CN116422366A - A kind of nickel-titanium layered mesoporous catalyst derived from attapulgite and its preparation method and application - Google Patents

Abstract

The invention discloses an attapulgite-derived nickel-titanium layer flaky mesoporous catalyst and a preparation method and application thereof, wherein the preparation method comprises the following steps: s1, dispersing attapulgite in a hydrochloric acid solution, and performing hydrothermal treatment to obtain an attapulgite-based silicon source; s2, reacting an attapulgite-based silicon source with a titanium source to obtain a reaction mixture containing Si-O-Ti polymer; s3, adding a template agent into the reaction mixture, and performing hydrothermal crystallization treatment to obtain a lamellar mesoporous zeolite carrier derived from attapulgite; s4, loading nickel on the carrier by an impregnation method to obtain the attapulgite-derived nickel-titanium layer lamellar mesoporous catalyst. The catalyst is applied to catalyzing biomass tar and a model object thereof to prepare hydrogen-rich gas by steam reforming, can realize the conversion rate of more than 95%, the hydrogen yield in the synthesis gas of more than 65%, the hydrogen selectivity of more than 70%, and the reaction for 30 hours still keeps higher activity, and has the advantages of environmental protection, high stability and low price.

Description

A kind of nickel-titanium layered mesoporous catalyst derived from attapulgite and its preparation method and application

technical field

The invention relates to the technical field of catalysts, in particular to an attapulgite-derived nickel-titanium layer-shaped mesoporous catalyst, a preparation method and application thereof.

Background technique

Catalytic steam reforming has attracted more and more attention because it can convert tar at low temperature (500-900°C) and produce high-value syngas and hydrogen-rich gas. The most important thing in catalytic steam reforming technology is the catalyst. Among various transition metals as catalysts, Ni-based catalysts promote the occurrence of WGS reactions due to their low cost and strong ability to break C-C bonds and C-H, O-H bonds. Widely used in restructuring.

However, because Ni-based catalysts are prone to deactivation due to carbon deposition and sintering of metallic nickel particles at high temperatures, many researchers have devoted themselves to exploring Ni-based catalysts with improved resistance to carbon deposition and sintering. Different promoters and supports are one of the solutions to improve catalyst life. For example, Yufei Zhao et al reported a titanium-modified attapulgite (ATP) as a support metal oxide catalyst to achieve alkali-resistant NOx catalytic reduction, through ion Exchange, without destroying the initial layered chain structure of ATP, remove the alkali metal cation impurities in ATP, and obtain Ti-modified ATP. The alkali metal is anchored by situ bond or ion exchange without damaging the active material, thereby improving the high NOx catalytic reduction ability of the catalyst. However, the catalytic ability of the catalyst is still unsatisfactory, and how to improve the catalytic effect of the catalyst remains to be studied.

Contents of the invention

The main purpose of the present invention is to provide an attapulgite-derived nickel-titanium layer-shaped mesoporous catalyst with better catalytic performance and its preparation method and application.

To achieve the above object, the invention provides a method for preparing an attapulgite-derived nickel-titanium layer sheet mesoporous catalyst, comprising the following steps:

S1. Disperse attapulgite in hydrochloric acid solution, hydrothermally treat at 150-200°C for 10-15 hours, filter, wash and dry to obtain attapulgite-based silicon source;

S2, adding the attapulgite-based silicon source into ethylene glycol, mixing evenly, adding the titanium source, and then reacting at a temperature of 100-200° C. for 1-4 hours to obtain a reaction mixture containing Si-O-Ti polymer;

S3. Add template agent to the reaction mixture, mix evenly, and conduct hydrothermal crystallization treatment at 150°C-200°C for 24-36 hours. The obtained product is centrifuged, washed, dried, and calcined to obtain attapulgite-derived lamellar Mesoporous zeolite carrier;

S4. Load nickel on the attapulgite-derived lamellar mesoporous zeolite carrier by an impregnation method, and then dry and calcinate to obtain the attapulgite-derived nickel-titanium lamellar mesoporous catalyst.

