CN116037106A - Noble metal modified catalyst and preparation method and application thereof - Google Patents

Noble metal modified catalyst and preparation method and application thereof Download PDF

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Publication number
CN116037106A
CN116037106A CN202111261788.8A CN202111261788A CN116037106A CN 116037106 A CN116037106 A CN 116037106A CN 202111261788 A CN202111261788 A CN 202111261788A CN 116037106 A CN116037106 A CN 116037106A
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catalyst
noble metal
carrier
total mass
doped
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李红伟
汪天也
张荣俊
孙霞
栾学斌
侯朝鹏
徐润
吴玉
夏国富
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/56—Platinum group metals
    • B01J23/62—Platinum group metals with gallium, indium, thallium, germanium, tin or lead
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J35/64—Pore diameter
    • B01J35/647—2-50 nm
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
    • C07C29/15—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively
    • C07C29/151—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases
    • C07C29/153—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used
    • C07C29/156—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used containing iron group metals, platinum group metals or compounds thereof
    • C07C29/157—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by reduction of oxides of carbon exclusively with hydrogen or hydrogen-containing gases characterised by the catalyst used containing iron group metals, platinum group metals or compounds thereof containing platinum group metals or compounds thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

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  • Chemical Kinetics & Catalysis (AREA)
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Abstract

The invention relates to the technical field of catalysts, and discloses a noble metal modified catalyst, a preparation method and application thereof. The noble metal modified catalyst provided by the invention contains an active component, a doped carrier and a noble metal component, wherein the active component is indium oxide with a cubic structure, the doped carrier is a mixture of magnesium oxide and aluminum oxide, and the noble metal component is Pd; wherein, the content of the active component accounts for 40-85% of the total mass of the active component and the doped carrier; the doping carrier accounts for 15% -60% of the total mass of the active component and the doping carrier; the noble metal component accounts for 0.01 to 1.5 percent of the total mass of the catalyst. The invention further provides a preparation method of the noble metal modified catalyst and application of the noble metal modified catalyst in the reaction of preparing methanol by hydrogenation of carbon dioxide. The catalyst provided by the invention not only has excellent catalytic performance, high reaction activity and high selectivity of target products, but also has simple preparation process and low production cost.

Description

Noble metal modified catalyst and preparation method and application thereof
Technical Field
The invention relates to the technical field of catalysts, in particular to a noble metal modified catalyst and a preparation method and application thereof.
Background
Rapid evolution of global economy to CO 2 The emissions are increasing, causing environmental problems such as greenhouse effect, global warming, etc., and thus an effective measure is required for capturing and converting CO 2 To reduce CO in the atmosphere 2 Concentration. Methanol is used as an important raw material of chemicals and as a substitute for fossil fuel, and CO is used as a catalyst for chemical industry 2 By co-operation with H from renewable energy sources 2 The reaction for preparing methanol not only solves the problem of greenhouse gas control but also solves the problem of an effective way for replacing fossil fuel.
For CO 2 The hydrogenation for preparing methanol has been studied and applied for a long time, however, the selectivity of methanol in the catalytic reaction process is only about 60%, and further side Reactions (RWG) existS) high activity, H 2 The further application of the copper-based catalyst is limited by the defects of O-induced active phase sintering, poor stability and the like. In addition, CO 2 Other catalytic systems for the hydrogenation of methanol also suffer from drawbacks such as the high cost of noble metal catalysts, the low activity and ease of migration of ZnO catalysts, which have limited the further use of these catalysts in this field to some extent.
Indium oxide has moderate CO 2 And CO adsorption ability, not only shows methanol selectivity remarkably superior to copper-based catalysts, cobalt-based catalysts, noble metal catalysts, but also has higher catalytic activity compared with ZnO catalysts, thereby attracting a wide attention of scientific researchers. How to further promote CO on the basis of indium oxide 2 And H 2 And stabilize key intermediates to achieve high activity, high selectivity and stability, are essential for industrial applications in the production of methanol by CO2 hydrogenation, although greatly improving their catalytic performance still faces significant challenges.
Disclosure of Invention
The invention aims to solve the problem that the catalytic performance of indium oxide needs to be further improved in the prior art, and provides a noble metal modified catalyst, a preparation method and application thereof.
In order to achieve the above object, a first aspect of the present invention provides a noble metal modified catalyst comprising an active component, a doped support and a noble metal component, wherein the active component is indium oxide having a cubic structure, the doped support is a mixture of magnesium oxide and aluminum oxide, and the noble metal component is Pd; wherein, the content of the active component accounts for 40-85% of the total mass of the active component and the doped carrier; the doping carrier accounts for 15% -60% of the total mass of the active component and the doping carrier; the noble metal component accounts for 0.01 to 1.5 percent of the total mass of the catalyst.
The second aspect of the present invention provides a method for producing a noble metal-modified catalyst, comprising:
(1) Mixing a solution containing metal indium salt, a precipitant solution and a doping carrier to obtain a precipitation mother solution; the doping carrier is a mixture of magnesium oxide and aluminum oxide;
(2) Aging the precipitation mother liquor to form a precipitate;
(3) Carrying out solid-liquid separation on the product obtained in the step (2), and then drying and roasting to obtain a catalyst semi-finished product;
(4) The solution containing the metallic palladium salt is contacted with the semi-finished catalyst and then dried and calcined.
In a third aspect, the present invention provides a noble metal modified catalyst prepared by the preparation method of the present invention.
The fourth aspect of the invention provides the noble metal modified catalyst and the application of the noble metal modified catalyst prepared by the preparation method in the reaction of preparing methanol by hydrogenation of carbon dioxide.
Through the technical scheme, the noble metal modified catalyst disclosed by the invention takes the mixture of magnesium oxide and aluminum oxide as the doped carrier of indium oxide, combines the doped carrier with supported noble metal palladium, and jointly modifies the indium oxide, so that the catalyst and catalytic substrates (such as carbon dioxide and H 2 ) The catalyst has high catalytic activity and high selectivity, and the noble metal modified catalyst can effectively improve the conversion rate of a catalytic substrate and the selectivity of a target product, and can be used for preparing methanol by hydrogenating carbon dioxide for 5MPa and 7000 hours -1 Under the condition, the selectivity of methanol on the catalyst can reach 95 percent;
according to the preparation method of the noble metal modified catalyst, the aging precipitation treatment is adopted to synthesize the indium oxide in the presence of the doped carrier, and the dipping method is further adopted to load the noble metal palladium on the semi-finished catalyst, so that the doped carrier and the noble metal palladium simultaneously modify the indium oxide, and the prepared catalyst has the advantages of excellent catalytic performance, high reaction activity, high target product selectivity and the like, is simple and convenient in production process step, can effectively reduce the production cost, and can realize mass production.
