A melt-alkalized attapulgite / platinum-based transition bimetallic catalyst and its preparation method and application

Abstract

The present invention discloses a melt-alkalized attapulgite / platinum-based transition bimetallic catalyst and its preparation method and application. The catalyst includes a carrier and an active component supported on the carrier, the carrier being melt-alkalized attapulgite, the active component being platinum and a transition metal, and the transition metal being selected from iron, cobalt, nickel and copper. The catalyst of the present invention can be applied to glycerol aqueous phase reforming hydrogen production and value-added products in the absence of an additional hydrogen source. Its stronger acid site is conducive to the dehydration of glycerol to form hydroxyacetone, and further hydrogenation on the acid site generates value-added products such as 1,2-propylene glycol and 1,3-propylene glycol, showing good prospects for industrial application.

Description

Technical Field

[0001] The present invention relates to the field of catalyst technology, and in particular to a melt-alkalized attapulgite / platinum-based transition bimetallic catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Glycerol is an inexpensive renewable resource, typically obtained from renewable feedstocks (including vegetable oils, animal fats, and lignocellulose) through hydrolysis or hydrodeoxygenation. Hydrogen energy, as a new renewable energy source, holds great promise for development. Aqueous phase reforming (APR) is a promising method for producing inexpensive, renewable hydrogen from glycerol, attracting extensive research due to its low temperature and the absence of glycerol and water evaporation.

[0003] In addition, the catalytic conversion of glycerol into high-value-added products is also an important decision for sustainable production. The added value of residual glycerol through catalytic conversion has attracted widespread attention. For example, propanol, propylene glycol or C3 hydrocarbons (propylene, propane) can be obtained from glycerol through a deoxygenation process. The catalytic hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PDO) is a very effective glycerol conversion pathway because 1,2-propylene glycol can be widely used in the production of polyester resins and pharmaceuticals, and 1,3-propylene glycol (1,3-PDO) has high industrial demand as a monomer of polytrimethyl terephthalate (PTT). The catalytic production of 1,3-propylene glycol through the selective hydrogenolysis of glycerol is one of the most promising industrial application reactions in the field of biomass catalysis.

[0004] However, traditional hydrogenolysis requires a high-pressure hydrogen atmosphere and a relatively high reaction temperature (generally 260-280°C), which often incurs higher costs. The current research focus is on how to reduce costs while achieving better hydrogen production efficiency and selectivity for value-added liquid products through catalyst design. Summary of the Invention

[0005] The main purpose of the present invention is to provide a catalyst having low reaction condition requirements, high conversion efficiency and selectivity, and capable of catalyzing glycerol aqueous phase reforming to produce hydrogen and value-added products without an additional hydrogen source, as well as a preparation method and application thereof.

[0006] To achieve the above objectives, the present invention provides a melt-alkalized attapulgite / platinum-based transition bimetallic catalyst, comprising a carrier and an active component supported on the carrier, wherein the carrier is melt-alkalized attapulgite, the active component is platinum and a transition metal, and the transition metal is selected from iron, cobalt, nickel and copper.

[0007] Furthermore, the content of platinum is 1 to 5 wt %, and the content of transition metal is 5 to 10 wt %.

[0008] Furthermore, the molten alkalized attapulgite is prepared by the following method: placing the attapulgite in a sodium hydroxide ethanol solution, heating and stirring until the ethanol is completely evaporated, drying the remaining solid, and then heating it to 550-700°C at a heating rate of 1-5°C / min and calcining it for 5-10 hours, cooling the calcined product, adding deionized water, stirring and dispersing it, and then standing it, taking out the flocculent layer, filtering and washing it with deionized water, and drying the filter cake to obtain the molten alkalized attapulgite.

[0009] Furthermore, the concentration of the sodium hydroxide ethanol solution is 3-5 mol / L, and the ratio of attapulgite to the sodium hydroxide ethanol solution is 40 g:1 L.

[0010] Furthermore, the temperature condition of the heating and stirring treatment is 150 to 220°C.