Further, in the catalyst, the nickel content is 5-20 wt%, and the titanium content is 1.0-3.5 wt%.

Further, in step S1, the concentration of the hydrochloric acid solution is 4 mol/L, and the dosage ratio of the attapulgite and the hydrochloric acid solution is 1 g: 5-10 mL.

Further, in step S2, tetrabutyl titanate is selected as the titanium source, and the dosage ratio of attapulgite-based silicon source, tetrabutyl titanate titanium source and ethylene glycol is 2-2.2g: 0.45-0.5mL: 10~10.2mL.

Further, in step S3, the template agent is tetrapropylammonium hydroxide, the mass ratio of the template agent to the attapulgite-based silicon source is 2.5-7.5g:1-3g, and the calcination treatment conditions are: air atmosphere, temperature 550°C, time 6-8h.

Further, nickel nitrate hexahydrate is selected as the precursor salt of nickel.

Further, in step S4, the operation process of the impregnation method is: dissolving the precursor salt of nickel in a mixture of water and ethanol in a volume ratio of 2-3:1, and then aging at room temperature for 8-12 hours, Stir at a temperature of 60-80°C for 5-8 hours.

Further, in step S4, the drying treatment conditions are: temperature 100-120°C, time 8-12h; the calcination treatment conditions are: air atmosphere, temperature 500-600°C, time 4-6h.

The present invention also provides a nickel-titanium layer sheet mesoporous catalyst derived from attapulgite, which is prepared according to the above preparation method.

The present invention also provides the application of the nickel-titanium layered mesoporous catalyst derived from attapulgite in steam reforming of biomass tar and its model to prepare hydrogen-rich gas.

The present invention also provides a method for preparing hydrogen-rich gas by steam reforming of biomass tar and its model substances, comprising the following steps: taking biomass tar or its model substances as reaction raw materials, adding the catalyst as claimed in claim 8 to carry out the reaction , the reaction conditions are: the amount of catalyst used is 0.1-0.5g, the water-to-carbon ratio in the feed is 1:1.5-3, the weight hourly space velocity is 0.0047-0.008min ^-1 , and the reaction temperature is 600-800°C; the catalyst reduction condition is: at 100 ~150mL/min, 10~15vol% H ₂ /N ₂ flow, 600~800°C for 1~3h.

The beneficial effects of the present invention are reflected in:

The catalyst of the present invention introduces titanium into the attapulgite skeleton, and the nickel-titanium layered flaky zeolite catalyst has a very high specific surface area, so that the dispersion of the metal is enhanced and the catalytic performance is further improved. The catalyst of the present invention uses nickel, Titanium is used as the active component, and a relatively high activity can be achieved by using attapulgite-derived lamellar mesoporous zeolite supports with low content of nickel. Compared with other nickel-based catalysts, the catalyst of the present invention uses attapulgite as a silicon source, tetrabutyl titanate as a titanium source, and ethylene glycol as a solution to undergo transesterification polymerization, and then hydrothermally The attapulgite-derived nickel-titanium layer sheet catalyst is obtained by crystallizing and synthesizing layered mesoporous zeolite carrier, and then loading nickel by impregnation method, which improves the catalyst's ability to resist carbon deposition and sintering.

The catalyst of the present invention is applied to the steam reforming of biomass tar and its model substances to prepare hydrogen-rich gas, which can achieve a conversion rate of more than 95%, a hydrogen yield of more than 65% in the synthesis gas, and a hydrogen selectivity of more than 70%. High activity, with the advantages of environmental protection, high stability, and low price, meeting the industrial requirements of steam reforming of biomass tar and its model substances to prepare hydrogen-rich gas, can significantly improve the ability of the catalyst to adsorb and activate water vapor, and improve the activity of the catalyst , has good industrial application prospects.

