Preparation method and application of cerium oxide loaded MIL-100 (Fe) composite catalyst

Abstract

The invention relates to a preparation method of a cerium oxide-loaded MIL-100 (Fe) composite catalyst and application of the cerium oxide-loaded MIL-100 (Fe) composite catalyst in catalytic oxidation of hydrogen sulfide (H2S) at normal temperature. The method comprises the following steps: mixing a cerous nitrate solution with an MIL-100 (Fe) suspension, carrying out ultrasonic treatment and centrifugal drying, calcining in an inert atmosphere, and carrying out vacuum activation to prepare the CeO2 highly dispersed composite catalyst. By regulating and controlling the molar ratio of Ce to Fe, a Ce < 3 + >-Ov-Fe < 2 + > active phase is formed, and the oxygen vacancy and Fe < 3 + > oxidation activity are synergistically enhanced. The catalyst has high breakthrough sulfur capacity to H2S at normal temperature, does not need a high-temperature condition, and solves the problems of low efficiency, difficult regeneration and high high-temperature operation cost of the existing catalyst. The characterization result shows that the introduction of CeO2 significantly promotes the generation of oxygen vacancies and the activation of O2, optimizes the circulation of Fe < 2 + > / Fe < 3 + >, and realizes the efficient conversion of H2S into elemental sulfur. The method is simple in process, excellent in catalyst stability and suitable for green and efficient removal of H2S in industrial waste gas.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a cerium oxide-loaded MIL-100 (Fe) composite catalyst. Background Art

[0002] Hydrogen sulfide (H2S) is a highly toxic and corrosive gas widely present in industrial production and daily life, such as coal-to-gas, liquefied petroleum gas, natural gas, pulp and paper industry, wastewater treatment, food processing, and sewage treatment. The presence of H2S can cause severe damage to industrial equipment and downstream catalysts, severely impacting industrial production. More importantly, its release into the environment is extremely harmful to the human body. Even at extremely low concentrations, such as 5 ppm, H2S can irritate the human senses; concentrations exceeding 500 ppm can quickly become life-threatening. When H2S is released into the atmosphere, it oxidizes to form sulfur dioxide, leading to the formation of acid rain and smog. Therefore, effective H2S removal is crucial for industrial applications and environmental sustainability.

[0003] Currently, H2S removal methods primarily include absorption, adsorption, and oxidation. Absorption is commonly used to treat high-throughput H2S gas, but its desulfurization efficiency is low and its equipment investment and operating costs are high. Adsorption can achieve deep H2S removal, but its sulfur capacity is relatively low and regeneration is difficult, posing challenges for solid waste disposal. Oxidation is a widely studied method, offering not only low desulfurization costs but also sulfur resource recovery, thus holding great promise for industrial application. The Claus process is a typical and mature oxidation method, but due to thermodynamic equilibrium limitations, it only achieves H2S conversion rates of 60%–70%. Even after catalytic conversion in a tertiary conversion reactor, the conversion rate reaches only around 97%, and a residual 3–5% content in the tail gas is unavoidable. While high-temperature selective oxidation can achieve deep H2S removal, the operating temperature is typically above 150°C, requiring additional heating equipment and generating sulfur dioxide in the tail gas. Selectivity is also challenging, and there is a risk of elemental sulfur overflow and pipeline blockage. Room-temperature catalytic oxidation converts H2S into elemental sulfur at room temperature and immobilizes it within the catalyst structure. This process has attracted widespread attention due to its mild operating conditions, ultra-high selectivity, zero secondary pollution, and the fact that elemental sulfur does not overflow the reactor and clog subsequent pipelines. Catalyst selection and design are key to achieving room-temperature catalytic oxidation desulfurization.

[0004] At present, H2S room temperature catalysts mainly include two categories: activated carbon materials and metal oxides. Although the former has a rich pore structure, its own activity is low and usually needs to be loaded with alkaline components. Although the latter contains redox metal active sites, it is easy to aggregate and has a low porosity, so it usually needs to be loaded onto a porous carrier. However, due to the limitation of the loading amount, the activity is still poor. In addition, these two types of catalysts usually require high humidity conditions to meet the basic desulfurization activity, which is extremely challenging for desulfurization applications under some specific dry atmospheres. Metal-organic framework materials (MOFs) are a new type of porous material assembled by bridging and coordinating metal centers or metal clusters with organic ligands. It has the advantages of both activated carbon materials and metal oxides. It not only has a developed pore structure and an ultra-large specific surface area, but also has abundant and evenly dispersed active sites. It is a more ideal catalyst. Among them, Fe-based MOF has rich Fe 3+ Lewis acidic sites can achieve direct oxidation of H2S to elemental sulfur, and may have great potential for application in room-temperature catalytic oxidation.

