A catalyst for preparing C2-C3 small molecule chemicals from sugars and a preparation method thereof

Abstract

The present invention discloses a catalyst for catalytically preparing C2-C3 small molecule chemicals from sugars and a preparation method thereof. Among them, the catalyst includes a metal core and an oxide layer. The oxide layer includes a first oxide layer and a second oxide layer. The first oxide layer is coated on the metal core, and the second oxide layer is coated on the first oxide layer. Among them, the metal core adopts any one of a Co metal core, a Ni metal core, a Co metal core modified by Sn, and a Ni metal core modified by Sn. The first oxide layer is an L acid or basic site doped oxide layer, and the second oxide layer is a weakly acidic oxide layer. Thus, by arranging the sites in an orderly manner, the spatial layout of the catalytic sites is regulated to guide the orderly relay catalysis of reaction intermediates. At the same time, the confinement space can also be used to inhibit the aggregation of metal particles, realizing the stable and efficient preparation of C2-C3 small molecule chemicals such as acetol from sugars.

Description

Technical Field

[0001] The present invention relates to the field of catalyst production, and particularly to a method for catalyzing sugars to prepare small molecule chemicals. Background Art

[0002] Biomass plays an important role in energy supply. It has the advantages of rich reserves, low price, environmental friendliness, and great potential. With the increasing global demand for renewable and valuable chemicals and fuels, the social demand for biomass materials and sustainable technologies is urgent. Currently, a promising strategy to alleviate energy depletion is to convert lignocellulosic biomass into high-value chemicals and fuels. Lignocellulose, as an important biomass resource, is mainly composed of cellulose, hemicellulose, and lignin. Among them, cellulose accounts for the largest proportion of lignocellulose, but a large amount of cellulose that has not been fully utilized is wasted every year, and new technologies need to be developed to better utilize cellulose resources. Therefore, in order to reduce the excessive dependence on fossil fuels, the conversion of cellulose into renewable chemicals and fuels to meet the growing global energy demand has attracted extensive attention in the academic and industrial fields.

[0003] Among chemicals, C2-C3 small molecule chemicals such as ethylene glycol and propylene glycol have great uses in the fields of medicine, cosmetics, daily necessities, etc. However, traditional preparation methods use fossil resources as raw materials and have long reaction paths, including hydrolysis, isomerization, reverse Aldol condensation, hydrogenation, dehydration, etc. Moreover, conventional supported catalysts are extremely prone to metal agglomeration and loss in a high-temperature and high-pressure aqueous phase system, resulting in poor catalyst stability and unsatisfactory product yields. Specifically, on the surface of conventional supported catalysts, the disordered arrangement of various catalytic sites makes it difficult to control the reaction direction. Different reactions may occur when intermediates come into contact with different catalytic sites. And on the open catalyst surface, various intermediates are prone to detach from the surface and enter the liquid phase main body. These intermediates far from the catalytic sites are very likely to undergo cross-linking polymerization reactions with each other in a high-temperature aqueous phase environment, further leading to a decrease in product selectivity. In addition, under the reaction conditions of a high cellulose / catalyst ratio, the phenomenon of product yield reduction due to polymerization and coking is particularly obvious. In terms of the stability of the catalyst, conventional supported catalysts are extremely prone to metal loss and agglomeration in a high-temperature, high-pressure, aqueous phase system, and the problem of poor catalyst stability is widespread. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a catalyst for catalyzing sugars to prepare C2-C3 small molecule chemicals, which can realize an orderly catalytic reaction, thereby realizing the stable and efficient conversion of sugars into C2-C3 small molecule chemicals.

[0005] A catalyst for catalytically preparing C2-C3 small molecule chemicals from saccharides according to the first aspect of the embodiments of the present invention, the catalyst being used for catalytically preparing C2-C3 small molecule chemicals from saccharides, characterized in that the catalyst comprises a metal core and an oxide layer, the oxide layer comprising a first oxide layer and a second oxide layer, the first oxide layer being coated on the metal core, and the second oxide layer being coated on the first oxide layer, wherein the metal core is any one of a Co metal core, a Ni metal core, a Co metal core modified by Sn, and a Ni metal core modified by Sn, the first oxide layer is any one of an L acid or basic site doped oxide layer, an SnO2 layer, and a Y2O3 layer, and the second oxide layer is a weakly acidic oxide layer.

