CN111701589A - Composite material compounded with atomic mixed grade alloy for catalyzing nitrobenzene hydrogenation, and preparation method and application thereof - Google Patents
Composite material compounded with atomic mixed grade alloy for catalyzing nitrobenzene hydrogenation, and preparation method and application thereof Download PDFInfo
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- CN111701589A CN111701589A CN202010599582.5A CN202010599582A CN111701589A CN 111701589 A CN111701589 A CN 111701589A CN 202010599582 A CN202010599582 A CN 202010599582A CN 111701589 A CN111701589 A CN 111701589A
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- cerium oxide
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- 239000000956 alloy Substances 0.000 title claims abstract description 156
- 229910045601 alloy Inorganic materials 0.000 title claims abstract description 144
- LQNUZADURLCDLV-UHFFFAOYSA-N nitrobenzene Chemical compound [O-][N+](=O)C1=CC=CC=C1 LQNUZADURLCDLV-UHFFFAOYSA-N 0.000 title claims abstract description 102
- 239000002131 composite material Substances 0.000 title claims abstract description 92
- 238000005984 hydrogenation reaction Methods 0.000 title claims abstract description 33
- 238000002360 preparation method Methods 0.000 title claims abstract description 30
- 229910052751 metal Inorganic materials 0.000 claims abstract description 92
- 239000002184 metal Substances 0.000 claims abstract description 86
- 238000002156 mixing Methods 0.000 claims abstract description 61
- 229910000420 cerium oxide Inorganic materials 0.000 claims abstract description 58
- BMMGVYCKOGBVEV-UHFFFAOYSA-N oxo(oxoceriooxy)cerium Chemical compound [Ce]=O.O=[Ce]=O BMMGVYCKOGBVEV-UHFFFAOYSA-N 0.000 claims abstract description 57
- 150000002739 metals Chemical class 0.000 claims abstract description 39
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 37
- 239000001301 oxygen Substances 0.000 claims abstract description 37
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 37
- 238000010438 heat treatment Methods 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 29
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 claims description 82
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 claims description 60
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 60
- 239000000203 mixture Substances 0.000 claims description 47
- 239000003054 catalyst Substances 0.000 claims description 45
- 229910052739 hydrogen Inorganic materials 0.000 claims description 37
- 239000001257 hydrogen Substances 0.000 claims description 36
- 239000010948 rhodium Substances 0.000 claims description 26
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 23
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 21
- 229910052763 palladium Inorganic materials 0.000 claims description 21
- 230000009467 reduction Effects 0.000 claims description 20
- 239000000243 solution Substances 0.000 claims description 19
- 229910052697 platinum Inorganic materials 0.000 claims description 18
- 238000001035 drying Methods 0.000 claims description 15
- 239000007864 aqueous solution Substances 0.000 claims description 13
- 239000002270 dispersing agent Substances 0.000 claims description 13
- 239000007789 gas Substances 0.000 claims description 13
- 229910001252 Pd alloy Inorganic materials 0.000 claims description 9
- 229910052703 rhodium Inorganic materials 0.000 claims description 7
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 claims description 6
- 229910000629 Rh alloy Inorganic materials 0.000 claims description 6
- 239000002245 particle Substances 0.000 claims description 6
- 239000001099 ammonium carbonate Substances 0.000 claims description 5
- XSKIUFGOTYHDLC-UHFFFAOYSA-N palladium rhodium Chemical compound [Rh].[Pd] XSKIUFGOTYHDLC-UHFFFAOYSA-N 0.000 claims description 5
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 claims description 5
- 238000005406 washing Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 claims description 3
- 235000012538 ammonium bicarbonate Nutrition 0.000 claims description 3
- 150000003839 salts Chemical class 0.000 claims description 3
- 238000003756 stirring Methods 0.000 claims description 3
- 235000012501 ammonium carbonate Nutrition 0.000 claims description 2
- PXXKQOPKNFECSZ-UHFFFAOYSA-N platinum rhodium Chemical compound [Rh].[Pt] PXXKQOPKNFECSZ-UHFFFAOYSA-N 0.000 claims description 2
- 230000003197 catalytic effect Effects 0.000 abstract description 38
- 239000000463 material Substances 0.000 abstract description 36
- 229910000422 cerium(IV) oxide Inorganic materials 0.000 abstract description 33
- CETPSERCERDGAM-UHFFFAOYSA-N ceric oxide Chemical compound O=[Ce]=O CETPSERCERDGAM-UHFFFAOYSA-N 0.000 abstract description 21
- 229910002064 alloy oxide Inorganic materials 0.000 abstract description 10
- 230000002195 synergetic effect Effects 0.000 abstract description 9
- 239000013067 intermediate product Substances 0.000 abstract description 7
- 239000006227 byproduct Substances 0.000 abstract description 4
- 238000010189 synthetic method Methods 0.000 abstract description 4
- 238000006243 chemical reaction Methods 0.000 description 37
- 239000000047 product Substances 0.000 description 30
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 22
- 229910052786 argon Inorganic materials 0.000 description 22
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 20
- 150000002431 hydrogen Chemical class 0.000 description 17
- 238000003786 synthesis reaction Methods 0.000 description 17
- 125000004429 atom Chemical group 0.000 description 15
- 230000000052 comparative effect Effects 0.000 description 15
- 230000008569 process Effects 0.000 description 14
- 238000011068 loading method Methods 0.000 description 13
- 239000002105 nanoparticle Substances 0.000 description 13
- 230000015572 biosynthetic process Effects 0.000 description 12
- 238000005054 agglomeration Methods 0.000 description 11
- 230000002776 aggregation Effects 0.000 description 11
- 238000006555 catalytic reaction Methods 0.000 description 11
- 238000009903 catalytic hydrogenation reaction Methods 0.000 description 9
- 238000012512 characterization method Methods 0.000 description 9
- 239000007795 chemical reaction product Substances 0.000 description 9
- 238000004587 chromatography analysis Methods 0.000 description 9
- 238000007599 discharging Methods 0.000 description 9
- 238000002474 experimental method Methods 0.000 description 9
- 239000006228 supernatant Substances 0.000 description 9
- 239000002994 raw material Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 229910021604 Rhodium(III) chloride Inorganic materials 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- SONJTKJMTWTJCT-UHFFFAOYSA-K rhodium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Rh+3] SONJTKJMTWTJCT-UHFFFAOYSA-K 0.000 description 5
- 239000004094 surface-active agent Substances 0.000 description 5
- 229910002666 PdCl2 Inorganic materials 0.000 description 4
- 239000007791 liquid phase Substances 0.000 description 4
- 101150003085 Pdcl gene Proteins 0.000 description 3
- 230000004075 alteration Effects 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000013021 overheating Methods 0.000 description 3
- 238000011946 reduction process Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- HSJPMRKMPBAUAU-UHFFFAOYSA-N cerium(3+);trinitrate Chemical compound [Ce+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O HSJPMRKMPBAUAU-UHFFFAOYSA-N 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 229910001325 element alloy Inorganic materials 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000010970 precious metal Substances 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000001308 synthesis method Methods 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 1
- 229910019017 PtRh Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 238000005915 ammonolysis reaction Methods 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 238000000231 atomic layer deposition Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 229940044927 ceric oxide Drugs 0.000 description 1