[0005] However, the research on room temperature H2S oxidation of Fe-based MOFs is very limited. Our recent research results (Yeshuang Wang, Chao Yang*, Huiling Fan*et al.Fe 2+ -Triggered Unexpected Roomtemperature H2S Catalytic Oxidation Activity in MIL-100(Fe).Separation and Purification Technology,2025:132695.). The penetration sulfur capacity of pure MIL-100(Fe) at room temperature is only 14.5mg S / g. Fortunately, the Fe in the MIL-100(Fe) structure was regulated by high temperature vacuum activation. 2+ After the addition of Fe, the catalytic activity was greatly improved, and the penetration sulfur capacity reached 267.3 mg S / g. The improvement in performance is due to the Fe generated in the structure. 2+ site, which effectively enhances the Fe 3+ The oxidation activity and activation of O2, thus achieving Fe 2+ / Fe 3+ However, there are still two key issues that make the sulfur capacity still very limited: 1) Fe 2+ The amount of regulation is limited by the activation process; 2) The insufficient activation ability of O2 restricts the catalytic cycle efficiency. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a method for preparing a cerium oxide-loaded MIL-100 (Fe) composite catalyst. The method introduces cerium oxide with oxygen vacancy regulation characteristics to provide an xCe-MIL-100 (Fe) composite catalyst synergistically modified with oxygen vacancies and diastereomers, and the preparation method is simple and efficient.

[0007] The second technical problem to be solved by the present invention is to provide an xCe-MIL-100(Fe) catalyst prepared according to the above-mentioned preparation method of the cerium oxide-loaded MIL-100(Fe) composite catalyst, which is used as an H2S catalyst at room temperature.

[0008] To solve the above technical problems, the present invention provides a method for preparing a cerium oxide-supported MIL-100 (Fe) composite catalyst, comprising the following steps:

[0009] (1) Disperse MIL-100(Fe) powder in anhydrous ethanol to form a uniform suspension with a concentration of 20-50 mg / mL and continue stirring until uniform;

[0010] (2) dissolving Ce(NO3)3·6H2O and MIL-100(Fe) in anhydrous ethanol at a mass ratio of 0.15:1 to 0.61:1 to form a cerium salt solution with a concentration of 0.03 to 0.14 mol / L;

[0011] (3) adding the cerium salt solution obtained in step (2) dropwise to the suspension in step (1), stirring at a speed of 600-650 r / min for 2-4 h to obtain a mixed solution;

[0012] (4) Transfer the mixed solution to an ultrasonic reactor and treat at 40 kHz frequency at 50 ± 5 °C for 25–35 min;

[0013] (5) After ultrasonic treatment, the sample was transferred to a centrifuge and centrifuged at 8000-10000 rpm for 10 min to obtain a solid sample, which was then dried in a forced air drying oven at 75-85°C for 3-5 h to obtain a dry sample;

[0014] (6) heating the dried sample obtained in step (5) to 240-260° C. at a rate of 2-5° C. / min under an Ar atmosphere and calcining for 3-5 h;

[0015] (7) The calcined sample obtained in step (6) is activated under continuous vacuum conditions at 240-260° C. for 10-12 hours to finally obtain the xCe-MIL-100(Fe) catalyst, wherein x represents the molar percentage of Ce in the total amount of Ce and Fe in the final product catalyst, and the range of x is 10-30%.

[0016] To solve the second technical problem mentioned above, the present invention provides an xCe-MIL-100(Fe) catalyst prepared according to the preparation method of the above-mentioned cerium oxide-loaded MIL-100(Fe) composite catalyst, which is used as an H2S catalyst at room temperature.

[0017] Advantages of the present invention: Compared with the prior art, the xCe-MIL-100 (Fe) composite catalyst prepared by the present invention has the following breakthrough technologies and technological advancements: By constructing Ce 3+ -O v -Fe 2+ active phase, realizing a dual oxygen activation mechanism and increasing the Fe 3+ The oxidation activity of Fe 2+ / Fe 3+ Specifically, after oxygen activation, a large number of superoxide radicals are generated to directly oxidize H2S and promote Fe 2+ Fe 3+ Conversion of Fe 3 + The enhanced oxidation activity promoted the direct oxidation reaction of H2S. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Comparative XRD spectra of different xCe-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0019] Figure 2 Comparative FTIR spectra of different xCe-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0020] Figure 3 SEM comparison images of 0.2Ce-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0021] Figure 4 TEM comparison images of 0.2Ce-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0022] Figure 5 Comparison of N2 adsorption-desorption isotherms of different xCe-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0023] Figure 6 Comparative EPR spectra of different xCe-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0024] Figure 7Comparison of breakthrough curves of different xCe-MIL-100(Fe) and MIL-100(Fe) catalysts.