Drawings
FIG. 1 is an XRD pattern of a doped support prepared in example 1 of the present invention;
fig. 2 is an XRD pattern of the noble metal-modified catalyst prepared in example 1 of the present invention.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The invention provides a noble metal modified catalyst, which comprises an active component, a doped carrier and a noble metal component, wherein the active component is indium oxide with a cubic structure, the doped carrier is a mixture of magnesium oxide and aluminum oxide, and the noble metal component is Pd; wherein, the content of the active component accounts for 40-85% of the total mass of the active component and the doped carrier; the doping carrier accounts for 15% -60% of the total mass of the active component and the doping carrier; the noble metal component accounts for 0.01 to 1.5 percent of the total mass of the catalyst.
The content of each component in the catalyst of the invention can be tested by XRF method.
According to the invention, the noble metal modified catalyst takes the mixture of magnesium oxide and aluminum oxide as the doping carrier of the indium oxide catalyst, and combines with noble metal palladium to jointly modify the indium oxide, thereby improving the catalyst and the catalytic substrate (such as carbon dioxide and H 2 ) The catalyst has high catalytic activity and high selectivity, and the noble metal modified catalyst can effectively improve the conversion rate of a catalytic substrate and the selectivity of a target product.
According to the present invention, in order to further enhance the catalytic performance of the noble metal modified catalyst, preferably, the active component content accounts for 55 to 75% of the total mass of the active component and the doped carrier; the doped carrier accounts for 25-45% of the total mass of the active component and the doped carrier.
According to the present invention, in order to further improve the catalytic performance of the noble metal-modified catalyst, preferably, the noble metal component accounts for 0.75 to 1.5% of the total mass of the catalyst;
according to the present invention, in order to further improve the catalytic performance of the noble metal-modified catalyst and the selectivity to the target product, it is preferable that the mass ratio of the active component to the doped carrier is 1 to 6:1, further preferably 1-3:1.
according to the invention, in order to improve the modification effect on the active component and improve the stability of the catalyst, preferably, magnesium oxide accounts for 2-18% of the total mass of the active component and the doped carrier, and more preferably, 2.5-12.5%; the alumina accounts for 14-54% of the total mass of the active component and the doped carrier, and more preferably 18.5-40.5%.
According to the invention, the doped carrier can adopt magnesia and alumina with conventional structures, in order to further increase the contact area of the catalyst and the catalytic substrate and promote the catalytic effect while modifying the active components, and preferably, the doped carrier has an ordered mesoporous structure.
According to the invention, the cubic structure of the indium oxide and the ordered mesoporous structure of the doped carrier can be determined by XRD method testing.
The second aspect of the present invention provides a method for producing a noble metal-modified catalyst, comprising:
(1) Mixing a solution containing metal indium salt, a precipitant solution and a doping carrier to obtain a precipitation mother solution; the doping carrier is a mixture of magnesium oxide and aluminum oxide;
(2) Aging the precipitation mother liquor to form a precipitate;
(3) Carrying out solid-liquid separation on the product obtained in the step (2), and then drying and roasting to obtain a catalyst semi-finished product;
(4) The solution containing the metallic palladium salt is contacted with the semi-finished catalyst and then dried and calcined.
According to the present invention, the specific operation method of solid-liquid separation, drying and calcination is not particularly limited, and may be carried out according to conventional operation means in the art.
According to the preparation method of the noble metal modified catalyst, the preparation method synthesizes indium oxide by adopting aging precipitation treatment in the presence of the doped carrier, and further adopts an impregnation method to load noble metal palladium on a semi-finished catalyst, so that the doped carrier and the noble metal palladium simultaneously modify the indium oxide, and the prepared catalyst has the advantages of excellent catalytic performance, high reaction activity, high selectivity of target products, good reaction stability, low catalyst deactivation rate and the like, and the production process is simple and convenient, so that the production cost can be effectively reduced, and mass production can be realized.
According to the invention, in order to improve the catalytic performance of the noble metal modified catalyst, preferably, the metal indium salt, the doped carrier and the metal palladium salt are used in amounts such that indium oxide accounts for 40% -85% of the total mass of indium oxide and the doped carrier in the prepared catalyst; the doped carrier accounts for 15-60% of the total mass of the indium oxide and the doped carrier; the palladium element accounts for 0.01 to 1.5 percent of the total mass of the catalyst.
Preferably, the metal indium salt, the doped carrier and the metal palladium salt are used in an amount such that the indium oxide accounts for 55-75% of the total mass of the indium oxide and the doped carrier in the prepared catalyst; the doped carrier accounts for 25-45% of the total mass of the indium oxide and the doped carrier; the palladium element accounts for 0.75 to 1.5 percent of the total mass of the catalyst.
According to the present invention, in order to further improve the catalytic performance and the selectivity to the target product of the noble metal modified catalyst, it is preferable that the amount mass ratio of the metal indium salt to the doped carrier in terms of oxide is 1 to 6:1, further preferably 1-3:1.
in the preparation of the noble metal modified catalyst according to the present invention, the doping carrier may be used either conventional commercially available magnesia and alumina, or magnesia and alumina prepared by existing methods. In order to further increase the contact area of the catalyst and the catalytic substrate and improve the catalytic effect while modifying the active component, preferably, the preparation method of the doped carrier enables the doped carrier to have an ordered mesoporous structure, and further preferably, the doped carrier is prepared by adopting a solvent evaporation induced self-assembly method.
According to a preferred embodiment of the present invention, the preparation method of the doped carrier comprises: the acid, aluminum precursor and magnesium precursor are mixed in the presence of a surfactant in the presence of a solvent, and then dried and calcined.
According to the invention, in order to improve the stability of the noble metal modified catalyst, preferably, the aluminum precursor and the magnesium precursor are used in amounts such that magnesium oxide accounts for 2-18% of the total mass of the indium oxide and the doped carrier in the prepared catalyst, and more preferably 2.5-12.5%; the alumina accounts for 14-54% of the total mass of the indium oxide and the doped carrier, and more preferably 18.5-40.5%.