[0006] In some embodiments of the present invention, the L acid or basic site doped oxide layer is any one of an Sn-doped SiO2 layer, a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer; or

[0007] any one of a Y-doped SiO2 layer, a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer.

[0008] In some embodiments of the present invention, when the L acid or basic site is Sn, the loading amount (mass fraction) of Sn is 1% to 30%, and when the L acid or basic site is Y, the loading amount (mass fraction) of Y is 0.5% to 20%.

[0009] In some embodiments of the present invention, the weakly acidic oxide layer is any one of a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer.

[0010] In some embodiments of the present invention, the saccharides include: cellulose, cellobiose, glucose, fructose, starch, sucrose.

[0011] In some embodiments of the present invention, the C2-C3 small molecule chemicals include: ethylene glycol, 1,2-propanediol, acetol, lactic acid.

[0012] A method for preparing a catalyst for catalytically preparing C2-C3 small molecule chemicals from saccharides according to the second aspect of the embodiments of the present invention, the method comprising the following steps:

[0013] Dissolve a metal oxide and PVP in absolute ethanol and carry out a hydrothermal reaction to synthesize metal oxide nanoparticles;

[0014] Coat an SiO2 layer on the metal oxide nanoparticles to form a first product;

[0015] Wrap the first product with an L acid or basic site-doped oxide layer and a weakly acidic oxide layer in sequence to form a second product;

[0016] Calcine the second product to remove the pore-forming template PVP to form confined pores;

[0017] Etch the SiO2 layer coated on the metal oxide nanoparticles of the calcined second product with an NaOH solution to form a cavity;

[0018] Under an inert gas atmosphere, purge the product in the above step to obtain the target catalyst.

[0019] According to some embodiments of the present invention, the method for coating the SiO2 layer on the metal oxide nanoparticles includes the following steps:

[0020] After cooling the hydrothermal reaction solution, add deionized water and ammonia water, mix evenly, and slowly dropwise add an ethanol solution of tetraethyl orthosilicate (TEOS) while stirring.

[0021] According to some embodiments of the present invention, the method for coating the L acid or basic site-doped oxide layer and the weakly acidic oxide layer on the first product in sequence includes the following steps:

[0022] Slowly dropwise add an ethanol solution of zirconium butoxide or tetrabutyl titanate into the solution in the above step, then dropwise add an aqueous solution of SnCl4·5H2O while stirring, react for a period of time, and then slowly dropwise add an ethanol solution of tetrabutyl titanate while stirring and continue to react for a period of time, and then rotary evaporate to remove the solvent and dry.

[0023] According to some embodiments of the present invention, after the step of etching the SiO2 layer coated on the metal oxide nanoparticles of the calcined second product with an NaOH solution, the following steps are further included:

[0024] Wash the above solution to neutrality, dry it to a powder state, and reduce the obtained powder in a 10% N2 / H2 gas stream at 500 °C for 2 h.

[0025] Advantageous effects:

[0026] The catalyst of the present invention regulates the spatial layout of catalytic sites by arranging sites in an orderly manner to guide the orderly relay catalysis of reaction intermediates, and at the same time can also use the confined space to inhibit the aggregation of metal particles, realizing the stable and efficient preparation of C2-C3 small molecule chemicals such as acetol from sugars. Specific embodiments

[0027] The embodiments of the present invention will be described in detail below.

[0028] In the catalyst for preparing C2-C3 small molecule chemicals from carbohydrates according to the embodiments of the present invention, during use, cellulose and the catalyst can be added into a high-pressure reaction kettle, with water as the solvent, and reacted for 1 h under the conditions of a H2 pressure of 4 MPa and a temperature of 250 °C to obtain C2-C3 small molecule chemicals. Among them, the carbohydrates include but are not limited to cellulose, cellobiose, glucose, fructose, starch, and sucrose, while the C2-C3 small molecule chemicals include but are not limited to ethylene glycol, 1,2-propanediol, acetol, and lactic acid.

[0029] Specifically, the catalyst includes a metal core and an oxide layer. The oxide layer includes a first oxide layer and a second oxide layer. The first oxide layer is coated on the metal core, and the second oxide layer is coated on the first oxide layer. Specifically, the metal core can be any one of a Co metal core, a Ni metal core, a Co metal core modified by Sn, and a Ni metal core modified by Sn. The first oxide layer can be any one of an L acid or basic site doped oxide layer, a SnO2 and Y2O3 layer, and the second oxide layer is a weakly acidic oxide layer.

