Rare-earth-based quaternary nano-catalyst as well as preparation method and application thereof

Abstract

The invention provides a rare-earth-based quaternary nano-catalyst as well as a preparation method and application thereof. The rare-earth-based quaternary nano-catalyst comprises a Ce0. 5La0. 3Y0. 2O1. 95 ternary solid solution serving as a rare-earth composite oxide, a Ni0. 7Co0. 3 at-core-shell nano-cluster serving as a bimetallic active phase, Ti3C2TxMXene serving as a two-dimensional carrier and Li2O-ZnO nanocrystalline serving as a phase change auxiliary agent. According to the invention, a rare earth-bimetal-two-dimensional carrier-phase change additive quaternary system is subjected to element function division, interface effect reinforcement and cross-scale structure regulation and control, so that the catalytic performance is improved in a breakthrough manner, the hydrogen production efficiency is remarkably improved, and a new direction is opened up for efficient hydrogen production of oil reservoirs.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical materials technology, specifically relating to a quaternary nanocatalyst doped with rare earth elements, its preparation method, and its application in hydrogen production from heavy oil reservoirs. Background Technology

[0002] Against the backdrop of global energy transition, hydrogen energy, as an important clean energy option, is facing key technological efficiency challenges. Current mainstream hydrogen production technologies all suffer from significant efficiency bottlenecks: water electrolysis for hydrogen production is limited by overpotential losses and electrolyzer performance, with actual energy conversion efficiency only maintaining a level of 60-70%; fossil fuel-based hydrogen production, while achieving initial efficiencies of 70-85%, experiences a significant reduction of over 20% in overall efficiency after the introduction of carbon capture systems; photocatalytic hydrogen production technology suffers from solar energy conversion efficiencies generally below 2% due to photogenerated carrier recombination issues; and bio-based hydrogen production is constrained by energy losses in microbial metabolic pathways, making it difficult to break through 33% in theoretical efficiency. Particularly noteworthy is the more complex efficiency challenges faced by emerging reservoir-based hydrogen production technologies: difficulties in precisely controlling underground reaction conditions, catalyst deactivation under high temperature and pressure environments, and hydrogen recovery rates generally below 50%, resulting in overall efficiency significantly lagging behind traditional hydrogen production methods. These technological inefficiencies not only directly affect the production cost of hydrogen but also become major obstacles restricting the large-scale and commercial development of the hydrogen energy industry. The future development of hydrogen energy technology urgently needs to overcome these efficiency bottlenecks in order to truly realize the large-scale application of clean energy.

[0003] In the complex conditions of in-situ hydrogen production via fire-driven combustion in heavy oil reservoirs, catalysts must simultaneously withstand high-temperature thermal shock of 800-1200℃, sulfur corrosion of 0.1%-1% H2S concentration, and the synergistic destructive effects of alternating oxidizing (O2-rich) and reducing (hydrocarbon-rich) atmospheres. Traditional catalysts suffer a sharp drop in efficiency due to sintering of active components, sulfur poisoning, and structural collapse. Therefore, it is essential to provide a catalyst that can adapt to the above-mentioned environment and improve hydrogen production efficiency. Summary of the Invention

[0004] To address the problems of high-temperature sintering, sulfur poisoning deactivation, and catalytic instability in existing in-situ hydrogen production technologies for fire-driven heavy oil reservoirs, this invention provides a rare-earth-based quaternary nanocatalyst, its preparation method, and its application. Using a quaternary system of "rare earth-bimetallic-two-dimensional support-phase change promoter," the catalytic performance is significantly improved through elemental functional division, interface effect enhancement, and cross-scale structural regulation, resulting in a breakthrough improvement in hydrogen production efficiency and opening up new directions for efficient hydrogen production from oil reservoirs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a rare earth-based quaternary nanocatalyst, wherein the rare earth-based quaternary nanocatalyst comprises Ce as a rare earth composite oxide.0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni as a bimetallic active phase 0.7 Co 0.3 @Core-shell nanoclusters, Ti3C2TxMXene as a two-dimensional carrier, and Li2O-ZnO nanocrystals as a phase transition aid; among them, Ce 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni 0.7 Co 0.3 The mass ratio of core-shell nanoclusters, Ti3C2TxMXene, and Li2O-ZnO nanocrystals is 99:1:300:21.

[0006] Furthermore, the Ce 0.5 La 0.3 Y 0.2 O 1.95 The ternary solid solution has a particle size of 10-20 nm; the Ni 0.7 Co 0.3 The core-shell nanoclusters have a particle size of 2-3 nm; the Ti3C2TxMXene has a lateral dimension of 50-100 nm and a thickness (i.e., a longitudinal dimension) of 5-10 nm; the Li2O-ZnO nanocrystals have a particle size of 10-20 nm.