According to the present invention, preferably, the surfactant is selected from at least one of P123 (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer), CTAB (cetyltrimethylammonium bromide), malic acid, sodium 2-ethylhexanesulfosuccinate, and nonylphenol polyoxyethylene ether.
According to the present invention, preferably, the solvent is selected from at least one of ethanol, methanol, isopropanol, ethylene glycol, triethylene glycol, and N, N-dimethylacetamide.
According to the present invention, preferably, the acid is selected from at least one of nitric acid, hydrochloric acid and phosphoric acid.
According to the present invention, preferably, the aluminum source is at least one of aluminum isopropoxide, aluminum nitrate, aluminum chloride and aluminum sulfate.
In the present invention, the kind of the magnesium precursor is not particularly limited as long as it contains magnesium element, and for example, at least one of magnesium nitrate, magnesium chloride and magnesium sulfate may be used.
The above materials are all routine choices in the art and are commercially available.
Preferably, the preparation method of the doped carrier in the invention comprises the following steps: p123 and absolute ethyl alcohol are mixed and then dissolved under ultrasound, then concentrated nitric acid is added, aluminum isopropoxide and magnesium nitrate are added after clarification, and after stirring reaction, drying and roasting are carried out.
Preferably, the molar ratio of the surfactant, the organic solvent, the acid to the aluminum precursor is 0.01-0.05:10-80:1-10:1, preferably 0.01 to 0.03:20-60:3-7:1.
according to the present invention, preferably, in the preparation method of the doped carrier, the mixing time is 3 to 9 hours, and further preferably, the mixing is performed under stirring conditions; wherein the stirring speed may be 100rpm to 500rpm.
According to the present invention, the drying conditions in the preparation method of the doped support preferably include: the temperature is 60-90deg.C, specifically 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, or any value in the range of any two values; the time is 36-60h, and can be specifically 36h, 40h, 45h, 50h, 55h and 60h, or any value in a range formed by any two values; the conditions of the calcination preferably include: the temperature is 600-1200deg.C, specifically 600 deg.C, 700 deg.C, 800 deg.C, 900 deg.C, 1000 deg.C, 1100 deg.C, 1200 deg.C, or any value in the range of any two values; the time is 3-6h, and specifically can be 3h, 4h, 5h, 6h, or any value in a range formed by any two values.
According to the present invention, the kind of the metal indium salt is not particularly limited as long as it can be formed into a corresponding salt solution form, and it reacts with a precipitant to form indium oxide, and for example, at least one of indium nitrate, indium chloride and indium sulfate, which are all conventional choices in the art, are commercially available.
According to the invention, preferably, the precipitant is urea. Under the preferred embodiment, the precipitation mother liquor formed by mixing the precipitant with the metal indium salt and the doped carrier is more beneficial to forming the indium oxide with a cubic structure in an aging precipitation mode, and meanwhile, the modification effect on the indium oxide is realized.
According to the present invention, it is preferable that the solvent in the solution containing the metal indium salt and the precipitant solution in step (1) are each independently an organic solvent and/or water, preferably an organic solvent and water.
Preferably, the organic solvent is selected from at least one of ethanol, methanol, isopropanol, ethylene glycol, triethylene glycol and N, N-dimethylacetamide; illustratively, the solution containing the metal indium salt is obtained by dissolving the metal indium salt in a mixed solution of ethanol and deionized water, and the precipitant solution is obtained by dissolving the precipitant in a mixed solution of ethanol and deionized water, wherein the use amount ratio of ethanol to deionized water is not particularly limited, and the metal indium salt or the precipitant can be effectively dissolved respectively.
According to the present invention, the concentration of the solution containing the metal indium salt and the precipitant solution is not particularly limited. In order to promote the sufficient reaction between the metal indium salt and the precipitant and to enhance the reaction efficiency, the concentration of the solution containing the metal indium salt is preferably 0.1 to 1mol/L, and specifically may be 0.1mol/L, 0.3mol/L, 0.5mol/L, 0.7mol/L, 0.9mol/L, 1mol/L, or any value in the range constituted by any two of the above values; preferably, the concentration of the precipitant solution is 1 to 3mol/L, and specifically may be 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, or any value in the range constituted by any two of the above values.
According to the invention, the ratio of the amount of the metal indium salt to the amount of the precipitant is such that the metal indium salt is sufficiently converted into indium oxide, and preferably the molar ratio of the indium in the metal indium salt to the precipitant is 1:5-7. The study proves that the carbon dioxide conversion rate and the methanol yield can be greatly improved under the condition of the molar ratio.
According to the invention, in order to make the metal indium salt, the precipitant and the doped carrier in the precipitation mother liquor fully and uniformly mixed and improve the aging precipitation efficiency, the mixing in the step (1) is preferably performed under stirring conditions, preferably for 1-10h, wherein the stirring speed can be 100rpm-500rpm.
According to the invention, preferably, the mixing in step (1) comprises first mixing a solution containing a metal indium salt and a precipitant solution, and then adding a doping carrier. The first mixing may be by conventional mixing means, for example by adding a solution containing the metal indium salt to the precipitant solution. In order to optimize the mixing effect of the two, the first mixing process is preferably: the precipitant solution was added dropwise to the solution containing the metal indium salt.
According to the present invention, preferably, the aging condition of step (2) includes: the temperature is 80-180deg.C, specifically 80 deg.C, 100deg.C, 120deg.C, 140deg.C, 160deg.C, 180deg.C, or any value in the range of any two values, more preferably 120-160deg.C; the time is 12 to 22 hours, specifically 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or any value in the range of any two values mentioned above, and more preferably 18 to 20 hours. The aging reaction in the step (2) is a hydrothermal reaction, and preferably the aging reaction is carried out under a closed condition. Aging of the precipitation mother liquor may be performed in a hydrothermal synthesis reaction kettle, specifically, the precipitation mother liquor may be placed in a hydrothermal synthesis reaction kettle, and the hydrothermal synthesis reaction kettle may be placed in an oven for the aging.
According to a preferred embodiment of the invention, the process further comprises washing the product obtained in step (2), preferably to a pH value of between 6 and 8. The manner of washing according to the present invention is not particularly limited and may be performed according to conventional technical means in the art. Preferably, the above-mentioned solid-liquid separation and washing can be simultaneously achieved by centrifugation.