[0030] Furthermore, in a feasible solution of the L acid or basic site doped oxide layer, any one of a SiO2 layer, a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer doped with Sn can be used. At this time, the loading amount (mass fraction) of Sn ranges from 1% to 30%. Preferably, the loading amount (mass fraction) of Sn is 10%, and the yield of C2-C3 small molecules / % can reach 83.3.

[0031] In another feasible solution of the L acid or basic site doped oxide layer, any one of a SiO2 layer, a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer doped with Y can be used. At this time, the loading amount (mass fraction) of Y ranges from 0.5% to 20%. Preferably, the loading amount (mass fraction) of Y is 5%, and at this time, the yield of C2-C3 small molecules / % can reach 80.2.

[0032] In addition, in a feasible solution of the weakly acidic oxide layer, the weakly acidic oxide layer can be any one of a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer. Preferably, when the weakly acidic oxide layer is selected as the TiO2 layer, the yield of C2-C3 small molecules / % can be as high as 83.3, which is much higher than 62.7 that can be achieved when the weakly acidic oxide layer is selected as the ZrO2 layer.

[0033] During use, a series of reactions will occur among sugars, water, and a catalyst in a high-pressure reactor. Among them, the catalyst uses weakly acidic metal oxides ZrO2 or TiO2 as the outer material of the porous shell, so that the cellulose hydrolysis reaction can be isolated from the subsequent reactions. Specifically, cellulose particles are gradually hydrolyzed to release glucose molecules under the catalysis of H+ generated by the autoionization of high-temperature water or the outer layer of weakly acidic oxides. The weakly acidic oxide layer isolates the cellulose hydrolysis reaction from the subsequent reactions, thereby inhibiting the intermediate from entering the liquid-phase main body and staying away from the catalytic sites, reducing the generation of by-products.

[0034] The catalyst uses ZrO2 or TiO2 doped with YOx or SnOx as the inner layer material of the shell, which is used to catalyze glucose isomerization, fructose retro-Aldol condensation, and the subsequent fructose retro-Aldol condensation to generate C3 intermediates.

[0035] Using Sn-modified Co or Ni as weak hydrogenation sites arranged in the reactor cavity, further hydrogenating the C3 intermediates to make the reaction selectively stay at C2-C3 small molecules.

[0036] Thus, the reaction intermediates are confined in a confined space filled with catalytic sites through the pore and cavity structures, thereby realizing efficient relay catalysis of the intermediates and reducing the problems of pore blockage and catalytic site coverage inactivation caused by polymerization and coking side reactions.

[0037] According to the catalyst preparation method for catalytically preparing C2-C3 small molecule chemicals from sugars according to an embodiment of the present invention, the preparation method includes the following steps:

[0038] Step 1: Completely dissolve 2 g of Co(NO3)2·6H2O and 2 g of PVP in 180 g of absolute ethanol, transfer it to a hydrothermal kettle, and react at 180 °C for 12 h, so that uniformly sized metal oxide nanoparticles, namely Co metal cores, can be synthesized by the solvothermal method.

[0039] Step 2: Coating the SiO2 layer using the classical method. Specifically, after cooling the reaction solution obtained in the above step 1, transfer it to a 500 mL flask, add 120 g of deionized water and 10 g of ammonia water, mix evenly, and slowly dropwise add an ethanol solution of tetraethyl orthosilicate (TEOS) under vigorous stirring.

[0040] Step 3: Coating the L acid or basic site-doped oxide layer using a similar method. Specifically, after reacting the mixed solution in the above step 2 for 24 h, slowly dropwise add an ethanol solution of zirconium butoxide under vigorous stirring, and then dissolve a certain amount of SnCl4·5H2O in 10 mL of water, and dropwise add it to the above suspension under stirring.

[0041] Step 4: Using a similar Wrap the weak acidic oxide layer. Specifically, after reacting the mixed solution in Step 3 above for 24 h, slowly drop the ethanol solution of tetrabutyl titanate into it with vigorous stirring and continue to react for 24 h. Rotavapor to remove the solvent and dry it overnight at 70 °C.

[0042] Step 5: Calcinate to remove the pore-forming template PVP to form confined pores. Specifically, calcinate the dried solid in Step 4 at 550 °C for 6 h, and grind it after cooling to room temperature.

