Preparation method of ruthenium bipyridine anchoring photocatalyst and application thereof in photocatalytic preparation of aviation oil

Abstract

This invention discloses a method for preparing a ruthenium bipyridine-anchored photocatalyst, and also relates to its application in the conversion of biomass-based oil into alkane fuels, belonging to the field of photocatalysis technology. The preparation method involves using a sulfonated semiconductor material in combination with divalent tripyridine ruthenium, wherein the divalent tripyridine ruthenium couples with sulfonic acid groups on the surface of the sulfonated semiconductor through secondary ion exchange to form a ruthenium bipyridine-sulfonic acid ligand structure. The photocatalyst prepared by this invention has the following characteristics: it can significantly improve the separation efficiency of photogenerated carriers, enhance the absorption performance of the catalyst in the visible light band, and achieve comprehensive enhancement of catalytic performance through optimized oxidation and reduction capabilities. The photocatalyst prepared by this invention exhibits excellent light energy utilization efficiency and product yield in the photocatalytic conversion of biomass-based oil into alkane fuels, overcoming the limitations of single photocatalytic materials, and possesses significant technological advancements and broad practical application prospects.

Description

Technical Field

[0001] This invention belongs to the field of photocatalysis technology, specifically relating to a method for preparing a ruthenium bipyridine-anchored photocatalyst, and also relating to the application of the above-mentioned ruthenium bipyridine-anchored photocatalyst in the photocatalytic preparation of aviation fuel. Background Technology

[0002] Energy is the fundamental support for modern industrial systems and social operations, and its acquisition and utilization efficiency directly affect economic development models and ecological environment security. For a long time, fossil fuels have dominated the global energy structure, but their large-scale development and use have been accompanied by the emission of greenhouse gases and various pollutants, posing significant pressure on the ecological environment and sustainable development. Therefore, building a clean energy system with renewable energy at its core has become a general consensus in the international community. Among various forms of renewable energy, wind and solar energy technologies have made significant progress in recent years, with continuously decreasing power generation costs and gradually becoming economically competitive with traditional fossil fuels. However, due to resource volatility and energy density limitations, relying solely on electricity cannot fully meet the needs of transportation and high-energy-density applications. Against this backdrop, the conversion of renewable carbon resources to liquid fuels is considered one of the important ways to achieve deep decarbonization of the energy structure.

[0003] Biomass energy is an important form of energy that can provide renewable carbon sources on a large scale, characterized by its wide distribution, stable source, and closed carbon cycle. With the development of conversion technologies, biomass can now be used to produce liquid fuels such as diesel, aviation kerosene, and gasoline through thermochemical conversion, bioconversion, and catalytic conversion. Among these, alkane fuels have significant application value in the aviation and transportation sectors due to their high energy density, good storage and transportation performance, and mature application systems. The main methods for preparing alkane fuels include thermochemical conversion, bioconversion, Fischer-Tropsch synthesis, and hydrogenation catalysis. Hydrogenation catalysis is favored for its rapid reaction and high yield, but its dependence on high temperature and pressure conditions (usually requiring temperatures above 350°C and hydrogen pressures of 2-6 MPa) significantly increases production costs and energy consumption, while also reducing safety. Furthermore, in life cycle assessments (LCAs), hydrogenation catalysis uses a large amount of hydrogen energy and electricity generated from thermal power generation, making the preparation of this "green" energy source a potential environmental burden. Therefore, developing an efficient and low-cost method for preparing alkane fuels under mild conditions has become a key research focus.

[0004] Photocatalysis technology has been widely applied in recent years in fields such as hydrogen production, CO2 reduction, and removal of volatile organic compounds, with some technologies already industrialized. Photocatalysts, represented by TiO2, are widely used for the photocatalytic degradation of pollutants due to their low cost, high efficiency, and stability. However, the photocatalytic ability of TiO2 is mainly concentrated in the ultraviolet light range, and its narrow spectral response limits the efficient utilization of sunlight. Furthermore, although the decarboxylation reaction of fatty acids under TiO2 catalysis can produce alkane products, its efficiency and selectivity still need further optimization. Chinese invention patent 202110276003.8 discloses a photothermal coupled catalyst for the production of aviation kerosene from biomass. This catalyst employs a coupling structure of semiconductor and acidic molecular sieve, supported with active noble metals and transition metal co-catalysts (loading 1-10%). By increasing the specific surface area and the separation efficiency of photogenerated carriers, it expands the spectral response range of TiO2 and improves the utilization efficiency of sunlight. However, the conversion efficiency of this catalyst in the reaction system is still relatively low, and the reaction time is relatively long.

[0005] In summary, existing catalysts for the photocatalytic production of alkane fuels from biomass-based oils still have significant limitations, and there is an urgent need to develop more efficient and economical catalyst systems. Summary of the Invention

[0006] One of the objectives of this invention is to provide a method for preparing a ruthenium bipyridine-anchored photocatalyst that can firmly fix a molecular photosensitizer on a semiconductor surface and significantly reduce the loading of noble metals.

[0007] The second objective of this invention is to provide a ruthenium bipyridine-anchored photocatalyst that has a strong photosensitizer binding, is not easily detached, has good synergistic effect with noble metals, and has high photocatalytic efficiency.

[0008] The third objective of this invention is to provide an application of ruthenium bipyridine-anchored photocatalyst in the photocatalytic preparation of aviation fuel from biomass-based oil.