According to the present invention, preferably, the drying conditions of step (3) include: the temperature is 60-90deg.C, specifically 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, or any value in the range of any two values; the time is 12-24h, and can be specifically 12h, 14h, 16h, 18h, 20h, 22h, 24h, or any value in a range formed by any two values.
According to the present invention, preferably, the conditions of the firing in step (3) include: the temperature is 300-500 ℃, specifically 300 ℃, 350 ℃, 400 ℃, 450 ℃, 500 ℃ or any value in the range formed by any two values; the time is 3-6h, and specifically can be 3h, 4h, 5h, 6h, or any value in a range formed by any two values.
According to the present invention, the type of the metal palladium salt is not particularly limited as long as the metal palladium salt can be formed in a corresponding solution form, and palladium is supported on the catalyst semifinished product by the impregnation method. Preferably, the metallic palladium salt is selected from at least one of palladium nitrate, palladium chloride, palladium acetate, ammonium tetrachloropalladate, ammonium hexachloropalladate, diamminedichloropalladium and tetraaminedichloropalladium; the above materials are all routine choices in the art and are commercially available.
According to the present invention, preferably, the contacting conditions of step (4) include: the stirring is carried out under the condition that the temperature is 20-35 ℃, specifically can be 20 ℃, 25 ℃, 30 ℃, 35 ℃ or any value in the range formed by any two values; the time is 0.5-2h, and specifically can be 0.5h, 1h, 1.5h, 2h, or any value in the range formed by any two values. Wherein the stirring speed may be 100rpm to 500rpm.
According to the present invention, the concentration of the solution containing the metallic palladium salt is not particularly limited. In order to promote the loading effect of the noble metal palladium on the semi-finished catalyst, the concentration of the solution containing the metallic palladium salt is preferably 0.005 to 0.3% by weight.
According to the present invention, preferably, the drying is spin-drying, and further preferably, the conditions of the spin-drying include: the temperature is 45-72deg.C, specifically 45 deg.C, 55 deg.C, 65 deg.C, 72 deg.C, or any value in the range of any two values; the rotation speed is 10-30rpm, specifically, 10rpm, 15rpm, 20rpm, 25rpm, 30rpm, or any value in the range formed by any two values; the vacuum degree is 0.05-0.1MPa, and specifically can be 0.05MPa, 0.06MPa, 0.07MPa, 0.08MPa, 0.09MPa, 0.1MPa or any value in a range formed by any two values; the spin steaming time is 1-3h, and specifically can be 1h, 2h, 3h, or any value in the range formed by any two values.
According to the present invention, preferably, the conditions of the firing in step (4) include: the temperature is 300-500 ℃, specifically 300 ℃, 400 ℃, 500 ℃ or any value in the range formed by any two values; the time is 1-5h, and can be specifically 1h, 2h, 3h, 4h, 5h, or any value in a range formed by any two values.
According to a particularly preferred embodiment of the present invention, the method for preparing a noble metal modified catalyst comprises the steps of:
(1) Mixing a surfactant and a solvent, dissolving under ultrasound, adding acid, adding an aluminum precursor and a magnesium precursor after clarification, stirring for 3-9h, drying at 60-90 ℃ for 36-60h, and roasting at 600-1200 ℃ for 3-6h to obtain a doped carrier;
(2) Dissolving metal indium salt in a solvent to prepare a solution containing the metal indium salt, and dissolving a precipitant in the solvent to prepare a precipitant solution; dropwise adding the precipitant solution into the solution containing the metal indium salt, then adding the doped carrier obtained in the step (1), and stirring for 1-10 h to obtain a precipitation mother solution;
(3) Aging the precipitation mother liquor obtained in the step (2) at 80-160 ℃ for 12-22 hours to form precipitate;
(4) After solid-liquid separation is carried out on the product obtained in the step (3), washing is carried out until the pH value is between 6 and 8, drying is carried out for 12 to 24 hours at the temperature of 60 to 90 ℃, and roasting is carried out for 3 to 6 hours at the temperature of 300 to 500 ℃ to obtain a semi-finished catalyst;
(5) And (3) contacting the solution containing the metal palladium salt with the semi-finished catalyst obtained in the step (4) for 0.5-2h at the temperature of 20-35 ℃ under stirring, then carrying out rotary evaporation drying for 1-3h at the temperature of 45-72 ℃ at the rotating speed of 10-30rpm and the vacuum degree of 0.05-0.1MPa, and then roasting for 1-5h at the temperature of 300-500 ℃.
The third aspect of the invention provides a noble metal modified catalyst prepared by the preparation method of the invention.
The noble metal modified catalyst provided by the invention has the advantages of high reaction activity, high selectivity of target products, good reaction stability and low catalyst deactivation rate when being used for preparing methanol by carbon dioxide hydrogenation. Accordingly, in a fourth aspect, the present invention provides the use of a noble metal modified catalyst according to the present invention and a noble metal modified catalyst prepared according to the method of preparation according to the present invention in a reaction for the hydrogenation of carbon dioxide to methanol.
According to the present invention, in order to improve the reaction efficiency of preparing methanol by hydrogenating carbon dioxide, it is preferable that the conditions of the reaction of preparing methanol by hydrogenating carbon dioxide include: the reaction pressure is 1.0-5.0MPa, the reaction temperature is 200-400 ℃, and the volume space velocity of the raw materials (comprising carbon dioxide and hydrogen) is 4500-18000h -1 ，H 2 /CO 2 The molar ratio is 1-10. Further preferably, the carbon dioxide hydrogenation conditions include: the reaction pressure is between 3 and 5MPa, the reaction temperature is between 240 and 300 ℃, and the volume space velocity of the raw material is between 7000 and 13000h -1 Between H 2 /CO 2 The molar ratio is between 3 and 6.
The present invention will be described in detail by examples.
In the following examples and comparative examples, all materials were commercially available at a room temperature of 25.+ -. 5 ℃ unless otherwise specified;
p123 is commercially available from Sigma-aldrich under the trade designation poly (ethylene glycol) -block-poly (propylene glycol) -block-poly (ethylene glycol).
The structure of the magnesium aluminum modified indium oxide catalyst is measured by XRD, and the content of each component in the catalyst is measured by XRF method.
