalytic performance of the Ni / CeO2 / BN catalyst provided in this invention after reacting at 450°C for 50 hours is shown. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should also be understood that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Specific mass, reaction time, temperature, process parameters, etc., in the examples are merely examples within a suitable range. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.

[0022] Example 1: The preparation steps of the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol are as follows: (1) Take 800 mg h -BN was dissolved in 60 ml of ethanol solvent and ultrasonically dispersed for 15 min until uniform dispersion was achieved, thus obtaining a carrier-containing solution. h -BN suspension; (2) The carrier-containing material obtained in step (1) h 0.326g of rare earth oxide precursor salt cerium nitrate hexahydrate was added to the suspension of -BN, and the resulting mixture was stirred at room temperature until homogeneous to obtain a mixed solution containing rare earth oxide precursor salt cerium nitrate hexahydrate. (3) Add 1.4 g of hexaethylaminetetraacetic acid to the mixture of rare earth oxide precursor salt cerium nitrate hexahydrate obtained in step (2). Stir the mixture at room temperature for 12 h. After centrifugation, wash the solid three times with 30 mL of deionized water. Dry the washed solid under vacuum at 60 °C for 6 h. Then calcine the dried solid at 550 °C for 4 h in air atmosphere to prepare a composite carrier containing cerium oxide nano islands. The obtained composite carrier is denoted as CeO2 / BN. (4) Add 0.8 g of the rare earth oxide-containing composite support CeO2 / BN obtained in step (3) to 60 ml of deionized water and ultrasonically disperse for 15 min. Then add 0.08 g of nickel nitrate hexahydrate and stir the mixture vigorously at room temperature for 12 h. Then remove the solvent by rotary evaporation of the product and dry the solid at 80 °C and -0.08 MPa for 6 h. Grind it into powder and calcine the powder at 550 °C in air atmosphere for 4 h to obtain the catalyst. The obtained catalyst is named Ni / CeO2 / BN-1.

[0023] The obtained composite support and catalyst were characterized. The morphology of the CeO2 / BN support was observed using a JEOL JEM-F200 high-resolution transmission electron microscope with an accelerating voltage of 200 kV. Particle size analysis was performed based on approximately 120 nanoparticles. The characterization results are as follows: Figure 1 As shown, from Figure 1As shown in Figure a, CeO2 is uniformly dispersed on the surface of the BN support mainly in the form of islands, with an average particle size of approximately 4.8 nm. The obtained catalyst Ni / CeO2 / BN-1 was characterized by X-ray powder diffraction (XRD) on a Rigaku Ultima-IV diffractometer equipped with a D / teX Ultra one-dimensional detector, using Cu Kα radiation (λ = 0.154 nm), a voltage of 40 kV, and a current of 30 mA. The data acquisition range was 2θ = 10–90°, and the scan rate was 10° min. -1 Characterization such as Figure 2 As shown, from Figure 2 As can be seen, no metal diffraction characteristic peaks belonging to Ni were observed after loading Ni metal, which indicates that Ni and CeO2 are well dispersed on the BN surface.

[0024] Example 2 The preparation steps of the nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol are the same as in Example 1, except that the support in step (1) is changed. h -BN was replaced with gaseous SiO2, and the remaining steps were the same as in Example 1. The resulting composite support was denoted as CeO2 / SiO2, and the resulting catalyst was denoted as Ni / CeO2 / SiO2. 2。 TEM characterization of the obtained CeO2 / SiO2 support is as follows: Figure 1 As shown, from Figure 1 As shown in b, CeO2 is mainly uniformly dispersed on the SiO2 surface in the form of islands, with an average particle size of approximately 7.8 nm. The X-ray powder diffraction (XRD) characterization of the obtained Ni / CeO2 / SiO2 catalyst is as follows: Figure 2 As shown, from Figure 2 As can be seen, no metal diffraction characteristic peaks belonging to Ni were observed after loading Ni, which indicates that Ni and CeO2 are well dispersed on the SiO2 surface.

