Nano graphene lubricating oil and preparation method thereof

Abstract

The invention discloses nano graphene lubricating oil and a preparation method thereof, and relates to the technical field of lubricating oil. Firstly, the modified zirconium-titanium composite particles are used as a catalyst to catalyze and synthesize base oil, so that the heat-resistant effect is improved; then graphene is stripped under the assistance of microwaves to improve the dispersity of graphene in lubricating oil, meanwhile, a hydrogen bond network is formed on the surfaces of modified zirconium-titanium particles, fatigue wear is reduced, the service life is prolonged, on the basis, electrochemical deposition is generated in the friction process of the particles and graphene, and the self-repairing effect is achieved. According to the modified zirconium-titanium composite particles, precursor sol is injected into a pre-cooled liquid nitrogen copper mold, ice crystals are removed through quick freezing and vacuum sublimation drying, a snowflake-like graded porous structure is formed, and the lubricating effect is improved; then low-temperature annealing is conducted, a Zr-O-Ti mixed oxide framework is formed, pore channel collapse is effectively inhibited, and the service life is prolonged; and through surface hydroxyl and capillary action, the ionic liquid is adsorbed to form a coating layer, so that the lubricating effect is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating oils, in particular to a nano-graphene lubricating oil and a preparation method thereof. Background Art

[0002] Lubricants play a vital role in today's industrial production and high-end manufacturing. They are one of the key materials that ensure the efficient and stable operation of mechanical equipment. The performance of lubricants is directly related to the lifespan of equipment, energy efficiency, and environmental safety. Among the many improved lubricant varieties, nanographene lubricants are widely considered to be a valuable alternative to traditional lubricants due to the unique two-dimensional structure and excellent performance of graphene materials. However, the practical application of nanographene lubricants still faces significant technical obstacles, which make it difficult to fully realize their theoretical advantages in practice.

[0003] The improved lubrication performance of nanographene lubricants is limited by several factors. First, graphene's dispersion stability in base oil is insufficient, making it prone to agglomeration into micron-sized particles. This, in turn, leads to increased abrasive wear on the friction pair surfaces. Second, graphene's relatively weak interfacial bonding with metal surfaces makes it difficult for it to form a stable physical adsorption film on the metal surface, resulting in lubrication failure under high-load operating conditions. For example, in a test bench of an automobile engine, it was found that when 0.5% graphene was added to a lubricant at 150°C and a load of 1000N, its friction coefficient was only reduced by 8% compared to fully synthetic oil. This result is far from the theoretically predicted 30% reduction. Furthermore, compatibility issues between graphene and traditional lubricant additives (such as ZDDP) limit the potential synergistic effects between them, further weakening the friction-reducing and anti-wear effects of nanographene lubricants. Summary of the Invention

[0004] The object of the present invention is to provide a nano-graphene lubricant and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a nanographene lubricant, calculated by weight, comprising the following preparation steps:

[0006] (1) Under a nitrogen atmosphere, zirconium-titanium porous particles were placed in a tube furnace, heated to 180-240°C for 2-6 hours, naturally cooled to room temperature, immersed in an ionic liquid, and ultrasonicated at 30 kHz for 30-50 minutes. The solid was collected by filtration and dried in an oven at 50°C for 16-24 hours to obtain modified zirconium-titanium composite particles;

[0007] (2) uniformly mixing the modified zirconium-titanium composite particles and α-olefin in a reactor, introducing hydrogen to a pressure of 5 MPa, raising the temperature to 150-210° C., reacting for 8-12 hours, and naturally cooling to room temperature to obtain a base oil;

[0008] (3) The nanographene and the base oil are mixed evenly, placed in a microwave reactor, reacted at a power of 800 W and a frequency of 2.45 GHz for 1 to 3 minutes, 10 wt% of boronated polyisobutylene bissuccinimide by weight of the base oil, 0.9 wt% of polymethacrylate by weight of the base oil, 0.4 wt% of a polyether defoamer by weight of the base oil, 1 wt% of a magnesium salt detergent by weight of the base oil, and 30 wt% of linseed oil by weight of the base oil are added, and stirred evenly to obtain a nanographene lubricant.

[0009] Furthermore, the preparation steps of the zirconium-titanium porous particles in step (1) are: injecting the precursor gel into a copper mold, freezing it in a liquid nitrogen environment for 5 to 15 minutes, and then transferring it to a vacuum freeze dryer for sublimation and deicing for 48 to 60 hours to obtain zirconium-titanium porous particles.

