CN112387293A - In-situ induction generation of MoOxHyMethod for preparing non-noble metal modified pure-phase alpha-type molybdenum carbide through one-step carbonization - Google Patents
In-situ induction generation of MoOxHyMethod for preparing non-noble metal modified pure-phase alpha-type molybdenum carbide through one-step carbonization Download PDFInfo
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Abstract
The invention provides a non-noble metal modified pure-phase alpha-molybdenum carbide catalyst, and a preparation method and application thereofxHyThe intermediate species is directly synthesized into the non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst by a single-pass carbonization method, and the non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst is applied to low-temperature water gas shift reaction, the preparation method is simple and effective, has wide universality, and fills the blank that the non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst cannot be synthesized by the conventional preparation method; meanwhile, the applicable temperature of the copper-based catalytic material is effectively reduced in the low-temperature water gas shift reaction, and 31.0umol can be achieved at 150 DEG CCO/gcatThe reaction rate per second is far higher than that of the traditional oxide carrier supported copper catalyst reported in the literature and has excellent stability.
Description
Technical Field
The invention belongs to the field of catalytic hydrogen production, and particularly relates to a one-way carbonization synthesis method of a non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst and application of the catalyst in low-temperature water gas shift reaction.
Background
Water gas shift reaction (WGS reaction, CO + H)2OчCO2+H2) Is a main reaction process of industrial hydrogen production and hydrogen purification (CO elimination), and has irreplaceable effects. Meanwhile, with the gradual rise of fuel cells, the mobile online hydrogen production system is widely concerned about being used for mobile equipment such as energy vehicles, and the importance and the application range of the water gas shift reaction are further increased. Current water gas shift reaction research has focused mainly on Cu-based and noble metal (group VIII) catalysts: the working temperature of the Cu-based catalyst is 250-300 ℃, the catalytic performance is superior, but the active metal copper is easy to agglomerate and sinter, so that the catalyst is irreversibly inactivated; the noble metal-based catalyst generally takes an oxide as a carrier, but the oxide carrier is inevitably reduced in a hydrogen atmosphere to cause catalyst deactivation; meanwhile, the reserves of the precious metals are limited and the price is high. Based on two aspects of catalytic performance and material cost, designing and synthesizing a novel efficient copper-based catalyst is an ideal choice for low-temperature water-gas shift reaction, and how to search for a proper carrier to disperse and anchor active metal copper is the important factor in designing the catalyst.
The inventors' preliminary work on the subject group showed that alpha-MoC (face centered cubic, FCC type) compares to beta-Mo2C (hexagonal close-packed structure, HCP type) has larger specific surface area, more active sites and more excellent WGS catalytic performance; in addition, the interaction between the alpha-MoC substrate and the active metal is stronger, and the dispersion and the anchoring of the metal are more facilitated. Therefore, the high-efficiency and stable Au/alpha-MoC interface catalyst is designed and synthesized by a nitridation-carbonization two-stage program heating method, the WGS reaction temperature can be greatly reduced to 120 ℃, and the reaction activity reaches 0.62 molCO/molΑuThe result is improved by twenty-over times compared with the result reported by the literature; meanwhile, the prior pre-research work has studied the differences in detailThe influence of the addition of the active metal on the carbonization process and the crystal structure of the carbide; research shows that the metal modified pure-phase alpha-type molybdenum carbide catalyst can be realized only by adding noble metals (Au, Pt, Pd and the like) by adopting a nitridation-carbonization two-stage program heating method; because of the higher reduction temperature of non-noble metals (Cu, Ni, Co, etc.) and the stable state composite oxide (CuMoO)4、 NiMoO4Etc.) so that pure-phase alpha-type molybdenum carbide (final product is mixed crystal of alpha phase and beta phase) cannot be obtained by adding non-noble metal. Further, to simplify the preparation process and avoid high contamination of NH3The patent (CN104923274A) granted by the inventor of the invention, namely a pure alpha-phase molybdenum carbide supported noble metal catalyst, and a preparation method and application thereof, adopts a non-equilibrium plasma treatment process to replace the traditional precursor roasting process, and directly obtains the pure-phase alpha-type molybdenum carbide modified by noble metal through a one-way carbonization method, but the method is still not suitable for non-noble metals (Cu, Ni, Co and the like), and the generated final product is mixed crystals of alpha phase and beta phase, so that the pure-phase non-noble metal modified alpha-type molybdenum carbide material cannot be obtained.
