CN114832819A - Mesoporous cerium oxide supported ruthenium catalyst and preparation method and application thereof - Google Patents

Mesoporous cerium oxide supported ruthenium catalyst and preparation method and application thereof Download PDF

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CN114832819A
CN114832819A CN202210526114.4A CN202210526114A CN114832819A CN 114832819 A CN114832819 A CN 114832819A CN 202210526114 A CN202210526114 A CN 202210526114A CN 114832819 A CN114832819 A CN 114832819A
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acetate
cerium oxide
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supported ruthenium
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李达林
王鹏
陈崇启
罗宇
江莉龙
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Fuzhou University
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Abstract

The invention provides a mesoporous cerium oxide supported ruthenium catalyst and a preparation method and application thereof, the mesoporous cerium oxide supported ruthenium catalyst comprises active metal, a carrier and an auxiliary agent, the active metal is ruthenium metal, the carrier is cerium oxide, the auxiliary agent is rubidium oxide, the mass content of the ruthenium metal is 3%, the mass content of the rubidium is 2.5-7.6%, acetate is used as a precursor, and the catalyst can be prepared by ball-milling, mixing, roasting and reducing treatment 2 The carrier precursor is roasted and decomposed to obtain mesoporous CeO 2 The most probable pore diameter is 3.3-3.6nm, and the BET specific surface area reaches 71-105m 2 g cat ‑1 Is favorable for the dispersion of Ru metal and the diffusion of reactants and shows good activity and stability at low temperature, wherein 3 percent of Ru-5.1 percent of Rb/CeO 2 Catalyst at space velocity of 30,000mLg cat ‑1 h ‑1 The ammonia conversion rate can reach 95 percent at 500 ℃; the reaction was continued at 475 ℃ for 50h, maintaining the ammonia conversion above 90%.

Description

Mesoporous cerium oxide supported ruthenium catalyst and preparation method and application thereof
Technical Field
The invention belongs to the technical field of ammonia decomposition, and relates to a mesoporous cerium oxide supported ruthenium catalyst, and a preparation method and application thereof.
Background
The use of traditional fossil fuels causes serious environmental pollution, and the reserves thereof are also continuously reduced, thus being difficult to satisfy the long-term demands of human beings. The hydrogen energy has high energy density and the combustion product is H 2 O, no environmental pollution, wide raw material source and reproducibility. Hydrogen energy is therefore considered to be one of the ideal energy sources for sustainable development.
The safety issues faced by hydrogen gas during storage and transportation are one of the major technical barriers to hydrogen energy utilization. Ammonia has received increasing attention in recent years as a carbon-free hydrogen storage medium. The ammonia liquefaction condition is mild (20 ℃, 8.6bars), and the safety problem in the hydrogen storage and transportation process can be avoided; high hydrogen and energy density of ammonia (17.8 wt.%, 3000 Wh/kg); ammonia is an important bulk chemical in modern industry and agriculture, and the annual global yield reaches 1 hundred million tons; h production by catalytic ammonia decomposition 2 Free of CO x The catalyst is applied to Proton Exchange Membrane Fuel Cells (PEMFCs) and can effectively avoid Pt electrode poisoning.
Ammonia gas molecules are very stable and the ammonia decomposition reaction is an endothermic reaction, so that a large amount of energy is consumed for catalyzing ammonia decomposition to produce hydrogen. In order to reduce the activation energy required for the ammonia decomposition reaction, a suitable catalyst needs to be found. At present, most of industrial catalysts are Fe or Ni-based catalysts, but the catalysts have higher activity only at the temperature of more than 800 ℃, and the problem of high reaction energy consumption is not solved. The Ru-based catalyst is the catalyst with the best activity reported in the literature at present, and generally shows higher activity at 500 ℃. Common supported Ru catalysts include Ru/CNTs (carbon nanotubes) and Ru/Al 2 O 3 、Ru/MgO、Ru/CeO 2 And the like. The Ru/CNTs have high low-temperature activity, but the CNTs have the problems of high price, instability in a hydrogen atmosphere, easiness in methanation and the like, and are not suitable for industrial hydrogen production. Ru/Al 2 O 3 The catalyst is very stable at high temperatures, but due to Al 2 O 3 Is a slightly acidic carrier, so the activity of the catalyst is low. The Ru/MgO catalyst has stronger alkalinity and higher low-temperature activity, but has the problems that MgO is easy to absorb moisture and generates crystal phase change and the like. Ru/CeO 2 The catalyst not only can overcome the problems of the above catalysts, but also can improve the sintering resistance of the catalyst, but the low-temperature activity and stability of the catalyst are still to be improved.