[0010] Furthermore, the precursor gel is prepared by dissolving 5 to 9 parts of zirconium oxychloride and 4 to 6 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjusting the pH to 3 to 4 with 0.5 mol / L nitric acid, and stirring at 100 rpm for 6 to 10 hours to obtain the precursor gel.

[0011] Furthermore, the parameters of the vacuum freeze dryer are temperature -50°C and pressure 10Pa.

[0012] Furthermore, the heating rate in step (1) is 10°C / min.

[0013] Furthermore, the ionic liquid in step (1) is selected from any one of 1-butyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide.

[0014] Furthermore, in step (2), the mass ratio of the modified zirconium-titanium composite particles to the α-olefin is (0.01-0.07):1.

[0015] Furthermore, the particle size of the nanographene in step (3) is 5 to 25 nm.

[0016] Furthermore, in step (3), the mass ratio of the nanographene to the base oil is (0.001-0.01):1.

[0017] Furthermore, a nano-graphene lubricant is prepared according to any of the above preparation methods.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention first uses modified zirconium-titanium composite particles as a catalyst to synthesize base oil through a catalytic reaction. This process effectively reduces the branched and unsaturated structures in the base oil, thereby significantly increasing the thermal decomposition temperature of the base oil. By inhibiting the mechanism of free radical chain decomposition and fracture, the present invention further enhances the heat resistance of the base oil. Subsequently, with the assistance of microwaves, the graphene is exfoliated. This process retains the active carboxyl functional groups between the graphene layers, greatly improving the dispersibility of graphene in the lubricating oil. At the same time, a hydrogen bond network is formed between the surface of the modified zirconium-titanium particles and the graphene. This structure realizes the carrying effect of graphene, effectively reduces fatigue wear caused by friction, and thus indirectly extends the service life of the lubricating oil. On this basis, the modified zirconium-titanium particles interact with graphene during the friction process, producing an electrochemical deposition phenomenon, which helps to repair microcracks on the metal surface and realize the self-repair function of the lubricating oil.

[0020] During the preparation of the modified zirconium-titanium composite particles, a precursor sol is first injected into a pre-cooled liquid nitrogen copper mold. Ice crystals are removed through rapid freezing and vacuum sublimation drying, resulting in a hierarchical, snowflake-like porous structure. This unique structure creates micro-nanoscale oil reservoirs that continuously release lubricating molecules through capillary action, activated by frictional heat, significantly enhancing the lubricating effect of the lubricant. Subsequently, a low-temperature annealing treatment forms a Zr-O-Ti mixed oxide framework, which effectively suppresses pore collapse. Furthermore, the semiconducting properties of the mixed oxide create an electron cloud shielding effect at the friction interface, effectively reducing metal-metal adhesion and further extending the service life of the lubricant. Finally, through surface hydroxyl groups and capillary action, an ionic liquid is adsorbed to form a coating, which enhances the dispersion stability of the graphene and forms an interfacial double layer effect, further enhancing the lubricating effect of the lubricant. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the various indicators of the high and low temperature resistant and anti-wear lubricating oil prepared in the following examples.

[0023] Four-ball bearing capacity load and wear spot diameter: The embodiment and comparative example of the same mass were tested in accordance with the standard GB / T3142.

[0024] Thermal decomposition temperature: The same mass of the embodiment and the comparative example were tested according to the standard ASTM E2550.

[0025] Improved repair performance: The same mass of the embodiment and the comparative example was taken, and after grinding the metal surface for 30 minutes, the metal surface repair rate was analyzed by spectroscopy.

[0026] Example 1

[0027] (1) Dissolve 5 parts of zirconium oxychloride and 4 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjust the pH to 3 with 0.5 mol / L nitric acid, and stir at 100 rpm for 6 hours to prepare a precursor gel;

[0028] (2) The precursor gel was injected into a copper mold, frozen in liquid nitrogen for 5 min, and then transferred to a vacuum freeze dryer for sublimation and deicing at -50 °C and a pressure of 10 Pa for 48 h to obtain zirconium-titanium porous particles;

[0029] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace, heated to 180°C at a rate of 10°C / min for 2 h, then naturally cooled to room temperature, immersed in 1-butyl-3-methylimidazolium tetrafluoroborate, and ultrasonicated at 30 kHz for 30 min. The solid was collected by filtration and dried in an oven at 50°C for 16 h to obtain modified zirconium-titanium composite particles;

[0030] (4) The modified zirconium-titanium composite particles and α-olefin were uniformly mixed in a reaction kettle at a mass ratio of 0.01:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 150° C., the reaction was carried out for 8 h, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0031] (5) Nanographene with a particle size of 5 nm and base oil were mixed uniformly in a mass ratio of 0.001:1, placed in a microwave reactor, reacted for 1 min at a power of 800 W and a frequency of 2.45 GHz, and 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent, and 30 wt% of linseed oil were added to the base oil. The mixture was stirred uniformly to obtain a nanographene lubricant.