Earlier research work showed that during carbonization, when MoOC was formedxIn the case of intermediate species, the final carbonized product is alpha-type molybdenum carbide; and the intermediate species is MoO2When the final carbonized product is beta-type molybdenum carbide. Hitherto, when the supported metal is a non-noble metal (Cu, Ni, Co, etc.), the composite oxide (CuMoO) has been formed due to a stable state4、NiMoO4Etc.) to generate MoO during carbonization2The intermediate species inevitably generates a part of beta phase by whatever preparation method, and the pure-phase non-noble metal (Cu, Ni, Co and the like) modified alpha-type molybdenum carbide catalyst cannot be synthesized. Although the noble metal catalyst has excellent performance, the noble metal catalyst has the problems of rare reserves, high price and the like; therefore, the preparation research of the non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst is particularly important, and the catalyst has wide application prospect.
Disclosure of Invention
The invention aims to provide a method for generating an in-situ hydrogenated molybdenum oxide precursor (MoO) by in-situ inductionxHy) By single pass carbonizationA preparation method of a non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst by grafting synthesis and application thereof in low-temperature water gas shift reaction. The preparation method is simple and effective, has wide universality, and fills the blank that the non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst cannot be synthesized by the existing preparation method;
in order to achieve the purpose, the technical scheme of the invention is as follows:
on one hand, the invention provides a non-noble metal modified pure-phase alpha-molybdenum carbide catalyst, which takes pure-phase alpha-molybdenum carbide as a carrier and non-noble metal as an active component.
Preferably, the active component is one or more of Ni, Co, Cu and Ag; the loading amount of the active component is 0.5-20 wt%.
Preferably, the loading amount of the active component is 0.5-10 wt%.
In another aspect, the present invention provides a preparation method of the above catalyst, where the method includes: in-situ induced generation of in-situ hydrogenated molybdenum oxide precursor (MoO)xHy) And then preparing non-noble metal modified pure-phase alpha-type molybdenum carbide through one-step carbonization, wherein the preparation method comprises the following steps:
1) impregnating non-noble metal precursor solution in MoO3Aging and drying the powder to obtain metal/MoO3A precursor;
2) mixing the metal/MoO3The precursor is subjected to pre-reduction treatment, the pre-reduction treatment atmosphere is mixed gas of hydrogen and inert gas or hydrogen, the pre-reduction treatment temperature is 150-350 ℃, the pre-reduction treatment time is 1-10 hours, and the in-situ hydrogenated molybdenum oxide precursor (MoO) loaded with the reduced active component is obtainedxHy)；
3) The MoO loaded with the reduced active componentxHyAnd carbonizing the precursor under the atmosphere of a carbon source to obtain the catalyst.
Preferably, the impregnation mode in the step 1) is an equal-volume impregnation method.
Preferably, in the step 2), the volume fraction of hydrogen in the mixed gas is 5-30%.
Preferably, the pre-reduction treatment temperature is 250-350 ℃, and the pre-reduction treatment time is 1-2 hours.
Preferably, the carbon source atmosphere in the step 3) is a mixed gas of methane and hydrogen, the volume percentage of methane in the mixed gas is 10-30%, and the carbonization temperature is 600-800 ℃.