- DRVWBEJJZZTIGJ-UHFFFAOYSA-N cerium(3+);oxygen(2-) Chemical class [O-2].[O-2].[O-2].[Ce+3].[Ce+3] DRVWBEJJZZTIGJ-UHFFFAOYSA-N 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- -1 coatings Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- FFEVHTMMGXLTCX-UHFFFAOYSA-N iron nitrobenzene Chemical compound [Fe].[N+](=O)([O-])C1=CC=CC=C1 FFEVHTMMGXLTCX-UHFFFAOYSA-N 0.000 description 1
- 239000012948 isocyanate Substances 0.000 description 1
- 150000002513 isocyanates Chemical class 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 1
- 238000005191 phase separation Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 229910001404 rare earth metal oxide Inorganic materials 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000006273 synthetic pesticide Substances 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000009827 uniform distribution Methods 0.000 description 1
Images
Classifications
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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
- B01J23/63—Platinum group metals with rare earths or actinides
-
- B01J35/23—
-
- B01J35/393—
-
- 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
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
- B01J37/03—Precipitation; Co-precipitation
- B01J37/031—Precipitation
- B01J37/035—Precipitation on carriers
-
- 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
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
-
- 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
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/16—Reducing
- B01J37/18—Reducing with gases containing free hydrogen
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C209/00—Preparation of compounds containing amino groups bound to a carbon skeleton
- C07C209/30—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds
- C07C209/32—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups
- C07C209/36—Preparation of compounds containing amino groups bound to a carbon skeleton by reduction of nitrogen-to-oxygen or nitrogen-to-nitrogen bonds by reduction of nitro groups by reduction of nitro groups bound to carbon atoms of six-membered aromatic rings in presence of hydrogen-containing gases and a catalyst
Abstract
The invention provides a composite material compounded with an atomic mixed grade alloy, which is obtained by carrying out heat treatment on a composite material compounded with more than two monoatomic metals; the composite material compounded with more than two kinds of monoatomic metals comprises a cerium oxide carrier with oxygen vacancies and more than two kinds of monoatomic metals compounded on the surface of the cerium oxide carrier. According to the atomic mixing level alloy composite material provided by the invention, the monatomic material is used as an intermediate product, the synthesized nano alloy has the maximum mixing degree, the synergistic effect between metals in the alloy is greatly improved, the catalytic performance is improved, the synthetic method is green and environment-friendly, the steps are simple and safe, and the preparation period is short; the carrier is simple and easy to obtain, and has a very high application prospect. The components of the atomic mixed grade alloy/cerium dioxide carrier prepared by the method have the maximum synergistic effect, and the atomic mixed grade alloy/cerium dioxide carrier has high catalytic performance in a nitrobenzene hydrogenation process and almost has no byproduct.
Description
Technical Field
The invention belongs to the technical field of hydrogenation catalysts, and relates to a composite material compounded with an atomic mixed alloy, a preparation method and application thereof, in particular to a composite material compounded with an atomic mixed alloy for catalyzing nitrobenzene hydrogenation, a preparation method and application thereof.
Background
The hydrogenation of nitrobenzene to aniline is an industrially important reaction. Aniline is an important organic chemical raw material and is widely applied to the fields of organic dyes, coatings, synthetic rubbers, pesticides and the like. Especially as the production raw material of isocyanate, the prepared chemical products have various types and very wide application prospect. At present, the aniline is produced by a nitrobenzene iron powder reduction method, a phenol ammonolysis method and a nitrobenzene catalytic hydrogenation reduction method in industry. However, the reaction process for preparing aniline from nitrobenzene is complex, and comprises a plurality of parallel reactions and a plurality of series reactions, a large amount of intermediate products exist in the reaction process, and the reaction conditions in the reaction process can greatly influence the activity and selectivity of the reaction. The nitrobenzene catalytic hydrogenation method takes clean hydrogen as a hydrogen source, and has the characteristics of low raw material cost, high yield, high selectivity, high cost of precious metals used for environmental nitrobenzene hydrogenation, high inactivation tendency and the like, wherein the precious metals mainly comprise platinum, palladium, rhodium and the like.
The main method for preparing aniline by nitrobenzene hydrogenation comprises the following steps: three processes of fixed bed gas-phase catalytic hydrogenation, fluidized bed gas-phase catalytic hydrogenation and nitrobenzene liquid-phase catalytic hydrogenation. The fixed bed hydrogenation reaction, the nitrobenzene is atomized and enters a fixed bed layer with circulating hydrogen, the reaction heat is absorbed by the circulating hydrogen, and the aniline is rectified and purified. The fixed bed has the advantages of mature technology, low reaction temperature, simple equipment and operation and the like, but side reactions caused by local overheating are easy to occur frequently due to high reaction pressure, and the catalyst is damaged due to overheating and the like. The fluidized bed gas phase catalysis has the advantages of better improving the heat transfer condition, controlling the reaction temperature, avoiding local overheating, reducing the generation of side reactions and prolonging the service life of the catalyst, but the whole process of the fluidized bed gas phase catalytic hydrogenation is complicated and complicated to operate, the consumption of the catalyst is overlarge, and the construction cost, the maintenance cost and the operation cost are overhigh. The production capacity of nitrobenzene liquid-phase catalytic hydrogenation is usually larger than that of gas-phase catalytic hydrogenation with the same volume, including a fixed bed and a fluidized bed, and the single-pass conversion rate of nitrobenzene is very high, but the liquid-phase hydrogenation has very high requirements on the catalyst, and the catalyst needs to show good activity on aniline preparation by liquid-phase hydrogenation of nitrobenzene.
The nano alloy has the characteristics of adjustable components, variable structure, rich active centers and the like, and has wide application prospect in the field of catalysis. The activity of the nano alloy is often related to the mixing degree of the nano particles, however, the existing nano alloy has the condition of uneven mixing in different degrees, so that the uniform distribution of metal elements in the alloy is difficult to ensure, and the activity of the nano alloy is further influenced.
Therefore, how to obtain a nano alloy capable of being uniformly mixed so as to ensure and improve the activity of the nano alloy has become one of the focuses of great concern of many prospective researchers in the industry.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a composite material compounded with an atomic mixed alloy, a preparation method and an application thereof, and in particular, to a composite material compounded with an atomic mixed alloy for catalyzing nitrobenzene hydrogenation. According to the brand-new atomic mixing grade alloy composite material provided by the invention, the monatomic material is used as an intermediate product, and the synthesized nano alloy has the maximum mixing degree, namely the atomic mixing grade, so that the synergistic effect between metals in the alloy is greatly improved, and the catalytic performance is improved. And the preparation method is economical, simple and convenient, and is suitable for large-scale popularization and application.