Ru/CeO reported in literature at present 2 The preparation method of the catalyst comprises an impregnation method, a deposition-precipitation method, a hydrothermal method, a colloid deposition method and the like. The impregnation method is a commonly used method for preparing a catalyst, but has problems of nonuniform dispersion of Ru particles, wide particle size distribution, and the like. There is literature on the preparation of Ru/CeO by precipitation 2 Catalyst: 1.0g of the carrier was added to 50mL of deionized water to prepare a suspension, and then 0.04g of RuCl was added 3 ·xH 2 O, then adding NH 4 OH adjusted pH 9.0. Then stirring the suspension at room temperature for 12h, and finally filtering, washing and drying to obtain Ru/CeO 2 A catalyst. There are reports in the literature of the preparation of Ru/CeO by colloidal deposition 2 Catalyst: 0.15g of RuCl 3 Adding into 50mL of glycol solution, adding into 0.16g of NaOH, stirring vigorously for 30min, and then carrying out hydrothermal treatment on the solution at 160 ℃ for 3h to obtain a Ru colloidal solution. Then 0.5g of CeO was added 2 Adding the carrier into 12.5mL deionized water to prepare a suspension, and then adding the Ru colloidal solution and CeO 2 Adding the suspension together, continuously stirring for 48h, and finally separating, washing, drying and roasting to obtain Ru/CeO 2 A catalyst. The method needs water or other organic matters as a solvent in the process of preparing the catalyst, is complex and time-consuming in process, can generate waste liquid, increases the production cost of the catalyst, and has large Ru metal particle size and low utilization rate, thus causing low activity of the catalyst.
Disclosure of Invention
The invention aims to provide a mesoporous cerium oxide supported ruthenium catalyst, and a preparation method and application thereof, so as to solve the problems in the background technology.
The purpose of the invention can be realized by the following technical scheme: the mesoporous cerium oxide supported ruthenium catalyst comprises active metal, a carrier and an auxiliary agent, wherein the active metal is ruthenium metal, the carrier is cerium oxide, the auxiliary agent is rubidium oxide, the mass content of the ruthenium metal is 3%, and the mass content of the rubidium is 2.5-7.6%.
2. A preparation method of a mesoporous cerium oxide supported ruthenium catalyst comprises the following steps:
s1: performing ball milling and mixing on ruthenium acetate, cerium acetate and rubidium acetate by using a planetary ball mill to obtain an acetate mixture, and roasting the acetate mixture to obtain a mixed oxide;
s2: and (4) reducing the mixed oxide in the step S1 to obtain the mesoporous cerium oxide supported ruthenium catalyst.
In the preparation method of the mesoporous cerium oxide supported ruthenium catalyst, in step S1, the mass ratio of ruthenium acetate, cerium acetate and rubidium acetate is 1: 20-30: 0.3-1.2.
In the preparation method of the mesoporous cerium oxide supported ruthenium catalyst, the mass ratio of the total mass of ruthenium acetate, cerium acetate and rubidium acetate to agate balls is 1: 30-60.
In the preparation method of the mesoporous cerium oxide supported ruthenium catalyst, the rotating speed of the planetary ball mill is 800r/min, and the running time is 0.5-2.5 h.
In the preparation method of the mesoporous cerium oxide supported ruthenium catalyst, in step S1, the roasting atmosphere is air, the temperature is 500 ℃, and the roasting time is 5 hours; in the step S2, the reducing atmosphere is high-purity hydrogen, the temperature is 500 ℃, and the reducing time is 0.5 h.
An application of a mesoporous cerium oxide supported ruthenium catalyst in ammonia decomposition hydrogen production reaction.