[0011] Furthermore, the drying process is carried out at a temperature of 105 to 120° C. and for a time of 12 to 24 hours.

[0012] Furthermore, the drying process is carried out at a temperature of 105 to 120° C. and for a time of 12 to 24 hours.

[0013] The present invention also provides a method for preparing the above-mentioned melt-alkalized attapulgite / platinum-based transition bimetallic catalyst, comprising the following steps: dissolving precursor salts of platinum and transition metals in anhydrous ethanol, adding the melt-alkalized attapulgite, then heating and stirring until the ethanol is completely evaporated, drying the remaining solid, grinding it into powder, and finally calcining it in an air atmosphere, and then cooling it to room temperature to obtain the melt-alkalized attapulgite / platinum-based transition bimetallic catalyst.

[0014] Furthermore, the temperature condition of the heating and stirring treatment is 80 to 95°C.

[0015] Furthermore, the drying treatment conditions are a temperature of 105 to 120° C. and a time of 12 to 24 hours.

[0016] Furthermore, the specific process of the calcination treatment is: heating the temperature to 400-700° C. at a heating rate of 5-10° C. / min, and then calcining at this temperature for 6-24 hours.

[0017] The present invention also provides the use of the melt-alkalized attapulgite / platinum-based transition bimetallic catalyst in catalyzing the aqueous phase reforming of glycerol to produce hydrogen and value-added products.

[0018] The present invention also provides the above-mentioned method for catalyzing the aqueous phase reforming of glycerol to produce hydrogen and value-added products, comprising the following steps: placing glycerol, deionized water, and the molten alkalized attapulgite / platinum-based transition bimetallic catalyst according to any one of claims 1 to 4 into a reactor, and conducting a sealed reaction under a nitrogen atmosphere.

[0019] Furthermore, the mass ratio of glycerol, water and catalyst is 9:21:0.1-0.5, and the reaction conditions are temperature 200-240° C. and time 1-4 h.

[0020] Attapulgite is a kind of aluminosilicate with high silicon content. It has a well-developed internal void structure, large surface area and strong adsorption capacity. It can fully disperse catalytic active components and adsorb reactant molecules. Using attapulgite as a carrier, the alkaline attapulgite is synthesized by high-temperature melting under the action of inorganic base. It not only retains the high structural stability of attapulgite, but also effectively destroys the original skeleton silicon and aluminum through molten alkali treatment, effectively improving the acidity of the carrier, thereby carrying out oxidative dehydrogenation and hydrogenation reactions of glycerol and intermediates at more acid sites, increasing the yield of 1,2-propylene glycol and 1,3-propylene glycol, but also optimizing the specific surface area and pore structure, which is conducive to the high dispersion of loaded metals.

[0021] Precious metal platinum effectively promotes the dehydrogenation reaction in glycerol molecules. During the aqueous phase reforming of glycerol, platinum catalysts adsorb glycerol molecules and activate C-H bonds, allowing them to dehydrogenate to produce hydrogen and other products (such as propylene glycol, ethylene, and propene). Transition metal oxides (Ni, Co, Fe, and Cu) not only enhance the sintering resistance of the active metals by interacting with the active components and support, but also offer high surface oxygen vacancy concentrations that promote H2O activation and increase the number of active oxygen species on the catalyst surface, favoring the water gas shift reaction (WGS) and promoting the forward reaction. This promotes the conversion of carbon-containing intermediates (C=O, C=C, and C=CH) into small carbon-containing molecules (CH4 and CO2), thereby suppressing carbon deposition. Fe2O3 and Co3O4, as multivalent metal oxides, possess excellent redox properties and high oxygen mobility. The present invention utilizes a melt-alkalized attapulgite / platinum-based transition bimetallic catalyst to facilitate the removal of carbon deposits on the catalyst surface, while enhancing the metal-support / metal oxide interlayer interaction and anchoring the active precious metal platinum.