The invention provides a composite material compounded with an atomic mixed grade alloy, which is obtained by carrying out heat treatment on a composite material compounded with more than two monoatomic metals;
the composite material compounded with more than two kinds of monoatomic metals comprises a cerium oxide carrier with oxygen vacancies and more than two kinds of monoatomic metals compounded on the surface of the cerium oxide carrier.
Preferably, the monoatomic metal includes a platinum monoatomic, palladium monoatomic, or rhodium monoatomic;
the cerium oxide carrier with oxygen vacancy is a cerium oxide carrier with oxygen vacancy on the surface;
the mass of each monoatomic metal accounts for 0.2-0.3% of the mass of the carrier;
the monoatomic metal is supported on the surface of the cerium oxide support in a monodispersed form.
Preferably, there are no interconnecting metallic bonds between the monoatomic metals;
the composite material comprises a cerium oxide carrier and an alloy of atomic level mixing grade compounded on the surface of the cerium oxide carrier;
the particle size of the cerium oxide carrier is 0.5-1 mu m;
the grain diameter of the alloy compounded on the surface of the cerium oxide carrier at the atomic level mixing level is 2-3 nm.
Preferably, the alloy comprises a platinum palladium alloy, a platinum rhodium alloy, a palladium rhodium alloy or a platinum palladium rhodium alloy;
the mass ratio of metal elements in the alloy is 1;
the mass of the alloy accounts for 0.4-0.9% of the mass of the carrier.
The invention provides a preparation method of a composite material compounded with an atomic mixed grade alloy, which comprises the following steps:
A) mixing cerium oxide with oxygen vacancy, a dispersing agent, more than two monoatomic metal source water solutions and water to obtain a composite material compounded with more than two monoatomic metals;
B) and (3) under the condition of hydrogen or hydrogen mixed gas, carrying out heat treatment reduction on the composite material compounded with more than two monoatomic metals obtained in the step to obtain the composite material compounded with the atomic mixed grade alloy.
Preferably, the mass ratio of the metal element between the two or more monoatomic metal sources is 1;
the source of the monoatomic metal comprises a soluble salt of the monoatomic metal;
the dispersant comprises ammonium bicarbonate and/or ammonium carbonate;
the molar ratio of the dispersing agent to the monoatomic metal source is (20-30): 1.
preferably, the two or more monoatomic metal source aqueous solutions include an aqueous solution of each of two or more monoatomic metal sources or a mixed aqueous solution of two or more monoatomic metal sources;
the pH value of the mixture is 1-2;
the mixing mode comprises stirring and mixing;
the mixing time is 30-60 min.
Preferably, the mixing further comprises one or more steps of centrifuging, drying and washing;
the temperature of the heat treatment reduction is 600-800 ℃;
the time for heat treatment reduction is 2-12 h;
the composite material is a composite nano alloy catalyst.
Preferably, the cerium oxide having oxygen vacancies is prepared by the following steps:
under the condition of hydrogen or hydrogen mixed gas, carrying out heat treatment on cerium oxide to obtain cerium oxide with oxygen vacancy;
the heat treatment time is 1-2 h;
the temperature of the heat treatment is 100-200 ℃.
The invention provides application of the composite material in any one of the technical schemes or the composite material prepared by the preparation method in any one of the technical schemes in the aspect of catalyzing hydrogenation of nitrobenzene to prepare aniline.
The invention provides a composite material compounded with an atomic mixed grade alloy, which is obtained by carrying out heat treatment on a composite material compounded with more than two monoatomic metals; the composite material compounded with more than two kinds of monoatomic metals comprises a cerium oxide carrier with oxygen vacancies and more than two kinds of monoatomic metals compounded on the surface of the cerium oxide carrier. Compared with the prior art, the invention aims at the condition that the existing nano alloy has uneven mixing in different degrees, and the metal elements in the alloy are difficult to be ensured to be evenly distributed, thereby further influencing the defect of the activity of the nano alloy.
The invention is based on research and believes that in the preparation process of the existing alloy, due to the difference of reduction potentials among metals in the nano alloy, preferential reduction of certain metal can occur in the reduction process, phase separation even a heterostructure can occur, if the uniformly mixed nano alloy needs to be obtained, high energy needs to be given to break the formed structure, so that the uniformly mixed nano alloy can be obtained, namely, the nano particles formed firstly need to be treated by ultra-high temperature, but the universality is greatly limited by the ultra-high temperature environment, the requirements on carriers and alloy materials are extremely high, and even the obtained alloy materials after the ultra-high temperature treatment can be more uncontrollable.
The brand-new atomic mixed grade alloy composite material provided by the invention utilizes the monatomic material as an intermediate product, and the synthesized nano alloy has the maximum mixing degree, namely the atomic mixed grade. The cerium dioxide carrier with oxygen vacancy is adopted, different monatomic materials are uniformly dispersed and matched on the substrate material, the uniformity among the monatomic materials is ensured, the further agglomeration process is carried out at high temperature, the randomness of agglomeration is ensured, and the randomness is the key for forming the atomic mixed level alloy catalyst, so that the composite material compounded with the atomic mixed level alloy is finally obtained. The invention greatly improves the synergy between metals in the alloy and improves the catalytic performance. The synthesis method provided by the invention has no participation of a surfactant, and is environment-friendly in synthesis; the synthetic method has simple and safe steps and short preparation period; the carrier is simple and easy to obtain, has very high application prospect, and is suitable for large-scale popularization and application. The components of the atomic mixed grade alloy/cerium dioxide carrier prepared by the method have the maximum synergistic effect, and the atomic mixed grade alloy/cerium dioxide carrier has high catalytic performance in a nitrobenzene hydrogenation process, and almost no by-product is generated.
Experimental results show that the composite material compounded with the atomic mixed alloy/cerium dioxide carrier is prepared, the components of the atomic mixed alloy/cerium dioxide carrier have the maximum synergistic effect, the conversion rate of nitrobenzene reaches 100% and the selectivity of aniline also reaches 97.23% in a catalytic nitrobenzene hydrogenation process.
Drawings
FIG. 1 is a transmission electron microscope photograph of spherical aberration of the composite material compounded with platinum-palladium nano alloy of atomic mixture grade prepared by the invention.
Detailed Description
For a further understanding of the invention, reference will now be made to the preferred embodiments of the invention by way of example, and it is to be understood that the description is intended to further illustrate features and advantages of the invention, and not to limit the scope of the claims.
All of the starting materials of the present invention, without particular limitation as to their source, may be purchased commercially or prepared according to conventional methods well known to those skilled in the art.