Description of drawings

Fig. 1 is the SEM figure of the carrier that the embodiment of the present invention 1 makes;

Fig. 2 is the SEM picture of the carrier that the embodiment of the present invention 1 makes;

Fig. 3 is the TEM figure of the 1# catalyst that the embodiment of the present invention 1 makes;

Fig. 4 is the TEM figure of the 1# catalyst that the embodiment of the present invention 1 makes;

Fig. 5 is the N of the 1# catalyst that the embodiment of the present invention makes ₁ Adsorption-desorption curve and pore size distribution figure;

Fig. 6 is the XRD spectrum of the 1# catalyst that the embodiment of the present invention 1 makes: N/TS (R): catalyst after reduction; N-TS (C): catalyst after calcining;

Figure 7 is the US-Vis spectrum of the 1# catalyst prepared in Example 1 of the present invention: N/TS (R): catalyst after reduction; N-TS (C): catalyst after calcination; TS: carrier.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The various raw materials used in the following examples are commercially available products known in the art unless otherwise specified.

Example 1

The active ingredient nickel (Ni) content in the attapulgite-derived nickel-titanium layer sheet mesoporous catalyst prepared in this embodiment is 5wt%, and the titanium (Ti) content is 2.7wt%. The preparation method is as follows:

S1. Weigh 20g of mechanically ground attapulgite clay, disperse it in 120mL 4mol/L hydrochloric acid solution to form a suspension I, stir it on a stirring table for 2 hours, and transfer the suspension I into a 200mL polytetrafluoroethylene liner In a hydrothermal kettle, hydrothermally treat at 160°C for 10h, cool to room temperature, filter, filter and wash with deionized water until neutral, dry in an oven at 100°C for 10h, and crush with a mortar to obtain attapulgite-based silicon source.

S2. Put 10ml of ethylene glycol into a beaker, then weigh 2g of attapulgite-based silicon source into it, put it on a stirring table and stir until it is evenly mixed, then add 0.5ml of tetrabutyl titanate , after uniform mixing, react at a temperature of 150°C for 2.5h to complete the polymerization reaction of silicon source and titanium source, and obtain a reaction mixture containing Si-O-Ti polymer;

S3. Add 4.6 g of tetrapropylammonium hydroxide to the above reaction mixture, mix evenly and move it into a polytetrafluoroethylene-lined hydrothermal reaction kettle for hydrothermal crystallization at 180° C. for 36 hours. The resulting product is centrifuged, washed, After drying at 100°C for 10 hours, heat up to 550°C for 6 hours at a heating rate of 4°C/min in an air atmosphere to obtain a layered mesoporous zeolite carrier derived from attapulgite;

S4. Weigh 0.132g of nickel nitrate hexahydrate, dissolve it in 80ml of deionized water and ethanol in a solution with a volume ratio of 2:1, add 0.5g of the above-mentioned carrier, first age at room temperature for 10h, and then put it on a stirring table at 60 Stir at ℃ for 5h, then put it into an oven at 100℃ and dry for 10h, then heat up to 550℃ for 4h at a rate of 4℃/min in air atmosphere to obtain attapulgite-derived nickel-titanium flakes Mesoporous catalyst, No. 1#.

Example 2

The nickel (Ni) content of the active components in the attapulgite-derived nickel-titanium layer sheet mesoporous catalyst prepared in this example is 10wt%, and the titanium (Ti) content is 1.9wt%. The preparation method is as follows:

S1. Weigh 20g of mechanically ground attapulgite clay and disperse it in 100mL 4mol/L hydrochloric acid solution to form a suspension I, stir it on a stirring table for 2h, and transfer the suspension I into a 200mL polytetrafluoroethylene-lined In a hydrothermal kettle, hydrothermally treat at 170°C for 12h, cool to room temperature, filter, filter and wash with deionized water until neutral, dry in an oven at 100°C for 8h, and crush with a mortar to obtain attapulgite-based silicon source .

