Sulfur-resistant Pt-based CO oxidation catalyst and preparation method thereof

Abstract

The invention discloses a sulfur-resistant Pt-based CO oxidation catalyst and a preparation method thereof, and belongs to the technical field of catalysts. According to the prepared catalyst, CZLY composite OSM is adopted as a carrier, rare earth oxide Gd2O3 is added for modification, and precious metal Pt is loaded through a polyhydric alcohol method. According to the preparation method, the catalyst has the advantages of rare earth elements and precious metals, the specific surface area of the material is effectively increased, loading and dispersion of active components are promoted, and the CO catalytic oxidation activity is remarkably improved. Meanwhile, by adding Gd2O3, the thermal stability and the sulfur-resistant stability of the catalyst are enhanced, so that the catalyst can keep efficient catalytic performance in an SO2-containing atmosphere for a long time, the catalytic combustion temperature and the catalytic cost are reduced, and the catalyst is suitable for popularization and application.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a sulfur-resistant Pt-based catalyst for catalytic oxidation of CO in industrial tail gas and a preparation method thereof. Background Art

[0002] Industrial tail gas emissions contain a variety of pollutants, such as carbon monoxide (CO), sulfur dioxide (SO2), etc. Pt-based catalysts in CO catalytic oxidation technology have attracted much attention due to their excellent catalytic activity and stability. However, existing Pt-based catalysts are easily poisoned and deactivated in sulfur-containing atmospheres, which limits their industrial applications.

[0003] Therefore, developing a Pt-based CO oxidation catalyst with sulfur resistance is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of this, the present invention provides a sulfur-resistant Pt-based CO oxidation catalyst, which can 2 It maintains efficient CO catalytic oxidation activity in the atmosphere, solves the problem of existing catalysts being easily poisoned and deactivated, and has good thermal stability and sulfur resistance stability, thus extending the service life of the catalyst.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] A method for preparing a sulfur-resistant Pt-based CO oxidation catalyst comprises the following steps:

[0007] (1) Preparation of Gd-doped modified OSM composites

[0008] (11) dissolving a soluble cerium salt, a soluble zirconium salt, a soluble lanthanum salt, a soluble yttrium salt and gadolinium trioxide in deionized water and uniformly stirring to obtain a mixed solution A;

[0009] (12) adding a precipitant dropwise into the mixed solution A to obtain a mixed solution B;

[0010] (13) placing the mixed solution B in a water bath for heating and stirring, allowing it to stand for aging, filtering, and washing to obtain a precipitate;

[0011] (14) drying and calcining the precipitate to obtain the OSM composite material CZLYGd;

[0012] (2) Preparation of sulfur-resistant Pt-based CO oxidation catalysts

[0013] (21) dispersing the composite material CZLYGd in an organic solvent to form a uniform slurry;

[0014] (22) dispersing chloroplatinic acid in an organic solvent and stirring to form a mixed solution;

[0015] (23) adding the mixed solution to the slurry, stirring evenly, and then slowly dropping the alkaline reagent at a rate of 2 mL / min to form a dispersion;

[0016] (24) The dispersion is heated and stirred, then cooled to room temperature, an acidic reagent is gradually added and stirred for 8-10 h, filtered, and washed to obtain a precipitate;

[0017] (25) The precipitate is dried and calcined to obtain a sulfur-resistant Pt-based CO oxidation catalyst.

[0018] Furthermore, in step (11), the soluble cerium salt is cerium nitrate, the soluble zirconium salt is zirconium nitrate, the soluble lanthanum salt is lanthanum nitrate, and the soluble yttrium salt is yttrium nitrate;

[0019] Among them, the atomic molar mass ratio of cerium, zirconium, lanthanum, yttrium and gadolinium is (35-45):(45-55):(4-6):(4-6):(4-6).

[0020] Furthermore, the specific operation of step (12) is: adding ammonia water dropwise to the mixed solution A under heating at 60° C. until the pH value of the solution reaches 10, to obtain a mixed solution B.

[0021] Furthermore, in step (13), the water bath heating temperature is 60 degrees Celsius, the heating stirring time is 2-4 hours, and the static aging time is 4-6 hours.

[0022] Furthermore, in step (14), the drying temperature is 110° C. and the drying time is 8-10 h; the calcination is carried out in an air atmosphere, the calcination temperature is 550° C. and the calcination time is 4 h.