Compared with the prior art, the mesoporous cerium oxide supported ruthenium catalyst and the preparation method and the application thereof have the following advantages:
1. the invention adopts acetate as a precursor, and the catalyst can be prepared by ball milling, mixing, roasting and reducing treatment.
2. The invention adopts cerium acetate as CeO 2 The carrier precursor is roasted and decomposed to obtain mesoporous CeO 2 The most probable pore diameter is 3.3-3.6nm, and the BET specific surface area reaches 71-105m 2 g cat -1 The dispersion of Ru metal and the diffusion of reactants are facilitated.
3. The invention adopts Rb auxiliary agent to modify Ru/CeO 2 The Rb additive can reduce the grain diameter of Ru metal, improve the dispersion degree of Ru and has obvious promotion effect on catalytic activity.
4. The mesoporous cerium oxide supported ruthenium catalyst prepared by the invention shows good activity and stability at low temperature, wherein 3% of Ru-5.1% of Rb/CeO 2 Catalyst at space velocity of 30,000mLg cat -1 h -1 The ammonia conversion rate can reach 95 percent at 500 ℃; the reaction was continued at 475 ℃ for 50h, maintaining the ammonia conversion above 90%.
Drawings
FIG. 1 is an X-ray powder diffraction pattern of the catalyst of example 1 of the present invention;
FIG. 2 is a transmission electron micrograph of a catalyst of example 1 of the present invention;
FIG. 3 is an X-ray powder diffraction pattern of the catalyst of example 2 of the present invention;
FIG. 4 is a transmission electron micrograph of a catalyst of example 2 of the present invention;
FIG. 5 is a graph of the pore size distribution of the catalyst of example 2 of the present invention;
FIG. 6 is an X-ray powder diffraction pattern of the catalyst of example 3 of the present invention;
FIG. 7 is a graph of the pore size distribution for the catalyst of example 3 of the present invention;
FIG. 8 is an X-ray powder diffraction pattern of the catalyst of comparative example 1 of the present invention;
FIG. 9 is a transmission electron micrograph of a catalyst of comparative example 1 of the present invention;
FIG. 10 is a pore size distribution plot for the catalyst of comparative example 1 of the present invention;
FIG. 11 is an X-ray powder diffraction pattern of the catalyst of comparative example 2 of the present invention;
FIG. 12 is a transmission electron micrograph of a catalyst of comparative example 2 of the present invention;
FIG. 13 is a pore size distribution diagram for the catalyst of comparative example 2 of the present invention;
FIG. 14 is an X-ray powder diffraction pattern of the catalyst of comparative example 3 of the present invention;
FIG. 15 is a transmission electron micrograph of a catalyst of comparative example 3 of the present invention;
FIG. 16 is a pore size distribution plot for the catalyst of comparative example 3 of the present invention;
FIG. 17 is an X-ray powder diffraction pattern of the catalyst of comparative example 4 of the present invention;
FIG. 18 is a transmission electron micrograph of a catalyst of comparative example 4 of the present invention;
FIG. 19 is a pore size distribution diagram for the catalyst of comparative example 4 of the present invention;
FIG. 20 is an X-ray powder diffraction pattern of the catalyst of comparative example 5 of the present invention;
FIG. 21 is a transmission electron micrograph of a catalyst of comparative example 5 of the present invention;
FIG. 22 is a pore size distribution diagram for the catalyst of comparative example 5 of the present invention;
FIG. 23 is a graph showing the results of the stability test of the catalyst of example 2 of the present invention against ammonia decomposition reaction.
Detailed Description
The examples do not show the specific experimental steps or conditions, and can be performed according to the conventional experimental steps described in the literature in the field. The reagents or instruments used are not indicated by manufacturers, and are all conventional reagent products which can be obtained commercially.
Example 1
A preparation method of a mesoporous cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1): putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.0254g of rubidium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of the acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2): placing the metal acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5 hours in an air atmosphere. Then tabletting, grinding and sieving the roasted mixed oxide powder to obtain particles of 30-60 meshes. Then 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-2.5% Rb/meso-CeO 2 Wherein the molar ratio Rb/Ru is 1.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 1, characteristic diffraction peaks detected at 2 θ of 50.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were assigned to CeO 2 The corresponding crystal planes are respectively (111), (200), (220), (311), (222), (400), (331) and (420), and no characteristic diffraction peak of Ru metal is detected, which indicates that Ru is in a high dispersion state, and no Rb is detected 2 Characteristic diffraction peak of O, indicating that Rb is in high dispersion state.