[0043] Step 6: Etch the SiO2 layer with NaOH solution to form a cavity, wash it with water until neutral, and dry it overnight at 70 °C.

[0044] Step 7: Reduce the obtained powder in a 10% N2 / H2 gas stream at 500 °C for 2 h. After cooling to room temperature, purge it with N2 for 2 h to obtain the catalyst.

[0045] Example 1

[0046] Preparation of C2-C3 small molecules from cellulose catalyzed by different weakly hydrogenating metal core catalysts

[0047] Specifically, add 50 mg of cellulose and 50 mg of catalyst to a 25 mL high-pressure reactor, use 10 mL of water as the solvent, react under the conditions of H2 pressure of 4 MPa and temperature of 250 °C for 1 h. After the reaction is completed, cool it. The reaction solution is filtered and used for liquid-phase detection (HPLC, Waters 1525, Shodex RI-201H detector, Bio-Rad Aminex HPX-87H chromatographic column, using 0.005 M H2SO4 as the mobile phase). The results are shown in Table 1:

[0048] Table 1. Preparation of C2-C3 small molecules from cellulose catalyzed by different weakly hydrogenating metal core catalysts

[0049] Catalyst Yield of C2-C3 small molecules / % Co@void@ZrO2-10% Sn@TiO2 83.3 Ni@void@ZrO2-10% Sn@TiO2 78.4 Sn-Co@void@ZrO2-10% Sn@TiO2 80.2 Sn-Ni@void@ZrO2-10% Sn@TiO2 78.0

[0050] Example 2

[0051] Preparation of C2-C3 small molecules from cellulose catalyzed by catalysts with different L acid or basic site-doped oxide layers

[0052] Specifically, add 50 mg of cellulose and 50 mg of catalyst to a 25 mL high-pressure reactor, use 10 mL of water as the solvent, react under the conditions of H2 pressure of 4 MPa and temperature of 250 °C for 1 h. After the reaction is completed, cool it. The reaction solution is filtered and used for liquid-phase detection (HPLC, Waters 1525, Shodex RI-201H detector, Bio-Rad Aminex HPX-87H chromatographic column, using 0.005 M H2SO4 as the mobile phase). The results are shown in Table 2:

[0053] Table 2. Catalytic preparation of C2-C3 small molecules from cellulose by catalysts doped with different L acidic or basic sites in the oxide layer

[0054] Catalyst Yield of C2-C3 small molecules / % Co@SiO2-10% Sn@TiO2 60.5 Co@void@TiO2-10% Sn@TiO2 72.3 Co@void@ZrO2-10% Sn@TiO2 83.3 Co@void@CeO2-10% Sn@TiO2 70.7 Co@void@Al2O3-10% Sn@TiO2 63.6 Co@void@10% SnO2@TiO2 69.8 Co@SiO2-10% Y@TiO2 61.5 Co@void@ZrO2-10% Y@TiO2 72.4 Co@void@TiO2-10% Y@TiO2 60.5 Co@void@CeO2-10% Y@TiO2 68.1 Co@void@Al2O3-10% Y@TiO2 71.9 Co@void@10% Y2O3@TiO2 60.3

[0055] Example 3

[0056] Catalytic preparation of C2-C3 small molecules from cellulose by catalysts with orderly arranged sites in different weakly acidic oxide layers

[0057] Add 50 mg of cellulose and 50 mg of catalyst to a 25 mL high-pressure reactor, use 10 mL of water as the solvent, react at a H2 pressure of 4 MPa and a temperature of 250 °C for 1 h. After the reaction, cool it down. The reaction solution is filtered and used for liquid-phase detection (HPLC, Waters 1525, Shodex RI-201H detector, Bio-Rad Aminex HPX-87H chromatographic column, using 0.005 M H2SO4 as the mobile phase). The results are shown in Table 3:

[0058] Table 3. Catalytic preparation of C2-C3 small molecules from cellulose by catalysts with orderly arranged sites in different weakly acidic oxide layers

[0059] Catalyst Yield of C2-C3 small molecules / % Co@void@ZrO2-10% Sn@ZrO2 62.7 Co@void@ZrO2-10% Sn@TiO2 83.3 <![CDATA[Co@void@ZrO2-10%Sn@CeO2]]> 71.9 <![CDATA[Co@void@ZrO2-10%Sn@Al2O3]]> 68.4