[0023] Furthermore, the organic solvents used in step (21) and step (22) are both ethylene glycol.

[0024] Furthermore, the mass ratio of the chloroplatinic acid to the composite material CZLYGd is 1:100.

[0025] Furthermore, the alkaline reagent in step (23) is a 1 mol / L NaOH solution, which is adjusted to a pH value of 13.

[0026] Further, step (24) is carried out under an inert atmosphere, the heating and stirring temperature is 120° C., the heating and stirring time is 3 h, and the acidic reagent is a 1 mol / L HCl solution adjusted to a pH value of 2;

[0027] In step (25), the drying temperature is 60° C. and the drying time is 8-10 h; the calcination is carried out in an air atmosphere at a temperature of 400° C. and a calcination time of 4 h.

[0028] The beneficial effects of the present invention are:

[0029] (1) Improve catalytic efficiency: The present invention can effectively increase the specific surface area of ​​the material by adding the rare earth element Gd, promoting Ce 3+ The formation of species and Olatt makes the Pt particles smaller and more evenly dispersed, thereby improving the catalytic efficiency.

[0030] (2) Enhanced sulfur resistance: Gd 2 O 3 The addition of can reduce the direct contact between sulfide and precious metal Pt, thereby alleviating the poisoning of the catalyst and making the catalyst 2 The catalytic activity can still be maintained stably under the conditions of the atmosphere.

[0031] (3) Improved thermal stability: The synergistic effect of CZLY carrier and Gd2O3 enhances the thermal stability of the catalyst, and their interaction helps to further increase the number and types of active sites, while improving the thermal stability of the catalyst and extending the service life of the catalyst.

[0032] (4) Prolonging service life: The catalyst of the present invention has good sulfur resistance stability and thermal stability, which can prolong the service life of the catalyst and reduce the replacement frequency and cost.

[0033] (5) Suitable for industrial applications: The catalyst provided by the present invention and its preparation method are suitable for the catalytic oxidation treatment of CO in industrial tail gas, especially the catalytic oxidation of CO in a sulfur-containing atmosphere, providing a new high-performance catalyst option for industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a CO combustion activity diagram of the catalyst prepared in Example 1 of the present invention;

[0035] Figure 2 This is a graph showing the sulfur resistance of the catalyst prepared in Example 1 of the present invention;

[0036] Figure 3 The XRD spectrum of the catalyst prepared in Example 1 of the present invention;

[0037] Figure 4 N of the catalyst prepared in Example 1 of the present invention 2 Adsorption–desorption isotherms and pore size distribution diagrams. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] Preparation method of sulfur-resistant Pt-based CO oxidation catalyst:

[0041] (I) Preparation of multi-component composite cerium-based oxygen storage material CZLYGd

[0042] (1) With Ce(NO 3 ) 4 6H 2 O、Zr(NO 3 ) 4 ·5H 2 O、La(NO 3 ) 3 6H 2 O、Y(NO 3 ) 3 6H 2 O and Gd 2 O 3 (5 mol%) is used as the precursor, which is fully dissolved in 200 mL of deionized water according to the stoichiometric ratio and stirred in a constant temperature water bath at 60 °C, and taken out after being fully dissolved;

[0043] (2) Under strong stirring, 3 mol / L NH 3 ·H 2 O solution as a precipitant, titrate the mixed solution at a rate of 2 mL / min until the pH value reaches 10, continue stirring for 2 h, let stand at room temperature for 4 h, then filter, and wash alternately with deionized water and anhydrous ethanol for 3 times;

[0044] (3) The washed and filtered precipitate was placed in an oven at 120°C and dried for 12 hours, and then the precipitate was placed in a muffle furnace and calcined at 550°C for 4 hours in an air atmosphere to obtain Ce prepared by the co-precipitation method. 0.4 Zr 0.5 La 0.05 Y 0.05 G 0.05 O 1.95 Composite materials.