By using N 2 The physical adsorption characterizes the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 2, the BET specific surface area is 105.5m 2 g cat -1 The pore diameter is concentrated below 10nm, and the most probable pore diameter is 3.6nm, which indicates that a uniform mesoporous structure is formed.
Example 2
A preparation method of a mesoporous cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.0509g of rubidium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of the acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2) placing the acetate mixture obtained in the step 1) in a muffle furnace, roasting in an air atmosphere, and keeping the roasting temperatureThe temperature is 500 ℃, the time is 5 hours, and then the mixture powder obtained after roasting is tabletted, milled and sieved to obtain 30-60 mesh granules. Then 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-5.1% Rb/meso-CeO 2 Wherein the molar ratio Rb/Ru is 2.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 3, characteristic diffraction peaks at 2 θ of 50.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were assigned to CeO 2 The corresponding crystal planes are (111), (200), (220), (311), (222), (400), (331) and (420), respectively. No characteristic diffraction peak of Ru metal was detected, indicating that Ru is in a highly dispersed state. No Rb was detected 2 Characteristic diffraction peak of O, indicating that Rb is in high dispersion state.
The ruthenium particles of the prepared catalyst are analyzed by a transmission electron microscope, and as shown in fig. 4, the ruthenium particles are mainly distributed in the range of 0.5-4.5 nm, and the average particle size is 2.8 nm.
By using N 2 The physical adsorption characterizes the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 5, the BET specific surface area is 74.6m 2 g cat -1 The pore diameter is concentrated below 10nm, and the most probable pore diameter is 3.3nm, which indicates that a uniform mesoporous structure is formed.
Example 3
A preparation method of a mesoporous cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.0763g of rubidium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of the acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2) placing the acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5 hours in an air atmosphere. Then the mixture powder obtained after roasting is mixedTabletting, grinding and sieving to obtain 30-60 mesh granules. Then 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-7.6% Rb/meso-CeO 2 Wherein the molar ratio Rb/Ru is 3.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 6, characteristic diffraction peaks detected at 2 θ of 50.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were assigned to CeO 2 The corresponding crystal planes are (111), (200), (220), (311), (222), (400), (331) and (420), respectively. No characteristic diffraction peak of Ru metal was detected, indicating that Ru is in a highly dispersed state. No Rb was detected 2 Characteristic diffraction peak of O, indicating that Rb is in high dispersion state.
By using N 2 The physical adsorption characterizes the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 7, the BET specific surface area is 71.4m 2 g cat -1 The pore diameter is concentrated below 10nm, and the most probable pore diameter is 3.4nm, which indicates that a uniform mesoporous structure is formed.
Comparative example 1
A preparation method of a mesoporous cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate and 1.7880g of cerium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2h to obtain an acetate mixture;
2) placing the acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5h in an air atmosphere. Then tabletting, grinding and sieving the mixture powder obtained after roasting to obtain granules of 30-60 meshes. Finally, 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru/meso-CeO 2 。
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 8, characteristic diffraction peaks detected at 2 θ of 50.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were assigned to CeO 2 The corresponding crystal planes are (111), (200), (220), (311), (222), (400), (331) and (420), respectively, and no characteristic diffraction peak of Ru metal is detected, indicating that Ru is in a high dispersion state.
The ruthenium particles of the prepared catalyst are analyzed by a transmission electron microscope, and as shown in fig. 9, the ruthenium particles are mainly distributed in the range of 1-7 nm, and the average particle size is 4.1 nm.
By using N 2 The physical adsorption represents the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 10, and the BET specific surface area of the prepared catalyst is 111.4m 2 g cat -1 The pore diameter is concentrated below 10nm, and the most probable pore diameter is 3.9nm, which indicates that a uniform mesoporous structure is formed.