[0022] The beneficial effects of the present invention are embodied in:

[0023] 1. The melt-alkalized attapulgite prepared by the present invention is green, economical, and highly structurally stable. It has a developed pore structure and a large specific surface area, which allows glycerol molecules with a kinetic diameter of 0.61 nm to enter its pores, significantly improving the adsorption and activation ability of glycerol molecules.

[0024] 2. The catalyst of the present invention adopts the construction of Pt-based and transition element bimetallic active metal sites, which can ensure that the catalyst has good dehydrogenation performance, accelerate the cracking of glycerol CH, OH and CC bonds, and further promote the production of H2.

[0025] 3. Compared to single-supported transition metal catalysts, the catalyst of this invention enhances the interaction between the active component and the support by creating dual sites of Pt and transition metal, improving the active metal's resistance to sintering. Furthermore, the catalyst surface has a higher number of oxygen vacancies, which promotes water activation and facilitates the water-gas shift reaction (WGS), further increasing hydrogen production. It also facilitates CO2 activation and increases the number of active oxygen species on the catalyst surface, thereby promoting the removal of carbon deposits. As a result, the catalyst exhibits high resistance to active component sintering and carbon deposition, as well as high catalytic stability, meeting the requirements for industrial catalyst use.

[0026] 4. The catalyst of the present invention can be used for the aqueous phase reforming of glycerol to produce hydrogen and value-added products without an additional hydrogen source. Its strong acid sites facilitate the dehydration of glycerol to form hydroxyacetone, which is then further hydrogenated at the acid sites to produce value-added liquid products such as 1,2-propylene glycol and 1,3-propylene glycol, showing good prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The raw material is attapulgite and melt-alkalized attapulgite 29 Si NMR spectroscopy.

[0028] Figure 2 The raw material is attapulgite and melt-alkalized attapulgite 27 A1 NMR spectrum.

[0029] Figure 3 This is the TEM image of the raw material attapulgite.

[0030] Figure 4 This is the TEM image of melt-alkalized attapulgite.

[0031] Figure 5 These are the N2 adsorption-desorption isotherms and pore size distribution diagrams of the raw material attapulgite.

[0032] Figure 6 These are the N2 adsorption-desorption isotherms and pore size distribution diagrams of melt-alkalized attapulgite.

[0033] Figure 7 These are the XRD patterns of raw material attapulgite, melt-alkalized attapulgite, and various catalysts. DETAILED DESCRIPTION

[0034] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0035] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial channels or by existing known methods; unless otherwise specified, the methods used in the examples of the present invention are methods known to those skilled in the art.

[0036] Example 1

[0037] Preparation of Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0038] The theoretical content of the catalyst components prepared in this embodiment is: 1 wt% of platinum (Pt), 5 wt% of cobalt (Co), and the remainder is melt-alkalized attapulgite; the specific preparation method is as follows:

[0039] (1) 40 g of raw material attapulgite was placed in 1 L, 3 mol / L sodium hydroxide ethanol solution, and stirred at a temperature of 150 ° C and a rotation speed of 400 r / min until the ethanol was completely evaporated. The remaining solid was dried at 120 ° C for 12 h, and then placed in a muffle furnace and heated to 550 ° C at a heating rate of 1 ° C / min and calcined for 10 h. After the calcined product was cooled to room temperature, 2 L of deionized water was added, stirred and dispersed, and then allowed to stand for 30 min. At this time, a precipitate was deposited at the bottom of the water body, and flocs were suspended in the upper layer of the water body. The floc layer was taken out and filtered and washed with deionized water until neutral. The filter cake was dried at 105 ° C for 24 h to obtain melt-alkalized attapulgite.