[0045] (II) Preparation of catalyst containing multi-component composite cerium-based oxygen storage material CZLYGd

[0046] (1) Disperse 1 g of CZLYGd in 100 mL of ethylene glycol to form a uniform slurry, then add H 2 PtCl 6 ·Ethylene glycol solution is stirred evenly to obtain a mixed 2 PtCl 6 The amount of addition is 1wt% of CZLYGd, and the NaOH solution is slowly dripped into the mixed solution at 2mL / min until the pH value is 13 to obtain a dispersion;

[0047] (2) Heat the dispersion to 120°C and reflux for 3 h under an inert atmosphere. After cooling to room temperature, add HCl solution to adjust the pH to 2 and stir for 8 h;

[0048] (3) After washing the precipitate with deionized water, it was dried in an oven at 60° C. for 8 h, and finally calcined in a muffle furnace at 400° C. for 4 h to prepare a 1% Pt / CZLYGd catalyst.

[0049] Comparative Example 1

[0050] (I) Preparation of composite cerium-based oxygen storage material CZLY

[0051] (1) With Ce(NO 3 ) 4 6H 2 O、Zr(NO 3 ) 4 ·5H 2 O、La(NO 3 ) 3 6H 2 O and Y(NO 3 ) 3 6H 2 O is the precursor, which is fully dissolved in 200 mL of deionized water according to the stoichiometric ratio and stirred in a constant temperature water bath at 60 °C. It is taken out after being fully dissolved;

[0052] (2) Under strong stirring, 3 mol / L NH 3 ·H 2 O solution as a precipitant, titrate the mixed solution at a rate of 2 mL / min until the pH value reaches 10, continue stirring for 2 h, let stand at room temperature for 4 h, then filter, and wash alternately with deionized water and anhydrous ethanol for 3 times;

[0053] (3) The washed and filtered precipitate was placed in an oven at 120°C and dried for 12 hours, and then the precipitate was placed in a muffle furnace and calcined at 550°C for 4 hours in an air atmosphere to obtain Ce prepared by the co-precipitation method. 0.4 Zr 0.5 La 0.05 Y 0.05 O 1.95Composite materials.

[0054] (II) Preparation of catalyst containing cerium-based composite oxygen storage material CZLY

[0055] (1) Disperse 1 g of CZLY in 100 mL of ethylene glycol to form a uniform slurry, then add H 2 PtCl 6 ·Ethylene glycol solution is stirred evenly to obtain a mixed 2 PtCl 6 The amount of CZLY added was 1 wt % and the NaOH solution was slowly dripped into the mixed solution at 2 mL / min until the pH value was 13 to obtain a dispersion;

[0056] (2) Heat the dispersion to 120°C and reflux for 3 h under an inert atmosphere. After cooling to room temperature, add HCl solution to adjust the pH to 2 and stir for 8 h;

[0057] (3) After washing the precipitate with deionized water, it was dried in an oven at 60° C. for 8 h, and finally calcined in a muffle furnace at 400° C. for 4 h to prepare a 1% Pt / CZLY catalyst.

[0058] Comparative Example 2

[0059] (I) Preparation of composite cerium-based oxygen storage material CZLGd

[0060] (1) With Ce(NO 3 ) 4 6H 2 O、Zr(NO 3 ) 4 ·5H 2 O、La(NO 3 ) 3 6H 2 O and Gd 2 O 3 (5 mol%) is used as the precursor, which is fully dissolved in 200 mL of deionized water according to the stoichiometric ratio and stirred in a constant temperature water bath at 60 °C, and taken out after being fully dissolved;

[0061] (2) Under strong stirring, 3 mol / L NH 3 ·H 2 O solution was used as a precipitant, and the mixed solution was titrated at a rate of 2 mL / min until the pH value reached 10, and the mixture was stirred for 2 h, and allowed to stand at room temperature for 4 h, and then filtered and washed alternately with deionized water and anhydrous ethanol for 3 times;

[0062] (3) The washed and filtered precipitate was placed in an oven at 120°C and dried for 12 hours. The precipitate was then placed in a muffle furnace and calcined at 550°C for 4 hours in an air atmosphere to obtain fresh Ce prepared by the co-precipitation method.0.4 Zr 0.5 La 0.05 G 0.05 O 1.95 Composite materials.

