Hierarchical pore noble metal-based catalyst for converting and upgrading glycerol and preparation method of hierarchical pore noble metal-based catalyst

Abstract

The preparation method comprises the following steps: firstly, constructing a hard template layer on a pretreated conductive substrate, then carrying out electro-deposition by taking the conductive substrate for constructing the hard template layer as a working electrode, and forming a noble metal-template agent composite deposition layer on the surface of the working electrode; and finally, removing the template agent in the noble metal-template agent composite deposition layer to obtain the three-dimensional porous noble metal catalyst electrode with a macroporous-mesoporous-microporous hierarchical structure. Through combination of soft and hard template cooperation and an electrodeposition technology, the hierarchical noble metal electrode with a continuous through pore channel system from macropores to mesopores to micropores is controllably prepared on the conductive substrate, the specific surface area is increased, a large number of contactable active sites are provided, and the conductivity of the electrode is improved. And the glycerol can be efficiently and highly selectively converted into high-added-value chemicals in glycerol electrocatalytic oxidation and other reactions.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary technical field of electrocatalytic materials and high-value utilization of biomass resources, specifically relating to a hierarchical porous noble metal-based catalyst for the efficient catalytic selective oxidation of glycerol to prepare high-value-added chemicals and its controllable preparation method. Background Technology

[0002] The rapid development of the global biodiesel industry, while providing renewable energy, has also led to a large accumulation of its byproduct—crude glycerol. Statistics show that approximately 100 kilograms of crude glycerol are produced as a byproduct for every ton of biodiesel produced. This transforms crude glycerol from a traditional fine chemical into a surplus raw material, and how to achieve its high-value utilization has become a key issue restricting the economic benefits and sustainable development of the biodiesel industry.

[0003] Selectively converting inexpensive and readily available crude glycerol into high-value-added chemicals such as glyceric acid, dihydroxyacetone (DHA), lactic acid, or formic acid through catalytic oxidation and other pathways is an effective strategy to improve the economics of the entire industrial chain. This not only consumes excess glycerol and significantly reduces the production cost of biodiesel, but also aligns with the core concepts of circular economy and resource reuse.

[0004] Among numerous conversion technologies, electrocatalytic selective oxidation (ECT) stands out. Unlike traditional thermocatalysis, which requires high temperature, high pressure, and an additional oxygen source, this technology uses electricity to drive the reaction, allowing it to proceed at room temperature and pressure. The reaction process is clean and highly controllable. The core advantage of ECT lies in its ability to couple the anodic oxidation of glycerol with the hydrogen evolution reaction (HER) at the cathode. This means that while converting glycerol into high-value chemicals, it also co-produces green hydrogen, achieving a "two birds with one stone" energy-saving and value-added process.

[0005] However, the commercial application of electrocatalytic selective oxidation technology still faces catalyst bottlenecks. Currently, high-performance catalysts heavily rely on precious metals such as gold (Au) and palladium (Pd). Although they exhibit high intrinsic activity in glycerol oxidation, they are expensive, scarce in crustal reserves, and prone to over-oxidation in actual reactions, leading to deactivation of active sites and decreased catalyst stability. Simultaneously, the simple pore structure of traditional catalysts makes it difficult to simultaneously meet the requirements of rapid diffusion of large molecular reactants and efficient exposure of active sites. Therefore, developing novel, highly efficient catalysts that can significantly reduce or even eliminate the use of precious metals while maintaining high activity is a core challenge in this field. Summary of the Invention

[0006] This invention is proposed to overcome the shortcomings of existing noble metal catalysts in terms of mass transfer efficiency and active site utilization. Its purpose is to provide a hierarchical porous noble metal-based catalyst for glycerol conversion and upgrading, which is directly prepared using a soft and hard template synergistic strategy, and its preparation method.