[0040] (2) 0.0323 g of platinum acetylacetonate and 0.2641 g of Co(NO3)2·6H2O were added to 100 mL of anhydrous ethanol and stirred thoroughly to dissolve to form a uniform solution. Then, 1.0000 g of molten alkalized attapulgite was added to the above solution and stirred at 95 °C and 100 r / min until all the ethanol evaporated. The remaining solid was dried at 105 °C for 24 h and then ground into solid powder. The solid powder was placed in a tube furnace and heated to 700 °C at a rate of 10 °C / min under a 100 mL / min air flow. Then, the mixture was calcined at 700 °C for 6 h and cooled naturally to room temperature to obtain a molten alkalized attapulgite / platinum-based transition bimetallic catalyst with a platinum content of 1 wt% and a cobalt content of 5 wt%, which was recorded as 1Pt5Co / A-OH.

[0041] Example 2

[0042] Preparation of Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0043] The theoretical content of the catalyst components prepared in this embodiment is: 1 wt% of platinum (Pt), 5 wt% of nickel (Ni), and the remainder is melt-alkalized attapulgite; the specific preparation method is as follows:

[0044] (1) 40 g of raw material attapulgite was placed in 1 L, 4 mol / L sodium hydroxide ethanol solution, and stirred at a temperature of 170 ° C and a rotation speed of 400 r / min until the ethanol was completely evaporated. The remaining solid was dried at 115 ° C for 16 h, and then placed in a muffle furnace and heated to 600 ° C at a heating rate of 2 ° C / min for 8 h. After the calcined product was cooled to room temperature, 2 L of deionized water was added, stirred and dispersed, and then allowed to stand for 30 min. At this time, a precipitate was deposited at the bottom of the water body, and flocs were suspended in the upper layer of the water body. The floc layer was taken out and filtered and washed with deionized water until neutral. The filter cake was dried at 110 ° C for 20 h to obtain melt-alkalized attapulgite;

[0045] (2) 0.0323 g of platinum acetylacetonate and 0.2650 g of Ni(NO3)2·6H2O were added to 100 mL of anhydrous ethanol and stirred thoroughly to dissolve to form a uniform solution. Then, 1.0000 g of molten alkalized attapulgite was added to the above solution and stirred at 90 °C and 100 r / min until all the ethanol was evaporated. The remaining solid was dried at 110 °C for 20 h and then ground into solid powder. The solid powder was placed in a tube furnace and heated to 600 °C at a rate of 8 °C / min under an air flow of 100 mL / min. Then, the mixture was calcined at a constant temperature of 600 °C for 12 h and finally cooled naturally to room temperature to obtain a molten alkalized attapulgite / platinum-based transition bimetallic catalyst with a platinum content of 1 wt% and a nickel content of 5 wt%, which was recorded as 1Pt5Ni / A-OH.

[0046] Example 3

[0047] Preparation of Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0048] The theoretical content of the catalyst components prepared in this embodiment is: 1 wt% of platinum (Pt), 5 wt% of iron (Fe), and the remainder is melt-alkalized attapulgite; the specific preparation method is as follows:

[0049] (1) 40 g of raw material attapulgite was placed in 1 L, 4 mol / L sodium hydroxide ethanol solution, and stirred at a temperature of 200 ° C and a rotation speed of 400 r / min until the ethanol was completely evaporated. The remaining solid was dried at 110 ° C for 20 h, and then placed in a muffle furnace and heated to 650 ° C at a heating rate of 3 ° C / min and calcined for 7 h. After the calcined product was cooled to room temperature, 2 L of deionized water was added, stirred and dispersed, and then allowed to stand for 30 min. At this time, a precipitate was deposited at the bottom of the water body, and flocs were suspended in the upper layer of the water body. The floc layer was taken out and filtered and washed with deionized water until neutral. The filter cake was dried at 115 ° C for 16 h to obtain melt-alkalized attapulgite.

[0050] (2) 0.0323 g of platinum acetylacetonate and 0.3868 g of Fe(NO3)2·9H2O were added to 100 mL of anhydrous ethanol and stirred thoroughly to dissolve to form a uniform solution. Then, 1.0000 g of molten alkalized attapulgite was added to the above solution and stirred at 80 °C and 100 r / min until all the ethanol evaporated. The remaining solid was dried at 115 °C for 16 h and then ground into solid powder. The solid powder was placed in a tube furnace and heated to 500 °C at a rate of 6 °C / min under a 100 mL / min air flow. It was then calcined at a constant temperature of 500 °C for 18 h and finally cooled naturally to room temperature to obtain a molten alkalized attapulgite / platinum-based transition bimetallic catalyst with a platinum content of 1 wt% and an iron content of 5 wt%, which was recorded as 1Pt5Fe / A-OH.