Example 1
(1) Mixing 4.1g of surfactant P123 and 80mL of absolute ethyl alcohol, dissolving under ultrasound, then adding 6.3mL of concentrated nitric acid, adding 4.9g of aluminum isopropoxide and 3.0g of magnesium nitrate after clarification, stirring and mixing for 5 hours at a rotating speed of 150rpm, drying for 48 hours at 60 ℃, and finally roasting for 3 hours at 800 ℃ to obtain a doped carrier, carrying out XRD characterization analysis on the obtained doped carrier, wherein the result of FIG. 1 shows that the doped component has an ordered mesoporous structure;
(2) 7.61g of In (NO 3 ) 3 ·4H 2 O is added into a mixed solution of 40mL of absolute ethyl alcohol and 24mL of deionized water to obtain a solution containing metal indium salt, 8g of urea is added into a mixed solution of 40mL of absolute ethyl alcohol and 10mL of deionized water to obtain a precipitant solution, and the precipitant solution is prepared in a concentration of 3:dropwise adding the precipitant solution into the solution containing the metal indium salt at the temperature of 0 ℃, then adding 2g of the doped carrier obtained in the step (1), and fully stirring for 6 hours at the rotating speed of 150rpm to obtain a precipitation mother solution;
(3) Adding the precipitation mother liquor obtained in the step (2) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 120 ℃ for 20 hours to form a precipitate;
(4) Naturally cooling the product obtained in the step (3) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH is 7, drying at 60 ℃ for 20 hours, and roasting at 350 ℃ for 3 hours to obtain a catalyst finished product;
(5) Dissolving 0.057g of palladium nitrate in 10mL of deionized water to obtain a solution containing metal palladium salt, adding 2g of the catalyst obtained in the step (4) into the solution containing metal palladium salt, stirring at a rotating speed of 150rpm for 1h at 25 ℃, then carrying out rotary evaporation and drying at a temperature of 45 ℃ and a rotating speed of 20rpm under a vacuum degree of 0.1MPa for 3h, finally roasting at 350 ℃ for 4h to obtain a noble metal modified catalyst (the content of each component is shown in table 1), tabletting and sieving to 40-60 meshes; XRD characterization analysis of the resulting catalyst showed that the indium oxide had a cubic structure as shown in fig. 2;
(6) Carrying out a reaction for preparing methanol by hydrogenating carbon dioxide in a stainless steel reactor with an inner diameter of 8mm, and adopting the noble metal modified catalyst prepared in the step (5) as a reaction catalyst, wherein the reaction conditions are as follows: the reaction pressure is 3.0MPa, the reaction temperature is 280 ℃, and the volume space velocity of raw materials (carbon dioxide and hydrogen) is 9000h -1 、H 2 /CO 2 The molar ratio was 4, and after the reaction was completed, the liquid phase product was collected by ice water bath, and the composition of the product was analyzed by gas chromatography, and the evaluation results are shown in Table 2.
Example 2
(1) 3.9g of surfactant P123 and 80mL of absolute ethyl alcohol are mixed and dissolved under ultrasound, then 6.1mL of concentrated nitric acid is added, 9.4g of aluminum isopropoxide and 1.6g of magnesium nitrate are added after clarification, stirring and mixing are carried out for 5 hours at a rotating speed of 300rpm, drying is carried out for 48 hours at 60 ℃, and finally roasting is carried out for 3 hours at 800 ℃, thus obtaining the doped carrier with ordered mesoporous structure;
(2) 7.58g of In (NO 3 ) 3 ·4H 2 O is added into a mixed solution of 40mL of absolute ethyl alcohol and 25mL of deionized water to obtain a solution containing metal indium salt, 8g of urea is added into a mixed solution of 60mL of absolute ethyl alcohol and 20mL of deionized water to obtain a precipitant solution, the precipitant solution is dropwise added into the solution containing metal indium salt at 30 ℃, then 1g of doped carrier obtained in the step (1) is added, and the mixture is fully stirred for 6 hours at the rotating speed of 300rpm to obtain a precipitation mother solution;
(3) Adding the precipitation mother liquor obtained in the step (2) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 140 ℃ for 15 hours to form a precipitate;
(4) Naturally cooling the product obtained in the step (3) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH is 7.5, drying at 60 ℃ for 24 hours, and roasting at 300 ℃ for 3 hours to obtain a catalyst finished product;
(5) Dissolving 0.039g of palladium nitrate in 5mL of deionized water to obtain a solution containing metal palladium salt, adding 2g of the catalyst obtained in the step (4) into the solution containing metal palladium salt, stirring at a rotating speed of 300rpm for 1h at 25 ℃, then carrying out rotary evaporation and drying at a temperature of 45 ℃ and a rotating speed of 20rpm under a vacuum degree of 0.1MPa for 3h, finally roasting at 350 ℃ for 4h to obtain a noble metal modified catalyst (the content of each component is shown in Table 1), tabletting and sieving to 40-60 meshes, wherein indium oxide in the obtained catalyst has a cubic structure;
(6) Carrying out a reaction for preparing methanol by hydrogenating carbon dioxide in a stainless steel reactor with an inner diameter of 8mm, and adopting the noble metal modified catalyst prepared in the step (5) as a reaction catalyst, wherein the reaction conditions are as follows: the reaction pressure is 5.0MPa, the reaction temperature is 220 ℃, and the volume space velocity of raw materials (carbon dioxide and hydrogen) is 7000h -1 、H 2 /CO 2 The molar ratio was 6, and after the reaction was completed, the liquid phase product was collected by ice water bath, and the composition of the product was analyzed by gas chromatography, and the evaluation results are shown in Table 2.
