PdO-PtS/SiO2Catalyst, preparation method and application thereof
阅读说明：本技术 一种PdO-PtS/SiO2催化剂及其制备方法与应用 (PdO-PtS/SiO2Catalyst, preparation method and application thereof ) 是由 马磊 龙慧敏 于 2021-10-21 设计创作，主要内容包括：本发明所述的PdO-PtS/SiO-(2)催化剂兼具耐硫性和高活性,在甲烷低温催化氧化反应具有独特的优势：表面PtS的存在可以保护PdO免受含硫物质的进攻,同时酸性的SiO-(2)载体本身不吸附酸性的含硫物质,这使得PdO-PtS/SiO-(2)催化剂具备了完全抵御硫中毒的能力；由于Pt与Pd、S与O分别位于同一主族的相邻位置,这使得PtS不但可以保护PdO免受含硫物质的毒化作用,而且具备与PdO相似的催化活性。PdO和PtS双活性组分在甲烷低温催化氧化反应中表现出非常高的催化活性,Pd负载量为3％和Pt负载量为1％的PdO-PtS/SiO-(2)催化剂在400℃时甲烷转化率接近90％。(The invention relates to PdO-PtS/SiO 2 The catalyst has sulfur resistance and high activity, and has unique advantages in the low-temperature catalytic oxidation reaction of methane: the presence of surface PtS can protect PdO from attack by sulfur-containing species, while the acidic SiO 2 The carrier itself does not adsorb acidic sulfur-containing substances, which makes PdO-PtS/SiO 2 The catalyst has the capability of completely resisting sulfur poisoning; because Pt and Pd, and S and O are respectively positioned at adjacent positions of the same main group, PtS not only can protect PdO from the poisoning effect of sulfur-containing substances, but also has catalytic activity similar to that of PdO. The double active components of PdO and PtS show very high catalytic activity in the low-temperature catalytic oxidation reaction of methane, and PdO-PtS/SiO with 3 percent of Pd load and 1 percent of Pt load 2 The conversion rate of methane of the catalyst is close to 9 at 400 DEG C0％。)
1. PdO-PtS/SiO2Catalyst, characterized in that the PdO-PtS/SiO2The catalyst was prepared as follows:
mixing SiO2Impregnation of the support in H2PdCl4In the solution, bubbles are removed through first ultrasonic treatment, the solution is kept stand overnight, dried for 1-3 hours at 70-130 ℃, and roasted for 2-5 hours at 400-600 ℃ in air atmosphere to obtain PdO/SiO2(ii) a The PdO/SiO2Impregnated in H2PtCl6In the solution, performing ultrasonic treatment for the second time to remove bubbles, standing overnight, drying for the second time at 60-120 ℃ for 2-5 h, and roasting for the second time at 100-400 ℃ for 2-5 h in an air atmosphere to obtain PdO-Pt/SiO2(ii) a The PdO-Pt/SiO2At H2S-N2The temperature of the mixed gas is 100-500 DEG CSulfurizing for 1-5 h to obtain the PdO-PtS/SiO2A catalyst;
said H2PdCl4H in solution2PdCl4The concentration of (b) is 0.005-0.02 g/mL based on the theoretical Pd content; said H2PdCl4Volume of solution in the SiO2The mass of the carrier is 1-5 mL/g; said H2PtCl6In solution, said H2PtCl6The concentration of (b) is 0.001-0.05 g/mL based on the theoretical Pt content; said H2PtCl6Volume of solution in the SiO2The mass of the carrier is 2-10 mL/g; said H2S-N2The flow rate of the mixed gas is 10-150 mL/min.
2. The PdO-PtS/SiO of claim 12A catalyst, characterized by: said H2S-N2H in the mixed gas2The volume fraction of S is 1-9%.
3. The PdO-PtS/SiO of claim 22A catalyst, characterized by: said H2S-N2H in the mixed gas2The volume fraction of S was 5%.
4. The PdO-PtS/SiO of claim 12A catalyst, characterized by: the temperature of the first drying is 120 ℃, and the time is 2 h.