[0025] Example 3 The preparation steps of the nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol are the same as in Example 1, except that the amount of nickel nitrate hexahydrate in step (4) is adjusted to 0.04 g, and the rest of the steps are the same as in Example 1. The resulting catalyst is denoted as Ni / CeO2 / BN-2.

[0026] Example 4 The preparation steps of the nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol are the same as in Example 1, except that the amount of nickel nitrate hexahydrate in step (4) is adjusted to 0.12 g, and the rest of the steps are the same as in Example 1. The resulting catalyst is denoted as Ni / CeO2 / BN-3.

[0027] The results of hydrogen temperature programmed reduction (H2-TPR) of catalysts with different particle sizes supported on CeO2 / BN composite supports are as follows: Figure 3 As shown, from Figure 3 As can be seen from the data, the highest reduction peak of the metal shifts to the high-temperature region as the metal loading increases, indicating that the metal particle size increases. At the same time, it should be noted that the temperature of the CeO2 reduction peak on BN shifts significantly to a lower temperature range after metal loading, which indicates that Ni and CeO2 islands have a strong metal-support interaction.

[0028] Comparative Example 1 The steps for preparing the cerium oxide-supported nickel catalyst Ni / CeO2 using the conventional impregnation method are as follows: (1) CeO2 support was prepared by placing 5 g of cerium nitrate hexahydrate in air atmosphere and calcining it at 500 °C for 4 h; (2) Weigh 0.8 g of the CeO2 support powder obtained in step (1) and add it to 60 ml of deionized water. After ultrasonic dispersion for 15 min, stir vigorously. Then add 0.08 g of nickel nitrate hexahydrate and stir vigorously for 12 h. After negative pressure rotary evaporation, dry and grind. Calcine the obtained sample powder at 550℃ in air atmosphere for 4 h. After pre-reduction, obtain the desired catalyst and record the obtained catalyst as Ni / CeO2.

[0029] Example 5 To verify that the nickel-rare earth oxide composite nanoisland catalyst for hydrogen production from ethanol by steam reforming provided by this invention has a high efficiency in inhibiting carbon deposition, the catalysts prepared in Examples 1-4 and the Ni / CeO2 catalyst prepared in Comparative Example 1 can be used to illustrate the reaction for hydrogen production from ethanol reforming.

[0030] The specific experimental steps for hydrogen production from ethanol reforming are as follows: The catalyst is granulated to 40–60 mesh, and then 0.1 g of the catalyst is placed in a fixed-bed reactor of a catalyst evaluation device. The inner diameter of the quartz reaction tube in the reactor is 9 mm. Before the reaction begins, a 10% H2 / N2 mixture is introduced to pretreat the catalyst at 550 °C for 2 h. After pretreatment, the feed gas is introduced to start the hydrogen production reaction. The feed gas is prepared in a molar ratio of CH3CH2OH∶H2O = 1∶6 and is fed into the reactor via N2 vaporization. The partial pressure of CH3CH2OH vapor is 1 kPa, the reaction temperature is 450 °C, and the space velocity is 36 L·g⁻¹. -1 ·h -1 The total reaction pressure was atmospheric pressure (101.3 kPa), and the reaction was carried out continuously for 20 h.

[0031] The catalytic results are shown in Table 1. As can be seen from Table 1, the nickel-rare earth oxide composite nano-island catalysts for hydrogen production by ethanol steam reforming prepared in this invention can effectively suppress the formation of ethylene and acetone. The product selectivity and hydrogen yield are better than those of the catalyst Ni / CeO2 prepared by the ordinary impregnation method.

[0032] Thermogravimetric analysis (TGA) was performed on the catalyst 50 hours after the catalytic reaction. The tests were conducted on a LoC-TGA 3000 chip-type molecular adsorption and thermogravimetric analyzer, with a test temperature range of 30–800 °C and a heating rate of 10 °C / min. The test results are as follows: Figure 4 As shown; the stability diagram of the Ni / CeO2 / BN-2 catalyst after 50 hours of reaction is shown in the figure. Figure 5 As shown. From Figure 4 and Figure 5 It can be found that the catalyst obtained by loading CeO2 islands with BN and SiO2 and then loading Ni metal has stronger anti-carbon deposition ability. Among them, the carbon deposition amount is only 6.3% when BN is used as support. Moreover, the Ni / CeO2 / BN-2 catalyst only loses 20% of its activity after 50 hours of reaction compared with the initial stage, and remains relatively stable thereafter, indicating that the catalyst has good catalytic stability.