The preparation method provided by the invention is detailed as follows:
1) non-noble metal/MoO3Preparing a precursor: firstly, a certain amount of ammonium heptamolybdate tetrahydrate ((NH) is taken4)6Mo7O24*4H2O, marked as AM) is placed in a muffle furnace to be heated to 500 ℃, and is roasted for 4 hours at 500 ℃ to prepare MoO3And (3) powder. Then soaking the completely dissolved target amount of metal salt solution in equal volume with MoO3Coating the powder on a preservative film, sealing the preservative film, standing the powder at room temperature overnight, and then drying the powder in a vacuum drying oven at 50 ℃ overnight to prepare the metal/MoO3And (3) precursor.
2) Pre-reduction treatment to obtain the product containing MoOxHyPrecursor: the precursor is placed in pure hydrogen atmosphere or mixed atmosphere of hydrogen and inert gas and reduced for 1-2 hours at the temperature of 250-350 ℃, and MoO loaded with reduced active components is generated by in-situ inductionxHyAn intermediate.
3) Preparation of metal/α -MoC catalyst: the MoO loaded with the reduction active component and generated by the pre-reduction treatmentxHyPutting precursor powder (40-60 meshes) in a micro fixed bed reactor, and introducing 10-30% of CH4/H2The mixed atmosphere (160mL/min) is heated to 350 ℃ at the heating rate of 5 ℃/min, then is heated to 800 ℃ at the heating rate of 1 ℃/min under the same atmosphere, is kept at the temperature for 2 hours, and after the reaction is finished, the reaction atmosphere is switched to 1% O when the quartz reaction tube is cooled to the room temperature2and/Ar (15mL/min) is deactivated for 6-8 hours and taken out to obtain the metal/alpha-MoC catalyst.
The preparation method adopts the pre-reduction treatment process to generate the molybdenum oxide precursor (MoO) after in-situ hydrogenation by in-situ inductionxHy) With simultaneous formation of the reduced active metal, MoOxHySpecies ratio MoO3Or other stable state composite oxides (CuMoO)4、NiMoO4Etc.) are more easily reduced and the presence of the reduced active metal accelerates the carbon source gas CH4Etc., thereby causing MoOxHyIntermediate species can insert carbon to form MoOC at lower temperaturesxIntermediate species other than MoO2(see FIG. 1), MoOCxThe intermediate species are finally carbonized to produce pure phase non-noble metal modified alpha-molybdenum carbide.
In yet another aspect, the present invention applies the above catalyst to a low temperature water gas shift reaction.
Preferably, in the reaction, the reaction temperature is 120-400 ℃, and the reaction atmosphere is 3-11% of CO and 6-26% of H2O、 10-26％H2、2-7％CO2And balance gas N2(ii) a The reaction space velocity is 10,000-90,000 mL/g/h.
The detailed application of the catalyst in the low-temperature water gas shift reaction is as follows:
the obtained catalytic material is tabletted and sieved to prepare powder with the granularity of 40-60 meshes, and the performance of the powder is evaluated through the following processes: the activity evaluation is carried out on a self-made normal-pressure miniature fixed bed reaction device, and the evaluation device mainly comprises a reaction gas simulation system, a reaction system and a detection system. The length of the quartz tube reactor in the reaction system is 40mm, and the inner diameter is 4 mm. The dosage of the activity test sample is determined according to specific conditions, and the upper end and the lower end of the catalyst bed layer are filled with high-temperature cotton and quartz sand to reduce the dead volume of the reactor. The reactor is heated by a program temperature control tube electric furnace, and the temperature control precision is +/-0.1 mL/min. At the beginning of the experiment, high-purity argon gas is introduced to exhaust air, and then the reaction is switched to 15% CH4/H2And (3) raising the temperature of the mixed gas from room temperature to 590 ℃ at a heating rate of 10 ℃/min, keeping for 2 hours, reducing to a target temperature under the protection of high-purity argon, and then switching to the reaction gas for evaluating the water gas conversion performance. The reaction temperature is 120-400 ℃; the reaction atmosphere is 3-11% of CO and 6-26% of H2O、 10-26％H2、2-7％CO2And balance gas N2(ii) a The reaction space velocity is 30,000-90,000mL/g/h。
Advantageous effects
1) The invention develops an in-situ induced MoOxHyAn effective preparation method for directly obtaining a pure-phase non-noble metal modified alpha-type molybdenum carbide catalyst by single-pass carbonization of species. The method has simple and effective process, avoids the use of high-pollution ammonia gas in the traditional preparation method, and solves the problem that the existing synthesis method can not prepare pure-phase non-noble metal modified alpha-type molybdenum carbide in one step; the method has wide universality, and different non-noble metal modified pure-phase alpha-type molybdenum carbide catalysts comprising Ni/alpha-MoC, Co/alpha-MoC, Cu/alpha-MoC and Ag/alpha-MoC are successfully synthesized by the method.