5. The PdO-PtS/SiO of claim 12A catalyst, characterized by: the temperature of the first roasting is 450-600 ℃, and the time is 4 hours.
6. The PdO-PtS/SiO of claim 12A catalyst, characterized by: the temperature of the second drying is 60-80 ℃, and the time is 4 hours.
7. The PdO-PtS/SiO of claim 12A catalyst, characterized by: the temperature of the second roasting is 200-300 ℃,the time is 3 h.
8. The PdO-PtS/SiO of claim 12A catalyst, characterized by: the vulcanizing temperature is 300-400 ℃, and the time is 2-4 h.
9. The PdO-PtS/SiO of claim 12The application of the catalyst in the catalytic oxidation reaction of methane.
10. The application according to claim 9, characterized in that the method of application is: the PdO-PtS/SiO2The method comprises the following steps of (1) loading a catalyst into a fixed bed reactor, introducing a mixed gas of methane, oxygen, nitrogen and hydrogen sulfide into the fixed bed reactor at a flow rate of 100-300 mL/min, and reacting at 300-600 ℃ under a normal pressure condition; in the mixed gas of methane, oxygen, nitrogen and hydrogen sulfide, the volume ratio of methane, oxygen, nitrogen and hydrogen sulfide is 3-5: 12-20: 174.8-184.8: 0.2.
(I) technical field
The invention relates to a PdO-PtS/SiO with sulfur resistance and high activity2A catalyst, a preparation method thereof and application of the catalyst in methane low-temperature catalytic oxidation reaction.
(II) background of the invention
The main component of natural gas, methane molecule, contains 4C-H bonds but only 1C atom, and the combustion of methane yields CO per unit energy2The least amount of the catalyst is added with CO2The control of emissions is becoming stricter, which makes the development of natural gas as a fuel in the energy field very bright. Theoretically, the combustion products of hydrocarbons are only carbon dioxide and water, but soot, carbon monoxide, unburned hydrocarbons are also detectable in the flameBurned hydrocarbons (UHC) and various nitrogen oxides (NOx). The first three substances are all products of incomplete combustion, and the nitrogen oxides (NOx) are oxidation products which are necessary for flame combustion under high-temperature conditions by taking air as a combustion medium. The use of a catalyst effectively reduces the activation energy of the combustion reaction, enabling the combustion reaction to proceed sufficiently below the 1300K temperature, below which NOx formation is negligible. Thus, the main advantage of the catalytic process compared to conventional flame combustion is that it enables low temperature oxidation of methane, providing the possibility to control ultra low emissions of CO, UHC and NOx without affecting the heat of reaction.
The supported PdO catalyst shows the best catalytic activity in the aspect of low-temperature oxidation of methane, but contains trace sulfur substances (H) in natural gas2S/SO2) The presence of (A) converts the gradual poisoning of the PdO active phase into a more stable inactive PdO-SOxSpecies of the type PdO-SOxThe poisoning effect of the species on the catalyst under low temperature conditions is almost irreversible. So as not to adsorb sulfur-containing substances (H)2S/SO2) Acid SiO of2As a carrier, with PdxSyPd constructed by substituting PdOxSy/SiO2The catalyst shows ideal sulfur resistance (the catalyst Pd is attractive and marbled in a sulfur-containing atmosphere) in the low-temperature catalytic oxidation reaction of methanexSy/SiO2Catalyzing low-temperature combustion reaction of methane, chemical production and technology, 22(2) (2015) 12-15), and PdxSyAnd SiO2No sulfur-containing substance (H) is adsorbed during the reaction2S/SO2) It is related. However, PdxSyThe low-temperature catalytic oxidation activity of the methane of the species has a larger difference with that of PdO, and the load is 5 percent of PdxSy/SiO2The catalyst has a methane conversion of up to about 80% at 400 ℃. Based on the above background, the present invention provides a PdO-PtS/SiO with both sulfur resistance and high activity at low temperature2A method for preparing the catalyst and application thereof.