Example 3
(1) Mixing 5.1g of surfactant P123 and 100mL of absolute ethyl alcohol, dissolving under ultrasound, adding 7.3mL of concentrated nitric acid, adding 10.7g of aluminum isopropoxide and 3.8g of magnesium nitrate after clarification, stirring and mixing for 5 hours at a rotating speed of 200rpm, drying for 48 hours at 60 ℃, and finally roasting for 3 hours at 800 ℃ to obtain a doped carrier with an ordered mesoporous structure;
(2) 8.34g of In (NO 3 ) 3 ·4H 2 O is added into a mixed solution of 50mL of absolute ethyl alcohol and 25mL of deionized water to obtain a solution containing metal indium salt, 8g of urea is added into a mixed solution of 60mL of absolute ethyl alcohol and 20mL of deionized water to obtain a precipitant solution, the precipitant solution is dropwise added into the solution containing metal indium salt at 30 ℃, then 1.2g of doped carrier obtained in the step (1) is added, and the mixture is fully stirred for 4 hours at a rotating speed of 200rpm to obtain a precipitation mother solution;
(3) Adding the precipitation mother liquor obtained in the step (2) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 120 ℃ for 18 hours to form a precipitate;
(4) Naturally cooling the product obtained in the step (3) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH is 8, drying at 60 ℃ for 15 hours, and roasting at 380 ℃ for 3 hours to obtain a catalyst finished product;
(5) Dissolving 0.038g of palladium nitrate in 6mL of deionized water to obtain a solution containing metal palladium salt, adding 2g of the catalyst obtained in the step (4) into the solution containing metal palladium salt, stirring at a rotating speed of 400rpm for 1h at 25 ℃, then carrying out rotary evaporation and drying at a temperature of 45 ℃ and a rotating speed of 20rpm under a vacuum degree of 0.1MPa for 3h, finally roasting at 350 ℃ for 4h to obtain a noble metal modified catalyst (the content of each component is shown in Table 1), tabletting and sieving to 40-60 meshes, wherein indium oxide in the obtained catalyst has a cubic structure;
(6) Carrying out a reaction for preparing methanol by hydrogenating carbon dioxide in a stainless steel reactor with an inner diameter of 8mm, and adopting the noble metal modified catalyst prepared in the step (5) as a reaction catalyst, wherein the reaction conditions are as follows: the reaction pressure is 5.0MPa, the reaction temperature is 340 ℃, and the volume space velocity of raw materials (carbon dioxide and hydrogen) is 18000h -1 、H 2 /CO 2 The molar ratio is 5, liquid phase products and gas phase color are collected by ice water bath after the reaction is finishedThe product composition was analyzed by spectrum and the evaluation results are shown in Table 2.
Example 4
(1) Mixing 4.6g of surfactant P123 and 90mL of absolute ethyl alcohol, dissolving under ultrasound, adding 7.6mL of concentrated nitric acid, adding 8.4g of aluminum isopropoxide and 4.8g of magnesium nitrate after clarification, stirring and mixing for 5 hours at a rotating speed of 350rpm, drying for 48 hours at 60 ℃, and finally roasting for 3 hours at 800 ℃ to obtain a doped carrier with an ordered mesoporous structure;
(2) 9.57g of In (NO 3 ) 3 ·4H 2 O is added into a mixed solution of 80mL of absolute ethyl alcohol and 40mL of deionized water to obtain a solution containing metal indium salt, 9.2g of urea is added into a mixed solution of 80mL of absolute ethyl alcohol and 30mL of deionized water to obtain a precipitant solution, the precipitant solution is dropwise added into the solution containing metal indium salt at 30 ℃, then 1.2g of doped carrier obtained in the step (1) is added, and the mixture is fully stirred for 7 hours at the rotating speed of 350rpm to obtain a precipitation mother solution;
(3) Adding the precipitation mother liquor obtained in the step (2) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 130 ℃ for 20 hours to form a precipitate;
(4) Naturally cooling the product obtained in the step (3) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH is 6, drying at 80 ℃ for 12 hours, and roasting at 450 ℃ for 3 hours to obtain a catalyst finished product;
(5) Dissolving 0.061g of palladium nitrate in 10mL of deionized water to obtain a solution containing metal palladium salt, adding 2g of the catalyst obtained in the step (4) into the solution containing metal palladium salt, stirring at a rotating speed of 350rpm for 1h at 25 ℃, then carrying out rotary evaporation and drying at a temperature of 45 ℃ and a rotating speed of 20rpm under a vacuum degree of 0.1MPa for 3h, finally roasting at 350 ℃ for 4h to obtain a noble metal modified catalyst (the content of each component is shown in Table 1), tabletting and sieving to 40-60 meshes, wherein indium oxide in the obtained catalyst has a cubic structure;
(6) Carrying out a reaction for preparing methanol by hydrogenating carbon dioxide in a stainless steel reactor with an inner diameter of 8mm, and adopting the noble metal modified catalyst prepared in the step (5) as a reaction catalyst and a reaction barThe parts are as follows: the reaction pressure is 1.0MPa, the reaction temperature is 400 ℃, and the volume space velocity of raw materials (carbon dioxide and hydrogen) is 9000h -1 、H 2 /CO 2 The molar ratio was 4, and after the reaction was completed, the liquid phase product was collected by ice water bath, and the composition of the product was analyzed by gas chromatography, and the evaluation results are shown in Table 2.
Example 5
(1) Mixing 6.3g of surfactant P123 and 120mL of absolute ethyl alcohol, dissolving under ultrasound, adding 8.5mL of concentrated nitric acid, adding 4.1g of aluminum isopropoxide and 5.3g of magnesium nitrate after clarification, stirring and mixing for 5 hours at a rotating speed of 150rpm, drying for 48 hours at 60 ℃, and finally roasting for 3 hours at 800 ℃ to obtain a doped carrier with an ordered mesoporous structure;
(2) 5.36g of In (NO 3 ) 3 ·4H 2 O is added into a mixed solution of 40mL of absolute ethyl alcohol and 20mL of deionized water to obtain a solution containing metal indium salt, 6g of urea is added into a mixed solution of 50mL of absolute ethyl alcohol and 20mL of deionized water to obtain a precipitant solution, the precipitant solution is dropwise added into the solution containing metal indium salt at 30 ℃, then 0.4g of doped carrier obtained in the step (1) is added, and the mixture is fully stirred for 6 hours at a rotating speed of 150rpm to obtain a precipitation mother solution;
(3) Adding the precipitation mother liquor obtained in the step (2) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 150 ℃ for 16 hours to form a precipitate;
(4) Naturally cooling the product obtained in the step (3) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH is 7.5, drying at 80 ℃ for 14 hours, and roasting at 500 ℃ for 3 hours to obtain a catalyst finished product;
(5) Dissolving 0.046g of palladium nitrate in 10mL of deionized water to obtain a solution containing metal palladium salt, adding 2g of the catalyst obtained in the step (4) into the solution containing metal palladium salt, stirring at a rotating speed of 150rpm for 1h at 25 ℃, then carrying out rotary evaporation and drying at a temperature of 45 ℃ and a rotating speed of 20rpm under a vacuum degree of 0.1MPa for 3h, finally roasting at 350 ℃ for 4h to obtain a noble metal modified catalyst (the content of each component is shown in Table 1), tabletting and sieving to 40-60 meshes, wherein indium oxide in the obtained catalyst has a cubic structure;
(6) Carrying out a reaction for preparing methanol by hydrogenating carbon dioxide in a stainless steel reactor with an inner diameter of 8mm, and adopting the noble metal modified catalyst prepared in the step (5) as a reaction catalyst, wherein the reaction conditions are as follows: the reaction pressure was 4.0MPa, the reaction temperature was 240℃and the volume space velocity of the raw materials (carbon dioxide and hydrogen) was 15000h -1 、H 2 /CO 2 The molar ratio was 6, and after the reaction was completed, the liquid phase product was collected by ice water bath, and the composition of the product was analyzed by gas chromatography, and the evaluation results are shown in Table 2.