S2. Weigh 10.2ml of ethylene glycol into a beaker, then weigh 2.1g of attapulgite-based silicon source into it, put it on a stirring table and stir until it is evenly mixed, then add 0.45ml of titanic acid Tetrabutyl ester, after uniform mixing, react at 140°C for 4 hours to complete the polymerization reaction of silicon source and titanium source, and obtain a reaction mixture containing Si-O-Ti polymer;

S3. Add 4.8 g of tetrapropylammonium hydroxide to the above reaction mixture, mix evenly and move it into a polytetrafluoroethylene-lined hydrothermal reaction kettle for hydrothermal crystallization at a temperature of 170° C. for 24 hours. The resulting product is centrifuged, washed, and After drying at 100° C. for 8 hours, the temperature was raised to 550° C. for 6 hours at a heating rate of 4° C./min in an air atmosphere to obtain a layered mesoporous zeolite carrier derived from attapulgite.

S4. Weigh 0.284g of nickel nitrate hexahydrate, dissolve in 60ml of deionized water and ethanol in a solution with a volume ratio of 2:1, add 0.5g of the above-mentioned carrier, first age at room temperature for 8h, and then put it on a stirring table at 70 Stir at ℃ for 4.5h, then put it in an oven at 100℃ to dry for 8h, and then heat up to 500℃ for 6h at a rate of 4℃/min in air atmosphere to obtain attapulgite-derived nickel-titanium laminates Shaped mesoporous catalyst, No. 2#.

Example 3

The nickel (Ni) content of the active ingredient in the attapulgite-derived nickel-titanium layer sheet mesoporous catalyst prepared in this embodiment is 15wt%, and the titanium (Ti) content is 1.7wt%. The preparation method is as follows:

S1. Weigh 20g of mechanically ground attapulgite clay and disperse it in 150mL 4mol/L hydrochloric acid solution to form suspension I, stir it on a stirring table for 4h, and transfer suspension I into a 200mL polytetrafluoroethylene-lined In a hydrothermal kettle, hydrothermally treat at 180°C for 10h, cool to room temperature, filter, filter and wash with deionized water until neutral, dry in an oven at 110°C for 12h, and crush with a mortar to obtain attapulgite-based silicon source .

S2. Weigh 10ml of ethylene glycol into a beaker, then weigh 2g of attapulgite-based silicon source into it, put it on a stirring table and stir until it is evenly mixed, then add 0.48ml of tetrabutyl titanate After uniform mixing, react at 180°C for 2 hours to complete the polymerization reaction of silicon source and titanium source to obtain a reaction mixture containing Si-O-Ti polymer;

S3. Add 4.8 g of tetrapropylammonium hydroxide to the above reaction mixture, mix evenly and move it into a polytetrafluoroethylene-lined hydrothermal reaction kettle for hydrothermal crystallization at a temperature of 180° C. for 36 hours. The resulting product is centrifuged, washed, After drying at 110° C. for 12 hours, the temperature was raised to 550° C. for 8 hours at a heating rate of 4° C./min in an air atmosphere to obtain a layered mesoporous zeolite carrier derived from attapulgite.

S4. Weigh 0.46g of nickel nitrate hexahydrate, dissolve it in 100ml of deionized water and ethanol with a volume ratio of 2:1, add 0.5g of the above-mentioned carrier, first age at room temperature for 9h, and then put it on a stirring table at 80 Stir at ℃ for 4h, then put it into an oven at 110℃ and dry for 12h, then heat up to 550℃ for 5h in air atmosphere at a rate of 4℃/min and calcinate for 5h to obtain attapulgite-derived nickel-titanium flakes Mesoporous catalyst, No. 3#.

Example 4

The nickel (Ni) content of the active components in the attapulgite-derived nickel-titanium layer sheet mesoporous catalyst prepared in this example is 20wt%, and the titanium (Ti) content is 1.3wt%. The preparation method is as follows:

S1. Weigh 20g of mechanically ground attapulgite clay and disperse it in 200mL 3.5mol/L hydrochloric acid solution to form suspension I. Stir on a stirring table for 3 hours, then transfer suspension I into 200mL polytetrafluoroethylene lining In a hydrothermal kettle, hydrothermally treat at 180°C for 12h, cool to room temperature, filter, filter and wash with deionized water until neutral, dry in an oven at 120°C for 12h, and use a mortar to crush to obtain attapulgite-based silicon source.