[0007] This invention is achieved through the following technical solution: A method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading includes the following steps: (I) Pretreatment of the conductive substrate; (II) A hard template layer is constructed on the pretreated conductive substrate, and the hard template layer forms a macroporous framework structure of a hierarchical porous noble metal-based catalyst. (III) Soft template-assisted electrodeposition: Using a conductive substrate with a hard template layer as the working electrode, the working electrode, counter electrode, and reference electrode are placed together in an electrodeposition solution containing noble metal salts and soft template agents. Electrodeposition is performed under the condition of applied current to form a noble metal-template agent composite deposition layer on the surface of the working electrode. During the deposition of noble metal, finer secondary channels are formed.

[0008] (IV) Template removal and channel activation: Remove the template agent from the noble metal-template agent composite deposition layer obtained in step (III) to release the final hierarchical pore structure, thereby obtaining a three-dimensional porous noble metal catalyst electrode with a macroporous-mesoporous-microporous hierarchical structure, and perform electrochemical activation to stabilize the surface state.

[0009] In the above technical solution, the pretreatment method of the conductive substrate is as follows: the conductive substrate is placed in dilute hydrochloric acid, organic solvent and deionized water in sequence for ultrasonic cleaning to thoroughly remove the oxide layer and organic contaminants on the surface, and then vacuum dried.

[0010] In the above technical solution, the conductive substrate is any one of carbon cloth, carbon paper, graphite felt, nickel foam, nickel sheet, nickel mesh, nickel felt, titanium sheet, titanium mesh, titanium felt, stainless steel sheet, stainless steel mesh, ITO conductive glass or FTO conductive glass.

[0011] In the above technical solution, the concentration of the dilute hydrochloric acid is 0.1 M ~ 1.0 M.

[0012] In the above technical solution, the organic solvent is acetone or ethanol.

[0013] The ultrasonic cleaning time is 15 min to 30 min.

[0014] In the above technical solution, the method for constructing the hard template layer is as follows: prepare a suspension containing a hard template agent, and form a single layer or multiple layers of tightly packed hard template layer on the pretreated conductive substrate by spin coating or drop coating.

[0015] In the above technical solution, the hard template agent is polystyrene (PS) microspheres or silica (SiO2) nanospheres.

[0016] In the above technical solution, the diameter of the polystyrene (PS) microspheres is 100 nm to 1000 nm.

[0017] In the above technical solution, the diameter of the silicon dioxide (SiO2) nanospheres is 50 nm to 500 nm.

[0018] In the above technical solution, the concentration of the suspension containing the hard template agent is 0.01 g / ~ 1 g / L; the suspension containing the hard template agent needs to be fully dispersed and uniformly distributed before use to ensure that the hard template agent particles are evenly distributed.

[0019] In the above technical solution, the counter electrode is a platinum sheet.

[0020] In the above technical solution, the reference electrode is a silver / silver chloride electrode.

[0021] In the above technical solution, the noble metal salt is at least one of chloroplatinic acid (HAuCl4), chloroauric acid (H2PtCl6), palladium chloride (PdCl2) or silver chloride (AgCl).

[0022] In the above technical solution, the soft template agent is any one of Pluronic series triblock copolymer F127, polyethylene oxide-polystyrene amphiphilic block copolymer (PEO-b-PS), polyvinylpyrrolidone-polystyrene copolymer (PVP-co-PS), or polystyrene-poly(4-vinylpyridine) block copolymer (PS-b-P4VP). The micelles formed by the self-assembly of the soft template agent (surfactant) molecules in the solution serve as dynamic soft templates, effectively guiding the formation of smaller fine channel structures, thereby significantly increasing the specific surface area and active site density of the electrode.

[0023] In the above technical solution, the concentration of the noble metal salt in the electrodeposition solution is 1 g / L ~ 10 g / L.

[0024] In the above technical solution, the concentration of the soft template agent in the electrodeposition solution is 0.01 g / L ~ 0.5 g / L.