[0007] Furthermore, the Ce 0.5 La 0.3 Y 0.2 O 1.95 The molar ratio of Ce:La:Y in the ternary solid solution is 0.5:0.3:0.2.

[0008] This invention also provides a method for preparing the above-mentioned rare earth-based quaternary nanocatalyst, the method comprising: preparing Ce... 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni 0.7 Co 0.3 @Core-shell nanoclusters, Ti3C2TxMXene, and Li2O-ZnO nanocrystals are then mixed; the Ce 0.5 La 0.3 Y 0.2 O 1.95The preparation method of the ternary solid solution includes: using a co-precipitation method, dissolving Ce(NO3)3·6H2O, La(NO3)3·6H2O, and Y(NO3)3·6H2O in deionized water at a molar ratio of 0.5:0.3:0.2, adding NH4HCO3 as a precipitant, adjusting the pH of the system to 9-10, aging at 80℃ for 12 hours, and then calcining at 600℃ for 4 hours to obtain the Ce... 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution.

[0009] Furthermore, the Ni 0.7 Co 0.3 The preparation method of the core-shell nanoclusters includes: dissolving a nickel precursor (Ni(NO3)2·6H2O) and a cobalt precursor (Co(NO3)2·6H2O) in deionized water at a molar ratio of 7:3 to obtain a homogeneous solution; heating the solution to 250°C and maintaining it for 4 hours, and then carrying out a reduction reaction under a hydrogen atmosphere, whereby the hydrogen gas reduces the Ni... 2+ and Co 2+ The ions were reduced to the metallic state, and the product was repeatedly washed with deionized water and ethanol to remove residual precursors and byproducts. Finally, the product was dried under vacuum to obtain Ni. 0.7 Co 0.3 Alloy; the Ni 0.7 Co 0.3 Alloy particles are placed in an ALD reactor, and atomic layer deposition is performed using alternating injections of gases containing rare earth metal precursors and oxidizing gases, so that the rare earth metals are uniformly deposited on Ni. 0.7 Co 0.3 A core-shell structure is formed on the surface of the alloy particles; after deposition, the particles are heat-treated at 500°C in a hydrogen atmosphere for 3 hours to remove organic residues and optimize the structure of the metal oxide shell, thus obtaining the Ni. 0.7 Co 0.3 @Core-shell nanoclusters.

[0010] Furthermore, the preparation method of Ti3C2TxMXene includes: first, dissolving Ti3AlC2 powder in a 20% HF solution at 50°C for 24 hours to remove the aluminum layer; after the reaction, washing Ti3C2 repeatedly with deionized water to remove residual HF and other byproducts; finally, removing moisture by freeze-drying to obtain a two-dimensional Ti3C2MXene.

[0011] Furthermore, the method for preparing Li2O-ZnO nanocrystals includes: dissolving equal masses of LiNO3 and Zn(NO3)2·6H2O in deionized water to form a homogeneous solution; adding ammonia solution to adjust the pH of the solution to 9-10, causing lithium and zinc ions to form hydroxide precipitates; maintaining stirring and continuing precipitation for 3 hours to obtain a precipitate of Li2O-ZnO nanocrystals; filtering the precipitate using filter paper and washing it multiple times with deionized water to remove impurities from the solution; drying the obtained precipitate at 80°C for 12 hours; and then calcining it at 500°C for 4 hours to obtain the Li2O-ZnO nanocrystals.

[0012] This invention also provides the application of the above-mentioned rare earth-based quaternary nanocatalyst in hydrogen production from heavy oil reservoirs.

[0013] Furthermore, when using the rare earth-based quaternary nanocatalyst for hydrogen production in heavy oil reservoirs, the rare earth-based quaternary nanocatalyst is dissolved in deionized water, and then xanthan gum thickener is added at a mass ratio of 8:2 to the rare earth-based quaternary nanocatalyst and mixed evenly. The mixture is then filtered through a 100-mesh filter cloth to obtain a catalyst dispersion. The catalyst dispersion is then injected into the heavy oil reservoir.

[0014] Furthermore, when the reservoir water salinity is >10000 mg / L, the rare earth-based quaternary nanocatalyst is encapsulated in the oil phase using water-in-oil emulsification technology before use.

[0015] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages: (1) The catalyst involved in this invention is adaptable to a wide range of complex working conditions and can be applied in the field in reservoir environments with high temperature of 800-1200℃, sulfur corrosion of 0.1%-1% H2S concentration and alternating redox atmosphere.