[0051] Example 4

[0052] Preparation of Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0053] The theoretical content of the catalyst components prepared in this embodiment is: 1 wt% of platinum (Pt), 5 wt% of copper (Cu), and the remainder is melt-alkalized attapulgite; the specific preparation method is as follows:

[0054] (1) 40 g of raw material attapulgite was placed in 1 L, 5 mol / L sodium hydroxide ethanol solution, and stirred at a temperature of 220 ° C and a rotation speed of 400 r / min until the ethanol was completely evaporated. The remaining solid was dried at 105 ° C for 24 h, and then placed in a muffle furnace and heated to 700 ° C at a heating rate of 5 ° C / min for 5 h. After the calcined product was cooled to room temperature, 2 L of deionized water was added, stirred and dispersed, and then allowed to stand for 30 min. At this time, a precipitate was deposited at the bottom of the water body, and flocs were suspended in the upper layer of the water body. The floc layer was taken out and filtered and washed with deionized water until neutral. The filter cake was dried at 120 ° C for 12 h to obtain molten alkalized attapulgite.

[0055] (2) 0.0323 g of platinum acetylacetonate and 0.2033 g of Cu(NO3)2·3H2O were added to 100 mL of anhydrous ethanol and stirred thoroughly to dissolve to form a uniform solution. Then, 1.0000 g of molten alkalized attapulgite was added to the above solution and stirred at 85 °C and 100 r / min until all the ethanol evaporated. The remaining solid was dried at 120 °C for 12 h and then ground into solid powder. The solid powder was placed in a tube furnace and heated to 400 °C at a rate of 5 °C / min under a 100 mL / min air flow. It was then calcined at 400 °C for 24 h and finally cooled naturally to room temperature to obtain a molten alkalized attapulgite / platinum-based transition bimetallic catalyst with a platinum content of 1 wt% and a copper content of 5 wt%, which was recorded as 1Pt5Cu / A-OH.

[0056] Example 5

[0057] Preparation of Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0058] In this example, the catalyst was prepared according to the same method as in Example 3, except that the amount of Fe(NO3)2·9H2O was adjusted to 0.7349 g. Finally, a molten alkalized attapulgite / platinum-based transition bimetallic catalyst with a Pt content of 1 wt% and an iron content of 10 wt% was obtained, which was recorded as 1Pt10Fe / A-OH.

[0059] Example 6

[0060] Preparation of Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0061] In this example, the catalyst was prepared according to the same method as in Example 3, except that the amount of platinum acetylacetonate was adjusted to 0.1615 g. Finally, a melt-alkalized attapulgite / platinum-based transition bimetallic catalyst having a Pt content of 5 wt% and an iron content of 5 wt% was obtained, which was recorded as 5Pt5Fe / A-OH.

[0062] Comparative Example 1

[0063] In this comparative example, a catalyst was prepared according to the same method as in Example 3, except that the molten alkalized attapulgite was replaced by raw attapulgite to obtain an attapulgite / platinum-based transition bimetallic catalyst with a platinum content of 1 wt% and an iron content of 5 wt%, which was recorded as 1Pt5Fe / A-Raw.

[0064] Comparative Example 2

[0065] In this comparative example, a catalyst was prepared according to the same method as in Example 3, except that the addition of platinum acetylacetonate was omitted and the amount of Fe(NO3)2·9H2O was adjusted to 0.3868 g, to obtain a molten alkalized attapulgite / iron metal catalyst with an Fe content of 5 wt%, which was recorded as 5Fe / A-OH.