[0025] In the above technical solution, the solvent of the electrodeposition solution is at least one of deionized water, ethanol, tetrahydrofuran, and N,N-dimethylformamide.

[0026] In the above technical solution, the electrodeposition employs a constant current (It) method or a constant potential (Et) method; the current density of the constant current (It) method is set at 1 mA cm⁻¹. -2 ~ 20 mA cm -2 Between; the operating voltage of the constant potential (Et) method is set at -0.1 V cm. -2 ~ -5 V cm -2 between.; In the above technical solution, the electrodeposition time is 3 min to 120 min, which ensures that the noble metal nanoparticles can be uniformly embedded in the multi-level pore structure guided by the soft template agent, and finally obtain a high-performance porous noble metal electrode.

[0027] In the above technical solution, when the hard template agent is polystyrene (PS) microspheres, the template agent is removed by heat treatment; the specific heat treatment method is: heat treatment at 300℃ ~ 600℃ for 1 h ~ 5 h in an inert atmosphere.

[0028] In the above technical solution, when the hard template agent is silicon dioxide (SiO2) nanospheres, the template agent is removed by chemical etching. The chemical etching method specifically involves immersing the conductive substrate forming the noble metal-template agent composite deposition layer into a sodium hydroxide (NaOH) solution, heating it to 50 ℃ ~ 80 ℃, maintaining it for 1 h ~ 3 h, and selectively dissolving the template. The concentration of the sodium hydroxide (NaOH) solution is 1 M ~ 5 M.

[0029] A hierarchical porous noble metal-based catalyst for glycerol conversion upgrading, prepared by the aforementioned method, was confirmed to have a hierarchical pore structure by scanning electron microscopy (SEM) and transmission electron microscopy (TEM); its specific surface area was determined to be in the range of 200 m² by nitrogen adsorption-desorption testing. 2 / g ~ 1500 m 2 / g, with a pore size distribution ranging from 2 nm to 1000 nm.

[0030] The application of a hierarchical porous noble metal-based catalyst prepared by the aforementioned method in the electrocatalytic oxidation of glycerol for the preparation of high-value-added chemicals, wherein the high-value-added chemicals include, but are not limited to, lactic acid, glyceric acid, formic acid, or glycolic acid.

[0031] The beneficial effects of this invention are: This invention provides a hierarchical porous noble metal-based catalyst for glycerol conversion and upgrading, and its preparation method. By combining soft and hard template synergy with electrodeposition technology, a hierarchical noble metal electrode with a continuous interconnected pore system from macropores to mesopores to micropores can be controllably fabricated on a conductive substrate. The catalyst's unique interconnected hierarchical pore structure greatly increases the specific surface area of ​​the electrode, providing a large number of accessible active sites for catalytic reactions. This significantly improves the reactant mass transfer efficiency and the utilization rate of noble metal active sites, enabling it to efficiently and selectively convert glycerol into high-value-added chemicals in reactions such as the electrocatalytic oxidation of glycerol, and couple it to the cathode for hydrogen production. This provides an efficient catalytic material solution for realizing the high-value utilization of biomass resources. Attached Figure Description

[0032] Figure 1 This is a SEM image of the hard template layer in Embodiment 1 of the present invention; Figure 2 This is a SEM image of the AuAg / NF hierarchical porous catalyst in Example 1 of this invention; Figure 3 This is a TEM image of the AuAg / NF hierarchical porous catalyst in Example 1 of this invention; Figure 4 These are the LSV curves of the AuAg / NF hierarchical porous catalyst in Example 1 of this invention and the AuAg / NF non-porous catalyst in Comparative Example 1; Figure 5 This refers to the high-performance liquid chromatography (HPLC) of the AuAg / NF hierarchical porous catalyst used in Example 1 of this invention for the oxidation products of glycerol; Figure 6 This is a high-performance liquid chromatography (HPLC) study of the AuAg / NF nonporous catalyst used in Comparative Example 1 of this invention for the oxidation products of glycerol. Figure 7 This is a product analysis of the two catalysts in Example 1 and Comparative Example 1 of the present invention.

