Hydrogen production catalyst for alcohol reforming and method for preparing the same

Abstract

The application discloses an alcohol reforming hydrogen production catalyst and a preparation method thereof, and relates to the technical field of catalytic reforming catalysts. Step one is to load Cu on titanium nanotubes to obtain copper titanium nanotubes (CuNTs); step two is to modify different functional group molecules on the copper titanium nanotubes to increase repulsive force between the nanotubes; step three is to add the copper titanium nanotubes into a mixed aqueous solution of short-chain polyacrylamide (PAM) and triethanolamine, control the temperature at 50-70 DEG C, stir for 1-2 h, add ethyl n-butyrate and n-hexane after the stirring is completed, stir for 8-12 h, then take out the product, and wash, dry and calcine the product to obtain the alcohol reforming hydrogen production catalyst. The application has the advantages that the functional groups on the titanium nanotubes can change the surface properties of the titanium nanotubes and reduce the mutual attraction between the nanotubes; the carboxylic acid functional groups modified on the titanium nanotubes can increase the repulsive force between the titanium nanotubes and prevent the nanotubes from agglomerating; and copper has good catalytic activity and selectivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic reforming, in particular to an alcohol reforming hydrogen catalyst and a preparation method thereof. BACKGROUND

[0002] Energy is an important issue related to the national economy and people's livelihood, and hydrogen energy is an ideal clean energy. Hydrogen production technology has become a widely concerned topic among domestic and foreign researchers. Alcohol reforming hydrogen production is a technology that uses alcohol (including monohydric alcohol, dihydric alcohol, and trihydric alcohol) as raw material to produce hydrogen. In industry, hydrogen is often produced by gas-phase reforming. However, the reforming reaction is a strong endothermic reaction that requires high temperature. At high temperatures, alcohol pyrolysis is easy to deposit carbon on the surface of the catalyst, reducing the probability of contact between the active component and the reaction raw material, and thus reducing the catalytic effect and even deactivating the catalyst. The ultimate goal of clean energy production is to achieve high selectivity for the products required by multiple pathways while maintaining activity and stability. In order to solve the problem of easy deactivation of nanocatalysts at high temperatures, various methods have been studied, such as embedding nanometer particles into the pores or channels of pre-synthesized mesoporous materials such as SBA or MCM series, carbon nanotubes, and metal organic frameworks (MOF); preparing materials with stronger interaction between nanometer particles and carriers, such as perovskite, spinel, hydrotalcite, and layered double hydroxide, as well as bimetallic alloy nanoparticle supported catalysts. Alcohol reforming reaction is a chemical reaction that converts alcohol compounds into hydrogen and carbon dioxide at high temperature and high pressure. This reaction is an important method for hydrogen production because alcohol compounds are a renewable resource, and the carbon dioxide produced by the reaction can be recycled.

[0003] Patent No. CN101530801A discloses a carbon nanotube supported nickel catalyst, its preparation method and application. The catalyst is composed of 10%-35% mass percentage of nickel metal and 65%-90% mass percentage of carbon nanotubes. The catalyst reduces the energy consumption in the process of bio-oil hydrogen production, and through the synergistic effect of the active component, it improves the bio-oil conversion rate, hydrogen production rate, and catalyst service life, which is conducive to the integration of biomass fast pyrolysis for bio-oil technology and reforming bio-oil for hydrogen production technology. However, the service life of the catalyst is limited, and after continuous operation for 12 hours, the conversion rate of the raw material bio-oil will sharply decrease, leading to serious deactivation. Therefore, we propose an alcohol reforming hydrogen catalyst and a preparation method thereof. SUMMARY

[0004] The present application aims to provide an alcohol reforming hydrogen catalyst and a preparation method thereof.