Comparative example 2
A preparation method of a cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.1224g of lithium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of the acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2) placing the metal acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5 hours in an air atmosphere. Then tabletting, grinding and sieving the roasted mixed oxide powder to obtain particles of 30-60 meshes. Then 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-0.4% Li/CeO 2 Wherein the molar ratio Li/Ru is 2.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, as shown in fig. 11, at 33.25 ° 2 θCharacteristic diffraction peaks detected at 38.65 degrees, 55.78 degrees, 66.45 degrees, 70.10 degrees, 82.91 degrees, 92.01 degrees and 95.48 degrees belong to CeO 2 The corresponding crystal planes are (111), (200), (220), (311), (222), (400), (331) and (420), respectively, and no characteristic diffraction peak of Ru metal is detected, indicating that Ru is in a high dispersion state. No Li was detected 2 And a characteristic diffraction peak of O indicates that Li is in a high dispersion state.
The particle size of the Ru particles of the prepared catalyst is analyzed by a transmission electron microscope, as shown in figure 12, the Ru particles are mainly distributed in the range of 1-8 nm, and the average particle size is 4.3 nm.
By using N 2 The physical adsorption characterizes the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 13, the BET specific surface area is 30.1m 2 g cat -1 The pore size distribution was very broad, with a mode pore size of 9.2nm, indicating the formation of particle packing pores.
Comparative example 3
A preparation method of a cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.0974 g of sodium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of the acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2) placing the acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5 hours in an air atmosphere. Then tabletting, grinding and sieving the mixture powder obtained after roasting to obtain granules of 30-60 meshes. Then 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-1.4% Na/CeO 2 Wherein the molar ratio of Na/Ru is 2.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 14, characteristic derivatives detected at 2 θ of 33.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were obtainedPeak emission attribution CeO 2 The corresponding crystal planes are (111), (200), (220), (311), (222), (400), (331) and (420), respectively, and no characteristic diffraction peak of Ru metal is detected, indicating that Ru is in a high dispersion state. No Na was detected 2 And a characteristic diffraction peak of O shows that Na is in a high dispersion state.
The particle size of the Ru particles of the prepared catalyst is analyzed by a transmission electron microscope, as shown in FIG. 15, the Ru particles are mainly distributed in the range of 1-4.5 nm, and the average particle size is 2.4 nm.
By using N 2 The physical adsorption characterizes the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 16, the BET specific surface area is 40.1m 2 g cat -1 The pore size distribution was very broad, with a mode pore size of 9.2nm, indicating the formation of particle packing pores.
Comparative example 4
A preparation method of a cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.0585g of potassium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of the total mass of the acetate to the agate balls of 1: 50, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2) placing the acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5h in an air atmosphere. Then tabletting, grinding and sieving the mixture powder obtained after roasting to obtain granules of 30-60 meshes. Then 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-2.3% K/CeO 2 Wherein the molar ratio K/Ru is 2.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 17, characteristic diffraction peaks detected at 2 θ of 33.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were assigned to CeO 2 The corresponding crystal planes are (111), (200), (220), (311), (222) and (4) respectively00) (331) and (420), no characteristic diffraction peak of Ru metal is detected, indicating that Ru is in a highly dispersed state. No K was detected 2 And a characteristic diffraction peak of O shows that K is in a high dispersion state.
The particle size of the Ru particles of the prepared catalyst is analyzed by a transmission electron microscope, as shown in figure 18, the Ru particles are mainly distributed in the range of 1-4 nm, and the average particle size is 1.9 nm.
By the use of N 2 The physical adsorption represents the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 19, the BET specific surface area is 33.8m 2 g cat -1 The pore size distribution is very wide, the most probable pore size is 3.6 and 10-20nm, and the pore size distribution corresponds to uniform mesopores and particle stacking pores respectively.