[0016] (2) The catalyst preparation process involved in this invention has low equipment requirements. It adopts a three-step method of atomic layer deposition-freeze drying-hydrothermal reduction, which does not require complex and precision equipment. The preparation process is safe and economical.

[0017] (3) The catalyst involved in this invention can achieve efficient hydrogen production. Through the synergistic effect of the quaternary system, the catalytic activity is greatly improved, and the efficiency of in-situ hydrogen production by fire-driven hydrogen production is increased.

[0018] (4) The catalyst involved in this invention can effectively solve the problems of high-temperature sintering, sulfur poisoning and deactivation and structural collapse of traditional catalysts, enhance catalyst stability and improve process reliability, and is one of the effective solutions for in-situ hydrogen production by fire flooding in heavy oil reservoirs.

[0019] (5) The catalyst involved in this invention is applicable to a variety of hydrogen production reaction scenarios. It can effectively play a role in the complex working conditions of in-situ hydrogen production by fire flooding in heavy oil reservoirs and has long-term stable catalytic performance.

[0020] (6) The oil reservoir temperature range targeted by this invention is relatively wide. Although the specific upper limit of temperature is not specified, the catalyst can still maintain stable performance in a high temperature environment of 800-1200℃ and can adapt to the high temperature environment in the fire-driven process.

[0021] (7) The present invention adopts a quaternary nanocatalytic system of “rare earth-bimetal-two-dimensional carrier-phase change agent”, which produces no harmful substances during preparation and application and is environmentally friendly. Attached Figure Description

[0022] Figure 1 This is a flowchart of a method for preparing a rare earth-based quaternary nanocatalyst provided in an embodiment of the present invention. Detailed Implementation

[0023] As can be seen from the background technology, catalyst performance is a key factor restricting technological development in the field of in-situ hydrogen production via fire-driven combustion in heavy oil reservoirs. This presents three major challenges: the easy sintering and agglomeration of active components at high temperatures of 800-1200℃; sulfur poisoning and deactivation caused by 0.1%-1% H2S concentration; and structural collapse due to alternating redox atmospheres.

[0024] Existing technology 1 provides a composite catalyst for hydrogen production from heavy oil reservoirs using microorganisms, its preparation method, and its application. This technology develops a microbial composite catalyst for hydrogen production from heavy oil reservoirs, which is composed of activated carbon powder, nitrogen-doped graphene, nickel compounds, composite enzymes, and nano-platinum powder in a specific ratio. By combining the catalyst with hydrogen-producing microorganisms (such as *Pseudothermotoga elfii* DSM-9442 strain), hydrogen is produced through dark fermentation using residual hydrocarbons in the reservoir, realizing the resource utilization of heavy oil reservoirs. However, it suffers from limited improvement in hydrogen production efficiency (only 37%), high catalytic cost (requiring the precious metal platinum), unverified applicability to actual reservoir environments, and a lack of long-term operational stability data, resulting in insufficient overall economic viability and scalability potential.

[0025] Existing technology 2 provides a rare-earth element-doped hydrogen evolution electrocatalyst, its preparation method, and its application. This technology involves a rare-earth element-doped hydrogen evolution electrocatalyst composed of a rare-earth element-doped nickel oxide support and ruthenium atoms, exhibiting a linear nanosheet structure. The preparation involves mixing, hydrothermal treatment, adsorption, and annealing steps. It exhibits low overpotential and good stability in alkaline water electrolysis for hydrogen production, making it suitable for such reactions. However, it suffers from drawbacks including a high overpotential, missing key performance data, insufficient stability testing time, complex and costly preparation process, environmentally unfriendly nature, inadequate research on its structure and catalytic mechanism, limited application to alkaline systems, lack of comprehensive comparison with similar catalysts, and a gap from industrial application.

[0026] Existing technology 3 provides a high-activity hydrogen production catalyst containing rare earth elements and its preparation method. This catalyst consists of a SiO2-modified CeO2-ZrO2 support, Ru nanoparticles, natural polymer materials, and wolfberry extract, exhibiting high hydrogen production activity. The preparation method includes preparing a Ce and Zr mixed solution and hydrothermally treating it to generate a gel, followed by drying and calcination to obtain the support; reacting palladium salt, Ru salt, and glucose to prepare Ru nanoparticles; adding wolfberry extract to the support to form a solution, impregnating the Ru nanoparticles, adding natural polymer materials, and drying and calcining; and finally, activating the particulate catalyst at high temperature. This catalyst exhibits high activity in hydrogen production reactions and can be used in the hydrogen production field. However, it has only undergone a short-term test of 4 hours without long-term stability data, and the comparison with conventional catalysts is vague and lacks persuasiveness. Furthermore, its preparation process is cumbersome and energy-intensive, relying on Ru and Pd precious metals to increase costs, and the batch stability of natural raw materials such as wolfberry extract has not been verified.