[0005] To solve the problems raised in the above background technology, the present application provides the following technical solution: an alcohol reforming hydrogen catalyst preparation method, the steps of which are as follows:

[0006] Step one, load Cu on the titanium nanotube to obtain copper titanium nanotube (CuNTs);

[0007] Step two, modify different functional group molecules on the copper titanium nanotube to increase the repulsive force between the nanotubes;

[0008] Step three, add the copper titanium nanotube to a mixed aqueous solution of short chain polyacrylamide (PAM) and triethanolamine, control the temperature at 50-70 DEG C, stir for 1-2 h, then add ethyl n-butyrate and n-hexane after stirring, take out the product, wash, dry and calcine to prepare an alcohol reforming hydrogen catalyst.

[0009] As a further scheme of the application, in step one, the titanium nanotube is soaked in a copper nitrate aqueous solution, copper ions are reduced to copper particles by chemical reaction and deposited on the surface of the titanium nanotube, and the concentration of the copper nitrate aqueous solution is 0.20 mol / L.

[0010] As a further scheme of the application, in step two, an acid catalyzed esterification reaction is carried out, carboxylic acid reacts with alcohol to form ester under the catalysis of alcohol and acid, and the ester is modified on the titanium nanotube.

[0011] As a further scheme of the application, in step three, the mass ratio of ethyl n-butyrate to the copper loaded CuNTs is 1:6, preferably 2.5:5.2, and more preferably 2.5:4.

[0012] As a further scheme of the application, in step three, the mass ratio of short chain polyacrylamide to the copper loaded CuNTs is 2:1, and the mass ratio of triethanolamine to the copper loaded CuNTs is 8:1, preferably 1.8:1 and 9:1.

[0013] As a further scheme of the application, in step three, stirring is carried out at 55 DEG C for 1.5 h, then ethyl n-butyrate and n-hexane are added and stirring is continued for 12 h.

[0014] As a further scheme of the application, in step three, the stirring speed is 150-350 r / min, and preferably 300 r / min.

[0015] As a further scheme of the application, in step three, inert gas is added for calcination, and calcination is carried out at 500-600 DEG C for 1.5-3 h, preferably at 550 DEG C for 2.5 h.

[0016] As a further scheme of the present application: in step three, the product is taken out and needs to be cleaned for 3-5 times, and is subjected to drying treatment at 105 DEG C, and the whole process needs to be subjected to sterile treatment.

[0017] The application discloses an alcohol reforming hydrogen production catalyst and a preparation method thereof.

[0018] Compared with the prior art, the application has the beneficial effects that:

[0019] 1、The functional groups are modified on the titanium nanotubes, the surface properties of the titanium nanotubes can be changed, and the mutual attraction between the nanotubes is reduced.

[0020] 2、The titanium nanotubes are soaked in a copper nitrate-containing aqueous solution, and the copper ions are reduced into copper particles through a chemical reaction and are deposited on the surface of the titanium nanotubes. Specific embodiments

[0021] The specific embodiments of the application are further described in combination with the tables. It should be noted that the description of the embodiments is used to help understand the application, but does not constitute a limitation on the application. In addition, the technical features involved in the various embodiments of the application described below can be combined with each other as long as they do not conflict with each other.

[0022] The application discloses an alcohol reforming hydrogen production catalyst and a preparation method thereof.

[0023] Step one, loading Cu on the titanium nanotubes to obtain copper titanium nanotubes (CuNTs);

[0024] Step two, modifying different functional group molecules on the copper titanium nanotubes to increase the repulsion between the nanotubes;

[0025] Step three, the copper titanium nanotube is added into the mixed aqueous solution of short chain polyacrylamide (PAM) and triethanolamine, the temperature is controlled at 50-70℃, and stirring is carried out for 1-2h, then ethyl n-butyrate and n-hexane are added and stirring is carried out for 8-12h, then the product is taken out, washed, dried, and calcined to obtain the alcohol reforming hydrogen catalyst.

[0026] In an embodiment of the present application, in step one, the titanium nanotube is soaked in the copper nitrate aqueous solution, copper ions are reduced to copper particles on the surface of the titanium nanotube through chemical reaction, and the concentration of the copper nitrate aqueous solution is 0.20 mol / L.