[0025] Figure 8 Comparison of breakthrough sulfur capacity of different xCe-MIL-100(Fe) and MIL-100(Fe) catalysts. DETAILED DESCRIPTION

[0026] Example 1:

[0027] Weigh 0.5 g of the prepared MIL-100(Fe) sample and dissolve it in 13 mL of anhydrous ethanol while stirring continuously to obtain solution A.

[0028] Weigh 0.079 g of Ce(NO3)3·6H2O and dissolve it in 5 mL of anhydrous ethanol, stirring continuously until it is completely dissolved; then, add it dropwise to solution A to obtain a mixed solution B;

[0029] The mixed solution B was stirred under magnetic stirring at 620 r / min for 3 h; then immediately subjected to ultrasonic treatment at 50°C for 30 min;

[0030] After the treatment was completed, the mixed solution was centrifuged at 9000 r / min for 10 min, and then placed in a forced air drying oven at 80 °C for 4 h to obtain a dry sample;

[0031] The dried sample was placed in a tube furnace and heated at 250°C in an Ar atmosphere at a gas flow rate of 100 mL / min for 4 h. Subsequently, the sample was activated at 250°C in a vacuum atmosphere for 12 h to obtain 0.1Ce-MIL-100(Fe).

[0032] The specific surface area of ​​the 0.1Ce-MIL-100(Fe) catalyst obtained in this example is 1754 m 2 / g, total pore volume 0.87cm 3 / g. After testing, the breakthrough sulfur capacity of the desulfurizer was calculated to be 373.3mg S / g.

[0033] Example 2:

[0034] Weigh 0.5 g of the prepared MIL-100(Fe) sample and dissolve it in 13 mL of anhydrous ethanol while stirring continuously to obtain solution A.

[0035] Weigh 0.1778 g of Ce(NO3)3·6H2O and dissolve it in 5 mL of anhydrous ethanol, stirring continuously until it is completely dissolved; then, add it dropwise to solution A to obtain a mixed solution B;

[0036] The mixed solution B was stirred under magnetic stirring at 620 r / min for 3 h; then immediately subjected to ultrasonic treatment at 50°C for 30 min;

[0037] After the treatment was completed, the mixed solution was centrifuged at 9000 r / min for 10 min, and then placed in a forced air drying oven at 80 °C for 4 h to obtain a dry sample;

[0038] The dried sample was placed in a tube furnace and heated at 250°C in an Ar atmosphere at a gas flow rate of 100 mL / min for 4 h. Subsequently, the sample was activated at 250°C in a vacuum atmosphere for 12 h to obtain 0.2Ce-MIL-100(Fe).

[0039] The specific surface area of ​​the 0.2Ce-MIL-100(Fe) catalyst obtained in this example is 1711 m 2 / g, total pore volume 0.85cm 3 / g. After testing, the breakthrough sulfur capacity of the desulfurizer was calculated to be 415.9mg S / g.

[0040] Example 3:

[0041] Weigh 0.5 g of the prepared MIL-100(Fe) sample and dissolve it in 13 mL of anhydrous ethanol while stirring continuously to obtain solution A.

[0042] Weigh 0.3047 g of Ce(NO3)3·6H2O and dissolve it in 5 mL of anhydrous ethanol, stirring continuously until it is completely dissolved; then, add it dropwise to solution A to obtain a mixed solution B;

[0043] The mixed solution B was stirred under magnetic stirring at 620 r / min for 3 h; then immediately subjected to ultrasonic treatment at 50°C for 30 min;

[0044] After the treatment was completed, the mixed solution was centrifuged at 9000 r / min for 10 min, and then placed in a forced air drying oven at 80 °C for 4 h to obtain a dry sample;

[0045] The dried sample was placed in a tube furnace and heated at 250°C in an Ar atmosphere at a gas flow rate of 100 mL / min for 4 h. Subsequently, the sample was activated at 250°C in a vacuum atmosphere for 12 h to obtain 0.3Ce-MIL-100(Fe).