[0063] (II) Preparation of catalyst containing cerium-based composite oxygen storage material CZLGd

[0064] (1) Disperse 1 g of CZLGd in 100 mL of ethylene glycol to form a uniform slurry, then add H 2 PtCl 6 ·Ethylene glycol solution is stirred evenly to obtain a mixed 2 PtCl 6 The amount of addition is 1wt% of CZLGd, and the NaOH solution is slowly dripped into the mixed solution at 2mL / min until the pH value is 13 to obtain a dispersion;

[0065] (2) Heat the dispersion to 120°C and reflux for 3 h under an inert atmosphere. After cooling to room temperature, add HCl solution to adjust the pH to 2 and stir for 8 h;

[0066] (3) After washing the precipitate with deionized water, it was dried in an oven at 60° C. for 8 h, and finally calcined in a muffle furnace at 400° C. for 4 h to prepare a 1% Pt / CZLGd catalyst.

[0067] Example 2

[0068] Preparation method of sulfur-resistant Pt-based CO oxidation catalyst:

[0069] (I) Preparation of multi-component composite cerium-based oxygen storage material CZLYGd2

[0070] (1) With Ce(NO 3 ) 4 6H 2 O、Zr(NO 3 ) 4 ·5H 2 O、La(NO 3 ) 3 6H 2 O、Y(NO 3 ) 3 6H 2 O and Gd 2 O 3 (3 mol%) is used as the precursor, which is fully dissolved in 200 mL of deionized water according to the stoichiometric ratio and stirred in a constant temperature water bath at 60 °C, and taken out after being fully dissolved;

[0071] (2) Under stirring, 3 mol / L NH 3 ·H 2O solution as a precipitant, titrate the mixed solution at a rate of 2 mL / min until the pH value reaches 10, continue stirring for 2 h, let stand at room temperature for 4 h, then filter, and wash alternately with deionized water and anhydrous ethanol for 3 times;

[0072] (3) The washed and filtered precipitate was placed in an oven at 120°C and dried for 12 hours, and then the precipitate was placed in a muffle furnace and calcined at 550°C for 4 hours in an air atmosphere to obtain Ce prepared by the co-precipitation method. 0.4 Zr 0.5 La 0.05 Y 0.05 G 0.03 O 1.95 The composite material is denoted as CZLYGd2.

[0073] (II) Preparation of catalyst containing multi-component composite cerium-based oxygen storage material CZLYGd2

[0074] (1) Disperse 1 g of CZLYGd2 in 100 mL of ethylene glycol to form a uniform slurry, then add H 2 PtCl 6 ·Ethylene glycol solution is stirred evenly to obtain a mixed 2 PtCl 6 The amount of addition is 1wt% of CZLYGd2, and the NaOH solution is slowly dripped into the mixed solution at 2mL / min until the pH value is 13 to obtain a dispersion;

[0075] (2) Heat the dispersion to 120°C and reflux for 3 h under an inert atmosphere. After cooling to room temperature, add HCl solution to adjust the pH to 2 and stir for 8 h;

[0076] (3) After washing the precipitate with deionized water, it was dried in an oven at 60°C for 8 h and finally calcined in a muffle furnace at 400°C for 4 h to prepare a 1% Pt / CZLYGd2 catalyst.

[0077] Example 3

[0078] Preparation method of sulfur-resistant Pt-based CO oxidation catalyst:

[0079] (I) Preparation of multi-component composite cerium-based oxygen storage material CZLYGd3

[0080] (1) With Ce(NO 3 ) 4 6H 2 O、Zr(NO 3 ) 4 ·5H 2 O、La(NO 3 ) 3 6H 2 O、Y(NO3 ) 3 6H 2 O and Gd 2 O 3 (7 mol%) was used as the precursor, which was fully dissolved in 200 mL of deionized water according to the stoichiometric ratio and stirred in a constant temperature water bath at 60 °C, and taken out after being fully dissolved;

[0081] (2) Under strong stirring, 3 mol / L NH 3 ·H 2 O solution as a precipitant, titrate the mixed solution at a rate of 2 mL / min until the pH value reaches 10, continue stirring for 2 h, let stand at room temperature for 4 h, then filter, and wash alternately with deionized water and anhydrous ethanol for 3 times;

[0082] (3) The washed and filtered precipitate was placed in an oven at 120°C and dried for 12 hours, and then the precipitate was placed in a muffle furnace and calcined at 550°C for 4 hours in an air atmosphere to obtain Ce prepared by the co-precipitation method. 0.4 Zr 0.5 La 0.05 Y 0.05 G 0.07 O 1.95 The composite material is denoted as CZLYGd3.