[0009] One of the technical solutions adopted by this invention to achieve its objective is to provide a method for preparing a ruthenium bipyridine-anchored photocatalyst, comprising the following steps: S1. Semiconductor material with oxygen defect sites on its surface is reacted with silane coupling agent containing mercapto groups in an organic solvent. After separation and washing, it is then oxidized with hydrogen peroxide solution to obtain sulfonated semiconductor material with sulfonic acid groups grafted on its surface. S2. The material obtained in step S1 is mixed with a saturated sodium chloride solution and reacted to convert the surface sulfonic acid groups into sodium sulfonate groups, thereby obtaining a sodium sulfonate semiconductor material. S3. The sodium sulfonate semiconductor material is mixed with an aqueous solution of a soluble salt of divalent tripyridine ruthenium to carry out an ion exchange reaction, so that the divalent tripyridine ruthenium is anchored to the surface of the semiconductor material by ionic bonds through sulfonate groups, thereby obtaining an intermediate support with ruthenium bipyridine complex anchored on the surface. S4. The noble metal active component is loaded onto the intermediate support obtained in step S3 to obtain a ruthenium bipyridine anchored photocatalyst; the loading amount of the noble metal active component in the ruthenium bipyridine anchored photocatalyst is 0.05 wt% to 0.3 wt% based on the mass of the noble metal element.

[0010] The preparation method provided by this invention involves a series of controllable chemical reactions to firmly anchor the [Ru(bpy)3]-[SO3]2 molecular photosensitizer on the surface of a semiconductor material, thereby constructing a highly efficient photocatalytic material. The specific preparation principle is as follows: First, a silane coupling agent containing a mercapto group (-SH) is reacted with the semiconductor material to form stable chemical bonds on its surface. Then, the terminal -SH group is oxidized with hydrogen peroxide solution to form a sulfonic acid group (-SO3H), which serves as a key site for subsequent fixation of the target molecule. However, the sulfonic acid group (-SO3H) itself is highly acidic, and if it directly reacts with the positively charged [Ru(bpy)3]... 2+ Ion mixing results in inefficient and difficult-to-control binding of the two ions. To address this issue, this invention adds a crucial step of treatment using a saturated sodium chloride solution. The sodium ions (Na+) in saturated sodium chloride... + This will combine with the sulfonic acid group, converting it into the more stable and reactive sodium sulfonate (-SO3Na) form. Finally, the material with the sodium sulfonate group on its surface is then combined with [Ru(bpy)3]... 2+ The solutions are mixed. At this point, [Ru(bpy)3] 2+ It efficiently replaces sodium ions on sodium sulfonate, anchoring them firmly to the material surface through ionic bonds (these ionic bonds are stable in solutions such as acetonitrile, water, and ethanol), thus precisely and stably mounting the photosensitive molecules onto the carrier. Based on this, a very small amount of noble metals (such as platinum or palladium) is loaded as a co-catalyst, resulting in the final photocatalytic material.

[0011] Further, in step S1, the semiconductor material is selected from at least one of TiO2, ZnO, WO3, CeO2, ZrO2, V2O5, CeZrO4, and La2O3. The metal oxide of the above semiconductor material can form MO-Si bonds with a silane coupling agent containing a mercapto group (-SH).

[0012] Further, in step S1, the thiol-containing silane coupling agent includes 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane.

[0013] Further, in step S1, the mass ratio of the semiconductor material to the mercapto-containing silane coupling agent is 1:(0.1-10). By controlling this ratio, the grafting density of the silane coupling agent on the semiconductor material surface can be effectively controlled. This avoids insufficient sulfonic acid anchor sites due to insufficient dosage, while also preventing excessive self-polymerization or waste of silane molecules due to excessive dosage. Preferably, the mass ratio of the semiconductor material to the mercapto-containing silane coupling agent is 1:(0.5-2), which can form a uniform and moderate sulfonic acid coating layer on the material surface, providing optimal conditions for subsequent ion exchange anchoring. More preferably, it is 1:1, which ensures high-density and high-stability anchoring of photosensitive molecules and is the optimal balance point for preparing high-performance catalysts.

[0014] Further, in step S1, the organic solvent is selected from toluene, ethyl acetate, and dichloromethane, preferably toluene. The reaction is carried out under stirring at 100-200°C for 6-12 h and then refluxed. Subsequently, the solid product is separated by vacuum filtration and washed repeatedly with ethanol.

[0015] Further, in step S1, the mass concentration of the hydrogen peroxide solution is 5%-30%. Hydrogen peroxide within this concentration range can effectively oxidize mercapto groups (-SH) to sulfonic acid groups (-SO3H). Preferably, the mass concentration of the hydrogen peroxide solution is 25%-30%. At this concentration, the oxidation reaction efficiency is high, and the reaction time is moderate. Preferably, the oxidation reaction is carried out under stirring conditions at room temperature for 10-48 hours. After separating the solid product, it is repeatedly washed with ethanol and water, and then vacuum dried at 30-60 °C for 10-18 hours to obtain a sulfonated semiconductor material SO3H-TiO2 with sulfonic acid groups grafted onto its surface.