[0027] This invention innovatively proposes a quaternary nanocatalytic system of "rare earth-bimetallic-two-dimensional support-phase change promoter." This system employs customized elemental functional design to precisely match the characteristics of each element, allowing rare earth elements to enhance anti-sintering capabilities and bimetallic elements to synergistically improve catalytic activity. It utilizes cross-scale structural coupling regulation to construct stable and efficient reaction structures at the nanoscale to microscale. Through extreme environment adaptability enhancement, leveraging the unique phase change behavior of the phase change promoter at high temperatures, it enhances the catalyst's structural stability and resists sulfur poisoning and atmospheric shocks. Through these three innovative pathways, it overcomes the traditional dilemma of synergistic optimization of activity, stability, and environmental tolerance in catalysts, achieving a qualitative leap in the efficiency and reliability of in-situ hydrogen production via fire-driven flooding, and providing a new direction for the efficient development of heavy oil reservoirs.

[0028] The present invention will now be described in detail with reference to specific embodiments.

[0029] The rare earth-based quaternary nanocatalyst provided by this invention comprises: 1. Rare earth composite oxides: Ce is selected. 0.5 La 0.3 Y0.2 O 1.95 Ternary solid solutions, as rare-earth composite oxides, utilize the electronic layer properties of rare-earth elements to construct a three-dimensional protective network. This composite oxide possesses a dynamic oxygen storage and release system, with Ce... 3+ It is oxidized to Ce in the oxidation zone. 4+ To increase the oxygen reserve in the lattice, when entering the reduction region, Ce 4+ It releases reactive oxygen species, oxidizing coking precursors (such as C2H2) to CO2, significantly reducing coking intensity. This is achieved through La... 3+ With Y 3+ The lattice anchoring stabilizes the cubic phase of CeO2, improving the high-temperature stability of the catalyst, which can reach temperatures up to 1300℃, and preventing oxygen vacancy loss. Furthermore, the composite oxide performs exceptionally well as a sulfur poisoning buffer layer, with La... 3+ With Y 3+ The Lewis alkaline sites can effectively adsorb H2S, forming stable La2S3 and Y2S3 nanoclusters. Sulfur capacity tests show that it can operate stably for 200 hours in a 100ppm H2S environment, with a sulfur adsorption capacity five times that of pure Al2O3 support, effectively preventing active metals from adsorbing sulfur. 2- reaction.

[0030] 2. Bimetallic active phase: The bimetallic active phase uses Ni 0.7 Co 0.3 Core-shell nanoclusters (2-3 nm in diameter) serve as the catalytic core, overcoming the performance limits of single metals through atomic-level alloying. The d-band center of the Ni-Co alloy shifts upward by 0.2 eV, lowering the CH bond adsorption energy of the CH4 molecule and thus enhancing the CH4 cleavage activity. DFT calculations show that the cleavage activation energy is reduced to 0.9 eV, and the CH4 conversion rate at 600 °C is increased by 35%. Ni sites dominate CH4 cleavage, while Co sites accelerate the WGS reaction through valence state cycling. In-situ DRIFTS analysis shows a 40% increase in CO2 generation rate and an H2 selectivity increase to 93%. Furthermore, Co... 2+ Ions intercalate into the Ni lattice to form distortion sites, effectively suppressing the sintering of Ni particles at high temperatures. TEM observation shows that after calcination at 1000℃ for 4 hours, the Ni-Co alloy particle size only increased by 15%, far lower than the 80% increase in pure Ni. The oxidation state of Co forms an oxide buffer layer in an alternating atmosphere, protecting Ni. 0 The active center prevents excessive oxidation and significantly improves redox stability.

[0031] 3. Two-dimensional MXene support: The two-dimensional MXene support uses Ti3C2Tx (thickness 5-10 nm, lateral dimension 50-100 nm) as the support for the catalytic active phase, utilizing its unique layered structure to improve mass transfer and thermal management performance. MXene has an in-plane thermal conductivity of 300 W / (mK), 10 times that of γ-Al2O3, enabling efficient heat dissipation from the combustion zone, preventing local overheating, reducing the catalyst surface temperature gradient from 500℃ / cm to 100℃ / cm, and increasing the heat resistance limit to 1100℃. The 0.8 nm interlayer slits in MXene restrict metal particle migration. Combined with atomic layer deposition (ALD) technology, it can effectively anchor Ni-Co@rare earth core-shell particles, increasing the dispersion of the active phase from 60% to 85%. Regarding interfacial active sites, the -OH and -O groups on the MXene surface form a hydrogen bond network with the rare earth oxide shell, promoting Ce... 4+ Electron transfer to the Ni-Co alloy enhances the adsorption and activation of H2O molecules, significantly improving the catalyst's activity.