[0027] In an embodiment of the present application, in step two, the carboxylic acid is reacted with alcohol to form ester through acid-catalyzed esterification under the catalysis of alcohol and acid, and the ester is modified on the titanium nanotube.

[0028] In an embodiment of the present application, in step three, the mass ratio of ethyl n-butyrate to the copper-loaded CuNTs is 1:6, preferably, the mass ratio of ethyl n-butyrate to the copper-loaded CuNTs is 2.5:5.2, and more preferably, the mass ratio of ethyl n-butyrate to the copper-loaded CuNTs is 2.5:4.

[0029] In an embodiment of the present application, in step three, the mass ratio of short chain polyacrylamide to the copper-loaded CuNTs is 2:1, and the mass ratio of triethanolamine to the copper-loaded CuNTs is 8:1, preferably, the mass ratio of short chain polyacrylamide to the copper-loaded CuNTs is 1.8:1, and the mass ratio of triethanolamine to the copper-loaded CuNTs is 9:1.

[0030] In an embodiment of the present application, in step three, stirring is carried out at 55℃ for 1.5h, then ethyl n-butyrate and n-hexane are added and stirring is continuously carried out for 12h.

[0031] In an embodiment of the present application, in step three, the stirring speed is 150-350r / min, and preferably, the stirring speed is 300r / min.

[0032] In an embodiment of the present application, in step three, inert gas is added during calcination, and calcination is carried out at 500-600℃ for 1.5-3h, preferably, calcination is carried out at 550℃ for 2.5h.

[0033] In an embodiment of the present application, in step three, the product is washed for 3-5 times after being taken out, and drying treatment is carried out at 105℃, and the whole process needs to be sterile.

[0034] The protective gas is a gas not participating in the reaction. In an embodiment of the present application, the protective gas is nitrogen or an inert gas, such as helium, neon, argon, krypton, xenon, and the like. In order to save cost, in the embodiments of the present application, the protective gas is nitrogen.

[0035] The method commonly used in the art for loading copper on the titanium nanotube is suitable for the present application. In an embodiment of the present application, the specific implementation of step one is as follows: after dissolving the titanium nanosheet tube, a mixed solution is obtained by adding a (NH4)2CO3 solution with a concentration of 1 mol / L and a CuCl2·2H2O solution with a concentration of 1.2 mol / L; the mixed solution is irradiated with 365 nm ultraviolet light for 10-15 min under the condition of -15℃ to -20℃, and then washed and dried.

[0036] The alcohol reforming hydrogen catalyst is prepared by the above method. The catalyst is a high-stability catalytic reforming catalyst with metal limitation, and can catalyze alcohol reforming to produce hydrogen, has good selectivity, high glycerol conversion rate, and good stability.

[0037] The alcohol reforming hydrogen catalyst is suitable for reforming hydrogen reactions of various monohydric alcohols, dihydric alcohols, or trihydric alcohols, etc. The alcohol reforming hydrogen includes, but is not limited to, ethanol reforming hydrogen, methanol reforming hydrogen, ethylene glycol reforming hydrogen, sorbitol reforming hydrogen, glycerol reforming hydrogen, and the like.

[0038] In the method of the present application, a shell layer is coated on the pre-synthesized nanoparticles to construct a core / shell nanostructure, so that the core / shell nanostructure has a limitation effect, which has a significant effect on inhibiting sintering and carbon deposition. The effects mainly include the following three aspects: first, sintering of the active component is inhibited, thereby improving the stability of the catalyst and inhibiting carbon deposition; second, the core material and the shell material have a relatively close contact and a relatively large contact area, so that the interaction between the two is relatively strong; and third, the active site is specially designed, which greatly improves the activity and selectivity of the catalyst.

[0039] The specific embodiments of the present application are further described below in conjunction with examples, and the present application is not limited in the scope of the described examples.

[0040] Example 1

[0041] According to the proportion of 1 g of copper titanium nanotube mixed with 50 ml of concentrated nitric acid, the mixture is stirred in a 140℃ oil bath for 12 h, filtered, repeatedly washed with deionized water until neutral, and then placed in a 105℃ oven for drying for 12 h to obtain titanium oxide nanotubes.