[0060] Example 4

[0061] Catalytic preparation of C2-C3 small molecules from cellulose by Co@void@ZrO2-Sn@TiO2 catalysts with different Sn / Y loadings;

[0062] Add 50 mg of cellulose and 50 mg of catalyst to a 25 mL high-pressure reactor, use 10 mL of water as the solvent, react at a H2 pressure of 4 MPa and a temperature of 250 °C for 1 h. After the reaction, cool it down. The reaction solution is filtered and used for liquid-phase detection (HPLC, Waters 1525, Shodex RI-201H detector, Bio-Rad Aminex HPX-87H chromatographic column, using 0.005 M H2SO4 as the mobile phase). The results are shown in Tables 4 and 5:

[0063] Table 4. Catalytic preparation of C2-C3 small molecules from cellulose by Co@void@ZrO2-Sn@TiO2 with different Sn loadings

[0064] Catalyst Yield of C2-C3 small molecules / % Co@void@ZrO2-1% Sn@TiO2 45.7 Co@void@ZrO2-3% Sn@TiO2 58.8 Co@void@ZrO2-5% Sn@TiO2 70.2 Co@void@ZrO2-10% Sn@TiO2 83.3 Co@void@ZrO2-15% Sn@TiO2 74.1 Co@void@ZrO2-20% Sn@TiO2 73.8 Co@void@ZrO2-30% Sn@TiO2 60.5

[0065] Table 5. Catalytic preparation of C2-C3 small molecules from cellulose by Co@void@ZrO2-Sn@TiO2 with different Y loadings

[0066] Catalyst Yield of C2-C3 small molecules / % Co@void@ZrO2-0.5% Y@TiO2 40.1 Co@void@ZrO2-1% Y@TiO2 42.2 Co@void@ZrO2-3% Y@TiO2 65.9 Co@void@ZrO2-5% Y@TiO2 80.2 Co@void@ZrO2-10% Y@TiO2 69.5 Co@void@ZrO2-15% Y@TiO2 45.8 Co@void@ZrO2-20% Y@TiO2 38.7

[0067] Example 5

[0068] Sn-Co@void@ZrO2-10% Sn@TiO2 Catalyzes the Preparation of C2-C3 Small Molecules from Various Sugars

[0069] Add 50 mg of cellulose and 50 mg of catalyst to a 25 mL high-pressure reactor, use 10 mL of water as the solvent, react at a H2 pressure of 4 MPa and a temperature of 250 °C for 1 h. After the reaction, cool down, filter the reaction solution and use it for liquid-phase detection (HPLC, Waters 1525, Shodex RI-201H detector, Bio-Rad Aminex HPX-87H chromatographic column, using 0.005 M H2SO4 as the mobile phase). The results are shown in Table 6:

[0070] Table 6. Co@void@ZrO2-10% Sn@TiO2 Catalyzes the Preparation of C2-C3 Small Molecules from Various Sugars

[0071]

[0072]

[0073] Example 6

[0074] Preparation of a Catalyst with an Ordered Site Arrangement Configuration (Taking Co@void@ZrO2-Sn@TiO2 as an Example)

[0075] Completely dissolve 2 g of Co(NO3)2·6H2O and 2 g of PVP in 180 g of absolute ethanol, transfer to a hydrothermal reactor and react at 180 °C for 12 h.

[0076] After cooling, transfer the reaction solution to a 500 mL flask, add 120 g of deionized water and 10 g of ammonia water, mix well, and slowly dropwise add an ethanol solution of 2 g of TEOS under vigorous stirring. After reacting for 24 h, slowly dropwise add an ethanol solution of 1.26 g of zirconium butoxide under vigorous stirring, then dissolve a certain amount of SnCl4·5H2O in 10 mL of water, and dropwise add it to the above suspension under stirring. After reacting for 24 h, slowly dropwise add an ethanol solution of 1.26 g of tetrabutyl titanate under vigorous stirring and continue to react for 24 h.

[0077] Remove the solvent by rotary evaporation and dry overnight at 70 °C. Calcinate the dried solid at 550 °C for 6 h, cool to room temperature and grind. Treat with 1 M NaOH solution for 24 h, wash with water until neutral, and dry overnight at 70 °C.

[0078] The obtained powder was reduced at 500 °C for 2 h under a 10% N2 / H2 gas flow. After cooling to room temperature, it was purged with N2 for 2 h to obtain the Co@void@ZrO2-Sn@TiO2 catalyst.