[0016] Further, in step S2, the mass ratio of the sulfonated semiconductor material to the saturated sodium chloride solution is 1:(50-200). This excess solution environment ensures that all sulfonic acid groups are completely immersed in a high-concentration sodium ion atmosphere, thereby achieving thorough and uniform ion exchange. Preferably, the mass ratio of the sulfonated semiconductor material to the saturated sodium chloride solution is 1:(80-150), and after mixing, the mixture is stirred at 50-70°C for 12-30 hours to obtain the sodium sulfonated semiconductor material SO3Na@TiO2.

[0017] Further, in step S3, the soluble salt of the divalent tripyridine ruthenium includes one or more combinations of tris(2,2'-bipyridine)ruthenium(II) dichloride, tris(2,2'-bipyridine)ruthenium(II) hexafluorophosphate, tris(2,2'-bipyridine)ruthenium(II) tetrafluoroborate, tris(2,2'-bipyridine)ruthenium(II) nitrate, and tris(2,2'-bipyridine)ruthenium(II) trifluoromethanesulfonic acid.

[0018] Furthermore, the mass ratio of the soluble salt of divalent tripyridine ruthenium to the sodium sulfonate semiconductor material is 1:(50-100). By controlling this ratio, the number of photosensitizer molecules ultimately anchored on the material surface can be precisely controlled, ensuring optimal matching with the available anchoring sites (sodium sulfonate groups) on the carrier surface. After mixing the soluble salt of divalent tripyridine ruthenium and the sodium sulfonate semiconductor material, the mixture is stirred at 60-90℃ for 12-30 hours, separated, and dried to obtain an intermediate carrier [Ru(bpy)3]-[SO3]2@TiO2 with the ruthenium bipyridine complex anchored on its surface.

[0019] Further, in step S4, the noble metal active component is selected from at least one of Au, Rh, Pd, and Pt. The noble metal active component is preferably Pd or Pt, and more preferably Pt. The noble metal acts as a co-catalyst, its function being to receive photogenerated electrons from the anchored divalent ruthenium tripyridine photosensitizer, thereby catalyzing the hydrogenation reaction.

[0020] Further, in step S4, the noble metal active component is loaded using an impregnation method, photochemical deposition method, or hydrothermal method. Preferably, the noble metal active component is loaded using photochemical deposition method. Under illumination of a specific wavelength, the anchored divalent ruthenium tripyridine photosensitizer is excited and generates electrons. These electrons are transferred to the semiconductor support and enriched at specific sites. At this time, the noble metal precursor ions in the solution are reduced in situ to metal nanoparticles at these electron-rich sites. This process can achieve precise spatial matching between the noble metal co-catalyst and the photogenerated electron transport path, which is key to obtaining high-performance catalysts.

[0021] Furthermore, the loaded product is first aged at 30-200 °C for 0.5-72 h, filtered, and then vacuum dried at 105±5 °C for 3-24 h. After grinding, particulate photocatalytic material with a particle size of 0.02-1 mm is obtained.

[0022] The second objective of this invention is to provide a ruthenium bipyridine-anchored photocatalyst, which is prepared by the preparation method described in one objective of this invention.

[0023] The photocatalyst prepared in this invention is based on divalent tripyridine ruthenium ([Ru(bpy)3)). 2+ The anchoring strategy of [Ru(bpy)3] not only overcomes the problem of semiconductor material surfaces lacking [Ru(bpy)3] 2+ Anchoring points prevent stable load control [Ru(bpy)3] 2+ And there's no need to modify [Ru(bpy)3] 2+ Make complex modifications. [Ru(bpy)3] 2+A synergistic effect was observed between the material and precious metals, significantly reducing the loading of each other (compared to previous studies, only 0.05 wt% to 0.3 wt% of precious metals were needed to achieve the same effect), thus significantly reducing production costs. Furthermore, this synergistic effect addressed the limitations of traditional photocatalytic materials in utilizing light energy, enhancing the material's absorption in the visible light band. Further, [Ru(bpy)3] 2+ The precious metals and the catalyst respectively play the roles of oxidation and reduction in the system, which is equivalent to simultaneously enhancing the oxidation and reduction capabilities of the catalyst. This greatly increases the catalyst's adsorption capacity for different substances, improves the reaction rate, shortens the reaction time, makes up for the material defects of single photocatalysis technology, and maximizes the utilization rate of light energy and the product yield.

[0024] The third objective of this invention is to provide an application of the ruthenium bipyridine anchored photocatalyst described in one of the objectives of this invention in the photocatalytic conversion of biomass-based oil into aviation fuel.

[0025] The principle of the ruthenium bipyridine anchored photocatalyst provided by this invention for the photocatalytic conversion of biomass-based oil to alkane fuel is as follows: Under certain illumination, the semiconductor material generates a large number of photogenerated electron-hole pairs. A Schottky barrier is formed at the interface between the noble metal component and the semiconductor material, while a strong oxidation site is generated on [Ru(bpy)3]-[SO3]2. On the one hand, the separated photogenerated electrons are migrated away, thereby effectively promoting the separation of photogenerated charge carriers and improving photocatalytic efficiency. On the other hand, due to the synergistic effect between the noble metal and [Ru(bpy)3]-[SO3]2, the adsorption capacity of the reaction substrate and the hydrogen spillover effect are enhanced. Under the synergistic effect of photogenerated electrons, photogenerated holes and strong oxidation sites, hydrogen undergoes multiphase hydrogen dissolution, and hydrogen radicals are generated by the interaction of hydrogen on the carboxyl groups in the raw material with photogenerated electrons. At the same time, fatty acids or fatty acid triglycerides in the raw material are decarboxylated under the action of photogenerated holes and strong oxidation sites to generate alkane radicals. The hydrogen radicals and alkane radicals are then quenched on the catalyst surface to generate alkanes.