[0032] 4. Phase Change Accelerator: The phase change accelerator introduces Li₂O-ZnO nanocrystals (particle size 10-20 nm) as thermally responsive functional units, constructing a "heat absorption-heat storage-heat release" cycle system. Li₂O-ZnO undergoes a solid-liquid phase transition at its eutectic point of 680 °C, absorbing excess heat in the high-temperature combustion zone (>800 °C), maintaining the local temperature below 900 °C. In-situ XRD shows that the Ni-Co alloy and rare earth oxide crystal structures remain stable at this temperature, preventing the formation of spinel phases. In the low-temperature pyrolysis zone (<600 °C), liquid Li₂O-ZnO recrystallizes, releasing latent heat and raising the local temperature back to 650 °C, increasing the catalytic reaction rate by 60%. Furthermore, liquid Li₂O-ZnO acts as an oxygen ion conductor (conductivity 10... -3 S / cm, 600℃), with Ce 0.5 La 0.3 Y 0.2 O 1.95 The formation of a "molten salt-oxide" interface accelerates oxygen ion migration, reduces the migration energy to 0.8 eV, and significantly increases the redox cycle frequency from 10 times / minute for traditional catalysts to 30 times / minute. DRT tests show that the fluctuation of H2 generation rate is reduced by 40%.

[0033] The present invention provides a method for preparing a rare earth-based quaternary nanocatalyst, comprising: 1. Catalyst composition and ratio Rare earth composite oxides: using Ce 0.5 La 0.3 Y 0.2 O 1.95A ternary solid solution (molar ratio Ce:La:Y = 0.5:0.3:0.2) enhances the catalyst's resistance to sintering and its stability through rare earth elements.

[0034] Bimetallic active phase: using Ni 0.7 Co 0.3 The alloy is coated with rare earth oxides on its surface using atomic layer deposition technology to form a Ni-Co@rare earth core-shell structure, thereby improving catalytic activity.

[0035] Two-dimensional support: Ti3C2TxMXene is selected, which has high thermal conductivity and excellent mass transfer performance, ensuring the stability of the catalyst under high temperature conditions.

[0036] Phase change aid: Li2O-ZnO nanocrystals are introduced to regulate the catalyst temperature and optimize the reaction rate through a phase change mechanism at high temperatures.

[0037] like Figure 1 The preparation method of rare earth-based quaternary nanocatalysts is as follows: The preparation method includes: preparing Ce separately. 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni 0.7 Co 0.3 @Core-shell nanoclusters, Ti3C2TxMXene and Li2O-ZnO nanocrystals are then mixed.

[0038] Ce 0.5 La 0.3 Y 0.2 O 1.95 The preparation method of the ternary solid solution includes: using a co-precipitation method, dissolving Ce(NO3)3·6H2O, La(NO3)3·6H2O, and Y(NO3)3·6H2O in deionized water at a molar ratio of 0.5:0.3:0.2, adding NH4HCO3 as a precipitant, adjusting the pH of the system to 9-10, aging at 80℃ for 12 hours, and then calcining at 600℃ for 4 hours to obtain Ce. 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution.

[0039] Ni 0.7 Co 0.3The preparation method of the core-shell nanoclusters includes: dissolving nickel precursor (Ni(NO3)2·6H2O) and cobalt precursor (Co(NO3)2·6H2O) in deionized water at a molar ratio of 7:3 to obtain a homogeneous solution; heating the solution to 250℃ and maintaining it for 4 hours, and then carrying out a reduction reaction under a hydrogen atmosphere; washing to remove residual precursors and byproducts; and finally drying the product to obtain Ni. 0.7 Co 0.3 Alloy; Ni 0.7 Co 0.3 Alloy particles are placed in an ALD reactor, and atomic layer deposition is performed using alternating injections of gases containing rare earth metal precursors and oxidizing gases, so that the rare earth metals are uniformly deposited on Ni. 0.7 Co 0.3 A core-shell structure is formed on the surface of the alloy particles; after deposition, it is heat-treated at 500℃ in a hydrogen atmosphere for 3 hours to remove organic residues and optimize the structure of the metal oxide shell, resulting in Ni. 0.7 Co 0.3 @Core-shell nanoclusters.

[0040] The preparation method of Ti3C2TxMXene includes: first, dissolving Ti3AlC2 powder in a 20% HF solution at 50℃ for 24 hours to remove the aluminum layer; after the reaction, washing Ti3C2 repeatedly with deionized water to remove residual HF and other byproducts; finally, removing moisture by freeze-drying to obtain a two-dimensional Ti3C2MXene.