2) The preparation method generates an in-situ hydrogenated molybdenum oxide precursor (MoO) through in-situ inductionxHy) The carbon insertion reaction temperature (below 650 ℃) is effectively reduced, so that the generation of a large amount of surface carbon under the high temperature (above 700 ℃) condition in the traditional carbonization process is avoided, the specific surface area of the material and the exposure of active sites are effectively improved, the interaction between active metal and a carrier is enhanced, and the active metal has smaller particle size and higher dispersity.
3) The Cu/alpha-MoC catalyst prepared by the method is applied to low-temperature water gas shift reaction, the applicable temperature of a copper-based catalytic material is effectively reduced, and 31.0umol can be achieved at 150 DEG CCO/gcatThe reaction rate per second is much higher than that of the traditional oxide carrier supported copper catalyst reported in the literature, as shown in Table 1. Meanwhile, the catalyst has excellent stability.
Drawings
FIG. 1 is XRD spectra of intermediate species and final product at different stages during carbonization in example 1 and comparative examples 1 and 2;
FIG. 2 is an XRD spectrum of different-phase molybdenum carbide supported different-metal (Co, Ni, Ag) catalysts prepared in examples 2-4 of the present invention and comparative examples 3-5;
FIG. 3 shows Cu/α -MoC, Cu/α + β -MoC prepared in example 1, comparative example 1 and comparative example 2xAnd Cu/beta-Mo2SEM photograph of catalyst C;
FIG. 4 is a HR-TEM photograph and an energy spectrum photograph of each element of the Cu/α -MoC catalyst prepared in example 1;
FIG. 5 is Cu/beta-Mo prepared in comparative example 22HR-TEM picture of the catalyst C and energy spectrum pictures of each element;
FIG. 6 is a graph comparing the activity of different crystalline phase molybdenum carbide supported copper catalysts of the present invention in a low temperature water gas shift reaction;
FIG. 7 shows the stability evaluation results of the Cu/α -MoC catalyst prepared in example 1 in the water gas shift reaction.
Detailed Description
The following examples are presented to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.
Example 1
Catalyst preparation
1)Cu/MoO3Preparing a precursor: first, 10g of ammonium heptamolybdate tetrahydrate ((NH)4)6Mo7O24*4H2O, marked as AM) is placed in a muffle furnace to be heated to 500 ℃, and is roasted for 4 hours at 500 ℃ to prepare MoO3And (3) powder. Then the target amount of Cu (NO) to be completely dissolved3)2Solution (0.592g in 1.25mLH2O) equal volume immersion in 5gMoO3Coating the powder on a preservative film, sealing the preservative film, standing the powder at room temperature overnight, and then drying the powder in a vacuum drying oven at 50 ℃ overnight to prepare Cu/MoO3And (3) precursor.
2) Pre-reduction treatment to obtain the product containing MoOxHyPrecursor: putting the precursor into pure H2Reducing for 1-2 hours at the temperature of 250-350 ℃ in the atmosphere, and generating the MoO loaded with the reduced Cu through in-situ inductionxHyThe intermediate was then prepared by the single pass carbonization method described below to yield the Cu/α -MoC catalyst.