[0033] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0034] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] The chemicals used in the embodiments and comparative examples of this invention were all purchased from Aladdin Reagent Company, and all were of analytical grade.

[0036] Example 1 A method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading includes the following steps: S1. Take a 2 cm × 3 cm piece of nickel foam (NF) and ultrasonically clean it for 20 min each in 0.5 M dilute hydrochloric acid, acetone and deionized water to remove surface oxides and oil stains; then vacuum dry it at 80℃ for 2 h. S2. Prepare an aqueous suspension with a concentration of 0.1 g / L by SiO2 nanospheres with an average diameter of about 300 nm; use a drop-coating method to uniformly coat 0.1 mL of the suspension onto the pretreated nickel foam to form a tightly packed hard template layer. S3. Preparation of electrodeposition solution: H2AuCl4 and AgCl are used as noble metal sources with concentrations of 5 g / L and 1 g / L, respectively; PVP-co-PS is added as a soft template agent with a concentration of 0.1 g / L; the solvent is a mixture of deionized water, ethanol and tetrahydrofuran (volume ratio 1:0.1:1). S4. Electrodeposition: Using nickel foam templated with SiO2 nanospheres as the working electrode, it is placed together with the platinum counter electrode and the silver / silver chloride reference electrode in the electrodeposition solution prepared in step S3. Electrodeposition is carried out at a potential of -3 V (vs. Ag / AgCl) for 60 min using the constant potential method. During this process, PVP-co-PS micelles guide AuAg to deposit in the gaps between SiO2 nanospheres, forming a preliminary composite structure. S5. After electrodeposition, immerse the electrode in a 5 M sodium hydroxide (NaOH) solution and keep it at 70 °C for 2 h to completely etch away the silicon dioxide template; then, thoroughly rinse the electrode with deionized water. S6. The AuAg / NF hierarchical porous catalyst prepared in this embodiment is used as the working electrode for the electrocatalytic oxidation of glycerol; the reaction electrolyte is 3.0 M KOH and 0.4 M glycerol, and the reaction voltage is 0.9 V (vs. RHE).

[0037] Figure 1 The scanning electron microscope images shown clearly demonstrate the surface morphology of the constructed SiO2 nanosphere hard template layer. It can be observed from the images that the SiO2 nanospheres exhibit good monodispersity and high size uniformity, with a narrow particle size distribution of approximately 300 nm. These nanospheres form a large-area, tightly packed, ordered array on the conductive substrate, with uniform gaps between the spheres, constituting a template for the macroporous framework of future hierarchical porous catalysts.

[0038] Figure 2The image shows a scanning electron microscope (SEM) image of the prepared AuAg / NF hierarchical porous catalyst at 30 kx magnification. It can be clearly observed from the image that after removing the SiO2 nanospheres, a three-dimensional interconnected hierarchical pore structure was successfully exposed on the catalyst surface. This pore structure is conducive to the rapid mass transfer of reactants and products, thereby significantly improving the performance of the catalyst in reactions such as the electro-oxidation of glycerol.

[0039] Figure 3 TEM images further revealed the fine structure of the catalyst. It can be observed that a large number of small pores left by soft template micelles are distributed inside the catalyst. These fine channels endow the catalyst with a high specific surface area, thus providing a large number of accessible active sites for catalytic reactions.

[0040] Figure 4 Linear sweep voltammetry (LSV) curves of the prepared AuAg / NF and the non-porous AuAg / NF prepared in Comparative Example 1 at 25 °C in a 3 M KOH solution containing 0.4 M glycerol were obtained. It can be seen that the hierarchical porous structure greatly improves the current density of the reaction.