[0041] The method for preparing Li2O-ZnO nanocrystals includes: dissolving equal masses of LiNO3 and Zn(NO3)2·6H2O in deionized water to form a homogeneous solution; then adding an ammonia solution to adjust the pH of the solution to 9-10, so that lithium and zinc ions form hydroxide precipitates; stirring and continuing precipitation for 3 hours to obtain a Li2O-ZnO nanocrystal precipitate; filtering the precipitate and washing it multiple times with deionized water to remove impurities from the solution; drying the obtained precipitate at 80°C for 12 hours, and then calcining it at 500°C for 4 hours to obtain Li2O-ZnO nanocrystals.

[0042] Example 1. Preparation of rare earth-based quaternary nanocatalysts 1.1 Preparation of rare earth composite oxides (1) Raw materials: Ce(NO3)3·6H2O: 10.0g; La(NO3)3·6H2O: 6.0g; Y(NO3)3·6H2O: 4.0g; Deionized water: appropriate amount; NH4HCO3 (precipitant): appropriate amount.

[0043] (2) Procedure: Dissolve Ce(NO3)3·6H2O, La(NO3)3·6H2O, and Y(NO3)3·6H2O in 100 mL of deionized water at a molar ratio of 0.5:0.3:0.2 to form a homogeneous solution. Add an appropriate amount of NH4HCO3 to the solution to adjust the pH to 9-10 to promote the precipitation reaction. Heat the reaction system to 80℃ and stir for 12 hours to ensure complete reaction. After precipitation, wash with deionized water several times to remove impurities. Calcine the precipitate at 600℃ for 4 hours to obtain Ce. 0.5 La 0.3 Y 0.2 O 1.95 Composite oxides.

[0044] 1.2 Preparation of bimetallic active phase (Ni 0.7 Co 0.3 @Core-shell nanoclusters) (1) Raw materials: Ni(NO3)2·6H2O: 6.5g; Co(NO3)2·6H2O: 2.8g; Hydrogen (H2): appropriate amount.

[0045] (2) Operation process: Ni(NO3)2·6H2O and Co(NO3)2·6H2O were dissolved in deionized water at a molar ratio of 7:3. The solution was heated to 250℃ and subjected to hydrothermal reduction in a hydrogen atmosphere for 4 hours. The obtained Ni-Co alloy particles were then subjected to atomic layer deposition (ALD) to deposit 5 nm of rare earth metal oxides on their surface, resulting in Ni... 0.7 Co 0.3 @Rare Earth Core-Shell Nanoclusters.

[0046] 1.3 Preparation of Ti3C2TxMXene (1) Raw materials: Ti3AlC2: 5.0g; HF (hydrogen fluoride solution): 50mL; deionized water: appropriate amount.

[0047] (2) Procedure: Ti3AlC2 powder was added to 50 mL of 20% HF solution. The reaction was carried out at room temperature for 24 hours. The aluminum layer was removed by HF etching to obtain the Ti3C2 structure. Ti3C2 was washed repeatedly with deionized water to remove residual HF. After ultrasonic treatment, Ti3C2TxMXene nanosheets were obtained.

[0048] 1.4 Preparation of Li₂O-ZnO nanocrystals (1) Raw materials: LiNO3: 4.0g; Zn(NO3)2·6H2O: 6.0g; ammonia (NH4OH): appropriate amount.

[0049] (2) Procedure: LiNO3 and Zn(NO3)2·6H2O were dissolved in deionized water at a molar ratio of 1:1. Ammonia was added to adjust the pH of the solution to 9-10 to promote the precipitation reaction. After stirring at room temperature for 3 hours, Li2O-ZnO nanocrystal precipitate was obtained. The precipitate was washed with deionized water and dried, and then calcined at 500℃ for 4 hours to obtain Li2O-ZnO nanocrystals.

[0050] 1.5 Catalyst Assembly Ce 0.5 La 0.3 Y 0.2 O 1.95 Composite oxides, Ni 0.7 Co 0.3 Rare earth core-shell nanoclusters, Ti3C2TxMXene, and Li2O-ZnO nanocrystals were mixed at a mass ratio of 99:1:300:21. Ultrasonic treatment was used to ensure uniform dispersion of the components, and freeze-drying was then employed to form the final catalyst.

[0051] 2. Application of catalysts in hydrogen production from heavy oil reservoirs 2.1 Preparation of catalyst dispersion (1) Raw materials: 0.8wt% rare earth-based quaternary nanocatalyst (about 8.0g); deionized water: appropriate amount; xanthan gum thickener: 0.2%.