All of the starting materials of the present invention are not particularly limited in their purity, and the present invention preferably employs purity requirements that are conventional in the art of analytical purity or atomic layer deposition.
All the raw materials and the process of the invention belong to the conventional trade marks or the abbreviation, each trade mark or the abbreviation is clear and definite in the field of related application, and the technical personnel in the field can purchase the raw materials or prepare the raw materials or the abbreviation from the market or prepare the raw materials or the abbreviation by a conventional method or adopt corresponding equipment to realize the raw materials or the abbreviation according to the trade marks, the abbreviation and the corresponding application.
The invention provides a composite material compounded with an atomic mixed grade alloy, which is obtained by carrying out heat treatment on a composite material compounded with more than two monoatomic metals;
the composite material compounded with more than two kinds of monoatomic metals comprises a cerium oxide carrier with oxygen vacancies and more than two kinds of monoatomic metals compounded on the surface of the cerium oxide carrier.
The definition of the surface oxygen vacancies in the present invention is not particularly limited, and can be defined by the conventional definition of the oxide having surface oxygen vacancies known to those skilled in the art, and can be selected and adjusted by those skilled in the art according to the actual needs, product requirements and quality requirements. The definition of the cerium oxide carrier with oxygen vacancies on the surface is not particularly limited in the present invention, and the definition of the oxide material with oxygen vacancies on the surface is known to those skilled in the art, and those skilled in the art can select and adjust the cerium oxide carrier according to the actual needs, the product requirements and the quality requirements. The definition of the single atom is not particularly limited in the present invention, and may be defined by the conventional definition of the single atom nano material well known to those skilled in the art, and those skilled in the art can select and adjust the definition according to the actual needs, the product requirements and the quality requirements.
The invention is not particularly limited to the specific selection of the monatomic metal in principle, and a person skilled in the art can select and adjust the monatomic metal according to actual needs, product requirements and quality requirements.
The specific structure of the cerium oxide carrier with oxygen vacancies is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements.
The definition of the composite is not particularly limited by the present invention, and may be defined by a conventional composite known to those skilled in the art, and the definition of the composite can be selected and adjusted by those skilled in the art according to the actual application needs, product requirements and quality requirements, and the present invention further ensures the performance of the product, and the composite preferably includes one or more of loading, embedding, growing, coating, doping, adsorbing and bonding, more preferably loading, embedding, growing, doping, adsorbing or bonding, most preferably loading, and particularly may be dispersed loading, and more particularly, the monoatomic metal is preferably loaded on the surface of the cerium oxide carrier in a monodispersed form.
The invention is not particularly limited to the specific connection relationship among the monatomic metals in principle, and a person skilled in the art can select and adjust the monatomic metals according to actual needs, product requirements and quality requirements. More specifically, the monoatomic metals preferably do not have an interconnecting metal bond therebetween, that is, the same monoatomic metals preferably do not have an interconnecting metal bond therebetween, and the different monoatomic metals preferably do not have an interconnecting metal bond therebetween.
The mass of each monoatomic metal in the carrier is preferably 0.2-0.3%, more preferably 0.22-0.28%, and even more preferably 0.24-0.26%, in order to improve the uniformity among different monoatomic materials and ensure that the uniformity of elements in the alloy reaches the atomic mixing level, and further the catalytic performance of the alloy, the mass of each monoatomic metal in the carrier is preferably 0.2-0.3%, more preferably 0.22-0.28%, and even more preferably 0.24-0.26%.
After more than two kinds of monoatomic metals are loaded, the monoatomic metals are uniformly distributed on the oxygen vacancy positions on the surface of the cerium oxide with the oxygen vacancy positions on the surface, whether all the oxygen vacancy positions on the surface of the cerium oxide are distributed by the monoatomic metals or are partially distributed is not particularly limited, and a person skilled in the art can select and adjust the composite material according to the actual application requirement, the product requirement and the quality requirement, wherein the composite material compounded with the atomic mixed grade alloy is preferably low in loading amount, so that most of the oxygen vacancy positions also exist.
The invention has no special limitation on the specific composition of the composite material compounded with the alloy with the atomic mixing level in principle, and a person skilled in the art can select and adjust the composition according to the actual needs, the product requirements and the quality requirements.
The particle size of the cerium oxide carrier is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, in order to improve the uniformity among different monatomic materials and ensure that the uniformity of elements in the alloy reaches an atomic mixing level and further the catalytic performance of the alloy, the particle size of the cerium oxide carrier is preferably 0.5-1 μm, more preferably 0.6-0.9 μm, and even more preferably 0.7-0.8 μm. The cerium oxide is cerium oxide.
The particle size of the alloy compounded on the surface of the cerium oxide carrier at the atomic mixing level is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements.
The specific kind of the alloy is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements.
In order to improve the uniformity among different monatomic materials and ensure that the uniformity of the elements in the alloy reaches the atomic mixing level and further the catalytic performance of the alloy, the mass ratio of the metal elements in the alloy is preferably 1, namely when the alloy is a bimetallic element alloy, the mass ratio is preferably 1:1, when the alloy is a trimetal element alloy, the mass ratio is preferably 1:1: 1.
the mass of the alloy in the carrier is preferably 0.4-0.9%, more preferably 0.45-0.8%, more preferably 0.5-0.7%, and more preferably 0.55-0.6% in order to improve the uniformity among different monatomic materials and ensure that the uniformity of elements in the alloy reaches the atomic mixing level, and further the catalytic performance of the alloy.
The invention provides a preparation method of a composite material compounded with an atomic mixed grade alloy, which comprises the following steps:
A) mixing cerium oxide with oxygen vacancy, a dispersing agent, more than two monoatomic metal source water solutions and water to obtain a composite material compounded with more than two monoatomic metals;
B) and (3) under the condition of hydrogen or hydrogen mixed gas, carrying out heat treatment reduction on the composite material compounded with more than two monoatomic metals obtained in the step to obtain the composite material compounded with the atomic mixed grade alloy.
The composition, structure and requirement of the composite material compounded with the atomic mixture level alloy in the preparation method and the corresponding optimization principle can preferably correspond to the composition, structure and requirement of the composite material compounded with the atomic mixture level alloy and the corresponding optimization principle, and are not described in detail herein.
The preparation method comprises the steps of mixing cerium oxide with oxygen vacancies, a dispersing agent, more than two monoatomic metal source aqueous solutions and water to obtain the composite material compounded with more than two monoatomic metals.
The invention is in principle not particularly limited to the extent of the cerium oxide with oxygen vacancies, as is customary for cerium oxides with oxygen vacancies (defects) known to the person skilled in the art, which can be selected and adjusted by the person skilled in the art according to the actual requirements, the product requirements and the quality requirements.
The mass ratio of the metal elements between the two or more monatomic metal sources is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements. In the invention, in the atom mixed grade alloy catalyst, the ratio of the single atom metal is 1:1, the catalyst shows the best catalytic performance. Under the condition of ensuring random agglomeration, the atomic mixture level nano alloy can be synthesized only in the same proportion.