[0083] (II) Preparation of catalyst containing multi-component composite cerium-based oxygen storage material CZLYGd3

[0084] (1) Disperse 1 g of CZLYGd3 in 100 mL of ethylene glycol to form a uniform slurry, then add H 2 PtCl 6 ·Ethylene glycol solution is stirred evenly to obtain a mixed 2 PtCl 6 The amount of addition is 1wt% of CZLYGd3, and the NaOH solution is slowly dripped into the mixed solution at 2mL / min until the pH value is 13 to obtain a dispersion;

[0085] (2) Heat the dispersion to 120°C and reflux for 3 h under an inert atmosphere. After cooling to room temperature, add HCl solution to adjust the pH to 2 and stir for 8 h;

[0086] (3) After washing the precipitate with deionized water, it was dried in an oven at 60°C for 8 h and finally calcined in a muffle furnace at 400°C for 4 h to prepare a 1% Pt / CZLYGd3 catalyst.

[0087] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a sulfur-resistant Pt-based CO oxidation catalyst, characterized in that: The following steps are involved: (1) Preparation of Gd-doped modified OSM composites (11) dissolving a soluble cerium salt, a soluble zirconium salt, a soluble lanthanum salt, a soluble yttrium salt and gadolinium trioxide in deionized water and uniformly stirring to obtain a mixed solution A; (12) adding a precipitant dropwise into the mixed solution A to obtain a mixed solution B; (13) placing the mixed solution B in a water bath for heating and stirring, allowing it to stand for aging, filtering, and washing to obtain a precipitate; (14) drying and calcining the precipitate to obtain the OSM composite material CZLYGd; (2) Preparation of sulfur-resistant Pt-based CO oxidation catalysts (21) dispersing the composite material CZLYGd in an organic solvent to form a uniform slurry; (22) dispersing chloroplatinic acid in an organic solvent and stirring to form a mixed solution; (23) adding the mixed solution to the slurry, stirring evenly, and then slowly dropping the alkaline reagent at a rate of 2 mL / min to form a dispersion; (24) The dispersion is heated and stirred, then cooled to room temperature, an acidic reagent is gradually added and stirred for 8-10 h, filtered, and washed to obtain a precipitate; (25) The precipitate is dried and calcined to obtain a sulfur-resistant Pt-based CO oxidation catalyst.

2. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: In step (11), the soluble cerium salt is cerium nitrate, the soluble zirconium salt is zirconium nitrate, the soluble lanthanum salt is lanthanum nitrate, and the soluble yttrium salt is yttrium nitrate; Among them, the atomic molar mass ratio of cerium, zirconium, lanthanum, yttrium and gadolinium is (35-45):(45-55):(4-6):(4-6):(4-6).

3. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: The specific operation of step (12) is: adding ammonia water dropwise to the mixed solution A under heating at 60° C. until the pH value of the solution reaches 10, thereby obtaining a mixed solution B.

4. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: In step (13), the water bath heating temperature is 60 degrees Celsius, the heating stirring time is 2-4 hours, and the standing aging time is 4-6 hours.

5. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: In step (14), the drying temperature is 110° C. and the drying time is 8-10 h; the calcination is carried out in an air atmosphere, the calcination temperature is 550° C. and the calcination time is 4 h.

6. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: The organic solvents used in step (21) and step (22) are both ethylene glycol.

7. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 6, characterized in that: The mass ratio of the chloroplatinic acid to the composite material CZLYGd is 1:

100.

8. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: The alkaline reagent in step (23) is a 1 mol / L NaOH solution, which is adjusted to a pH value of 13 for the dispersion.

9. The method for preparing a sulfur-resistant Pt-based CO oxidation catalyst according to claim 1, characterized in that: Step (24) is carried out under an inert atmosphere, the heating and stirring temperature is 120° C., the heating and stirring time is 3 h, and the acidic reagent is a 1 mol / L HCl solution adjusted to a pH value of 2; In step (25), the drying temperature is 60° C. and the drying time is 8-10 h; the calcination is carried out in an air atmosphere at a temperature of 400° C. and a calcination time of 4 h.

10. A sulfur-resistant Pt-based CO oxidation catalyst, characterized in that: The method is prepared by any one of claims 1 to 9.

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