3) Preparation of Cu/alpha-MoC catalyst: the pretreated MoO loaded with reduced Cu is subjected to a pretreatmentxHyPutting the precursor powder (40-60 meshes) in a micro fixed bed reactor, and introducing 20% CH4/H2The temperature of the mixed atmosphere (160mL/min) was raised to 300 ℃ at a temperature rise rate of 5 ℃/min, and then the mixed atmosphere was maintained at 1 ℃/minThe temperature rising rate is increased to 700 ℃, the temperature is kept for 2 hours, and after the reaction is finished, the reaction atmosphere is switched to 1 percent of O when the quartz reaction tube is cooled to the room temperature2the/Ar (15mL/min) was deactivated for 6-8 hours and withdrawn, yielding 3 wt.% Cu/α -MoC catalyst.
The BET result shows that the catalyst has the maximum specific surface area of 131m2(ii)/g; the high resolution transmission electron microscopy and EDX results show that the copper species are dispersed on the surface of the α -MoC substrate in the form of highly uniform small-sized nanoparticles, and no agglomeration of the copper species is observed, as shown in fig. 4.
Evaluation of catalyst Activity
The water gas shift reaction is carried out in a quartz tube fixed bed reactor with the inner diameter of 4mm, the flow of each path of gas required by the experiment is regulated and controlled by a mass flow meter, and the gas flows into the reactor after being uniformly mixed. 100mg of Cu/alpha-MoC catalyst is weighed and placed in a quartz tube reactor with 15 percent of CH4/H2Pretreating the catalyst for 2 hours at 590 ℃ by using mixed gas, and then performing performance evaluation under the following reaction conditions, wherein the reaction temperature is 150-300 ℃, and the reaction atmosphere is: 120 ℃ and 400 ℃ are 11% CO-26% H2O-26％H2-7％CO2-N2(ii) a The reaction space velocity is 36,000 mL/g/h; the CO conversion of the catalyst was 65% at 150 ℃ and 95% at 160 ℃, as shown in fig. 6.
Example 2
The steps and process conditions of this example are the same as those of example 1, except for the following points: a. weighing a certain amount of cobalt nitrate (0.611g dissolved in 1.25 mLH)2O) isovolumic impregnation in MoO3The powder is subjected to a single-pass carbonization process to prepare a 3 wt.% Co/alpha-MoC catalyst; b. the performance of the catalyst was evaluated, the reaction space velocity was 18,000mL/g/h, and the CO conversion of the catalyst was 78% at 150 ℃.
Example 3
The steps and process conditions of this example are the same as those of example 1, except for the following points: a. weighing a certain amount of nickel nitrate (0.766g dissolved in 1.25 mLH)2O) isovolumic impregnation in MoO3The powder was prepared in a single pass carbonization process to yield 3 wt.% Ni/α -MoC catalysisAn agent; b. the performance of the catalyst was evaluated, the reaction space velocity was 18,000mL/g/h, and the CO conversion of the catalyst was 70% at 150 ℃.
Example 4
The steps and process conditions of this example are the same as those of example 1, except for the following points: a. weighing a certain amount of silver nitrate (0.245g dissolved in 1.25 mLH)2O) isovolumic impregnation in MoO3The powder is subjected to a single-pass carbonization process to prepare a 3 wt.% Ag/alpha-MoC catalyst; b. the performance of the catalyst was evaluated, the reaction space velocity was 18,000mL/g/h, and the CO conversion of the catalyst was 80% at 150 ℃.