The specific selection of the two or more monoatomic metal source aqueous solutions is not particularly limited in principle, and those skilled in the art can select and adjust the two or more monoatomic metal source aqueous solutions according to actual needs, product requirements and quality requirements.
The specific selection of the monatomic metal source is not particularly limited in principle, and a person skilled in the art can select and adjust the monatomic metal source according to actual needs, product requirements and quality requirements.
The specific selection of the dispersant is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements. The invention particularly uses a dispersant, such as NH, because the noble metal salt contains anions such as chloride ions which are easy to agglomerate the noble metal4 +The replacement of chloride ions can make the synthesis of monatomic materials easier.
In the invention, the molar ratio of the dispersing agent to the monatomic metal source is not particularly limited in principle, and a person skilled in the art can select and adjust the dispersing agent and the monatomic metal source according to actual needs, product requirements and quality requirements, in order to improve the uniformity among different monatomic materials and ensure that the uniformity of elements in the alloy reaches the atomic mixing level and further the catalytic performance of the alloy, the molar ratio of the dispersing agent to the monatomic metal source is preferably (20-30): 1, more preferably (22-28): 1, more preferably (24-26): 1.
the pH value of the mixture is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, the uniformity among different monatomic materials is improved, the uniformity of elements in the alloy is ensured to reach the atomic mixing level, and further the catalytic performance of the alloy is ensured, and the pH value of the mixture is preferably 1-2, more preferably 1.2-1.8, and more preferably 1.4-1.6.
The mixing mode is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements.
The mixing time is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, the uniformity among different monatomic materials is improved, the uniformity of elements in the alloy is ensured to reach the atomic mixing level, and further the catalytic performance of the alloy is improved, and the mixing time is preferably 30-60 min, more preferably 35-55 min, and even more preferably 40-50 min.
The invention is a complete and refined integral preparation process, improves the uniformity among different monatomic materials, ensures that the uniformity of elements in the alloy reaches an atomic mixing level, and further ensures the catalytic performance of the alloy.
Finally, under the condition of hydrogen or hydrogen mixed gas, the composite material compounded with more than two monoatomic metals obtained in the steps is subjected to heat treatment reduction to obtain the composite material compounded with the atomic mixed alloy.
The specific composition and proportion of the hydrogen gas mixture are not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements. In the invention, hydrogen gas mixture is also preferably adopted to improve the safety of the preparation process.
The temperature of the heat treatment reduction is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, the uniformity among different monatomic materials is improved, the uniformity of elements in the alloy is ensured to reach the atomic mixing level, and further the catalytic performance of the alloy is ensured, and the temperature of the heat treatment reduction is preferably 600-800 ℃, more preferably 630-770 ℃, more preferably 660-740 ℃, and more preferably 690-710 ℃.
The time for the heat treatment reduction is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, the uniformity among different monatomic materials is improved, the uniformity of elements in the alloy is ensured to reach the atomic mixing level, and further the catalytic performance of the alloy is improved, and the time for the heat treatment reduction is preferably 2-12 hours, more preferably 4-10 hours, and even more preferably 6-8 hours.
The invention is a complete and refined integral preparation process, improves the uniformity among different monatomic materials, ensures that the uniformity of elements in the alloy reaches an atomic mixing level, and further ensures the catalytic performance of the alloy, wherein the cerium oxide with oxygen vacancy is preferably prepared by the following steps:
and (3) carrying out heat treatment on the cerium oxide under the condition of hydrogen or hydrogen mixed gas to obtain the cerium oxide with oxygen vacancy.
The heat treatment time is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, the uniformity among different monatomic materials is improved, the uniformity of elements in the alloy is ensured to reach the atomic mixing level, and further the catalytic performance of the alloy is improved, and the heat treatment time is preferably 1-2 hours, more preferably 1.2-1.8 hours, and more preferably 1.4-1.6 hours.
The heat treatment temperature is not particularly limited in principle, and can be selected and adjusted by a person skilled in the art according to actual needs, product requirements and quality requirements, the uniformity among different monatomic materials is improved, the uniformity of elements in the alloy is ensured to reach the atomic mixing level, and further the catalytic performance of the alloy is ensured, and the heat treatment temperature is preferably 100-200 ℃, more preferably 120-180 ℃, and more preferably 140-160 ℃.
The invention is a complete and refined integral preparation process, improves the uniformity among different monatomic materials, ensures that the uniformity of elements in the alloy reaches an atomic mixing level, and further ensures the catalytic performance of the alloy, and the cerium oxide with oxygen vacancy can be prepared by the following steps:
taking Ce (NO)3)3·6H2Heating O in air to obtain CeO2Followed by the addition of CeO2In hydrogen argon gas mixture (H)210% and Ar 90%) by heat treatment.
The carrier of the nano alloy with atom mixing level provided by the invention is Ce (NO) directly burned at high temperature3)3·6H2Polyhedral CeO obtained by O and having good thermal stability and easy preparation2. The ceria obtained above is subjected to a simple reduction treatment to obtain a ceria support having a large number of oxygen vacancies.
The specific use of the composite material is not particularly limited in principle, and a person skilled in the art can select and adjust the composite material according to actual needs, product requirements and quality requirements.
The invention is a complete and refined integral preparation process, improves the uniformity among different monatomic materials, ensures that the uniformity of elements in the alloy reaches the atomic mixing level, and further ensures the catalytic performance of the alloy, and the preparation method of the composite material compounded with the alloy at the atomic mixing level can be specifically prepared by the following steps:
taking CeO with oxygen vacancies2The carrier is dissolved in water, stirred and subsequently treated by addition of NH4HCO3Adjusting pH value, adding platinum-palladium aqueous solution, centrifugally drying the mixed solution, washing and centrifuging for several times after drying, and drying again to obtain the monoatomic materialAnd (4) feeding a sample.
And (3) carrying out heat treatment on the single-atom sample in a high-temperature hydrogen-argon mixed gas to obtain a nano alloy sample.
The present invention uses cerium oxide (CeO) having a large number of oxygen vacancies2) The active component is platinum-palladium alloy, and the mixing degree of the synthesized nano alloy reaches the atomic mixing level by utilizing the characteristic that single atoms in a single-atom material are randomly agglomerated at high temperature. In the synthesis process of the platinum-palladium and other atom mixed grade alloy, firstly, a Pt/Pd and other double-monoatomic material or a three-monoatomic material is synthesized, wherein metals such as Pt, Pd and the like exist on the surface of a cerium dioxide carrier in a monoatomic form and are used as intermediate products in the synthesis process of the alloy. Pt/Pd or other bi-or tri-monatomic materials followed by hydrogen and argon (e.g., 10% H)290% Ar) is burnt at high temperature to automatically agglomerate to obtain the alloy catalyst with the atom mixing level, and the obtained alloy catalyst such as PtPd and the like has the maximum mixing degree, namely the atom mixing level. The invention does not use any surfactant in the process of forming the nano alloy, and the agglomeration and the reduction of the nano alloy are carried out in the high-temperature reducing atmosphere, wherein the reduction process is preferentially agglomerated, and the agglomerated nano alloy reaches the maximum mixing degree, namely the atomic mixing grade alloy catalyst. The invention effectively overcomes the condition that the final alloy components are not uniformly distributed due to the non-uniform reduction process caused by different reduction potentials of different metal elements in the existing alloy preparation process.