Comparative example 5
A preparation method of a cerium oxide supported ruthenium catalyst specifically comprises the following steps:
1) putting 0.0667g of ruthenium acetate, 1.7880g of cerium acetate and 0.2281g of cesium acetate into a 250mL agate ball milling tank, putting agate balls according to the mass ratio of 1: 50 of the total mass of acetate to the agate balls, and then carrying out ball milling at the ball milling speed of 800r/min for 2 hours to obtain an acetate mixture;
2) placing the acetate mixture obtained in the step 1) in a muffle furnace, and roasting at 500 ℃ for 5h in an air atmosphere. Then tabletting, grinding and sieving the mixture powder obtained after roasting to obtain granules of 30-60 meshes. Finally, 50mg of the particles are placed in a fixed bed reactor, high-purity hydrogen (30mL/min) is introduced for reduction at the temperature of 500 ℃ for 0.5h to obtain the mesoporous cerium oxide supported ruthenium catalyst, which is recorded as 3% Ru-7.9% Cs/CeO 2 Wherein the Cs/Ru molar ratio is 2.
The crystal phase structure of the catalyst prepared above was characterized by X-ray powder diffraction, and as shown in fig. 20, characteristic diffraction peaks detected at 2 θ of 33.25 °, 38.65 °, 55.78 °, 66.45 °, 70.10 °, 82.91 °, 92.01 ° and 95.48 ° were assigned to CeO 2 The corresponding crystal planes are respectively (111), (200), (220), (311), (222), (400), (331) and (420), and no characteristic diffraction peak of Ru metal is detected, indicating that Ru is highA dispersed state. No Cs detected 2 Characteristic diffraction peak of O, indicating that Cs is in high dispersion state.
The particle size of the Ru particles of the prepared catalyst is analyzed by a transmission electron microscope, as shown in figure 21, the Ru particles are mainly distributed in the range of 1-5 nm, and the average particle size is 2.8 nm.
By using N 2 The physical adsorption characterizes the texture property of the prepared catalyst, the pore size distribution diagram of the catalyst is shown in figure 22, the BET specific surface area is 17.6m 2 g cat -1 The pore size distribution is very wide, the most probable pore size is 3.6nm and 17.0nm, and the pore size distribution corresponds to uniform mesopores and particle stacking pores respectively.
Test example 1
The BET specific surface area, pore volume and average pore diameter of the cerium oxide-supported ruthenium catalysts prepared in examples 1 to 3 and comparative examples 1 to 5 were measured, and the results are shown in table 1.
TABLE 1 texture Properties of the catalysts
Figure BDA0003644430620000121
Comparing examples 1-3 with comparative example 1, it can be seen that the specific surface area of the catalyst is reduced, but the specific surface area is still kept high, and the pore size distribution and the most probable pore size are not changed, indicating that the uniform mesoporous structure is not changed. Comparing comparative example 1 and comparative examples 2 to 5, it can be seen that the addition of the Li, Na, K, Cs additives greatly reduces the specific surface area, widens the pore size distribution, and increases the most probable pore size, indicating that the addition of these additives destroys the uniform mesoporous structure.
Test example 2
The ammonia decomposition catalysts prepared in examples 1 to 3 and comparative examples 1 to 5 were tested for low temperature activity. The ammonia decomposition catalytic activity of the catalyst is carried out in a fixed bed quartz tube reactor. And (3) testing conditions are as follows: the dosage of the catalyst is 50mg, the raw material gas is pure ammonia, the flow is 25mL/min, and the space velocity is 30,000mLgcat -1 h -1 The ammonia conversion rate was calculated at normal pressure at 350 ℃, 450 ℃, 500 ℃ and 550 ℃ as shown in formula (1), and the results are shown in Table 2.
Figure BDA0003644430620000131
TABLE 2 Ammonia decomposition Activity test results for catalysts
Figure BDA0003644430620000132
Comparing examples 1-3 with comparative example 1, it can be seen that the addition of the Rb adjuvant increased the ammonia conversion, with example 2 having the greatest increase in activity, indicating an optimum Rb/Ru molar ratio of 2. Comparing example 2 with comparative examples 1 to 5, it can be seen that the addition of Li and Na auxiliary agents reduces the ammonia conversion rate, and the addition of K, Rb and Cs auxiliary agents improves the ammonia conversion rate, wherein the addition of Rb auxiliary agent has the best effect of promoting the ammonia conversion rate.