[0046] The specific surface area of ​​the 0.3Ce-MIL-100(Fe) catalyst obtained in this example is 1671 m 2 / g, total pore volume 0.83cm3 / g. After testing, it was calculated that the breakthrough sulfur capacity of the desulfurizer is 380.8mg S / g.

[0047] Comparative Example 1:

[0048] Comparative Example 1 is a sample without CeO2 loading, i.e., the preparation of pure MIL-100 (Fe) catalyst, the steps are as follows:

[0049] Weigh 37.4 mL of deionized water into a polytetrafluoroethylene-lined container, add 0.4187 g of reduced iron powder and 1.0553 g of trimesic acid, and stir with a glass rod at room temperature until the mixture is uniform to obtain Solution A.

[0050] Weigh 0.305 mL of concentrated nitric acid and 0.665 mL of hydrofluoric acid and add them to solution A respectively. Then transfer the polytetrafluoroethylene liner into the autoclave and place it in a forced air drying oven. React at 150°C for 24 hours.

[0051] After the reaction is completed, the mixture is cooled to room temperature naturally, and the reaction product is taken out and placed in a beaker. Deionized water is added and the mixture is immersed in an 80°C water bath for 6 hours, with the deionized water replaced every 1.5 hours. Subsequently, the deionized water is replaced with anhydrous ethanol and the mixture is immersed for another 3 hours, with the solvent replaced every 1.5 hours.

[0052] After the soaking is completed, the product is placed on a circulating water vacuum pump filter bottle device for filtration, and washed twice with anhydrous ethanol. After the filtration is completed, it is placed in a blast drying oven to dry for 2 hours;

[0053] The dried sample was then placed under vacuum conditions and dried and activated at 250°C for 12 h to obtain the MIL-100(Fe) catalyst.

[0054] The specific surface area of ​​the MIL-100(Fe) catalyst obtained in this comparative example is 1824 m 2 / g, total pore volume 0.88cm 3 / g, of which the micropore volume is 0.27cm 3 / g. After testing, it was calculated that the breakthrough sulfur capacity of the desulfurizer is 267.4mg S / g.

[0055] Comparative Example 2:

[0056] 2 g of Ce(NO3)3·6H2O was weighed and placed in a tube furnace, and heated for 4 h at a gas flow rate of 100 mL / min and an Ar atmosphere at 250°C. Subsequently, the obtained sample was activated under vacuum conditions at 250°C for 12 h to finally obtain a CeO2 catalyst.

[0057] The specific surface area of ​​the CeO2 catalyst obtained in this embodiment is 92m2 / g, total pore volume 0.28cm 3 / g. After testing, it was calculated that the breakthrough sulfur capacity of the desulfurizer is 1.7mg S / g.

[0058] In the above examples, a fixed bed experimental apparatus was used to test the room temperature H2S catalytic oxidation performance of the catalysts of each example and comparative example. The specific process is as follows:

[0059] Take an appropriate amount of catalyst and fill it into a U-shaped reactor with an inner diameter of 6mm and a wall thickness of 1.5mm. The catalyst filling height is 2cm and fixed at both ends with quartz wool. Then, a mixture of 5% O2 and 95% H2S and N2 is introduced into the U-shaped tube reactor. The H2S concentration at the inlet is adjusted to 520mg / m 3 , the gas flow rate was 80 mL / min, the reaction temperature was 30°C, and the reaction pressure was normal pressure.

[0060] Record the inlet and outlet H2S concentrations at different time periods. When the outlet gas concentration is 1% of the inlet gas concentration, that is, 5.2 mg / m 3 , is regarded as the desulfurizer breakthrough point, corresponding to the breakthrough sulfur capacity Q. The calculation formula is as follows:

[0061]

[0062] Where N represents the gas flow rate, C in and C out They represent the inlet and outlet H2S concentrations respectively, and m represents the mass of the catalyst.

[0063] Through this experimental method, the H2S removal performance of different catalysts at room temperature can be effectively evaluated.

[0064] In order to more clearly and intuitively compare the texture parameters and performance of the xCe-MIL-100(Fe) catalyst prepared by the present invention, they are summarized in Table 1. As can be seen from Table 1, compared with pure MIL-100(Fe), CeO2 loading will slightly reduce the specific surface area and pore volume of the MIL-100(Fe) catalyst, but the effect is very small. However, the room temperature catalytic activity of H2S shows a very significant difference. Specifically, the room temperature penetration sulfur capacity of MIL-100(Fe) is 267.3mg S / g, while after CeO2 loading, the sulfur capacity reaches 373.3–415.9mg S / g, and the performance can be improved by up to 55.6%. This is due to the oxygen-rich vacancies and divalent iron CeO2 prepared by the present invention. x @MIL-100(Fe) composite catalyst not only improves the Fe 3+ The activity of metal sites also greatly promotes the adsorption and activation of O2, thus significantly improving the catalytic performance at room temperature.