[0066] Comparative Example 3

[0067] In this comparative example, the catalyst was prepared according to the same method as in Example 3, except that the addition of Fe(NO3)2·9H2O was omitted and the amount of platinum acetylacetonate was adjusted to 0.0323 g, to obtain a molten alkalized attapulgite / platinum metal catalyst with a Pt content of 1 wt%, which was recorded as 1Pt / A-OH.

[0068] Experimental Example 1

[0069] Structure Determination of Attapulgite and Melt-Alkalinized Attapulgite / Pt-Based Transition Bimetallic Catalysts

[0070] The structural analysis of the raw material attapulgite (denoted as A-Raw), the melt-alkalized attapulgite prepared in Example 3 (denoted as A-OH), and the catalysts prepared in Examples 1 to 5 was performed. The results are as follows: Figures 1 to 7 shown.

[0071] See also Figure 1 The raw material attapulgite has detection peaks of tetrahedral silicon at -92 and -97 ppm. After being treated with molten alkali, the alkalized attapulgite shows a large peak at -85 ppm belonging to tetrahedral silicon tetrasubstituted aluminum, indicating that the molten alkali treatment completely destroys the silicon skeleton unique to the original attapulgite.

[0072] See also Figure 2 Only one detection peak attributable to hexacoordinated aluminum was detected at 8 ppm in the raw material attapulgite. After being treated with molten alkali, the intensity of the detection peak at 8 ppm of the alkalized attapulgite increased eightfold, and a detection peak attributable to tetracoordinated aluminum was detected at 65 ppm, indicating that the molten alkali treatment destroyed the original aluminum skeleton and formed a carrier rich in tetracoordinated aluminum and hexacoordinated aluminum with high acid sites, which can effectively improve the oxidative decomposition performance of glycerol.

[0073] See also Figure 3 、 Figure 4 ,from Figure 3 The TEM image shows that the raw material attapulgite is a rod-shaped silicon-based material. After being treated with molten alkali, Figure 4 The TEM image shows that the molten alkalized attapulgite is an amorphous silicon-based carrier, indicating that the structural skeleton of the rod-shaped substrate of attapulgite is crushed under the condition of high-temperature molten alkali, forming an amorphous silicon-based carrier with a high specific surface area.

[0074] See also Figure 5 、 Figure 6 Through the isotherms and pore size distribution diagrams of attapulgite before and after melt alkalization treatment, it can be seen that the melt alkalized attapulgite has a type III isotherm and is accompanied by an H4 type hysteresis loop, which is an obvious mesoporous structure.

[0075] See also Figure 7 , XRD spectra of various metal loadings Figure 2 Characteristic diffraction peaks of Pt were detected at θ=39.8° and 46.4°, indicating successful loading of Pt. The catalyst used in the optimal group, Example 3, had lower characteristic peaks of Pt and Fe, indicating that Pt, Fe and the carrier had stronger interactions, promoting high dispersion of the metal.

[0076] Experimental Example 2

[0077] Catalytic Performance Test of Attapulgite and Melt-Alkalinized Attapulgite / Platinum-Based Transition Bimetallic Catalysts

[0078] Test method: Weigh 9g of glycerol, 21g of deionized water (the concentration of this glycerol aqueous solution system is 30wt%) and 0.1-0.5g of catalyst and add them to a high-pressure reactor, fill it with 1.0-4.0MPa high-purity nitrogen, and then seal it for reaction at a temperature of 200-240℃ and a stirring rate of 450-550r / min for 1-4h. After the reaction is completed, quickly cool it to room temperature with ice water, collect the gas product with an air bag, transfer it to a chromatograph to measure the gas product composition, open the reactor, and use a sand core funnel to separate the liquid and solid products; then, store the liquid product in a brown reagent bottle and measure its liquid product composition by gas chromatography.

[0079] The specific reaction conditions and results are shown in Table 1.

[0080] Table 1

[0081]

[0082] Note: Catalyst life refers to the usage time when the glycerol conversion rate of the catalyst decreases by 50%.