[0042] Take 1, 2 g of titanium oxide nanotube, mix according to the mass ratio of titanium oxide nanotube: xylene = 1:15, stir for 3h, then immerse the titanium nanotube in a copper nitrate aqueous solution, stir in a water bath at 80℃ until dry, put it into a 105℃ oven and dry for 12h, put the dried sample into a tube furnace, pass nitrogen, keep at 30℃ for 8h, raise the temperature from 30℃ to 450℃ and keep for 5h, naturally cool in inert gas, obtain the loaded copper titanium nanotube, reduce copper ions to copper particles by chemical reaction, deposit on the surface of titanium nanotube, the concentration of copper nitrate aqueous solution is 0.20mol / L.

[0043] Disperse 1g of copper titanium nanotube into 100g of ionized water, ultrasonic treatment for 15min, then add to a mixed solution containing 1.1g of short chain polyacrylamide, 0.5g of triethanolamine and 90g of deionized water, continuously stir the prepared solution at a stable 70℃ environment for 1h, the stirring rate is 300r / min, then add a mixed solution composed of 2g of tetraethyl silicate and 60ml of n-ethane, magnetically stir the reaction at 60-70℃ for 10h, repeatedly wash the obtained product with ethanol and suction filter, then put it into a 100℃ vacuum oven and dry for 12h, put the dried product sample into a tube furnace and calcine at 550℃ for more than 2h, add inert gas nitrogen in the tube furnace, finally obtain the product copper mesoporous silicon carbon nanotube (Cu-MPS-CNTs), and standardize it as Cu-MPS-CNTs-2.

[0044] Example two:

[0045] Mix 1g of copper titanium nanotube with 50ml of concentrated nitric acid, stir in a 140℃ oil bath for 12h, filter, repeatedly wash with deionized water until neutral, then put it into a 105℃ oven and dry for 12h, obtain the titanium oxide nanotube.

[0046] Take 1, 2 g of titanium oxide nanotube, mix according to the mass ratio of titanium oxide nanotube: xylene = 1:15, stir for 3h, then immerse the titanium nanotube in a copper nitrate aqueous solution, stir in a water bath at 80℃ until dry, put it into a 105℃ oven and dry for 12h, put the dried sample into a tube furnace, pass nitrogen, keep at 30℃ for 8h, raise the temperature from 30℃ to 450℃ and keep for 5h, naturally cool in inert gas, obtain the loaded copper titanium nanotube, reduce copper ions to copper particles by chemical reaction, deposit on the surface of titanium nanotube, the concentration of copper nitrate aqueous solution is 0.20mol / L.

[0047] 1 g of copper titanate nanotubes was dispersed in 100 g of ionized water solution, and after ultrasonic treatment for 15 min, it was added to a mixed solution containing 1.1 g of short-chain polyacrylamide, 0.5 g of triethanolamine and 90 g of deionized water. The prepared solution was continuously stirred at a stirring rate of 300 r / min in a stable environment at 70°C for 1 h, and then a mixed solution of 1 g, 2 g, 3 g and 4 g of tetraethyl silicate and 60 ml of n-ethane was added and magnetically stirred at 60-70°C for 10 h. The rest of the samples were the same as in Example 1. The obtained product was repeatedly washed and filtered with ethanol and then dried in a vacuum oven at 100°C for 12 h. The dried product sample was placed in a tube furnace and calcined at 550°C for more than 2 h. Inert nitrogen gas was added to the tube furnace. Finally, the products were labeled as Cu-MPS-CNTs-1, Cu-MPS-CNTs-2, Cu-MPS-CNTs-3 and Cu-MPS-CNTs-4.

[0048] The catalytic properties of the four groups of samples prepared in Examples 1 and 2 were determined under the following conditions: 10 wt.% glycerol aqueous solution, 150 mg of catalyst, reduction temperature 500°C, reaction temperature 400°C, feed rate 0.1 ml / min, and nitrogen flow rate 60 ml / min.