[0065] Table 1 Physical structure and performance parameters of catalysts in various embodiments and comparative examples

[0066] sample <![CDATA[S BET (m 2 / g)]]> <![CDATA[V t (cm 3 / g)]]> Q(mg S / g) Comparative Example 1 1824 0.89 267.3 Comparative Example 2 92 0.28 1.7 Example 1 1754 0.87 373.3 Example 2 1711 0.85 415.9 Example 3 1581 0.83 379.8

[0067] In order to understand the effect of the introduction of CeO2 on the crystal structure of MIL-100(Fe) material, the following characterization experiments were conducted, with 0.1Ce-MIL-100(Fe), 0.2Ce-MIL-100(Fe), and 0.3Ce-MIL-100(Fe) as the experimental groups, and MIL-100(Fe) as the control group:

[0068] The XRD characterization of MIL-100(Fe) and xCe-MIL-100(Fe) catalysts was carried out. Figure 1 As shown in the figure, compared to MIL-100(Fe), the XRD diffraction peaks after CeO2 loading did not change significantly, indicating that the crystal structure of the xCe-MIL-100(Fe) composite catalyst remains intact. In addition, no characteristic diffraction peaks of CeO2 were observed in xCe-MIL-100(Fe), indicating that the morphology of CeO2 loaded into the MIL-100(Fe) structure is likely amorphous or highly dispersed.

[0069] The infrared spectra of MIL-100(Fe) and xCe-MIL-100(Fe) are shown in Figure 2. Figure 2 As shown. MIL-100(Fe) exhibits an obvious characteristic absorption peak: at 3400 cm -1 The peaks at 1377, 1443, and 1640 cm-1 are O–H vibration peaks, which are attributed to water adsorbed on the catalyst; -1 Symmetrical and asymmetric vibration peaks corresponding to the carboxyl group of the ligand; 711 cm -1 The C—H stretching vibration of the aromatic benzene ring. After the introduction of CeO2, the infrared absorption peak retained the typical absorption peak of MIL-100 (Fe). However, a careful comparison found that after CeO2 loading, 484 cm –1 The absorption peak near is slightly enhanced, which may be caused by the Ce–O vibration in CeO2.

[0070] Scanning electron microscope images of MIL-100(Fe) and 0.2Ce-MIL-100(Fe) are shown in Figure 2. Figure 3 As shown. MIL-100(Fe) presents a cubic octahedral structure with a particle size of about 5μm, a smooth surface and no particle accumulation. When loaded with 20% CeO2 ( Figure 3c, d), 0.2Ce-MIL-100(Fe) still maintains the same octahedral morphology and particle size as MIL-100(Fe). The difference is that the crystal surface is densely distributed with flaky nanoparticles, which may be attributed to the loaded CeO2.

[0071] Transmission electron microscope image of 0.2Ce-MIL-100(Fe) catalyst Figure 4 After CeO2 loading, a large number of elongated nanocrystals grow on the surface of the catalyst, mainly distributed on the surface of the crystals within the range of ~50nm, and the distribution content gradually decreases from the outside to the inside. Figure 4 The lattice fringe spacing of the nanocrystals in b is mainly 0.18 nm and 0.31 nm, corresponding to the (220) and (111) crystal planes of CeO2, respectively, indicating that CeO2 is successfully loaded into the MIL-100(Fe) structure in a highly dispersed and amorphous form, and is mainly distributed on the surface of the crystal.

[0072] The physical structure of the prepared catalyst was further analyzed by nitrogen adsorption, such as Figure 5 As shown. MIL-100(Fe) exhibits a type I adsorption isotherm, showing a high N2 adsorption capacity. After CeO2 loading, the N2 adsorption-desorption isotherm still maintains an isotherm type similar to that of MIL-100(Fe), indicating that the pore structure of xCe-MIL-100(Fe) is still dominated by micropores. However, with the increase of CeO2 loading, the N2 adsorption capacity gradually decreases, indicating that the specific surface area and pore volume show a slight downward trend. These results indicate that after CeO2 loading, a small amount of CeO2 will be deposited into the pores, causing pore blockage.