[0041] Figure 5 The selectivity of the prepared AuAg / NF hierarchical porous catalyst for glycerol oxidation products was determined after reacting the catalyst in a 3 M KOH solution containing 0.4 M glycerol at a potential of 0.9 V (vs. RHE) for 1 h, with the C3 product being the predominant component.

[0042] Example 2 A method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading includes the following steps: S1. Take a 2 cm × 3 cm nickel mesh (NM) and ultrasonically clean it for 20 min each in 0.5 M dilute hydrochloric acid, acetone and deionized water to remove surface oxides and oil stains; then vacuum dry it at 80℃ for 2 h. S2. SiO2 nanospheres with an average diameter of approximately 100 nm were prepared into an aqueous suspension with a concentration of 0.1 g / L. Using a drop-coating method, 0.05 mL of the suspension was uniformly coated onto a pretreated nickel mesh to form a tightly packed hard template layer. S3. Preparation of electrodeposition solution: PdCl2 and H2PtCl6 are used as noble metal sources, with concentrations of 1 g / L and 5 g / L, respectively; F127 is added as a soft template agent with a concentration of 5 g / L; the solvent is a mixture of deionized water and ethanol (volume ratio 1:1). S4. Electrodeposition: Using a nickel mesh loaded with SiO2 nanosphere templates as the working electrode, it is placed together with the platinum counter electrode and the silver / silver chloride reference electrode in the electrodeposition solution prepared in step S3. Electrodeposition is carried out at a potential of -1 V (vs. Ag / AgCl) for 30 min using a constant potential method. During this process, F127 micelles guide AuPt to deposit in the gaps between SiO2 nanospheres, forming a preliminary composite structure. S5. After electrodeposition, immerse the electrode in a 5 M sodium hydroxide (NaOH) solution and keep it at 70°C for 2 h to completely etch away the silicon dioxide template; then, thoroughly rinse the electrode with deionized water.

[0043] S6. The AuAg / NM hierarchical porous catalyst prepared in this embodiment was used as the working electrode for the electrocatalytic oxidation of glycerol. The electrolyte was 3.0 M KOH and 0.4 M glycerol, and the reaction voltage was 0.8 V (vs. RHE).

[0044] Example 3 A method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading includes the following steps: S1. Take a piece of carbon paper (CP) with dimensions of 2 cm × 3 cm and ultrasonically clean it for 20 min each in 0.5 M dilute hydrochloric acid, acetone and deionized water to remove surface oxides and oil stains; then vacuum dry it at 80 ℃ for 2 h. S2. Prepare an aqueous suspension with a concentration of 0.1 g / L by preparing PS microspheres with an average diameter of about 500 nm. Use the drop-coating method to uniformly coat 0.1 mL of the suspension onto the pretreated carbon paper to form a tightly packed hard template layer. S3. Preparation of electrodeposition solution: H2AuCl4 and H2PtCl6 are used as noble metal sources, with concentrations of 5 g / L and 1 g / L, respectively; PVP-co-PS is added as a soft template agent with a concentration of 0.1 g / L; the solvent is a mixed solvent of deionized water, ethanol and tetrahydrofuran (volume ratio 1:0.1:1). S4. Electrodeposition: Using carbon paper loaded with PS microsphere template as the working electrode, it is placed together with the counter electrode platinum sheet and the reference electrode silver / silver chloride electrode in the electrodeposition solution prepared in step S3. The electrodeposition is carried out at a current of -10 mA for 60 min using the constant current method. During this process, PVP-co-PS micelles guide AuPt to deposit in the gaps between SiO2 spheres to form a preliminary composite structure. S5. After electrodeposition, immerse the electrode in a 5 M sodium hydroxide (NaOH) solution and keep it at 80°C for 2 h to completely etch away the silicon dioxide template; then, thoroughly rinse the electrode with deionized water.