Example 6
The procedure of example 1 was followed, except that the preparation of the doped support was as follows: adding 9.1g of aluminum nitrate and 3.2g of magnesium nitrate into 500mL of water to prepare a salt solution, adding 6.5g of sodium carbonate into 500mL of deionized water to prepare a precipitant solution, carrying out parallel flow precipitation on the two solutions, controlling the pH value to be about 7.5, stirring the mixed solution for 1h, standing and ageing for 2h, centrifugally washing for 3 times by adopting the deionized water, drying for 48h at 60 ℃, and finally roasting for 3h at 800 ℃ to obtain the doped carrier.
Example 7
The procedure of example 1 was followed except that the amount of magnesium nitrate used in step (1) was replaced with 6.6g.
Example 8
The procedure of example 1 was followed except that the amount of the doping carrier used in step (2) was replaced with 0.5g.
Comparative example 1
(1) 7.61g of In (NO 3 ) 3 ·4H 2 Adding O into a mixed solution of 40mL of absolute ethyl alcohol and 24mL of deionized water to obtain a solution containing metal indium salt, adding 8g of urea into a mixed solution of 40mL of absolute ethyl alcohol and 10mL of deionized water to obtain a precipitant solution, adding the precipitant solution into the solution containing metal indium salt at 30 ℃, and fully stirring for 6 hours at a rotating speed of 150rpm to obtain a precipitation mother solution;
(2) Adding the precipitation mother liquor obtained in the step (1) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 120 ℃ for 20 hours to form a precipitate;
(3) Naturally cooling the product obtained in the step (2) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH is 7, drying at 60 ℃ for 20 hours, roasting at 350 ℃ for 3 hours to obtain an indium oxide catalyst, and tabletting and sieving to 40-60 meshes;
(4) The activity of the indium oxide catalyst obtained in the step (3) was evaluated on a fixed bed reactor, and the reaction conditions were the same as in example 1, and the test results are shown in Table 2.
Comparative example 2
(1) Preparation of indium oxide was the same as comparative example 1;
(2) Dissolving 0.057g of palladium nitrate in 10mL of deionized water to obtain a solution containing metal palladium salt, adding 2g of indium oxide obtained in the step (1) into the solution containing metal palladium salt, stirring at a rotating speed of 150rpm for 1h at 25 ℃, then carrying out rotary evaporation and drying at a temperature of 45 ℃ at 20rpm under a vacuum degree of 0.1MPa for 3h, finally roasting at 350 ℃ for 4h to obtain a Pd modified indium oxide catalyst, and tabletting and sieving to 40-60 meshes;
(3) The activity of the Pd modified indium oxide catalyst obtained in the step (2) was evaluated on a fixed bed reactor, and the reaction conditions were the same as in example 1, and the test results are shown in Table 2.
Comparative example 3
(1) Mixing 4.1g of surfactant P123 and 80mL of absolute ethyl alcohol, dissolving under ultrasound, adding 6.3mL of concentrated nitric acid, adding 4.9g of aluminum isopropoxide and 3.0g of magnesium nitrate after clarification, stirring and mixing for 5 hours at a rotating speed of 150rpm, drying for 48 hours at 60 ℃, and finally roasting for 3 hours at 800 ℃ to obtain a doped carrier;
(2) 7.61g of In (NO 3 ) 3 ·4H 2 O is added into a mixed solution of 40mL of absolute ethyl alcohol and 24mL of deionized water to obtain a solution containing metal indium salt, 8g of urea is added into a mixed solution of 40mL of absolute ethyl alcohol and 10mL of deionized water to obtain a precipitant solution, the precipitant solution is dropwise added into the solution containing metal indium salt at 30 ℃, then 2g of doped carrier obtained in the step (1) is added, and the mixture is fully stirred for 6 hours at a rotating speed of 150rpm to obtain a precipitation mother solution;
(3) Adding the precipitation mother liquor obtained in the step (2) into a hydrothermal synthesis reaction kettle with a polytetrafluoroethylene lining of 100mL, placing the reaction kettle into a forced air drying oven for standing and ageing at 120 ℃ for 20 hours to form a precipitate;
(4) Naturally cooling the product obtained in the step (3) to room temperature, centrifuging, washing centrifugal precipitation with deionized water until the pH value is 7, drying at 60 ℃ for 20 hours, roasting at 350 ℃ for 3 hours to obtain a magnesium aluminum modified indium oxide catalyst, tabletting and sieving to 40-60 meshes;
(5) The activity of the magnesium aluminum modified indium oxide catalyst obtained in the step (4) was evaluated on a fixed bed reactor, and the reaction conditions were the same as in example 1, and the test results are shown in table 2.
TABLE 1
Figure BDA0003326015210000201
Note that: the contents of the components in Table 1 are in mass percent
TABLE 2
Figure BDA0003326015210000202
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Figure BDA0003326015210000211
As can be seen from the results of Table 1, the noble metal modified catalyst prepared by the method provided by the invention in examples 1-8 has significantly better catalytic performance, high reaction activity, high selectivity of target products and good reaction stability compared with the catalyst prepared in comparative examples 1-3 when being used for catalyzing the reaction of preparing methanol by hydrogenating carbon dioxide.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (12)

1. The noble metal modified catalyst comprises an active component, a doped carrier and a noble metal component, wherein the active component is indium oxide with a cubic structure, the doped carrier is a mixture of magnesium oxide and aluminum oxide, and the noble metal component is Pd; wherein, the content of the active component accounts for 40-85% of the total mass of the active component and the doped carrier; the doping carrier accounts for 15% -60% of the total mass of the active component and the doping carrier; the noble metal component accounts for 0.01 to 1.5 percent of the total mass of the catalyst.