Comparative example 1
Catalyst preparation
1)Cu/MoO3Preparing a precursor: first, 5g of ammonium heptamolybdate tetrahydrate ((NH)4)6Mo7O24*4H2O, marked as AM) is dissolved in 40mL of deionized water, and the mixture is magnetically stirred at room temperature to be completely dissolved; then adding 0.83g of copper nitrate into the solution, fully stirring for 4-5 hours at room temperature, then placing the solution in a water bath at 80 ℃ for evaporation to dryness, drying the solution in an oven at 110 ℃ overnight, and roasting the obtained solid powder in a muffle furnace for 4 hours at 500 ℃ to obtain Cu/MoO3A precursor;
2)Cu/α+β-MoCxpreparation of the catalyst: mixing the above Cu/MoO3Putting the precursor powder (40-60 meshes) in a micro fixed bed reactor, and introducing 20% CH4/H2The mixed atmosphere (160mL/min) is heated to 300 ℃ at the heating rate of 5 ℃/min, then is heated to 700 ℃ at the heating rate of 1 ℃/min under the same atmosphere, is kept for 2 hours, and after the reaction is finished, the reaction atmosphere is switched to 1% O when the quartz reaction tube is cooled to the room temperature2the/Ar (15mL/min) is passivated and taken out for 6-8 hours to obtain 3 wt.% Cu/alpha + beta-MoCxA catalyst. The BET result showed that the specific surface area of the catalyst was 86m2In g, significantly lower than the catalyst obtained in example 1 (131 m)2/g)。
Evaluation of catalyst Activity
The activity of the catalyst was evaluated with reference to the reaction conditions described in example 1, and the CO conversion on the catalyst was 18% at 150 ℃ and 63% at 200 ℃.
Comparative example 2
Catalyst preparation
1) Preparing a precursor: firstly, 0.195gCuO powder and 5gMoO are weighed3Mechanically mixing the powder, and fully grinding the powder in a mortar to obtain a required precursor;
2)Cu/β-Mo2c, preparation of a catalyst: putting the precursor powder (40-60 meshes) into a miniature fixed bed reactor, and introducing 20% CH4/H2The mixed atmosphere (160mL/min) is heated to 300 ℃ at the heating rate of 5 ℃/min, then is heated to 700 ℃ at the heating rate of 1 ℃/min under the same atmosphere, is kept for 2 hours, and after the reaction is finished, the reaction atmosphere is switched to 1% O when the quartz reaction tube is cooled to the room temperature2the/Ar (15mL/min) is passivated and taken out for 6-8 hours to obtain 3 wt.% Cu/beta-Mo2And C, a catalyst. The BET result showed that the specific surface area of the catalyst was 40m2The specific surface area of the three different crystal form molybdenum carbide loaded copper catalysts prepared by the invention is the minimum; the results of high-resolution transmission electron microscopy and EDX show that the agglomeration phenomenon of the metallic copper in the catalyst is obvious, and the particle size of the metallic copper is larger than that of the catalyst obtained in example 1, as shown in figure 5.
Evaluation of catalyst Activity
The activity of the catalyst was evaluated with reference to the reaction conditions described in example 1, and the CO conversion on the catalyst was 7% at 150 ℃ and 31% at 200 ℃, as shown in fig. 6.
Comparative example 3
The steps and process conditions of this comparative example are the same as those of comparative example 1, except for the following points: a. weighing a certain amount of cobalt nitrate (0.609g) and adding the cobalt nitrate into an ammonium molybdate solution to obtain a precursor, and then preparing the Co/beta-Mo through a one-way carbonization process2C, a catalyst; b. the performance of the catalyst was evaluated, the reaction space velocity was 18,000mL/g/h, and the CO conversion of the catalyst was 35% at 200 ℃.
Comparative example 4
The steps and process conditions of this comparative example are the same as those of comparative example 1, except for the following points: a. weighing a certain amount of nickel nitrate (0.61g) and adding the nickel nitrate into an ammonium molybdate solution to obtainTo a precursor, and then the precursor is prepared into 3 wt.% Ni/beta-Mo through a single-pass carbonization process2C, a catalyst; b. the performance of the catalyst was evaluated, the reaction space velocity was 18,000mL/g/h, and the CO conversion of the catalyst was 17% at 200 ℃.