[0032] Polymethacrylate was purchased from Romanx, Germany, model SCR-168A;

[0033] The magnesium salt detergent was purchased from Chevron Corporation and the model number was OLOA182.

[0034] Example 2

[0035] (1) Dissolve 7 parts of zirconium oxychloride and 5 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 hours to prepare a precursor gel;

[0036] (2) The precursor gel was injected into a copper mold, frozen in liquid nitrogen for 10 min, and then transferred to a vacuum freeze dryer for sublimation and deicing at -50 °C and a pressure of 10 Pa for 54 h to obtain zirconium-titanium porous particles;

[0037] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace, heated to 210°C at a rate of 10°C / min for 4 h, then naturally cooled to room temperature, immersed in 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt, and ultrasonicated at 30 kHz for 40 min. The solid was collected by filtration and dried in an oven at 50°C for 20 h to obtain modified zirconium-titanium composite particles;

[0038] (4) The modified zirconium-titanium composite particles and α-olefin were uniformly mixed in a reactor at a mass ratio of 0.04:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, the reaction was carried out for 10 hours, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0039] (5) Nanographene with a particle size of 15 nm and base oil were mixed uniformly in a mass ratio of 0.005:1, placed in a microwave reactor, reacted for 2 min at a power of 800 W and a frequency of 2.45 GHz, and 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent, and 30 wt% of linseed oil were added to the base oil. The mixture was stirred uniformly to obtain a nanographene lubricant.

[0040] Polymethacrylate was purchased from Romanx, Germany, model SCR-168A;

[0041] The magnesium salt detergent was purchased from Chevron Corporation and the model number was OLOA182.

[0042] Example 3

[0043] (1) 9 parts of zirconium oxychloride and 6 parts of tetrabutyl titanate were dissolved in 90 parts of anhydrous ethanol, the pH was adjusted to 4 with 0.5 mol / L nitric acid, and the mixture was stirred at 100 rpm for 10 h to prepare a precursor gel;

[0044] (2) The precursor gel was injected into a copper mold, frozen in liquid nitrogen for 15 min, and then transferred to a vacuum freeze dryer for sublimation and deicing at -50 °C and a pressure of 10 Pa for 60 h to obtain zirconium-titanium porous particles;

[0045] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace, heated to 240°C at a rate of 10°C / min for 6 h, then naturally cooled to room temperature, immersed in 1-butyl-3-methylimidazolium tetrafluoroborate, and ultrasonicated at 30 kHz for 50 min. The solid was collected by filtration and dried in an oven at 50°C for 24 h to obtain modified zirconium-titanium composite particles;

[0046] (4) The modified zirconium-titanium composite particles and α-olefin were uniformly mixed in a reaction kettle at a mass ratio of 0.07:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 210°C, the reaction was carried out for 12 hours, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0047] (5) Nanographene with a particle size of 25 nm and base oil were mixed uniformly in a mass ratio of 0.01:1, placed in a microwave reactor, reacted for 3 minutes at a power of 800 W and a frequency of 2.45 GHz, and 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent, and 30 wt% of linseed oil were added to the base oil. The mixture was stirred uniformly to obtain a nanographene lubricant.

[0048] Polymethacrylate was purchased from Romanx, Germany, model SCR-168A;

[0049] The magnesium salt detergent was purchased from Chevron Corporation and the model number was OLOA182.

[0050] Comparative Example 1

[0051] (1) Aluminum chloride and α-olefin were mixed uniformly in a reaction kettle at a mass ratio of 0.04:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, the reaction was carried out for 10 hours, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0052] (2) Nanographene with a particle size of 15 nm and base oil were mixed uniformly in a mass ratio of 0.005:1, placed in a microwave reactor, reacted for 2 min at a power of 800 W and a frequency of 2.45 GHz, and then 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent and 30 wt% of linseed oil were added to the base oil. The mixture was stirred uniformly to obtain nanographene lubricant.