The invention also provides application of the composite material in any one of the technical schemes or the composite material prepared by the preparation method in any one of the technical schemes in the aspect of catalyzing hydrogenation of nitrobenzene to prepare aniline.
The invention has no special limitation on the specific process of preparing aniline by catalyzing nitrobenzene hydrogenation in principle, and the technicians in the field can select and adjust the process according to the actual needs, product requirements and quality requirements, and in order to ensure the catalytic performance of the alloy, the specific process can be as follows:
mixing organic solvent, nitrobenzene and composite atomAdding the gold composite material catalyst into a high-temperature reaction kettle for reaction. (specific ratio and parameters may be 10mg for catalyst, 2mL for nitrobenzene, and isopropanol for organic solvent H2Pressure 5MPa, rotation speed 800r/min)
The steps of the invention provide a composite material compounded with an atomic mixed alloy for catalyzing nitrobenzene hydrogenation, a preparation method and application thereof. The mixing degree of the alloy composite catalyst provided by the invention reaches atomic level mixing. The catalyst takes oxide ceric oxide as a carrier, uses a Pt/Pd and other single-atom materials as precursors, and utilizes the characteristic of high-temperature agglomeration of the single-atom catalytic material in a reducing atmosphere, so that single atoms on the surface of the carrier are randomly and automatically agglomerated into an atom-mixed grade platinum-palladium alloy. The synthesized catalyst does not participate in a surfactant, and the synthesis is environment-friendly; the synthetic method has simple and safe steps and short preparation period; the carrier is simple and easy to obtain, and has a very high application prospect. The components of the atomic mixed grade platinum-palladium alloy/cerium dioxide obtained by the method have the maximum synergistic effect, show high catalytic performance in a nitrobenzene hydrogenation process, and hardly generate byproducts.
The invention prepares a brand-new alloy catalyst with atom mixing level, uses monoatomic material as an intermediate product, and the synthesized nano alloy has the maximum mixing degree, namely the atom mixing level, thereby greatly improving the synergistic effect between metal and metal in the alloy. The whole synthesis process does not use any surfactant, and is an economical and simple method for preparing the atom mixed nano alloy. The composite material (platinum-palladium alloy catalyst) compounded with the alloy of the atomic mixing grade prepared by the invention shows excellent catalytic property in the reaction of catalyzing nitrobenzene hydrogenation to prepare aniline. The hydrogenation catalyst in the invention is rare earth oxide cerium dioxide (CeO)2) The supported platinum-palladium atom mixed-grade alloy catalyst is prepared by taking Pt and Pd as components in the alloy as a carrier, a monatomic material is taken as an intermediate product, the alloy is obtained by random agglomeration at a high temperature in a reducing atmosphere, and the reduction and agglomeration processes are carried out on the surface of cerium dioxide. The agglomeration process is thatThe high temperature ensures the randomness of agglomeration, which is the key to the formation of the atomic mixture grade alloy catalyst.
The cerium oxide carrier with oxygen vacancy is adopted, different monoatomic materials are uniformly dispersed and matched on the substrate material, the uniformity among the monoatomic materials is ensured, the further agglomeration process is carried out at high temperature, the randomness of agglomeration is ensured, and the randomness is the key for forming the atomic mixed level alloy catalyst, so that the cerium oxide composite material compounded with the atomic mixed level alloy is obtained. The invention greatly improves the synergy between metals in the alloy and improves the catalytic performance. The synthesis method provided by the invention has no participation of a surfactant, and is environment-friendly in synthesis; the synthetic method has simple and safe steps and short preparation period; the carrier is simple and easy to obtain, has very high application prospect, and is suitable for large-scale popularization and application. The components of the atomic mixed grade alloy/cerium dioxide carrier prepared by the method have the maximum synergistic effect, and the atomic mixed grade alloy/cerium dioxide carrier has high catalytic performance in a nitrobenzene hydrogenation process, and almost no by-product is generated.
Experimental results show that the composite material compounded with the atomic mixed alloy/cerium dioxide carrier is prepared, the components of the atomic mixed alloy/cerium dioxide carrier have the maximum synergistic effect, the conversion rate of nitrobenzene reaches 100% and the selectivity of aniline also reaches 97.23% in a catalytic nitrobenzene hydrogenation process.
For further illustration of the present invention, the following will describe in detail a composite material compounded with an atomic mixture grade alloy, and its preparation method and application in conjunction with the following examples, but it should be understood that these examples are implemented on the premise of the technical solution of the present invention, and the detailed embodiments and specific operation procedures are given, only for further illustration of the features and advantages of the present invention, and not for limitation of the claims of the present invention, and the protection scope of the present invention is not limited to the following examples.
In the active components of the catalyst, the platinum-palladium atom mixed grade nano alloy is marked as PtPd NAs (NAs: nano alloy), and the intermediate platinum-palladium single atom material is marked as Pt/Pd SAs (SAs: single atom). Nanometer particles of Pt, Rh and Pd and nanometer alloy of PtPdRh, PtRh and PdRh are synthesized at the same time to serve as a comparison sample, and different single-atom materials are marked as SA.
Cerium nitrate (Ce (NO)3)3·6H2O), chloroplatinic acid (H)2PtCl6·6H2O), palladium chloride (PdCl)2) Rhodium trichloride (RhCl)3·3H2O) ammonium bicarbonate (NH)4HCO3)
Synthesis and modification of cerium dioxide carrier
Taking Ce (NO)3)3·6H2Heating O in air at 350 deg.C for 4 hr to obtain CeO2Sample, then in hydrogen argon (H)210%, Ar 90%) at 200 ℃ for 1 hour to obtain ceria having a large number of oxygen vacancies as a carrier in the catalyst.
Example 1
Pt1Pd1Synthesis and catalytic characterization of NAs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH was adjusted and then 20mL of an aqueous platinum palladium solution, in which HPtCl was added4·6H2O and PdCl2The contents of (A) and (B) were all 2mg, and the resulting solution was centrifuged and dried directly in air at 70 ℃, washed with water several times after drying and centrifuged, and then dried in an oven at 70 ℃ for 12 hours to obtain Pt1/Pd1SAs, followed by hydrogen argon (H)210% of Ar 90%) at 800 ℃ for 2 hours to obtain Pt1Pd1NAs. The obtained loading amounts of Pt and Pd are close to 0.2 percent, and the mass ratio is 1:1.
the composite material compounded with the platinum-palladium nano alloy of the atomic mixture level prepared in the embodiment 1 of the invention is characterized.