S2. Weigh 10.2ml of ethylene glycol into a beaker, then weigh 2.2g of attapulgite-based silicon source into it, put it on a stirring table and stir until it is evenly mixed, then add 0.49ml of titanic acid Tetrabutyl ester, after uniform mixing, react at 200°C for 1 hour to complete the polymerization reaction between the silicon source and the titanium source, and obtain a reaction mixture containing Si-O-Ti polymer;

S3. Add 5g of tetrapropylammonium hydroxide to the above reaction mixture, mix evenly and move it into a polytetrafluoroethylene-lined hydrothermal reaction kettle, and hydrothermally crystallize at 180°C for 36h. The product is centrifuged, washed, After drying at 120° C. for 12 hours, the temperature was raised to 550° C. for 6 hours at a heating rate of 4° C./min and calcined for 6 hours in an air atmosphere to obtain a layered mesoporous zeolite carrier derived from attapulgite.

S4. Weigh 0.67g nickel nitrate hexahydrate, dissolve in 80ml of deionized water and ethanol with a volume ratio of 3:1, add 0.5g of the above-mentioned carrier, first age at room temperature for 12h, and then put it on a stirring table at 65 Stir at ℃ for 5h, then put it into an oven at 120℃ and dry for 12h, and then heat up to 600℃ for 4.5h in air atmosphere at a rate of 4℃/min to calcinate for 4.5h to obtain attapulgite-derived nickel-titanium laminates Shaped mesoporous catalyst, No. 4#.

Example 5

Catalyst Structure Determination

The pore size of the catalyst prepared in Example 1 was analyzed by means of _N2 adsorption-desorption test, and the results are shown in FIG. 5 and Table 1.

Table 1

The above table shows the pore diameter data of the catalyst. The figure shows that the pore diameter of the catalyst is about two or three nanometers, which belongs to the mesopore level. In addition, it can be seen from Figure 5A that the nitrogen adsorption-desorption isotherm of the catalyst is classified as having H1 type hysteresis The type IV of the ring indicates that it has a regular pore structure, and proves that the catalyst is a regular lamellar mesoporous material with a narrow pore size distribution, which is clearly illustrated by the pore size distribution of N/TS in Figure 5B.

Referring to Fig. 6, when 2θ=24.4° in the XRD pattern, there is a very complete characteristic peak without splitting, indicating that titanium species are successfully introduced into the zeolite framework. Referring to Figure 7, the signal generated at 210nm in the US-Vis spectrum is attributed to the transition of the 2p electrons of the bonded oxygen to the 3d empty orbitals of Ti ⁴⁺ ions, and charge transfer has occurred, which can prove the presence of skeleton titanium. The shoulder peak at 310nm is attributed to the extra-framework anatase TiO ₂ , and the peak intensity at 210nm is very strong, indicating that most of the titanium enters the lamellar carrier derived from attapulgite.

Example 6

Catalyst Catalyzed Biomass Tar and Its Model Product Steam Reforming to Produce Hydrogen-rich Gas Performance Test

Take 0.1-0.5g of the above-mentioned 1#~4# catalysts in a fixed-bed reactor, and perform a performance test after reduction treatment at 600-800°C for 2 hours in a flow of 100mL/min and 10vol% H ₂ /N ₂ . The steam supply is 0.0001mol/min, and the steam supply is obtained by injecting water into the evaporator through a peristaltic pump. Adjusting the water injection speed of the pump can change the water-carbon ratio (S/C), and the water-carbon ratio in the feed is 1:1.5～3 , weight hourly space velocity 0.0047～0.008min ^-1 Table 2 Laboratory biomass tar and its model product steam reforming to prepare hydrogen-rich gas performance test

From the above results, it can be concluded that the catalyst of the present invention can achieve a raw material conversion rate of more than 95%, a hydrogen production rate of more than 65%, a hydrogen selectivity of more than 70%, and maintain good stability within 30 hours. .