[0045] S6. The AuPt / CP hierarchical porous catalyst prepared in this embodiment was used as the working electrode for the electrocatalytic oxidation of glycerol. The electrolyte was 3.0 M KOH and 0.4 M glycerol, and the reaction voltage was 0.8 V (vs. RHE). Comparative Example 1 The difference between this embodiment and Embodiment 1 is that a hard template layer is not constructed on the conductive substrate and no soft template micelles are added during the electrodeposition process.

[0046] Specifically as follows: S1. Take a 2 cm × 3 cm piece of nickel foam (NF) and ultrasonically clean it for 20 min each in 0.5 M dilute hydrochloric acid, acetone and deionized water to remove surface oxides and oil stains; then vacuum dry it at 80℃ for 2 h. S2. Preparation of electrodeposition solution: H2AuCl4 and AgCl are used as noble metal sources, with concentrations of 5 g / L and 1 g / L, respectively; the solvent is a mixed solvent of deionized water, ethanol and tetrahydrofuran (volume ratio 1:0.1:1). S3. Electrodeposition: Using nickel foam as the working electrode, it is placed together with the platinum counter electrode and the silver / silver chloride reference electrode in the electrodeposition solution prepared in step S2. Electrodeposition is carried out at a potential of -3 V (vs. Ag / AgCl) for 60 min using the constant potential method. During this process, AuAg nanoparticles are deposited on the nickel foam substrate.

[0047] S3. To maintain the variable, after electrodeposition, the electrode was immersed in a 5 M sodium hydroxide (NaOH) solution and kept at 70°C for 2 h. Then, the electrode was thoroughly rinsed with deionized water.

[0048] S4. The AuAg / NF nonporous catalyst prepared in this embodiment was used as the working electrode for the electrocatalytic oxidation of glycerol. The electrolyte was 3.0 M KOH and 0.4 M glycerol, and the reaction voltage was 0.9 V (vs. RHE).

[0049] Figure 6 The selectivity of the prepared AuAg / NF nonporous catalyst for glycerol oxidation products was measured after reacting in a 3 M KOH solution containing 0.4 M glycerol at a potential of 0.9 V (vs. RHE) for 1 h. The selectivity for C3 products was significantly lower than that of the catalyst in Example 1.

[0050] Figure 7 The comparison analysis diagram shows that the AuAg / NF non-porous catalyst and the AuAg / NF porous catalyst prepared in Example 1 have significantly better product yields than the non-porous catalyst, demonstrating an overwhelming catalytic performance advantage.

[0051] The principle of this invention: The key to addressing the need for rapid diffusion of macromolecular reactants and efficient exposure of active sites lies in the precise control of the catalyst's microstructure, as catalytic performance is strongly dependent on the physical structure of nanomaterials. Constructing hierarchical porous structures is an effective strategy for improving catalytic performance: high specific surface area provides abundant active sites for the reaction, while interconnected hierarchical channels greatly promote the mass transfer efficiency between reactants and products. Therefore, this invention utilizes morphology engineering to design non-noble metal or low-noble metal supported catalysts with ideal pore structures to achieve efficient and stable electrocatalytic oxidation of glycerol.

[0052] This invention constructs a macroporous framework using a hard template to ensure mass transfer during the reaction; simultaneously, it utilizes soft template micelles to guide the formation of secondary channels during electrodeposition, successfully constructing a continuous, interconnected pore system from macropores to mesopores to micropores, significantly increasing specific surface area and active site density; the synergistic design of the multi-level pores achieves high catalytic performance. Channels of different sizes each serve a specific function: macropores act as "fast channels" for reactants and products, while micropores ensure an extremely high density of active sites.

[0053] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0054] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading, characterized in that: Includes the following steps: (I) Pretreatment of the conductive substrate; (II) Construct a hard template layer on the pretreated conductive substrate; (III) Soft template-assisted electrodeposition: Using a conductive substrate with a hard template layer as the working electrode, the electrode, along with the counter electrode and the reference electrode, is placed in an electrodeposition solution containing noble metal salts and soft template agents. Electrodeposition is performed under the condition of applied current to form a noble metal-template agent composite deposition layer on the surface of the working electrode. (IV) Template removal and channel activation: Remove the template agent from the noble metal-template agent composite deposition layer obtained in step (III) to obtain a three-dimensional porous noble metal catalyst electrode with a macroporous-mesoporous-microporous hierarchical structure.