Comparative example 5
The steps and process conditions of this comparative example are the same as those of comparative example 1, except for the following points: a. weighing a certain amount of silver nitrate (0.132g) and adding the silver nitrate into an ammonium molybdate solution to obtain a precursor, and then preparing the precursor through a single-pass carbonization process to obtain 3 wt.% of Ag/beta-Mo2C, a catalyst; b. the performance of the catalyst was evaluated, the reaction space velocity was 18,000mL/g/h, and the CO conversion of the catalyst was 42% at 150 ℃.
Comparative example 6
Commercial Cu/ZnO/alpha2O3Catalyst (HiFUELTM W220) was purchased from Α lfa Α esar company. The catalyst performance evaluation procedure and process parameters were in accordance with those described in the examples, except that commercial Cu/ZnO/Al2O3The catalyst was evaluated with 20% H2At a rate of 5 ℃/min to 250 ℃ for 2 hours in/ar (100 mL/min). At 150 ℃, the catalyst has a CO conversion rate of 7% (reaction atmosphere 10.5% CO/21% H)2O/20％N2/Αr)。
Comparative example 7
TABLE 1 comparison of the hydrogen production rates in the water gas shift reaction for Cu/alpha-MoC catalysts prepared according to the invention and existing catalysts in the literature
1.J.Catal.2003,217(1),233；2.J.Catal.2014,314,32；3.Catal.Lett.2007,118(1-2),91；4.Appl.Catal.,B 2000,27(3),179；5.Catal.Sci.Technol.2015,6(10),3394；6.Appl.Catal.,B 2012,123,367；7.Int.J.Hydrogen Energy 2012,37(8),6381；8.Int.J.Hydrogen Energy 2011,36(15),8839；9.J.Catal.2009,263(1),155；10.Catal.Lett.2006,112(3-4),139.
Claims (10)
1. A non-noble metal modified pure-phase alpha-type molybdenum carbide catalyst is characterized in that the catalyst takes pure-phase alpha-type molybdenum carbide as a carrier and non-noble metal as an active component.
2. The catalyst of claim 1, wherein the active component is one or more of Ni, Co, Cu, Ag; the loading amount of the active component is 0.5-20 wt%.
3. The catalyst according to claim 1, wherein the loading of the active component is 0.5 to 10 wt%.
4. A method for preparing the catalyst of claim 1, wherein the method comprises: generating an in-situ hydrogenated molybdenum oxide precursor based on in-situ induction, and then preparing non-noble metal modified pure-phase alpha-type molybdenum carbide through one-step carbonization, wherein the preparation method comprises the following steps:
1) impregnating non-noble metal precursor solution in MoO3Aging and drying the powder to obtain the metal/MoO3A precursor;
2) mixing the metal/MoO3Carrying out pre-reduction treatment on the precursor, wherein the pre-reduction treatment atmosphere is mixed gas of hydrogen and inert gas or hydrogen, the pre-reduction treatment temperature is 150-350 ℃, and the pre-reduction treatment time is 1-10 hours, so as to obtain the in-situ hydrogenated molybdenum oxide precursor loaded with the reduced active component;
3) and carbonizing the in-situ hydrogenated molybdenum oxide precursor loaded with the reduced active component in a carbon source atmosphere to obtain the catalyst.
5. The method according to claim 4, wherein the impregnation in step 1) is an isovolumetric impregnation method.
6. The method according to claim 4, wherein the volume fraction of hydrogen in the mixed gas in the step 2) is 5% to 30%.
7. The method as claimed in claim 4, wherein the pre-reduction treatment temperature is 250 ℃ to 350 ℃, and the pre-reduction treatment time is 1-2 hours.
8. The method as claimed in claim 4, wherein the carbon source atmosphere in step 3) is a mixture of methane and hydrogen, the volume percentage of methane in the mixture is 10-30%, and the carbonization temperature is 600-800 ℃.