[0053] Comparative Example 2

[0054] (1) Dissolve 7 parts of zirconium oxychloride and 5 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 hours to prepare a precursor gel;

[0055] (2) The precursor gel was injected into a copper mold, frozen in liquid nitrogen for 10 min, and then transferred to a vacuum freeze dryer for sublimation and deicing at -50 °C and a pressure of 10 Pa for 54 h to obtain zirconium-titanium porous particles;

[0056] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace, heated to 210°C at a rate of 10°C / min for 4 h, then naturally cooled to room temperature, immersed in 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt, and ultrasonicated at 30 kHz for 40 min. The solid was collected by filtration and dried in an oven at 50°C for 20 h to obtain modified zirconium-titanium composite particles;

[0057] (4) The modified zirconium-titanium composite particles and α-olefin were uniformly mixed in a reactor at a mass ratio of 0.04:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, the reaction was carried out for 10 hours, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0058] (5) Nanographene with a particle size of 15 nm was mixed evenly with base oil in a mass ratio of 0.005:1, and 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent and 30 wt% of linseed oil were added. The mixture was stirred evenly to obtain nanographene lubricant.

[0059] Comparative Example 3

[0060] (1) Dissolve 7 parts of zirconium oxychloride and 5 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 hours to prepare a precursor gel;

[0061] (2) Under a nitrogen atmosphere, the precursor gel was placed in a tube furnace, heated to 410°C at a rate of 10°C / min for 4 hours, then naturally cooled to room temperature, immersed in 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide salt, and ultrasonicated at 30 kHz for 40 minutes. The solid was collected by filtration and dried in an oven at 50°C for 20 hours to obtain modified zirconium-titanium composite particles.

[0062] (3) The modified zirconium-titanium composite particles and α-olefin were uniformly mixed in a reactor at a mass ratio of 0.04:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, the reaction was carried out for 10 hours, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0063] (4) Nanographene with a particle size of 15 nm and base oil were mixed evenly in a mass ratio of 0.005:1, placed in a microwave reactor, and reacted for 2 minutes at a power of 800 W and a frequency of 2.45 GHz. 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent and 30 wt% of linseed oil were added to the base oil. The mixture was stirred evenly to obtain nanographene lubricant.

[0064] Comparative Example 4

[0065] (1) Dissolve 7 parts of zirconium oxychloride and 5 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjust the pH to 3.5 with 0.5 mol / L nitric acid, and stir at 100 rpm for 8 hours to prepare a precursor gel;

[0066] (2) The precursor gel was injected into a copper mold, frozen in liquid nitrogen for 10 min, and then transferred to a vacuum freeze dryer for sublimation and deicing at -50 °C and a pressure of 10 Pa for 54 h to obtain zirconium-titanium porous particles;

[0067] (3) Under a nitrogen atmosphere, the zirconium-titanium porous particles were placed in a tube furnace, heated to 210°C at a rate of 10°C / min for 4 hours, and then naturally cooled to room temperature to obtain modified zirconium-titanium composite particles;

[0068] (4) The modified zirconium-titanium composite particles and α-olefin were uniformly mixed in a reactor at a mass ratio of 0.04:1, hydrogen was introduced to a pressure of 5 MPa, the temperature was raised to 180°C, the reaction was carried out for 10 hours, and the mixture was naturally cooled to room temperature to obtain a base oil;

[0069] (5) Nanographene with a particle size of 15 nm was mixed evenly with base oil in a mass ratio of 0.005:1, placed in a microwave reactor, and reacted for 2 min at a power of 800 W and a frequency of 2.45 GHz. 10 wt% of boronated polyisobutylene bissuccinimide, 0.9 wt% of polymethacrylate, 0.4 wt% of polyether defoamer, 1 wt% of magnesium salt detergent, and 30 wt% of linseed oil were added to the mixture and stirred evenly to obtain nanographene lubricant.

[0070] Effect Examples

[0071] Table 1 below shows the performance analysis results of the nanographene lubricating oils of Examples 1, 2, and 3 of the present invention and Comparative Examples 1, 2, 3, and 4.