2. The method for preparing the hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: The pretreatment method for the conductive substrate is as follows: the conductive substrate is placed in dilute hydrochloric acid, organic solvent and deionized water in sequence for ultrasonic cleaning; The concentration of the dilute hydrochloric acid is 0.1 M ~ 1.0 M; The organic solvent is acetone or ethanol; The ultrasonic cleaning time is 15 min to 30 min; The conductive substrate is any one of carbon cloth, carbon paper, graphite felt, nickel foam, nickel sheet, nickel mesh, nickel felt, titanium sheet, titanium mesh, titanium felt, stainless steel sheet, stainless steel mesh, ITO conductive glass, or FTO conductive glass.

3. The method for preparing the hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: The method for constructing the hard template layer is as follows: prepare a suspension containing a hard template agent, and form a single or multiple tightly packed hard template layers on a pretreated conductive substrate by spin coating or drop coating.

4. The method for preparing the hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 3, characterized in that: The hard template agent is a polystyrene microsphere or a silica nanosphere; the diameter of the polystyrene microsphere is 100 nm to 1000 nm; the diameter of the silica nanosphere is 50 nm to 500 nm; and the concentration of the suspension containing the hard template agent is 0.01 g / L to 1 g / L.

5. The method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: The counter electrode is a platinum sheet; the reference electrode is a silver / silver chloride electrode.

6. The method for preparing the hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: The noble metal salt is at least one of chloroplatinic acid, chloroauric acid, palladium chloride, or silver chloride; the soft template agent is any one of Pluronic series triblock copolymer F127, polyethylene oxide-polystyrene amphiphilic block copolymer, polyvinylpyrrolidone-polystyrene copolymer, or polystyrene-polyblock copolymer; the solvent of the electrodeposition solution is at least one of deionized water, ethanol, tetrahydrofuran, or N,N-dimethylformamide.

7. The method for preparing the hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: The concentration of the noble metal salt in the electrodeposition solution is 1 g / L to 10 g / L; the concentration of the soft template agent in the electrodeposition solution is 0.01 g / L to 0.5 g / L.

8. The method for preparing the hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: The electrodeposition is performed using either a constant current method or a constant potential method; the current density for the constant current method is set at 1 mA / cm². -2 ~ 20 mA cm -2 Between; the operating voltage of the constant potential method is set at -0.1 V cm. -2 ~ -5 V cm -2 The electrodeposition time is between 3 min and 120 min.

9. The method for preparing a hierarchical porous noble metal-based catalyst for glycerol conversion upgrading according to claim 1, characterized in that: When the hard template agent is polystyrene microspheres, the template agent is removed in step (IV) by heat treatment; the specific heat treatment method is: heat treatment at 300℃ ~ 600℃ for 1 h ~ 5 h in an inert atmosphere. When the hard template agent is silica nanospheres, the template agent is removed in step (IV) by chemical etching. The chemical etching method is as follows: the conductive substrate forming the noble metal-template agent composite deposition layer is immersed in sodium hydroxide solution, heated to 50 ℃ ~ 80 ℃, and kept for 1 h ~ 3 h to selectively dissolve the template. The concentration of the sodium hydroxide solution is 1 M ~ 5 M.

10. A hierarchical porous noble metal-based catalyst for glycerol conversion upgrading, characterized in that: Prepared by the method described in any one of claims 1 to 9; the catalyst has a specific surface area in the range of 200 m². 2 / g ~ 1500 m 2 / g, with a pore size distribution ranging from 2 nm to 1000 nm.

Images