9. Use of a catalyst according to any one of claims 1 to 3 in a low temperature water gas shift reaction.
10. The method as claimed in claim 8, wherein the reaction temperature is 120-400 ℃, and the reaction atmosphere is 3-11% CO and 6-26% H2O、10-26％H2、2-7％CO2And balance gas N2(ii) a The reaction space velocity is 10,000-90,000 mL/g/h.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113231090A (en) * | 2021-05-08 | 2021-08-10 | 广东工业大学 | Cu-Mo2C catalyst and preparation method and application thereof |
| CN114655985A (en) * | 2022-04-08 | 2022-06-24 | 济南大学 | Metal oxide MoO3Nanobelt and preparation method thereof |
| CN116273034A (en) * | 2023-02-28 | 2023-06-23 | 青岛大学 | Molybdenum oxide supported nickel-based catalyst and preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020013221A1 (en) * | 2000-03-31 | 2002-01-31 | Thompson Levi T. | Transition metal carbides, nitrides and borides, and their oxygen containing analogs useful as water gas shift catalysts |
| CN102698783A (en) * | 2012-05-30 | 2012-10-03 | 大连理工大学 | Method for preparing metal-modified alpha type molybdenum carbide catalyst and application of metal-modified alpha type molybdenum carbide catalyst in low-temperature water-gas shift reaction |
| CN105540588A (en) * | 2015-12-08 | 2016-05-04 | 大连理工大学 | Application of alpha-molybdenum carbide and metal-modified alpha-molybdenum carbide catalyst to reaction for preparing carbon monoxide through hydrogenation of carbon dioxide |
| CN107352543A (en) * | 2017-07-13 | 2017-11-17 | 东莞理工学院 | A kind of preparation method of molybdenum carbide micro-nano powder |
| US20180305205A1 (en) * | 2015-10-29 | 2018-10-25 | Johnson Matthey Public Limited Company | Water gas shift process |
-
2020
- 2020-10-23 CN CN202011147209.2A patent/CN112387293A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20020013221A1 (en) * | 2000-03-31 | 2002-01-31 | Thompson Levi T. | Transition metal carbides, nitrides and borides, and their oxygen containing analogs useful as water gas shift catalysts |
| CN102698783A (en) * | 2012-05-30 | 2012-10-03 | 大连理工大学 | Method for preparing metal-modified alpha type molybdenum carbide catalyst and application of metal-modified alpha type molybdenum carbide catalyst in low-temperature water-gas shift reaction |
| US20180305205A1 (en) * | 2015-10-29 | 2018-10-25 | Johnson Matthey Public Limited Company | Water gas shift process |
| CN105540588A (en) * | 2015-12-08 | 2016-05-04 | 大连理工大学 | Application of alpha-molybdenum carbide and metal-modified alpha-molybdenum carbide catalyst to reaction for preparing carbon monoxide through hydrogenation of carbon dioxide |
| CN107352543A (en) * | 2017-07-13 | 2017-11-17 | 东莞理工学院 | A kind of preparation method of molybdenum carbide micro-nano powder |
Non-Patent Citations (1)
| Title |
|---|
| 张晓: "碳化钼基复合纳米材料的结构设计及性能研究", 《中国优秀博士学位论文全文数据库》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113231090A (en) * | 2021-05-08 | 2021-08-10 | 广东工业大学 | Cu-Mo2C catalyst and preparation method and application thereof |
| CN113231090B (en) * | 2021-05-08 | 2022-08-02 | 广东工业大学 | Cu-Mo 2 C catalyst and preparation method and application thereof |
| CN114655985A (en) * | 2022-04-08 | 2022-06-24 | 济南大学 | Metal oxide MoO3Nanobelt and preparation method thereof |
| CN114655985B (en) * | 2022-04-08 | 2023-08-04 | 济南大学 | Metal oxide MoO 3 Nanoribbon and method for producing the same |
| CN116273034A (en) * | 2023-02-28 | 2023-06-23 | 青岛大学 | Molybdenum oxide supported nickel-based catalyst and preparation method and application thereof |
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