[0072] Table 1

[0073]

[0074] From the comparison of the experimental data of Examples 1, 2, and 3 with those of Comparative Examples 1 and 2, it can be found that the modified zirconium-titanium composite particles are used as catalysts to catalyze the synthesis of base oil, reduce branching and unsaturated structures, increase the thermal decomposition temperature of the base oil, inhibit free radical chain decomposition and fracture, and improve the heat resistance effect; then, the graphene is peeled off under the assistance of microwaves, the interlayer active carboxyl functional groups are retained, the dispersibility of graphene in the lubricating oil is improved, and at the same time, a hydrogen bond network is formed with the surface of the modified zirconium-titanium particles to achieve a carrying effect, reduce fatigue wear, and extend service life. On this basis, the particles and graphene produce electrochemical deposition during the friction process, repairing microcracks on the metal surface to achieve a self-repairing effect; from Examples 1, 2, and 3 with Comparative Examples 3 and 4, By comparing the experimental data, it can be found that by injecting the precursor sol into a pre-cooled liquid nitrogen copper mold, rapidly freezing, and vacuum sublimation drying to remove ice crystals, a snowflake-like hierarchical porous structure is formed, and a micro-nano-scale micro-oil reservoir is constructed. Under the activation of friction heat, lubricating molecules are continuously released through capillary action to improve the lubrication effect; then low-temperature annealing is performed to form a Zr-O-Ti mixed oxide skeleton, which effectively inhibits pore collapse. At the same time, the semiconductor properties of the mixed oxide produce electron cloud shielding at the friction interface, reducing metal adhesion and thus extending the service life; then through surface hydroxyl groups and capillary action, ionic liquid is adsorbed to form a coating layer, which enhances the dispersion stability of graphene, forms an interfacial double layer effect, and enhances the lubrication effect.

[0075] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A nanographene lubricant, characterized in that: The method comprises the following preparation steps by weight: (1) Under a nitrogen atmosphere, zirconium-titanium porous particles were placed in a tube furnace, heated to 180-240°C for 2-6 hours, naturally cooled to room temperature, immersed in an ionic liquid, and ultrasonicated at 30 kHz for 30-50 minutes. The solid was collected by filtration and dried in an oven at 50°C for 16-24 hours to obtain modified zirconium-titanium composite particles; (2) uniformly mixing the modified zirconium-titanium composite particles and α-olefin in a reactor, introducing hydrogen to a pressure of 5 MPa, raising the temperature to 150-210° C., reacting for 8-12 hours, and naturally cooling to room temperature to obtain a base oil; (3) The nanographene and the base oil are mixed evenly, placed in a microwave reactor, reacted at a power of 800 W and a frequency of 2.45 GHz for 1 to 3 minutes, 10 wt% of boronated polyisobutylene bissuccinimide by weight of the base oil, 0.9 wt% of polymethacrylate by weight of the base oil, 0.4 wt% of a polyether defoamer by weight of the base oil, 1 wt% of a magnesium salt detergent by weight of the base oil, and 30 wt% of linseed oil by weight of the base oil are added, and stirred evenly to obtain a nanographene lubricant.

2. A nano-graphene lubricant according to claim 1, characterized in that, The preparation steps of the zirconium-titanium porous particles in step (1) are as follows: the precursor gel is injected into a copper mold, frozen in a liquid nitrogen environment for 5 to 15 minutes, and then transferred to a vacuum freeze dryer for sublimation and deicing for 48 to 60 hours to obtain the zirconium-titanium porous particles.

3. A nano-graphene lubricant according to claim 2, characterized in that, The precursor gel is prepared by dissolving 5 to 9 parts of zirconium oxychloride and 4 to 6 parts of tetrabutyl titanate in 90 parts of anhydrous ethanol, adjusting the pH to 3 to 4 with 0.5 mol / L nitric acid, and stirring at 100 rpm for 6 to 10 hours to obtain the precursor gel.

4. A nano-graphene lubricant according to claim 2, characterized in that, The parameters of the vacuum freeze dryer are temperature -50°C and pressure 10Pa.

5. A nano-graphene lubricant according to claim 1, characterized in that: The heating rate in step (1) is 10°C / min.

6. The nano-graphene lubricant according to claim 1, characterized in that: The ionic liquid in step (1) is selected from any one of 1-butyl-3-methylimidazolium tetrafluoroborate and 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide.

7. The nano-graphene lubricant according to claim 1, characterized in that: The mass ratio of the modified zirconium-titanium composite particles to α-olefin in step (2) is (0.01-0.07):

1.

8. The nano-graphene lubricant according to claim 1, characterized in that: The particle size of the nanographene in step (3) is 5 to 25 nm.

9. The nano-graphene lubricant according to claim 1, characterized in that: The mass ratio of the nanographene to the base oil in step (3) is (0.001-0.01):

1.

10. A nanographene lubricant, characterized in that: Prepared according to any one of claims 1 to 9.

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