Test example 3
The catalyst prepared in example 2 was tested for stability, conditions of testing: the fixed bed quartz tube reactor is adopted, the dosage of the catalyst is 50mg, the raw material gas is pure ammonia, the flow rate is 25mL/min, and the space velocity is 30000mLg cat -1 h -1 At normal pressure, the test temperature was 475 ℃. The test results are shown in fig. 23, the initial conversion of ammonia is 93.4%, the conversion after 50h is reduced, but still more than 90.0%, indicating that the catalyst has good stability.
Those not described in detail in this specification are within the skill of the art. The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Claims (7)

1. The mesoporous cerium oxide supported ruthenium catalyst is characterized by comprising active metal, a carrier and an auxiliary agent, wherein the active metal is ruthenium metal, the carrier is cerium oxide, the auxiliary agent is rubidium oxide, the mass content of the ruthenium metal is 3%, and the mass content of the rubidium is 2.5-7.6%.
2. The preparation method of the mesoporous cerium oxide supported ruthenium catalyst is characterized by comprising the following steps of:
s1: performing ball milling and mixing on ruthenium acetate, cerium acetate and rubidium acetate by using a planetary ball mill to obtain an acetate mixture, and roasting the acetate mixture to obtain a mixed oxide;
s2: and (4) reducing the mixed oxide in the step S1 to obtain the mesoporous cerium oxide supported ruthenium catalyst.
3. The method for preparing a mesoporous cerium oxide supported ruthenium catalyst according to claim 2, wherein in step S1, the mass ratio of ruthenium acetate, cerium acetate and rubidium acetate is 1: 20-30: 0.3-1.2.
4. The preparation method of the mesoporous cerium oxide supported ruthenium catalyst according to claim 2, wherein the mass ratio of the total mass of ruthenium acetate, cerium acetate and rubidium acetate to the mass of the agate spheres is 1: 30-60.
5. The method for preparing a mesoporous cerium oxide supported ruthenium catalyst according to claim 2, wherein the rotation speed of the planetary ball mill is 800r/min, and the operation time is 0.5-2.5 h.
6. The method for preparing the mesoporous cerium oxide supported ruthenium catalyst according to claim 2, wherein in step S1, the calcination atmosphere is air, the temperature is 500 ℃, and the calcination time is 5 hours; in the step S2, the reducing atmosphere is high-purity hydrogen, the temperature is 500 ℃, and the reducing time is 0.5 h.
7. The application of the mesoporous cerium oxide supported ruthenium catalyst is characterized by being applied to ammonia decomposition hydrogen production reaction.
CN202210526114.4A 2022-05-16 2022-05-16 Mesoporous cerium oxide supported ruthenium catalyst and preparation method and application thereof Pending CN114832819A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016164109A (en) * 2015-03-06 2016-09-08 国立大学法人 大分大学 Ammonia oxidation decomposition catalyst, and hydrogen production method and hydrogen production device using the ammonia oxidation decomposition catalyst
CN109529865A (en) * 2018-11-22 2019-03-29 福州大学化肥催化剂国家工程研究中心 A kind of ruthenium base ammonia decomposition hydrogen producing catalyst and the preparation method and application thereof
CN109954493A (en) * 2017-12-14 2019-07-02 中国科学院大连化学物理研究所 The rare-earth oxide supported ruthenium catalyst of preparing hydrogen by ammonia decomposition and preparation and application
CN113289693A (en) * 2021-04-30 2021-08-24 福州大学化肥催化剂国家工程研究中心 Ammonia decomposition catalyst and preparation method and application thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016164109A (en) * 2015-03-06 2016-09-08 国立大学法人 大分大学 Ammonia oxidation decomposition catalyst, and hydrogen production method and hydrogen production device using the ammonia oxidation decomposition catalyst
CN109954493A (en) * 2017-12-14 2019-07-02 中国科学院大连化学物理研究所 The rare-earth oxide supported ruthenium catalyst of preparing hydrogen by ammonia decomposition and preparation and application
CN109529865A (en) * 2018-11-22 2019-03-29 福州大学化肥催化剂国家工程研究中心 A kind of ruthenium base ammonia decomposition hydrogen producing catalyst and the preparation method and application thereof
CN113289693A (en) * 2021-04-30 2021-08-24 福州大学化肥催化剂国家工程研究中心 Ammonia decomposition catalyst and preparation method and application thereof

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