Referring to fig. 1, fig. 1 is a transmission electron microscope photograph of a spherical aberration of a composite material compounded with an atomic mixture grade platinum-palladium nano alloy prepared by the present invention.
As shown in the spherical aberration electron microscope of fig. 1, platinum-palladium alloy nanoparticles have been formed on the ceria support.
The performance of the composite material compounded with the platinum-palladium nano alloy of the atomic mixture level prepared in the embodiment 1 of the invention is tested.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in example 1.
0.01g of Pt was weighed1Pd1NAs catalyst was added to a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPa H2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results show that the nitrobenzene conversion is 100% and the aniline selectivity is 97.23%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
TABLE 1
Reaction conditions are as follows: nitrobenzene (2mL), rotor speed (800r/min), temperature (100 ℃), H2Pressure (5 MPa).
Example 2
Pt1Pd1.5Synthesis and catalytic characterization of NAs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH was adjusted and then 20mL of an aqueous platinum palladium solution, in which HPtCl was added4·6H2O and PdCl2The contents of the Pt/Pd SAs are respectively 2mg and 4mg, then the obtained solution is dried in the air at 70 ℃ after being centrifuged, washed and centrifuged for several times after being dried, and then dried in an oven at 70 ℃ for 12 hours to obtain the Pt/Pd SAsFollowed by hydrogen argon mixture (H)210 percent of Ar 90 percent) is roasted for 2h at 800 ℃ to obtain PtPd NAs. The loading of Pt was then close to 0.2% and the loading of Pd was close to 0.3%, with a mass ratio of 1: 1.5.
The performance of the composite material compounded with the platinum-palladium alloy of the atomic mixture level prepared in the embodiment 2 of the invention is tested.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in example 2.
0.01g of Pt was weighed1Pd1.5NAs catalyst was added to a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPaH2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results show that the nitrobenzene conversion is 100% and the aniline selectivity is 94.21%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Example 3
Pt1.5Pd1Synthesis and catalytic characterization of NAs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH was adjusted and then 20mL of an aqueous platinum palladium solution, in which HPtCl was added4·6H2O and PdCl2The contents of (A) and (B) are respectively 4mg and 2mg, then the obtained solution is dried in air at 70 ℃ directly after centrifugation, washed and centrifuged for several times after drying, then dried in an oven at 70 ℃ for 12 hours to obtain Pt/Pd SAs, and then mixed gas of hydrogen and argon (H)210% and Ar 90%) at 800 deg.C for 2 hr to obtain PtPd NAs. The loading of Pt was then close to 0.3% and the loading of Pd was close to 0.2%, with a mass ratio of 1.5: 1.
The performance of the composite material compounded with the platinum-palladium alloy of the atomic mixture level prepared in the embodiment 3 of the invention was tested.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in example 3.
0.01g of Pt was weighed1.5Pd1NAs catalyst was added to a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPaH2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results showed that the nitrobenzene conversion was 95.21% and the aniline selectivity was 94.52%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Example 4
Pt1Pd1Rh1Synthesis and catalytic characterization of NAs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH was adjusted and then 20mL of an aqueous platinum palladium solution, in which HPtCl was added4·6H2O，PdCl2And RhCl3·3H2The O content is 2mg, the obtained solution is dried directly in air at 70 ℃ after being centrifuged, washed and centrifuged for several times after being dried, and then dried in an oven at 70 ℃ for 12 hours to obtain Pt1/Pd1/Rh1SAs, followed by hydrogen argon (H)210% of Ar 90%) at 800 ℃ for 2 hours to obtain Pt1Pd1Rh1NAs. The supported amounts of Pt, Pd and Rh obtained in this case were all close to 0.2%, and the mass ratio was 1:1: 1.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in example 4.
Weighing 0.01gPt1Pd1Rh1NAs catalyst was added to a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPaH2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results show that the nitrobenzene conversion is 75.12% and the aniline selectivity is 45.87%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Example 5
Pt1Rh1Synthesis and catalytic characterization of NAs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH is adjusted and then 20mL of an aqueous solution of platinum and rhodium are added, the HPtCl4·6H2O and RhCl3·3H2O content is 2mg and 2mg respectively, then centrifuging the obtained solution, directly drying in air at 70 ℃, washing with water and centrifuging for several times after drying, and then drying in an oven at 70 ℃ for 12 hours to obtain Pt1/Rh1SAs, followed by hydrogen argon (H)210% of Ar 90%) at 800 ℃ for 2 hours to obtain Pt1Rh1NAs. The supported amount of Rh in the obtained Pd was close to 0.2%, and the mass ratio was 1:1.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in example 5.
0.01g of Pt was weighed1Rh1NAs catalyst was added to a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPa H2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results showed that the nitrobenzene conversion was 25.53% and the aniline selectivity was 27.47%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Example 6
Pd1Rh1Synthesis and catalytic characterization of NAs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH is adjusted and then 20mL of an aqueous palladium rhodium solution, in which PdCl is added2And RhCl3·3H2O contents of 2mg and 2mg, respectively, centrifuging the obtained solution, drying in air at 70 deg.C, washing with water for several times, centrifuging, drying in oven at 70 deg.C for 12 hr to obtain Pd/Rh SAs, and adding hydrogen-argon mixture (H)210 percent of Ar and 90 percent of Pd) is roasted for 2 hours at 800 ℃ to obtain Pd1Rh1NAs. The supported amount of Rh in the obtained Pd was close to 0.2%, and the mass ratio was 1:1.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in example 6.
Weighing 0.01g Pd1Rh1NAs catalyst was added to a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPa H2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results show that the nitrobenzene conversion is 65.49% and the aniline selectivity is 78.46%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Comparative example 1
Synthesis and catalytic characterization of Pt NPs (NP: nanoparticles)
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH was adjusted and then 20mL of an aqueous solution containing platinum, in which HPtCl was added4·6H2The O content was 2mg, and the resulting solution was centrifuged and dried directly in air at 70 deg.C, washed with water several times after drying, and dried in an oven at 70 deg.C for 12 hours to give Pt SA, followed by hydrogen-argon mixture (H)210%, Ar 90%) at 800 ℃ for 2 hours to obtain Pt NP. The Pt loading of the sample obtained at this time was close to 0.2%.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in comparative example 1.
0.01g of Pt NP catalyst was weighed into a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPa H2Placing the mixture in an oil bath pot, stirring the mixture for 6 hours at the temperature of 100 ℃, centrifugally separating reaction products, and taking supernatant fluid for chromatographic analysis.