2. The noble metal modified catalyst of claim 1, wherein the active component content is 55-75% of the total mass of active component and doped support; the doping carrier accounts for 25-45% of the total mass of the active component and the doping carrier;
preferably, the noble metal component accounts for 0.75-1.5% of the total mass of the catalyst;
preferably, the mass ratio of the active component to the doping carrier is 1-6:1, further preferably 1-3:1.
3. the noble metal modified catalyst according to claim 1 or 2, wherein magnesium oxide accounts for 2-18% of the total mass of the active component and the doped support, further preferably 2.5-12.5%; the alumina accounts for 14-54% of the total mass of the active component and the doped carrier, and more preferably 18.5-40.5%.
4. A noble metal modified catalyst as claimed in any one of claims 1 to 3, wherein the doped support has an ordered mesoporous structure.
5. A method of preparing a noble metal modified catalyst, the method comprising:
(1) Mixing a solution containing metal indium salt, a precipitant solution and a doping carrier to obtain a precipitation mother solution; the doping carrier is a mixture of magnesium oxide and aluminum oxide;
(2) Aging the precipitation mother liquor to form a precipitate;
(3) Carrying out solid-liquid separation on the product obtained in the step (2), and then drying and roasting to obtain a catalyst semi-finished product;
(4) The solution containing the metallic palladium salt is contacted with the semi-finished catalyst and then dried and calcined.
6. The method of claim 5, wherein the metal indium salt, the doped support, and the metal palladium salt are used in an amount such that the indium oxide comprises 40% -85% of the total mass of indium oxide and doped support in the resulting catalyst; the doped carrier accounts for 15-60% of the total mass of the indium oxide and the doped carrier; the palladium element accounts for 0.01 to 1.5 percent of the total mass of the catalyst;
preferably, the metal indium salt, the doped carrier and the metal palladium salt are used in an amount such that the indium oxide accounts for 55-75% of the total mass of the indium oxide and the doped carrier in the prepared catalyst; the doped carrier accounts for 25-45% of the total mass of the indium oxide and the doped carrier; the palladium element accounts for 0.75 to 1.5 percent of the total mass of the catalyst;
Preferably, the metal indium salt and the doping carrier are used in an amount mass ratio of 1-6 in terms of oxide: 1, further preferably 1-3:1.
7. the method of claim 5 or 6, wherein the doped support is prepared using a solvent evaporation induced self-assembly method;
preferably, the preparation method of the doped carrier comprises the following steps: mixing an acid, an aluminum precursor and a magnesium precursor in the presence of a surfactant and in the presence of a solvent, and then drying and roasting;
preferably, the aluminum precursor and the magnesium precursor are used in an amount such that magnesium oxide accounts for 2-18% of the total mass of the indium oxide and the doped carrier, and more preferably 2.5-12.5% of the total mass of the indium oxide and the doped carrier in the prepared catalyst; the alumina accounts for 14-54% of the total mass of the indium oxide and the doped carrier, and more preferably 18.5-40.5%;
preferably, the surfactant is selected from at least one of P123, CTAB, malic acid, sodium 2-ethyl hexane sulfosuccinate and nonylphenol polyoxyethylene ether; the solvent is at least one selected from ethanol, methanol, isopropanol, ethylene glycol, triethylene glycol and N, N-dimethylacetamide; the acid is at least one selected from nitric acid, hydrochloric acid and phosphoric acid; the aluminum precursor is at least one of aluminum isopropoxide, aluminum nitrate, aluminum chloride and aluminum sulfate;
Preferably, the molar ratio of the surfactant, the organic solvent, the acid to the aluminum precursor is 0.01-0.05:10-80:1-10:1, preferably 0.01 to 0.03:20-60:3-7:1, a step of;
preferably, the mixing is carried out for a period of 3 to 9 hours, more preferably the mixing is carried out under stirring conditions;
preferably, the roasting conditions include: the temperature is 600-1200 ℃ and the time is 3-6h.
8. The method according to any one of claims 5-7, wherein the solvent in the solution containing the metal indium salt and the precipitant solution in step (1) is each independently an organic solvent and/or water, preferably an organic solvent and water, the organic solvent being selected from at least one of ethanol, methanol, isopropanol, ethylene glycol, triethylene glycol and N, N-dimethylacetamide;
preferably, the concentration of the solution containing the metal indium salt is 0.1 to 1mol/L;
preferably, the concentration of the precipitant solution is 1-3mol/L;
preferably, the precipitant is urea;
preferably, the mixing in step (1) is carried out under stirring conditions, preferably for a period of time ranging from 1 to 10 hours;
preferably, the mixing in step (1) comprises first mixing the solution containing the metal indium salt and the precipitant solution, and then adding the doping carrier.
9. The method of any one of claims 5-7, wherein the aging conditions in step (2) include: the temperature is 80-180 ℃ and the time is 12-22h;
preferably, the process further comprises washing the product obtained in step (2), preferably to a pH value of between 6 and 8;
preferably, the roasting conditions of step (3) include: the temperature is 300-500 ℃ and the time is 3-6h.
10. The method of any of claims 5-7, wherein the metallic palladium salt is selected from at least one of palladium nitrate, palladium chloride, palladium acetate, ammonium tetrachloropalladate, ammonium hexachloropalladate, diamminedichloropalladium, and tetraaminedichloropalladium;
preferably, the contacting conditions of step (4) include: the process is carried out under the stirring condition, the temperature is 20-35 ℃ and the time is 0.5-2h;
preferably, the concentration of the solution containing the metallic palladium salt is 0.005 to 0.03 wt%;
preferably, the drying is spin-drying, and further preferably, the conditions of the spin-drying include: the temperature is 45-72 ℃, the rotating speed is 10-30rpm, the vacuum degree is 0.05-0.1MPa, and the rotary steaming time is 1-3h;
preferably, the conditions of calcination in step (4) include: the temperature is 300-500 ℃ and the time is 1-5h.
11. A noble metal modified catalyst made by the process of any one of claims 5-10.
12. Use of the noble metal modified catalyst of any one of claims 1-4 and 11 in a reaction for the hydrogenation of carbon dioxide to produce methanol;
preferably, the conditions for the hydrogenation of carbon dioxide to methanol include: the reaction pressure is 1.0-5.0MPa, the reaction temperature is 200-400 ℃, and the volume space velocity of the raw materials is 4500-18000h -1 ，H 2 /CO 2 The molar ratio is 1-6.
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