[0049] wherein Conversion (Gas) is a calculation formula for the conversion rate of carbon-containing gas phase products:

[0050] Conversion (Gas) = nout,CH4+ nout,CO + nout,CO2 / 3 x (nin,glycerol- nout,glycerol) x 100%

[0051] wherein nin,glycerol and nout,glycerol represent the total amount of glycerol input into the system and the total amount of glycerol in the product, respectively, within 1 h, and nout,CH4, nout,CO and nout,CO2 represent the total amount of CO, CO2 and CH4 in the product, respectively, within 1 h.

[0052]

[0053] From the above table, it can be seen that the glycerol conversion rate is the highest when Cu-MPS-CNTs-3, and the carbon-containing gas phase product conversion rate is also the highest, the glycerol conversion rate and the carbon-containing gas phase product conversion rate of Cu-MPS-CNTs-4 are the lowest, generally, the higher the carbon-containing gas phase product conversion rate, the better the reaction efficiency and the catalyst performance, changing the amount of added tetraethyl silicate can change the catalyst performance of the product, and according to the table, it can be analyzed that the catalyst activity and stability of the silica shell coated catalyst are greatly improved, which shows that the alcohol reforming hydrogen catalyst copper mesoporous silicon carbon nanotube (Cu-MPS-CNTs) can be obtained by the method

[0054] In the description of the specification, the description of the terms "one embodiment", "example", "specific example" and the like means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the description of the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0055] The above is only an example and description of the present application, and those skilled in the art can make various modifications or supplements or replace with similar ways in the specific embodiments described, as long as they do not deviate from the invention or exceed the scope defined by the present claims, which shall fall within the protection scope of the present application.

[0056] The above describes the embodiments of the present application in detail in combination with the table, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and modifications can be made to these embodiments without departing from the principles and spirits of the present application, which still fall within the protection scope of the present application.

[0057] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can make equivalent replacement or change according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application.

Claims

1. A method for preparing a catalyst for hydrogen production by alcohol reforming, characterized by: 1 g of titanium nanotubes was mixed with 50 ml of concentrated nitric acid, stirred in an oil bath at 140 ℃ for 12 h, filtered and washed with deionized water until neutral, and then dried in an oven at 105 ℃ for 12 h to obtain titanium oxide nanotubes; 1.2 g of titanium oxide nanotubes was mixed with 15 g of xylene according to a mass ratio of 1:15, stirred for 3 h, and then immersed in a copper nitrate aqueous solution, stirred in a water bath at 80 ℃ until dry, dried in an oven at 105 ℃ for 12 h, and then placed in a tube furnace, nitrogen was introduced, and the temperature was kept at 30 ℃ for 8 h, then increased to 450 ℃ and kept for 5 h, and then naturally cooled in an inert gas, to obtain copper-loaded titanium nanotubes, copper ions were reduced to copper particles by chemical reaction and deposited on the surface of the titanium nanotubes, and the concentration of the copper nitrate aqueous solution was 0.20 mol / L; 1 g of copper titanium nanotubes was dispersed in 100 g of ionized water, ultrasonically treated for 15 min, and then added to a mixed solution containing 1.1 g of short-chain polyacrylamide, 0.5 g of triethanolamine, and 90 g of deionized water, the prepared solution was continuously stirred at a speed of 300 r / min in a stable environment at 70 ℃ for 1 h, then a mixed solution of 2 g of tetraethyl silicate and 60 ml of n-ethane was added, and the mixture was magnetically stirred at 60-70 ℃ for 10 h, the obtained product was repeatedly washed and filtered with ethanol, and then dried in a vacuum oven at 100 ℃ for 12 h, the dried product sample was placed in a tube furnace and calcined at 550 ℃ for more than 2 h, an inert atmosphere of nitrogen was introduced into the tube furnace, and finally the product copper mesoporous silicon carbon nanotubes were obtained.

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