[0052] Procedure: Disperse 0.8 wt% of rare earth-based quaternary nanocatalyst in an appropriate amount of deionized water to form a homogeneous dispersion. Add 0.2% xanthan gum thickener and stir until homogeneous, ensuring stable catalyst dispersion. Filter the dispersion using a 100-mesh filter cloth to remove any potential agglomerates.

[0053] (2) Application in heavy oil reservoirs The catalyst dispersion was injected into the heavy oil reservoir through the wellhead, with nitrogen used for displacement during the injection process. Hydrogen generation was then carried out in the heavy oil reservoir at a controlled temperature of 800-1200℃. During the reaction, the rare earth-based quaternary nanocatalyst improved hydrogen production efficiency and ensured stable operation of the catalyst in a high-temperature and sulfur-corrosion environment. This method significantly improved hydrogen production efficiency and reduced the deactivation problems associated with traditional catalysts.

[0054] 2.2 Water-in-oil emulsification technology If the reservoir water salinity is >10000mg / L, water-in-oil emulsification technology (Span-80 emulsifier) ​​is used to encapsulate the catalyst in the oil phase to avoid particle agglomeration caused by electrolytes.

[0055] It can be seen that the different application methods used in 2.1 and 2.2 can better adapt to different reservoir environments.

[0056] Block A has an average reservoir depth of 2100m. As of the end of February 2022, proven geological reserves of oil reached 824,000 tons, with 127,000 tons utilized, representing a utilization rate of 15.4%. The oilfield currently has 141 production wells, with 74 in operation, and 28 gas injection wells, with 10 in operation. Daily oil production is 58.25 t / d, with a water cut of 71.2%. Cumulative oil production is 53.2 × 10⁴ t / d, and cumulative water production is 63.0 × 10⁴ t / d. 4 m 3 The oil recovery rate was 0.33%, and the recovery rate was 9.59%. Daily gas injection was 1200 tons, with a cumulative gas injection of 59.7 × 10⁻⁶ tons. 4 m 3 The reservoir's sedimentary facies morphology is characterized by parallel bedding, horizontal bedding, and cross bedding. Vegetation pores and bioturbation structures are visible. Carbonaceous debris is present in the cross-section of the dark gray mudstone, and the sedimentary structures exhibit deltaic front depositional characteristics. The reservoir's average porosity is 11.2%, reaching a maximum of 24.2%; the average permeability is 1.56 × 10⁻⁶. -3 μm 2 The highest is 6.8×10 -3 μm 2 The saturation pressure is 2.6 MPa, the viscosity under reservoir conditions is 20 mPa·s, and the viscosity of the degassed crude oil at 50℃ is 21.5 mPa·s.

[0057] Well 2-40 was selected as the gas injection well and well 2-41 as the production well in this oilfield. The concentration, injection rate, and gas injection rate of rare earth-based quaternary nanocatalysts injected into each well group are shown in Table 1.

[0058] Table 1

[0059] The parameters such as the first cycle production time, cumulative gas production, and average hydrogen content are shown in Table 2.

[0060] Table 2

[0061] In summary, this invention provides a rare earth-based quaternary nanocatalyst, its preparation method, and its application. It constructs a quaternary nanocatalytic system of "rare earth-bimetallic-two-dimensional support-phase change promoter," wherein the rare earth composite oxide is Ce. 0.5 La 0.3 Y 0.2 O 1.95 A ternary solid solution with Ni as the bimetallic active phase. 0.7 Co 0.3 @Core-shell nanoclusters, with Ti3C2Tx MXene as the two-dimensional support and Li2O-ZnO nanocrystals as the phase change promoter, enhance the performance of the catalyst under high temperature, high sulfur and redox alternating atmosphere through the synergistic effect of each component.

[0062] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of the present invention. Any person skilled in the art can make their own modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A rare earth-based quaternary nanocatalyst, characterized in that, The rare earth-based quaternary nanocatalyst includes Ce as a rare earth composite oxide. 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni as a bimetallic active phase 0.7 Co 0.3 @Core-shell nanoclusters, Ti3C2TxMXene as a two-dimensional carrier, and Li2O-ZnO nanocrystals as a phase change aid; Among them, Ce 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni 0.7 Co 0.3 The mass ratio of core-shell nanoclusters, Ti3C2TxMXene, and Li2O-ZnO nanocrystals is 99:1:300:

21.