[0026] Furthermore, the biomass-based oil is a biomass raw material containing carboxyl groups or capable of generating carboxyl groups, including one or more of the following: palmitic acid, lauric acid, oleic acid, linoleic acid, jatropha oil, palm oil, rubber seed oil, cottonseed oil, soybean oil, rapeseed oil, corn oil, linseed oil, castor oil, lard, tallow, fish oil, microbial oil, and waste cooking oil.

[0027] Furthermore, the photocatalytic reaction is carried out in an acetonitrile solvent and a hydrogen atmosphere, with a light intensity of 50-500 mW / cm². 2The mass ratio of ruthenium bipyridine-anchored photocatalyst to biomass feedstock is 1:(1-10), the reaction temperature is 20-80℃, and the reaction time is 1-6 hours.

[0028] The photocatalyst provided by this invention uses acetonitrile as the reaction solvent. The strong polarity of acetonitrile helps stabilize the ionic bond anchoring structure of the photosensitizer on the catalyst surface and provides a suitable reaction medium, enabling the catalyst to exhibit excellent photocatalytic hydrogenation and deoxygenation activity for biomass molecules such as palmitic acid under mild conditions. Preferably, the mass-to-volume ratio of biomass feedstock to acetonitrile solvent is (1-10):1 mg / mL.

[0029] The photocatalytic product of this invention is an alkane fuel, preferably C8-C. 18 Alkanes within the range, more preferably C40, are preferred. 10 -C 16 The alkane fuel is within the specified range. It can be used as aviation kerosene, diesel fuel, or a blending component thereof, and features low oxygen content, good stability, and high energy density. Preferably, the selectivity of alkane in the photocatalytic product is not less than 80%, more preferably, the selectivity of alkane is not less than 90%.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention provides a method for preparing a ruthenium bipyridine-anchored photocatalyst, which adopts a method based on [Ru(bpy)3]. 2+ A photocatalyst was prepared using an ionic bond anchoring strategy. This strategy achieves stable, quantitative, and controllable immobilization of the [Ru(bpy)3]-[SO3]2 photosensitizer molecule by constructing sulfonic acid group anchor sites on the semiconductor surface. This overcomes the problem that traditional semiconductor materials lack specific binding sites, making it impossible to stably load such molecular photosensitizers. Furthermore, it eliminates the need for [Ru(bpy)3]... 2+ It undergoes complex chemical modification.

[0031] (2) The present invention provides a method for preparing a ruthenium bipyridine-anchored photocatalyst. The anchored [Ru(bpy)3]-[SO3]2 and the subsequently loaded trace amounts of noble metal co-catalyst produce a significant synergistic effect: On the one hand, [Ru(bpy)3]-[SO3]2, as a highly efficient light scavenger and electron donor, greatly enhances the absorption and utilization of visible light by the system and drives photogenerated electrons to migrate to noble metal sites, effectively promoting charge separation; on the other hand, this synergistic effect allows for a significant reduction in the amount of noble metal co-catalyst used (0.05% to 0.3%). Compared with traditional photothermal catalytic systems (noble metal loading is usually ≥0.5%), this method significantly reduces the amount of noble metal used while achieving near-complete conversion of substrates such as palmitic acid, greatly reducing the production cost of the catalyst. At the same time, [Ru(bpy)3]-[SO3]2 and the noble metal respectively enhance the oxidation and reduction capabilities of the system, synergistically promoting the adsorption and activation of the reaction substrate, thereby significantly increasing the reaction rate.

[0032] (3) The ruthenium bipyridine-anchored photocatalyst provided by this invention, through precise molecular-level assembly, overcomes the shortcomings of single semiconductor photocatalytic materials in terms of light absorption and charge separation, maximizing light energy utilization and reaction space-time yield, and the photocatalytic reaction system can operate efficiently under mild conditions. Specifically, this system can selectively convert fatty acids or fatty acid triglycerides into alkanes of corresponding chain lengths in 1-6 h under acetonitrile solvent, atmospheric pressure hydrogen atmosphere, and room temperature light irradiation. Compared to traditional thermocatalytic hydrodeoxygenation processes (which typically require high pressure and high temperature conditions of 3-5 MPa and 350-450°C), this method avoids the use of high-pressure equipment and significantly reduces hydrogen and energy consumption. Compared to existing photocatalytic or photothermal catalytic methods for preparing alkanes (which typically require initial hydrogen pressure above 0.1 MPa, heating at 50-200°C, and reaction times of more than 10 hours), this invention further shortens the reaction time and improves reaction efficiency while maintaining mild conditions, achieving highly efficient conversion with lower hydrogen and energy consumption, demonstrating outstanding technical and economic advantages and environmental friendliness. Attached Figure Description