[0033] Table 1 Data on catalytic ethanol steam reforming for hydrogen production

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A nickel-rare earth oxide composite nanoisland catalyst for hydrogen production by steam reforming of ethanol, characterized in that: The catalyst is composed of metallic Ni and rare earth oxide ReO. x The composite nanoisland structure is the active component, and its general chemical formula can be expressed as Ni / ReO. x / S; where ReO x The catalyst is composed of one or more of CeO2, Sm2O3 or La2O3, and the support S is composed of one or more of Al2O3, SiO2, MgO, ZnO, silicalite-1, ZSM-5, activated carbon, C3N4 or BN. The weight ratio of metallic Ni in the catalyst is 1% to 10%, the weight ratio of ReOx is 0% to 50%, and the balance is the support S.

2. The nickel-rare earth oxide composite nanoisland catalyst for hydrogen production from ethanol via steam reforming as described in claim 1, characterized in that, The rare earth oxide ReOx loaded on the support S has a size of 1 to 15 nm and is uniformly distributed on the support S.

3. A method for preparing a nickel-rare earth oxide composite nano-island catalyst for hydrogen production from ethanol via steam reforming as described in claim 1, characterized in that, The specific steps are as follows: (1) Add carrier S to solvent and disperse evenly to obtain a suspension containing carrier S; (2) Add rare earth oxide precursor salt to the suspension containing carrier S obtained in step (1), stir evenly, and then prepare a mixture containing rare earth oxide precursor salt. (3) Add a precipitant to the mixture of rare earth oxide precursor salts obtained in step (2), stir and react, then centrifuge and separate. The resulting solid is washed, dried and calcined to obtain a composite carrier containing rare earth oxides. (4) The composite support containing rare earth oxides obtained in step (3) is added to the precursor solution containing metallic Ni. The resulting mixture is dispersed evenly and then stirred vigorously. The solvent is then evaporated, and the resulting solid is dried and calcined to obtain the catalyst.

4. The method for preparing the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol as described in claim 3, characterized in that, The solvent mentioned in step (1) is composed of one or more of water, methanol, ethanol, acetone or acetonitrile.

5. The method for preparing the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol as described in claim 3, characterized in that, The rare earth oxide precursor salt described in step (2) is composed of one or more of lanthanum nitrate, cerium nitrate, or samarium nitrate.

6. The method for preparing the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol as described in claim 3, characterized in that, The precipitant mentioned in step (3) is composed of one or more of ammonia, urea, sodium hydroxide, potassium hydroxide or hexamethylenetetramine.

7. The method for preparing the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol as described in claim 3, characterized in that, The solvent mentioned in step (4) is one or a combination of water, methanol, ethanol, acetone, acetonitrile or tetrahydrofuran.

8. The method for preparing the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol as described in claim 3, characterized in that, The stirring reaction conditions described in step (3) are: stirring temperature of 20-100 ℃ and stirring time of 0.5-48 h.

9. The method for preparing the nickel-rare earth oxide composite nano-island catalyst for hydrogen production by steam reforming of ethanol as described in claim 3, characterized in that, The calcination conditions described in step (4) are as follows: the calcination atmosphere is one of air, nitrogen or argon, the calcination temperature is 300 to 1000 ℃, and the calcination time is 1 to 12 h.

10. The application of the nickel-rare earth oxide composite nanoisland catalyst as described in claim 1 for hydrogen production by steam reforming of ethanol, characterized in that, The specific steps are as follows: After granulation, the catalyst is pretreated, and then the pretreated catalyst is loaded into a fixed-bed reactor. The ethanol steam reforming reaction can be carried out by introducing a feed gas composed of ethanol, water and nitrogen.

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