Disclosure of the invention
The invention aims to provide PdO-PtS/SiO with sulfur resistance and high activity2Catalyst and its preparationPreparation method and application.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the invention provides a PdO-PtS/SiO2Catalyst, said PdO-PtS/SiO2The catalyst is prepared by the following method:
mixing SiO2Impregnation of the support in H2PdCl4In the solution, bubbles are removed through first ultrasonic treatment, the solution is kept stand overnight, the solution is dried for 1 to 3 hours (preferably dried for 2 hours at 120 ℃) for the first time at 70 to 130 ℃, and is roasted for 2 to 5 hours (preferably dried for 450 to 600 ℃ and 4 hours) for the first time in an air atmosphere at 400 to 600 ℃ to obtain PdO/SiO2(ii) a The PdO/SiO2Impregnated in H2PtCl6In the solution, performing ultrasonic treatment for the second time to remove bubbles, standing overnight, performing secondary drying at 60-120 ℃ for 2-5 h (preferably 60-80 ℃ for 4h), and performing secondary roasting at 100-400 ℃ in an air atmosphere for 2-5 h (preferably 200-300 ℃ for 3h) to obtain PdO-Pt/SiO2(ii) a The PdO-Pt/SiO2At H2S-N2Vulcanizing the mixed gas at 100-500 ℃ for 1-5 h (preferably vulcanizing at 300-400 ℃ for 2-4 h) to obtain the PdO-PtS/SiO2A catalyst;
said H2PdCl4In solution, the H2PdCl4The concentration of (b) is 0.005 to 0.02g/mL (preferably 0.01g/mL) in terms of the theoretical Pd content; said H2PdCl4Volume of solution in the SiO2The mass of the carrier is 1-5 mL/g (preferably 3 mL/g); said H2PtCl6In solution, the H2PtCl6The concentration of (b) is 0.001 to 0.05g/mL (preferably 0.0025g/mL) in terms of the theoretical Pt content; said H2PtCl6Volume of solution in the SiO2The mass of the carrier is 2-10 mL/g (preferably 4 mL/g); said H2S-N2The flow rate of the mixed gas is 10-150 mL/min.
Note: said H2PdCl4Solution and H2PtCl6The solvent of the solution is water.
Preferably, the temperature of the first ultrasonic treatment is room temperature, and the time is 45 min. The temperature of the second ultrasonic treatment was room temperature and the time was 45 min.
Preferably, said H2S-N2H in the mixed gas2The volume fraction of S is 1-9%, preferably 5%.
Preferably said H2S-N2The flow rate of the mixed gas is 10-150 mL/min, and particularly preferably 80 mL/min.
The invention also provides the PdO-PtS/SiO2The application of the catalyst in methane (low-temperature) catalytic oxidation reaction.
The present invention investigates PdO-PtS/SiO2The method for the activity and the sulfur poisoning resistance of the catalyst comprises the following steps: the PdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, the mixed gas of methane, oxygen, nitrogen and hydrogen sulfide is used as reaction gas, the reaction is carried out at the temperature of 300-600 ℃ under the normal pressure condition, and the product is analyzed by gas chromatography.
Specifically, the application method comprises the following steps: the PdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, mixed gas of methane, oxygen, nitrogen and hydrogen sulfide is introduced into the fixed bed reactor at a flow rate of 100-300 mL/min (preferably 200mL/min), and the reaction is carried out at 300-600 ℃ (preferably 400 ℃) under the normal pressure condition.
Preferably, in the mixed gas of methane, oxygen, nitrogen and hydrogen sulfide, the volume ratio of methane, oxygen, nitrogen and hydrogen sulfide is 3-5: 12-20: 174.8-184.8: 0.2 (preferably 4:16:179.8: 0.2).
The invention provides PdO-PtS/SiO with sulfur resistance and high activity2The catalyst is used for catalyzing and oxidizing reaction of methane at low temperature, and compared with a conventionally prepared supported PdO catalyst without sulfur resistance or Pd with sulfur resistancexSy/SiO2Compared with the catalyst, the catalyst has the unique advantages that:
(1) the presence of surface PtS can protect PdO from sulfur-containing species (H)2S/SO2) Attack of (2) and simultaneously acidic SiO2The carrier itself does not adsorb acidic sulfur-containing substances (H)2S/SO2) This results in PdO-PtS/SiO2The catalyst has the capability of completely resisting sulfur poisoning.