[0033] Figure 1 These are transmission electron microscope (TEM) images of the photocatalyst prepared in Example 1 of this invention; wherein, (A) is a low-magnification morphology image with a scale bar of 50 nm; (B) has a scale bar of 10 nm; (C) and (D) are high-magnification images used to observe the dispersion state of noble metal nanoparticles, with a scale bar of 5 nm for each image. Figure 2 This is the ultraviolet-visible absorption spectrum of the photocatalyst prepared in Example 1 of this invention; Figure 3 This is the photoluminescence spectrum of the photocatalyst prepared in Example 1 of this invention; Figure 4 This is a photocurrent curve of the photocatalyst prepared in Example 1 of the present invention. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention provides a method for preparing a ruthenium bipyridine-anchored photocatalyst, comprising the following steps: Step 1: A semiconductor material with oxygen defect sites on its surface is reacted with a thiol-containing silane coupling agent in an organic solvent. After separation and washing, it is then oxidized with hydrogen peroxide solution to obtain a sulfonated semiconductor material with sulfonic acid groups grafted onto its surface. The semiconductor material is selected from at least one of TiO2, ZnO, WO3, CeO2, ZrO2, V2O5, CeZrO4, and La2O3. The thiol-containing silane coupling agent includes 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane. The mass ratio of the semiconductor material to the thiol-containing silane coupling agent is 1:(0.1-10). The organic solvent is toluene.

[0036] Step 2: Mix the material obtained in Step 1 with a saturated sodium chloride solution to react and convert the surface sulfonic acid groups into sodium sulfonate groups to obtain sodium sulfonate semiconductor material; in the mixing reaction, the mass ratio of the sulfonated semiconductor material to the saturated sodium chloride solution is 1:(50-200).

[0037] Step 3: The sodium sulfonate semiconductor material is mixed with an aqueous solution of a soluble salt of ruthenium divalent tripyridine to undergo an ion exchange reaction, so that ruthenium divalent tripyridine is anchored to the surface of the semiconductor material by ionic bonds through sulfonate groups, resulting in an intermediate support with a ruthenium bipyridine complex anchored on the surface; the soluble salt of ruthenium divalent tripyridine includes one or more combinations of tris(2,2'-bipyridine)ruthenium(II) dichloride, tris(2,2'-bipyridine)ruthenium(II) hexafluorophosphate, tris(2,2'-bipyridine)ruthenium(II) tetrafluoroborate, tris(2,2'-bipyridine)ruthenium(II) nitrate, and tris(2,2'-bipyridine)ruthenium(II) trifluoromethanesulfonic acid; the mass ratio of the soluble salt of ruthenium divalent tripyridine to the sodium sulfonate semiconductor material is 1:(50-100).

[0038] Step 4: Load the noble metal active component onto the intermediate support obtained in Step 3 to obtain a ruthenium bipyridine-anchored photocatalyst; the noble metal active component is selected from at least one of Au, Rh, Pd, and Pt; the noble metal active component is loaded using an impregnation method, a photochemical deposition method, or a hydrothermal method. The loading amount of the noble metal active component in the ruthenium bipyridine-anchored photocatalyst is 0.05 wt% to 0.3 wt% based on the mass of the noble metal element.

[0039] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0040] The main conditions and variables of each embodiment and comparative example of the present invention are shown in Table 1 below.

[0041] Table 1

[0042] Example 1 This embodiment provides a method for preparing a ruthenium bipyridine-anchored photocatalyst, comprising the following steps: Step 1: 1 g TiO2 was ultrasonically dispersed in a system of 99 mL toluene and 1 mL 3-mercaptopropyltrimethoxysilane (MPTMS), and refluxed at 120 °C for 8 h. The solid product was then separated by vacuum filtration and washed repeatedly with ethanol. 100 mL of 30% hydrogen peroxide solution was added, and the mixture was stirred at room temperature for 24 h. The solid product was then separated and washed repeatedly with ethanol and water. The solid product was vacuum dried at 40 °C for 12 h to obtain SO3H@TiO2. Step 2: Take 1g of SO3H@TiO2 for the first ion exchange, mix the dried solid with 100 mL of saturated sodium chloride solution, and stir at 60 °C for 24 h to obtain SO3Na@TiO2; Step 3: Disperse [Ru(bpy)3]Cl2 and SO3Na@TiO2 in 100 mL of deionized water at a mass ratio of 1:100 for a second ion exchange. After stirring at 80 °C for 24 h, separate, wash and dry to obtain [Ru(bpy)3]-[SO3]2@TiO2. Step 4: Take 1 g of [Ru(bpy)3]-[SO3]2@TiO2 and disperse it in a 10% methanol aqueous solution. Add 0.0021 g of potassium chloroplatinate powder and ultrasonically disperse for 5 min. Then add the slurry to a quartz reactor, seal the system and purge with nitrogen for 10 min to remove the air. At the same time, stir under 320 nm irradiation for 1 h to obtain Pt / [Ru(bpy)3]-[SO3]2@TiO2 catalyst.

[0043] Figure 1This is a transmission electron microscope (TEM) image of the catalyst prepared in Example 1. Figure 1 It can be seen that the prepared catalyst uses nano-sized titanium dioxide particles as a support, and the overall structure is a loose aggregate morphology composed of multiple primary particles. Clear and continuous lattice fringes can be observed in the high-resolution transmission electron microscopy (HRTEM) image, indicating that the titanium dioxide support has a high degree of crystallinity. Meanwhile, several nanoscale dark spots with significantly increased contrast are visible on the support surface and at the particle interfaces, exhibiting a highly dispersed clustered loading. No obvious aggregation or sintering of large-sized metal particles was observed, indicating that the supported component forms a tight interfacial contact with the titanium dioxide support in a nano-cluster / highly dispersed morphology.