[0083] From the above results, it can be concluded that the present invention can achieve a high rate of hydrogen production under a nitrogen atmosphere. Moreover, in the absence of an additional hydrogen source, the catalyst can achieve self-transfer hydrogenolysis of glycerol molecules in a glycerol-water solvent system to generate value-added products 1,2-propylene glycol and 1,3-propylene glycol, achieving a glycerol conversion rate of more than 80%, wherein the 1,2-propylene glycol yield exceeds 25%, the 1,3-propylene glycol yield exceeds 23%, and the hydrogen production rate is above 300 μmol / g / min. Among them, the optimal group Example 3 can achieve a hydrogen production rate of 795 μmol / g / min, and the liquid products 1,2-propylene glycol and 1,3-propylene glycol generated by self-transfer hydrogenolysis of glycerol molecules have selectivities of 46% and 37%, respectively, and the glycerol conversion rate is as high as 92%. Comparing the two pure supports, the melt-alkalized attapulgite exhibited higher catalytic performance, indicating that the melt-alkali treatment effectively destroyed the original framework silicon and aluminum, effectively increasing the acidity of the support. This allowed for the oxidative dehydrogenation and hydrogenation of glycerol and intermediates at more acid sites, increasing the yields of 1,2-propylene glycol and 1,3-propylene glycol. Furthermore, the specific surface area and pore structure were optimized, facilitating high dispersion of the supported metals. Comparing the effects of varying platinum and iron loadings on catalysis, the appropriate platinum and iron content of Example 3 resulted in a higher hydrogen production rate and a higher selectivity for value-added liquid products.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products, characterized in that: The invention comprises a carrier and an active component loaded on the carrier, wherein the carrier is melt-alkalized attapulgite, the active component is platinum and a transition metal, and the transition metal is selected from iron, cobalt, nickel and copper; the melt-alkalized attapulgite is prepared according to the following method: placing the attapulgite in a sodium hydroxide ethanol solution, heating and stirring until the ethanol is completely evaporated, drying the remaining solid, then heating the temperature to 550-700°C at a heating rate of 1-5°C / min and calcining for 5-10 hours, cooling the calcined product, adding deionized water, stirring and dispersing the product, and then standing the product, removing the flocculent layer, filtering and washing the product with deionized water, and drying the filter cake to obtain the melt-alkalized attapulgite.

2. The attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products according to claim 1, characterized in that: The content of platinum is 1-5wt%, and the content of transition metal is 5-10wt%.

3. The attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products according to claim 1, characterized in that: The temperature condition for the heating and stirring treatment is 150 to 220°C.

4. The method for preparing the attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: dissolving precursor salts of platinum and transition metals in anhydrous ethanol, adding molten alkalized attapulgite, then heating and stirring until all the ethanol evaporates, drying the remaining solid, grinding it into powder, and finally calcining it in an air atmosphere, and then cooling it to room temperature to obtain the molten alkalized attapulgite / platinum-based transition bimetallic catalyst.

5. The method for preparing the attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products according to claim 4, characterized in that: The temperature condition for the heating and stirring treatment is 80 to 95°C.

6. The method for preparing the attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products according to claim 4, characterized in that: The specific process of the calcination treatment is: heating the temperature to 400-700°C at a heating rate of 5-10°C / min, and then calcining at this temperature for 6-24 hours.

7. A method for producing hydrogen and value-added products by catalytic aqueous phase reforming of glycerol, characterized in that: The following steps are involved: Glycerol, deionized water and the attapulgite / platinum-based transition bimetallic catalyst for catalyzing the melt alkalization of glycerol aqueous phase reforming to produce hydrogen and value-added products as claimed in any one of claims 1 to 3 are put into a reactor and a sealed reaction is carried out under a nitrogen atmosphere.

8. The method for producing hydrogen and value-added products by catalytic aqueous phase reforming of glycerol as claimed in claim 7, characterized in that: The mass ratio of glycerol, water and catalyst is 1:9-21:0.1-0.5, and the reaction conditions are temperature 200-240°C and time 1-4h.

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