2. The rare earth-based quaternary nanocatalyst according to claim 1, characterized in that, The Ce 0.5 La 0.3 Y 0.2 O 1.95 The ternary solid solution has a particle size of 10-20 nm; the Ni 0.7 Co 0.3 The core-shell nanoclusters have a particle size of 2-3 nm; the Ti3C2TxMXene has a lateral dimension of 50-100 nm and a thickness of 5-10 nm; the Li2O-ZnO nanocrystals have a particle size of 10-20 nm.

3. The rare earth-based quaternary nanocatalyst according to claim 1, characterized in that, The Ce 0.5 La 0.3 Y 0.2 O 1.95 The molar ratio of Ce:La:Y in the ternary solid solution is 0.5:0.3:0.

2.

4. A method for preparing a rare earth-based quaternary nanocatalyst according to any one of claims 1 to 3, characterized in that, The preparation method includes: preparing Ce separately. 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution, Ni 0.7 Co 0.3 @Core-shell nanoclusters, Ti3C2TxMXene and Li2O-ZnO nanocrystals are then mixed together; The Ce 0.5 La 0.3 Y 0.2 O 1.95 The preparation method of the ternary solid solution includes: using a co-precipitation method, dissolving Ce(NO3)3·6H2O, La(NO3)3·6H2O, and Y(NO3)3·6H2O in deionized water at a molar ratio of 0.5:0.3:0.2, adding NH4HCO3 as a precipitant, adjusting the pH of the system to 9-10, aging at 80℃ for 12 hours, and then calcining at 600℃ for 4 hours to obtain the Ce... 0.5 La 0.3 Y 0.2 O 1.95 Ternary solid solution.

5. The method for preparing rare earth-based quaternary nanocatalysts according to claim 4, characterized in that, The Ni 0.7 Co 0.3 The preparation method of the core-shell nanoclusters includes: dissolving nickel precursor and cobalt precursor in deionized water at a molar ratio of 7:3 to obtain a homogeneous solution; The solution was heated to 250°C and maintained for 4 hours. A reduction reaction was then carried out under a hydrogen atmosphere. Residual precursors and byproducts were removed by washing, and the product was finally dried to obtain Ni. 0.7 Co 0.3 alloy; The Ni 0.7 Co 0.3 Alloy particles are placed in an ALD reactor, and atomic layer deposition is performed using alternating injections of gases containing rare earth metal precursors and oxidizing gases, so that the rare earth metals are uniformly deposited on Ni. 0.7 Co 0.3 A core-shell structure is formed on the surface of the alloy particles; after deposition, the particles are heat-treated at 500°C in a hydrogen atmosphere for 3 hours to remove organic residues and optimize the structure of the metal oxide shell, thus obtaining the Ni. 0.7 Co 0.3 @Core-shell nanoclusters.

6. The method for preparing rare earth-based quaternary nanocatalysts according to claim 4, characterized in that, The preparation method of Ti3C2TxMXene includes: first, dissolving Ti3AlC2 powder in a 20% HF solution at 50°C for 24 hours to remove the aluminum layer; after the reaction, washing Ti3C2 repeatedly with deionized water to remove residual HF and other byproducts; finally, removing moisture by freeze-drying to obtain a two-dimensional Ti3C2MXene.

7. The method for preparing rare earth-based quaternary nanocatalysts according to claim 4, characterized in that, The method for preparing Li2O-ZnO nanocrystals includes: dissolving equal masses of LiNO3 and Zn(NO3)2·6H2O in deionized water to form a homogeneous solution; adding ammonia solution to adjust the pH of the solution to 9-10, causing lithium and zinc ions to form hydroxide precipitates; stirring and continuing precipitation for 3 hours to obtain a Li2O-ZnO nanocrystal precipitate; filtering the precipitate and washing it multiple times with deionized water to remove impurities from the solution; drying the obtained precipitate at 80°C for 12 hours; and then calcining it at 500°C for 4 hours to obtain the Li2O-ZnO nanocrystals.

8. The application of a rare earth-based quaternary nanocatalyst according to any one of claims 1 to 3 in hydrogen production from heavy oil reservoirs.

9. The application according to claim 8, characterized in that, When the rare earth-based quaternary nanocatalyst is used for hydrogen production in heavy oil reservoirs, the rare earth-based quaternary nanocatalyst is dissolved in deionized water, and then xanthan gum thickener is added at a mass ratio of 8:2 to the rare earth-based quaternary nanocatalyst and mixed evenly. The mixture is then filtered through a 100-mesh filter cloth to obtain a catalyst dispersion. The catalyst dispersion is then injected into the heavy oil reservoir.

10. The application according to claim 8, characterized in that, When the reservoir water salinity is >10000 mg / L, the rare earth-based quaternary nanocatalyst is encapsulated in the oil phase using water-in-oil emulsification technology before use.

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