[0044] Example 2 This embodiment provides a method for preparing a ruthenium bipyridine-anchored photocatalyst, comprising the following steps: Step 1: 1 g TiO2 was ultrasonically dispersed in a system of 99 mL toluene and 1 mL 3-mercaptopropyltrimethoxysilane (MPTMS), and refluxed at 120 °C for 8 h. The solid product was then separated by vacuum filtration and washed repeatedly with ethanol. 100 mL of 30% hydrogen peroxide solution was added, and the mixture was stirred at room temperature for 24 h. The solid product was then separated and washed repeatedly with ethanol and water. The solid product was vacuum dried at 40 °C for 12 h to obtain SO3H@TiO2. Step 2: Take 1g of SO3H@TiO2 for the first ion exchange. Mix the dried solid with 100 mL of saturated sodium chloride solution and stir at 60 ℃ for 24 h to obtain SO3Na@TiO2. Step 3: Disperse [Ru(bpy)3]Cl2 and SO3Na@TiO2 in 100 mL of deionized water at a ratio of 1:100 for a second ion exchange. After stirring at 80 °C for 24 h, separate, wash and dry to obtain [Ru(bpy)3]-[SO3]2@TiO2. Step 4: Take 1 g of [Ru(bpy)3]-[SO3]2@TiO2 and disperse it in a 10% methanol aqueous solution. Add 0.0028 g of tetraamminepalladium nitrate powder and ultrasonically disperse for 5 min. Then add the slurry to a quartz reactor, seal the system and purge with nitrogen for 10 min to remove the air. At the same time, stir under 320 nm irradiation for 1 h to obtain Pd / [Ru(bpy)3]-[SO3]2@TiO2 catalyst.

[0045] Example 3 This embodiment provides a method for preparing a ruthenium bipyridine-anchored photocatalyst, comprising the following steps: Step 1: 1 g ZnO was ultrasonically dispersed in a system of 99 mL toluene and 1 mL 3-mercaptopropyltrimethoxysilane (MPTMS), and refluxed at 120 °C for 8 h. The solid product was then separated by vacuum filtration and washed repeatedly with ethanol. 100 mL of 30% hydrogen peroxide solution was added, and the mixture was stirred at room temperature for 24 h. The solid product was then separated and washed repeatedly with ethanol and water. The solid product was vacuum dried at 40 °C for 12 h to obtain SO3H@TiO2. Step 2: Take 1g of SO3H@TiO2 for the first ion exchange. Mix the dried solid with 100 mL of saturated sodium chloride solution and stir at 60 ℃ for 24 h to obtain SO3Na@TiO2. Step 3: Disperse [Ru(bpy)3]Cl2 and SO3Na@TiO2 in 100 mL of deionized water at a ratio of 1:100 for a second ion exchange. After stirring at 80 °C for 24 h, separate, wash and dry to obtain [Ru(bpy)3]-SO3@TiO2. Step 4: Take 1 g of [Ru(bpy)3]-SO3@TiO2 and disperse it in a 10% methanol aqueous solution. Add 0.0021 g of potassium chloroplatinate powder and ultrasonically disperse for 5 min. Then add the slurry to a quartz reactor, seal the system and purge with nitrogen for 10 min to remove the air. At the same time, stir under 320 nm irradiation for 1 h to obtain Pt / [Ru(bpy)3]-SO3@ZnO catalyst.

[0046] Example 4 This embodiment provides a method for preparing a ruthenium bipyridine-anchored photocatalyst. The only difference from Example 1 is that the mass ratio of [Ru(bpy)3]Cl2 to SO3Na@TiO2 in step 3 is adjusted to 1:80, and the weight of potassium chloroplatinate powder added in step 4 is adjusted to 0.006 g (Pt loading 0.3%). The other conditions and operations remain unchanged, and the Pt / [Ru(bpy)3]-[SO3]2@TiO2 catalyst is obtained.

[0047] Example 5 This embodiment provides a method for preparing a ruthenium bipyridine-anchored photocatalyst. The only difference from Example 1 is that the mass ratio of [Ru(bpy)3]Cl2 to SO3Na@TiO2 in step 3 is adjusted to 1:50, and the weight of potassium chloroplatinate powder added in step 4 is adjusted to 0.001 g (Pt loading 0.05%). The other conditions and operations remain unchanged, and the Pt / [Ru(bpy)3]-[SO3]2@TiO2 catalyst is obtained.

[0048] Comparative Example 1 This comparative example provides a method for preparing a ruthenium bipyridine-anchored photocatalyst without noble metal loading, comprising the following steps: Step 1: 1 g TiO2 was ultrasonically dispersed in a system of 99 mL toluene and 1 mL 3-mercaptopropyltrimethoxysilane (MPTMS), and refluxed at 120 °C for 8 h. The solid product was then separated by vacuum filtration and washed repeatedly with ethanol. 100 mL of 30% hydrogen peroxide solution was added, and the mixture was stirred at room temperature for 24 h. The solid product was then separated and washed repeatedly with ethanol and water. The solid product was vacuum dried at 40 °C for 12 h to obtain SO3H@TiO2. Step 2: Take 1g of SO3H@TiO2 for the first ion exchange, mix the dried solid with 100 mL of saturated sodium chloride solution, and stir at 60 °C for 24 h to obtain SO3Na@TiO2; Step 3: Subsequently, [Ru(bpy)3]Cl2 and SO3Na@TiO2 were dispersed in 100 mL of deionized water at a ratio of 1:100 for a second ion exchange. After stirring at 80 °C for 24 h, the catalyst [Ru(bpy)3]-[SO3]2@TiO2 was obtained by separation, washing and drying.