(2) Since Pt and Pd, S and O are respectivelyLocated adjacent to each other in the same main group, this allows PtS to protect PdO from sulfur-containing species (H)2S/SO2) Has similar catalytic activity to PdO. The double active components of PdO and PtS show very high catalytic activity in the low-temperature catalytic oxidation reaction of methane, and PdO-PtS/SiO with 3 percent of Pd load and 1 percent of Pt load2The catalyst has methane conversion rate near 90% at 400 deg.c.
(IV) detailed description of the preferred embodiments
The invention will be further described with reference to specific examples, but the scope of the invention is not limited thereto.
SiO2Is purchased from Qingdao ocean chemical Co., Ltd, spherical, 40-60 mesh.
Preparation H2PdCl4The palladium chloride content used>59.0% from Kyozhou Kai catalytic Metal materials, Inc.
H2PtCl6The purity is 99.999 percent, and the product is purchased from Shanxi Kaida chemical industry, Inc.
H2S-N2The mixed gas was purchased from Hangzhou mixed gas Co.
CH4、O2、N2And H2The purity of S is 99.999 percent and is purchased from Hangzhou modern engineering special gas company.
Example 1
EXAMPLE 1 preparation of one-component PdO/SiO2The catalyst is prepared by the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain the PdO/SiO2A catalyst.
The 4gPdO/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, and the reaction is carried out at the temperature of 400 ℃ under the normal pressure conditionThe time was 10h, the product was sampled every 0.25h and the methane conversion (C) was analyzed on-line by gas chromatography. PdO/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples
C0.25h(％)
C10h(％)
Deactivation Rate (%)
1
81.3
4.2
94.8
Example 2
Example 2 preparation of a Single component PtS/SiO2The catalyst is prepared by the following steps: 5g of SiO2The support was immersed in 20mL of H at a concentration of 0.0025g/mL2PtCl6In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 70 ℃ for 4h to remove water, and then roasting at 200 ℃ in air atmosphere for 3h to obtain Pt/SiO2. Then adding Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2S% 5%) at 300 ℃ for 3h to give the PtS/SiO mixture2A catalyst.
The 4gPtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples
C0.25h(％)
C10h(％)
Deactivation Rate (%)
2
19.5
19.4
0.50
Examples 3 to 11:
examples 3-11 compare SiO2Impregnation of the support H2PdCl4After the solution is dried, the solution is subjected to PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: mixing 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 70-130 ℃ for 1-3 h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6Performing ultrasonic treatment at room temperature for 45min to remove bubbles, and soakingOvernight, then dried at 70 ℃ for 4h to remove water, and then roasted at 200 ℃ for 3h in an air atmosphere to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2SPercent (5%) at 300 ℃ for 3h to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples 12 to 18:
examples 12-18 compare SiO2Impregnation of the support H2PdCl4After the solution is calcined, the solution is calcined to PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 400-600 ℃ in air atmosphere for 2-5 h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 70 deg.C for 4h to remove water, and calcining at 200 deg.C in air atmosphere for 3h to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2SPercent (5%) at 300 ℃ for 3h to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples 19 to 24:
examples 19-24 compare H2PdCl4Concentration of the solution and its reaction with SiO2Ratio of carriers PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier is immersed in H with the concentration of 0.005-0.02 g/mL2PdCl4In solution, SiO2Vector and H2PdCl4The solution ratio was 1 g: 1 mL-1 g: 5mL, sonicate for 45min at room temperature to remove air bubbles, and soak overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 400-600 ℃ in air atmosphere for 2-5 h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 70 deg.C for 4h to remove water, and calcining at 200 deg.C in air atmosphere for 3h to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2SPercent (5%) at 300 ℃ for 3h to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S＝4:16:179.8:0.2) introducing the mixed gas into a fixed bed reactor at the flow rate of 200mL/min, reacting at 400 ℃ under the normal pressure condition for 10h, sampling the product every 0.25h, and analyzing the methane conversion rate (C) by gas chromatography on line. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples 25 to 33:
examples 25 to 33 compare PdO/SiO2Impregnation H2PtCl6After the solution is dried, the solution is subjected to PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 60-120 ℃ for 2-5 h to remove water, and then roasting at 200 ℃ for 3h in air atmosphere to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2SPercent (5%) at 300 ℃ for 3h to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16: 160: 20) introducing the mixed gas into a fixed bed reactor at the flow rate of 200mL/min, reacting at 400 ℃ under the normal pressure condition for 10h, sampling the product every 0.25h, and analyzing the methane conversion rate (C) on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following tableAs shown.