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (10)

1. a kind of preparation method of the nickel-titanium layer sheet mesoporous catalyst derived from attapulgite, is characterized in that, comprises the following steps: S1. Disperse attapulgite in hydrochloric acid solution, hydrothermally treat at 150-200°C for 10-15 hours, filter, wash and dry to obtain attapulgite-based silicon source; S2, adding the attapulgite-based silicon source into ethylene glycol, mixing evenly, adding the titanium source, and then reacting at a temperature of 100-200° C. for 1-4 hours to obtain a reaction mixture containing Si-O-Ti polymer; S3. Add template agent to the reaction mixture, mix evenly, and conduct hydrothermal crystallization treatment at 150°C-200°C for 24-36 hours. The obtained product is centrifuged, washed, dried, and calcined to obtain attapulgite-derived lamellar Mesoporous zeolite carrier; S4. Load nickel on the attapulgite-derived lamellar mesoporous zeolite carrier by an impregnation method, and then dry and calcinate to obtain the attapulgite-derived nickel-titanium lamellar mesoporous catalyst. 2. the preparation method of the nickel-titanium layer sheet mesoporous catalyst derived from attapulgite as claimed in claim 1, is characterized in that, in the catalyst, the content of nickel is 5～20wt%, and titanium content is 1.0～3.5wt %. 3. the preparation method of the nickel-titanium layer sheet mesoporous catalyst derived from attapulgite as claimed in claim 1 or 2, it is characterized in that, in step S1, the concentration of hydrochloric acid solution is 4mol/L, attapulgite and hydrochloric acid The dosage ratio of the solution is 1g:5-10mL. 4. the preparation method of the nickel-titanium layer sheet mesoporous catalyst derived from attapulgite as claimed in claim 1 or 2, it is characterized in that, in step S2, described titanium source selects tetrabutyl titanate for use, attapulgite The dosage ratio of the stone-based silicon source, tetrabutyl titanate titanium source and ethylene glycol is 2-2.2g: 0.45-0.5mL: 10-10.2mL. 5. the preparation method of the nickel-titanium layer sheet mesoporous catalyst derived from attapulgite as claimed in claim 1 or 2, is characterized in that, in step S3, described templating agent is tetrapropyl ammonium hydroxide, template The mass ratio of the agent and the attapulgite-based silicon source is 2.5-7.5g:1-3g, and the calcination treatment conditions are: air atmosphere, temperature 550°C, time 6-8h. 6. The preparation method of the attapulgite-derived nickel-titanium layer sheet mesoporous catalyst as claimed in claim 1 or 2, characterized in that, in step S4, the operation process of the impregnation method is: the precursor salt of nickel Dissolve in the mixture of water and ethanol at a volume ratio of 2-3:1, then age at room temperature for 8-12 hours, and then stir at 60-80°C for 5-8 hours. 7. The preparation method of the attapulgite-derived nickel-titanium layered mesoporous catalyst according to claim 1 or 2, characterized in that, in step S4, the drying treatment conditions are: temperature 100-120°C, time 8 ～12h; the calcination treatment conditions are: air atmosphere, temperature 500～600°C, time 4～6h. 8. A nickel-titanium layer sheet-like mesoporous catalyst derived from attapulgite, characterized in that it is prepared according to the preparation method described in any one of claims 1-7. 9. The application of the attapulgite-derived nickel-titanium layer sheet-like mesoporous catalyst according to claim 8 in the preparation of hydrogen-rich gas by steam reforming of biomass tar and its model. 10. A method for preparing hydrogen-rich gas by steam reforming of biomass tar and its model substance, characterized in that it comprises the following steps: taking biomass tar or its model substance as reaction raw material, adding the catalyst as claimed in claim 8 To carry out the reaction, the reaction conditions are: the catalyst dosage is 0.1-0.5g, the water-to-carbon ratio in the feed is 1:1.5-3, the weight hourly space velocity is 0.0047-0.008min ^-1 , and the reaction temperature is 600-800°C; the catalyst reduction conditions are: Treat at 100-150mL/min, 10-15vol% H ₂ /N ₂ flow, 600-800°C for 1-3 hours.

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