[0049] Comparative Example 2 This comparative example provides a TiO2 photocatalyst that directly uses TiO2 semiconductor material without sulfonation, ruthenium bipyridine anchoring, or noble metal loading steps.

[0050] Comparative Example 3 This comparative example provides a Pt / TiO2 photocatalyst, which uses a TiO2 semiconductor material support to directly load the noble metal Pt. The preparation method includes the following steps: 1 g of TiO2 was dispersed in a 10% methanol aqueous solution, and 0.042 g of potassium chloroplatinate powder was added. The mixture was ultrasonically dispersed for 5 min, and then the slurry was added to a quartz reactor. The system was sealed and nitrogen gas was introduced for 10 min to purge the air. At the same time, the mixture was stirred for 1 h under irradiation in the 320 nm band to obtain a Pt / TiO2 catalyst with a noble metal Pt loading of 2% (equivalent to 20 times the noble metal loading in Example 1).

[0051] Application performance testing The catalysts prepared in Examples 1-5 and Comparative Examples 1-3 were used to photocatalyze the preparation of alkane fuels from biomass-based oils. Their photocatalytic performance was tested using the following methods: Add 50 mg of palmitic acid, 50 mg of photocatalyst material, and 50 mL of solvent (acetonitrile) to the photocatalytic reactor. Continuously purge the reactor with hydrogen gas for 10 minutes to remove air. Turn on the xenon lamp simulating sunlight and magnetic stirring. The reactor is then irradiated at an intensity of 200 mW / cm². 2 Photocatalytic experiments were conducted under irradiation for 1 hour at room temperature and pressure. After cooling to room temperature, the liquid products and catalysts were separated, and qualitative and quantitative analyses were performed using gas chromatography-mass spectrometry and computational methods. The specific test conditions and the conversion rates of palmitic acid and alkane selectivity for each photocatalytic material are shown in Table 2 below.

[0052] Table 2

[0053] It can be seen from Table 2 above that Compared with Comparative Examples 1-3, the photocatalysts prepared by the ruthenium bipyridine anchoring strategy in Examples 1-5 exhibited better photocatalytic performance under conditions of lower noble metal loading, and the conversion rate of palmitic acid was significantly improved compared with Comparative Examples 1-3, especially Comparative Examples 2 and 3.

[0054] Figure 2-4 The UV absorption spectrum, photoluminescence spectrum, and photocurrent curves of the catalysts prepared in Comparative Examples 1-3 and Example 1 are shown respectively. According to the characterization results, the catalysts prepared in Comparative Examples 1-3 did not exceed the Pt / [Ru(bpy)3]-[SO3]2@TiO2 catalyst prepared in Example 1 in terms of absorbance, fluorescence lifetime, and photocurrent intensity. Specifically, from... Figure 2 The UV-Vis absorption spectrum shows that [Ru(bpy)3] is bound and anchored. 2+ Subsequently, the catalyst exhibited enhanced absorption peaks for ultraviolet-visible light, significantly higher than that of unloaded TiO2. Simultaneously, a signal peak indicating electron transfer by metal ligands appeared in the 450 nm band, corresponding to the effective separation of holes and electrons. Figure 3 It can be seen that [Ru(bpy)3] is anchored simultaneously. 2+ After loading Pt, the photoluminescence intensity of the catalyst decreased significantly, corresponding to a decrease in the radiative recombination degree of the catalyst, resulting in more photogenerated carriers that could participate in the reaction. Figure 4 This further verifies the improved optical performance of the catalyst Pt / [Ru(bpy)3]-[SO3]2@TiO2. Photocurrent testing shows that the photogenerated current of Pt / [Ru(bpy)3]-[SO3]2@TiO2 reached 0.058 mA cm⁻¹. -2 The concentration was much higher than that of unloaded TiO2 (0.01 mA cm⁻¹). -2 A higher photocurrent means the emergence of more photogenerated electrons.

[0055] The above spectroscopic and photoelectrochemical characterization results corroborate each other, jointly revealing the sulfonation anchoring of [Ru(bpy)3]. 2+ The synergistic interface constructed with trace amounts of Pt plays a key role in enhancing light-harvesting ability, inhibiting charge recombination, and promoting charge separation, thereby enabling the photocatalyst of Example 1 to exhibit higher photocatalytic activity in applications, with a palmitic acid conversion rate close to 100% within a 1-hour reaction time.

[0056] Furthermore, through comprehensive analysis of the catalytic performance data of the above embodiments and comparative examples, the following conclusions can be drawn: sulfonation of the semiconductor support and subsequent [Ru(bpy)3] 2+ The stable anchoring of photosensitizers is an indispensable basic structure for constructing highly active catalysts, greatly expanding the absorption and utilization of visible light by the material. Based on this, loading trace amounts of noble metal co-catalysts (such as Pt) can efficiently separate and transfer photogenerated charges, further enhancing catalytic activity. Specifically, in this system, Pt performs slightly better than Pd, and the performance of the TiO2 support is superior to ZnO, indicating that the intrinsic properties of the metal and the support are crucial. Ultimately, the precise interface and synergistic effect formed between the sulfonate groups, the molecular photosensitizer, and the nano-noble metal are the fundamental reasons for the superior performance, far exceeding the effects of traditional methods using only heavily loaded noble metals.