[0079] Table 7. Preparation of catalysts with different Sn loadings

[0080] Catalyst Dosage of SnCl4·5H20 / g Co@void@ZrO2-1% Sn@TiO2 0.0298 Co@void@ZrO2-3% Sn@TiO2 0.0913 Co@void@ZrO2-5% Sn@TiO2 0.1554 Co@void@ZrO2-10% Sn@TiO2 0.3281 Co@void@ZrO2-15% Sn@TiO2 0.5212 Co@void@ZrO2-20% Sn@TiO2 0.7383 Co@void@ZrO2-30% Sn@TiO2 1.2657

[0081] Table 8. Preparation of catalysts with different Y loadings

[0082]

[0083]

[0084] In the description of this specification, the descriptions with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example.

[0085] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A catalyst for preparing C2-C3 small molecule chemicals from sugars, characterized in that, The catalyst includes a metal core and an oxide layer. The oxide layer includes a first oxide layer and a second oxide layer. The first oxide layer is coated on the metal core, and the second oxide layer is coated on the first oxide layer. Among them, the metal core is any one of a Co metal core, a Ni metal core, a Co metal core modified by Sn, and a Ni metal core modified by Sn. The first oxide layer is any one of a SnO2 layer, a Y2O3 layer, an L acid or basic site doped oxide layer. The L acid or basic site doped oxide layer is any one of a SiO2 layer, a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer doped by Sn, or a SiO2 layer, a ZrO2 layer, a TiO2 layer, a CeO2 layer, and an Al2O3 layer doped by Y. When the L acid or basic site is Sn, the loading amount of Sn is 1% - 30% by mass fraction. When the L acid or basic site is Y, the loading amount of Y is 0.5% - 20% by mass fraction; the second oxide layer is a weakly acidic oxide layer.

2. The catalyst for preparing C2-C3 small molecule chemicals from carbohydrates according to claim 1, characterized in that, The weakly acidic oxide layer is any one of a ZrO2, TiO2, CeO2, and Al2O3 layer.

3. The catalyst for preparing C2-C3 small molecule chemicals by catalyzing saccharides according to claim 1, wherein The saccharides include: cellulose, cellobiose, glucose, fructose, starch, or sucrose.

4. The catalyst for preparing C2-C3 small molecule chemicals from carbohydrates according to claim 1, characterized in that, The C2-C3 small molecule chemicals include: ethylene glycol, 1,2-propanediol, acetol, or lactic acid.

5. A method for preparing a catalyst for the preparation of C2-C3 small molecule chemicals from sugars, characterized in that, The catalyst is the catalyst for preparing C2-C3 small molecule chemicals from saccharides as described in any one of claims 1 to 4. The preparation method includes the following steps: Dissolve metal oxide and PVP in absolute ethanol and carry out a hydrothermal reaction to synthesize metal oxide nanoparticles; Coat a SiO2 layer on the metal oxide nanoparticles to form a first product; Successively coat an L acid or basic site doped oxide layer and a weakly acidic oxide layer on the first product to form a second product; Calcine the second product to remove the pore-forming template PVP to form confined pores; Etch the SiO2 layer coated on the metal oxide nanoparticles of the calcined second product with a NaOH solution to form a cavity; Under a reducing gas atmosphere, purge the product in the above steps to obtain the target catalyst.

6. The preparation method of a catalyst for catalytically preparing C2-C3 small molecule chemicals from saccharides according to claim 5, characterized in that, The method for coating a SiO2 layer on the metal oxide nanoparticles includes the following steps: After cooling the hydrothermal reaction solution, add deionized water and ammonia water, mix evenly, and slowly dropwise add an ethanol solution of tetraethyl orthosilicate (TEOS) while stirring.

7. The method for preparing a catalyst for catalytically preparing C2-C3 small molecule chemicals from saccharides according to claim 6, characterized in that, The method for successively coating an L acid or basic site doped oxide layer and a weakly acidic oxide layer on the first product includes the following steps: In the hydrothermal reaction solution after dropping the ethanol solution of tetraethyl orthosilicate (TEOS), slowly dropwise add an ethanol solution of zirconium butoxide or tetrabutyl titanate, then dropwise add an aqueous solution of SnCl4•5H2O while stirring. After reacting for a period of time, slowly dropwise add an ethanol solution of tetrabutyl titanate while stirring and continue to react for a period of time, then rotary evaporate to remove the solvent and dry.

Images