[0073] In order to further verify the formation of oxygen vacancies in the catalyst structure, the samples before and after CeO2 loading were characterized and analyzed using electron paramagnetic resonance (EPR). Figure 6 As shown in Figure a, all samples exhibit a unique peak at g = 2.003, which is associated with the presence of vacancies within the sample. MIL-100(Fe) exhibits a weak peak intensity, attributed to the presence of ligand vacancies within its structure. When CeO2 is loaded, the intensity of this peak increases 3.73-fold compared to the unloaded sample, indicating that CeO2 loading facilitates the generation of oxygen vacancies.

[0074] Analysis of O2 Generation by Catalysts Using EPR Spectroscopy and DMPO Scavenger ·- The ability of free radicals, as a result Figure 6 As shown in b, MIL-100(Fe) showed a gradually enhanced 1:1:1:1 quadruple signal characteristic peak, which is attributed to the Fe in the structure. 2+ O2 generated by activated O2 ·-After CeO2 was loaded onto MIL-100(Fe), the signal peak intensity increased significantly. Compared with the unloaded sample, the O2 generated by 0.2Ce-MIL-100(Fe) ·- The content increased by 1.1 times, O2 ·- The increase in concentration is attributed to the increase in Fe 2+ and O v .

[0075] The prepared MIL-100(Fe) and xCe-MIL-100(Fe) catalysts were tested for catalytic activity at room temperature using a fixed bed. The breakthrough curves and breakthrough sulfur capacity results were shown in Figures 2 and 3, respectively. Figure 7 and Figure 8 As shown. The penetration time of MIL-100(Fe) is 1060 min, and the corresponding penetration sulfur capacity is 265.3 mg S / g, while CeO2 has almost no catalytic oxidation activity at room temperature, and the corresponding penetration time and penetration sulfur capacity are only 2 min and 0.3 mg S / g, respectively. When CeO2 is introduced into MIL-100(Fe), the penetration sulfur capacity shows a "volcano-type" trend of first increasing and then decreasing with the increase of the introduction amount. 0.2Ce-MIL-100(Fe) has the highest penetration time and penetration sulfur capacity, which are 1650 min and 415.9 mg S / g, respectively. Compared with the unloaded sample, the performance is improved by 55.6%.

[0076] In summary, CeO2 loading has little effect on the physical structure of MIL-100(Fe), but the room temperature catalytic activity is significantly improved. On the one hand, the introduction of CeO2 will produce a strong interaction with Fe, generating a large amount of O v and Fe 2+ active sites, which greatly promotes the activation of O2; on the other hand, it also improves the Fe 3+ The oxidation activity of H2S greatly promotes the catalytic oxidation reaction of H2S at room temperature.

Claims

1. A method for preparing a cerium oxide-supported MIL-100 (Fe) composite catalyst, characterized in that: The following steps are involved: (1) Disperse MIL-100(Fe) powder in anhydrous ethanol to form a uniform suspension with a concentration of 20-50 mg / mL and continue stirring until uniform; (2) dissolving Ce(NO3)3·6H2O and MIL-100(Fe) in anhydrous ethanol at a mass ratio of 0.15:1 to 0.61:1 to form a cerium salt solution with a concentration of 0.03 to 0.14 mol / L; (3) adding the cerium salt solution obtained in step (2) dropwise to the suspension in step (1), stirring at a speed of 600-650 r / min for 2-4 h to obtain a mixed solution; (4) Transfer the mixed solution to an ultrasonic reactor and treat at 40 kHz frequency at 50 ± 5 °C for 25–35 min; (5) After ultrasonic treatment, the sample was transferred to a centrifuge and centrifuged at 8000-10000 rpm for 10 min to obtain a solid sample, which was then dried in a forced air drying oven at 75-85°C for 3-5 h to obtain a dry sample; (6) heating the dried sample obtained in step (5) to 240-260° C. at a rate of 2-5° C. / min under an Ar atmosphere and calcining for 3-5 h; (7) The calcined sample obtained in step (6) is activated under continuous vacuum conditions at 240-260° C. for 10-12 hours to finally obtain the xCe-MIL-100(Fe) catalyst, wherein x represents the molar percentage of Ce in the total amount of Ce and Fe in the final product catalyst, and the range of x is 10-30%.

2. The method for preparing a cerium oxide-supported MIL-100(Fe) composite catalyst according to claim 1, wherein the prepared xCe-MIL-100(Fe) catalyst is used as an H2S catalyst at room temperature.

Images