[0057] Furthermore, 500 mg of palmitic acid and 100 mg of the photocatalyst prepared in Example 1 (biomass-based oil to catalyst mass ratio of 5:1) were reacted under the same test conditions, with the reaction time extended to 6 h. Quantitative analysis of the products showed that the conversion rate of palmitic acid reached 100%, and the alkane selectivity was 95.17%. This test demonstrates that the catalyst prepared in this invention maintains high activity even under harsh conditions of increased substrate concentration, fully proving its structural robustness and practical application potential.

[0058] It should be noted that, in order to demonstrate the photocatalytic performance and application potential of this invention in a focused and clear manner, the embodiments of this invention only used palmitic acid, a representative compound, as a model substrate for systematic testing. This does not mean that the application scope of this invention is limited to this. Based on the catalyst design principles disclosed in this invention, it can be reasonably expected that the photocatalyst provided by this invention will also have excellent conversion effects and application prospects for other structurally similar fatty acids, fatty acid glycerides, and even a wider range of carboxyl-containing biomass raw materials, under suitable catalytic conditions.

[0059] In summary, compared with existing solutions, the photocatalyst and its preparation method provided by this invention anchor ruthenium bipyridine on the surface of titanium dioxide, solving the problem of the lack of ruthenium bipyridine binding sites in conventional titanium dioxide materials. Furthermore, because this invention establishes both an oxidation and a reduction section for the catalyst, the synergistic effect of these two sections can significantly improve the photocatalytic reaction rate. While increasing the catalytic rate, it also significantly reduces the loading of precious metals, decreasing it by nearly 20 times compared to previous studies. The photocatalyst provided by this invention is widely applicable to various biomass-based oils, offering a new approach to the treatment of catering waste and agricultural and forestry waste, facilitating the comprehensive disposal and resource utilization of biomass, and possessing promising prospects for promotion and application.

[0060] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A method for preparing a ruthenium bipyridine-anchored photocatalyst, characterized in that, Includes the following steps: S1. Semiconductor material with oxygen defect sites on its surface is reacted with silane coupling agent containing mercapto groups in an organic solvent. After separation and washing, it is then oxidized with hydrogen peroxide solution to obtain sulfonated semiconductor material with sulfonic acid groups grafted on its surface. S2. The material obtained in step S1 is mixed with a saturated sodium chloride solution and reacted to convert the surface sulfonic acid groups into sodium sulfonate groups, thereby obtaining a sodium sulfonate semiconductor material. S3. The sodium sulfonate semiconductor material is mixed with an aqueous solution of a soluble salt of divalent tripyridine ruthenium to carry out an ion exchange reaction, so that the divalent tripyridine ruthenium is anchored to the surface of the semiconductor material by ionic bonds through sulfonate groups, thereby obtaining an intermediate support with ruthenium bipyridine complex anchored on the surface. S4. The noble metal active component is loaded onto the intermediate support obtained in step S3 to obtain a ruthenium bipyridine anchored photocatalyst; the loading amount of the noble metal active component in the ruthenium bipyridine anchored photocatalyst is 0.05 wt% to 0.3 wt% based on the mass of the noble metal element.

2. The preparation method according to claim 1, characterized in that, In step S1, the semiconductor material is selected from at least one of TiO2, ZnO, WO3, CeO2, ZrO2, V2O5, CeZrO4, and La2O3; the mercapto-containing silane coupling agent includes 3-mercaptopropyltrimethoxysilane or 3-mercaptopropyltriethoxysilane.

3. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of the semiconductor material to the mercapto-containing silane coupling agent is 1:(0.1-10).

4. The preparation method according to claim 1, characterized in that, In step S3, the soluble salts of the divalent tripyridine ruthenium include one or more combinations of tris(2,2'-bipyridine)ruthenium(II) dichloride, tris(2,2'-bipyridine)ruthenium(II) hexafluorophosphate, tris(2,2'-bipyridine)ruthenium(II) tetrafluoroborate, tris(2,2'-bipyridine)ruthenium(II) nitrate, and tris(2,2'-bipyridine)ruthenium(II) trifluoromethanesulfonic acid.

5. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the soluble salt of divalent tripyridine ruthenium to the sodium sulfonate semiconductor material is 1:(50-100).

6. The preparation method according to claim 1, characterized in that, In step S4, the noble metal active component is selected from at least one of Au, Rh, Pd, and Pt.

7. The preparation method according to claim 1, characterized in that, In step S4, the noble metal active component is loaded using an impregnation method, a photochemical deposition method, or a hydrothermal method.

8. A ruthenium bipyridine-anchored photocatalyst, characterized in that, It is prepared by the method according to any one of claims 1-7.

9. The application of the ruthenium bipyridine anchored photocatalyst according to claim 8 in the photocatalytic conversion of biomass-based oil to prepare aviation fuel.

10. The application according to claim 9, characterized in that, The photocatalytic reaction is carried out in an acetonitrile solvent and hydrogen atmosphere, with a light intensity of 50-500 mW / cm². 2 The mass ratio of ruthenium bipyridine-anchored photocatalyst to biomass-based oil is 1:(1-10), the reaction temperature is 20-80℃, and the reaction time is 0.5-10 hours.

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