Examples 34 to 41:
examples 34 to 41 compare PdO/SiO2Impregnation H2PtCl6After the solution is calcined, the solution is calcined to PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 70 ℃ for 4h to remove water, and then roasting at 100-400 ℃ in air atmosphere for 2-5 h to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2SPercent (5%) at 300 ℃ for 3h to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples 42 to 45:
examples 42-45 compare PdO-Pt/SiO2At H2S-N2In the atmosphere vulcanization process, the concentration of hydrogen sulfide is PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 70 deg.C for 4h to remove water, and calcining at 200 deg.C in air atmosphere for 3h to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2H with hydrogen sulfide concentration of 1-9%2S-N2Vulcanizing at 300 ℃ for 3h at the flow rate of 80ml/min in the atmosphere to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples 46 to 52:
examples 46-52 compare PdO-Pt/SiO2At H2S-N2In the atmosphere vulcanization process, the flow rate of the mixed gas is PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In solution, ultrasonic treating at room temperature for 45minRemove air bubbles and soak overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 70 deg.C for 4h to remove water, and calcining at 200 deg.C in air atmosphere for 3h to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2H at a hydrogen sulfide concentration of 5%2S-N2Vulcanizing at 300 ℃ for 3h at a flow rate of 10-150 ml/min in the atmosphere to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.
Examples 53 to 63:
examples 53-63 compare PdO-Pt/SiO2At H2S-N2In the atmosphere vulcanization process, the vulcanization condition is PdO-PtS/SiO2Influence of catalyst performance. The preparation method of the catalyst comprises the following steps: 5g of SiO2The carrier was immersed in 15mL of H at a concentration of 0.01g/mL2PdCl4In the solution, ultrasonic treatment is carried out at room temperature for 45min to remove bubbles, and the solution is immersed overnight. Then drying at 90 ℃ for 2h to remove water, and then roasting at 500 ℃ in air atmosphere for 4h to obtain PdO/SiO2. PdO/SiO2Immersing in 20mL of H with a concentration of 0.0025g/mL2PtCl6In the solution, performing ultrasonic treatment at room temperature for 45min to remove bubbles, soaking overnight, drying at 70 deg.C for 4h to remove water, and calcining at 200 deg.C in air atmosphere for 3h to obtain PdO-Pt/SiO2. Finally, PdO-Pt/SiO2At a flow rate of 80ml/min H2S-N2Atmosphere (V)H2SPercent (5%) at 100-500 ℃ for 1-5 h to obtain the PdO-PtS/SiO2A catalyst.
The 4gPdO-PtS/SiO2The catalyst is loaded into a fixed bed reactor, and methane, oxygen, nitrogen and hydrogen sulfide (V) are addedCH4:VO2:VN2:VH2S4:16:179.8:0.2) mixed gas is introduced into a fixed bed reactor at the flow rate of 200mL/min, the reaction is carried out at the temperature of 400 ℃ under the normal pressure condition for 10h, the product is sampled every 0.25h, and the methane conversion rate (C) is analyzed on line by gas chromatography. PdO-PtS/SiO2Deactivation rate of catalyst ═ C0.25h-C10h)/C0.25h. The reaction results are shown in the following table.