The results showed 23.18% nitrobenzene conversion and 69.56% aniline selectivity.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Comparative example 2
Synthesis and catalytic characterization of Pd NPs
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH is adjusted and then 20mL of an aqueous solution containing palladium, in which PdCl is added2The content of (b) is 2mg, the obtained solution is dried directly in air at 70 ℃ after centrifugation, washed with water several times after drying and then dried in an oven at 70 ℃ for 12 hours to obtain PdSA, and then the PdSA is obtained in a mixed gas of hydrogen and argon (H)210% Ar 90%) at 800 ℃ for 2 hours to obtain Pd NP. The sample obtained at this time had a Pd loading of approximately 0.2%.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in comparative example 2.
0.01g of the Pd NP catalyst was weighed into a 50mL autoclave containing 2mL of aniline, 5mL of isopropanol. Then is carried out for a plurality of timesCharging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPa H2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results showed that the nitrobenzene conversion was 74.43% and the aniline selectivity was 63.84%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
Comparative example 3
Synthesis and catalytic characterization of Rh NP
200mg of CeO2Dissolved in 40mL of water, stirred for half an hour and then treated by addition of NH4HCO3The pH is adjusted and then 20mL of an aqueous rhodium-containing solution are added, in which RhCl3·3H2O content of 2mg, then the resulting solution was centrifuged, directly dried in air at 70 deg.C, washed with water several times after drying, then dried in an oven at 70 deg.C for 12 hours to give Rh SA, then in a hydrogen-argon mixture (H)210% Ar 90%) at 800 ℃ for 2 hours to obtain Rh NP. The Rh loading of the sample obtained at this time was close to 0.2%.
An experiment for preparing aniline by hydrogenation of nitrobenzene was carried out using the catalyst obtained in comparative example 3.
0.01g of Rh NP catalyst was weighed into a 50mL autoclave containing 2mL aniline, 5mL isopropanol. Then performing multiple charging and discharging H2Ensuring that the air in the reaction kettle is basically exhausted, then introducing hydrogen, and finally ensuring 5MPa H2And the mixture is placed in an oil bath pot, stirred for 6 hours at the temperature of 100 ℃, and the reaction product is centrifugally separated, and supernatant is taken to be analyzed by chromatography.
The results show that the nitrobenzene conversion is 15.29% and the aniline selectivity is 97.23%.
Referring to table 1, table 1 shows the results of catalytic reactions of the composite material compounded with the alloy of atomic mixture grade prepared in the examples of the present invention and the nanoparticles prepared in the comparative examples.
The foregoing detailed description of the composite material compounded with an atomic mixture grade alloy for catalytic hydrogenation of nitrobenzene, and the method and application thereof, and the specific examples used herein to illustrate the principles and embodiments of the present invention, are provided only to aid in understanding the method and its core ideas, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any combination thereof. It should be noted that, for those skilled in the art, it is possible to make various improvements and modifications to the present invention without departing from the principle of the present invention, and those improvements and modifications also fall within the scope of the claims of the present invention. The scope of the invention is defined by the claims and may include other embodiments that occur to those skilled in the art. Such other embodiments are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims (10)
1. A composite material compounded with an atomic mixed grade alloy is characterized in that the composite material compounded with more than two kinds of monoatomic metals is obtained after heat treatment;
the composite material compounded with more than two kinds of monoatomic metals comprises a cerium oxide carrier with oxygen vacancies and more than two kinds of monoatomic metals compounded on the surface of the cerium oxide carrier.
2. The composite material of claim 1, wherein the monoatomic metal comprises a platinum monoatomic, palladium monoatomic, or rhodium monoatomic;
the cerium oxide carrier with oxygen vacancy is a cerium oxide carrier with oxygen vacancy on the surface;
the mass of each monoatomic metal accounts for 0.2-0.3% of the mass of the carrier;
the monoatomic metal is supported on the surface of the cerium oxide support in a monodispersed form.
3. The composite material of claim 1, wherein there are no interconnecting metallic bonds between the monoatomic metals;
the composite material comprises a cerium oxide carrier and an alloy of atomic level mixing grade compounded on the surface of the cerium oxide carrier;
the particle size of the cerium oxide carrier is 0.5-1 mu m;
the grain diameter of the alloy compounded on the surface of the cerium oxide carrier at the atomic level mixing level is 2-3 nm.
4. The composite material of claim 3, wherein the alloy comprises a platinum palladium alloy, a platinum rhodium alloy, a palladium rhodium alloy, or a platinum palladium rhodium alloy;
the mass ratio of metal elements in the alloy is 1;
the mass of the alloy accounts for 0.4-0.9% of the mass of the carrier.
5. A preparation method of a composite material compounded with an atomic mixed grade alloy is characterized by comprising the following steps:
A) mixing cerium oxide with oxygen vacancy, a dispersing agent, more than two monoatomic metal source water solutions and water to obtain a composite material compounded with more than two monoatomic metals;
B) and (3) under the condition of hydrogen or hydrogen mixed gas, carrying out heat treatment reduction on the composite material compounded with more than two monoatomic metals obtained in the step to obtain the composite material compounded with the atomic mixed grade alloy.
6. The production method according to claim 5, wherein the mass ratio of the metal element between the two or more monoatomic metal sources is 1;
the source of the monoatomic metal comprises a soluble salt of the monoatomic metal;
the dispersant comprises ammonium bicarbonate and/or ammonium carbonate;
the molar ratio of the dispersing agent to the monoatomic metal source is (20-30): 1.
7. the production method according to claim 5, wherein the two or more monoatomic metal source aqueous solutions include an aqueous solution of each of two or more monoatomic metal sources or a mixed aqueous solution of two or more monoatomic metal sources;
the pH value of the mixture is 1-2;
the mixing mode comprises stirring and mixing;
the mixing time is 30-60 min.
8. The method of claim 5, wherein the mixing further comprises one or more of centrifuging, drying, and washing;
the temperature of the heat treatment reduction is 600-800 ℃;
the time for heat treatment reduction is 2-12 h;
the composite material is a composite nano alloy catalyst.
9. The method according to claim 5, wherein the cerium oxide having oxygen vacancies is prepared by:
under the condition of hydrogen or hydrogen mixed gas, carrying out heat treatment on cerium oxide to obtain cerium oxide with oxygen vacancy;
the heat treatment time is 1-2 h;
the temperature of the heat treatment is 100-200 ℃.
10. Use of the composite material according to any one of claims 1 to 4 or the composite material prepared by the preparation method according to any one of claims 5 to 9 in the aspect of catalyzing hydrogenation of nitrobenzene to prepare aniline.
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| CN102091626A (en) * | 2010-12-31 | 2011-06-15 | 南京工业大学 | Catalyst for catalytic hydrogenation of p-nitrophenol and preparation method thereof |
| CN106824165A (en) * | 2017-04-17 | 2017-06-13 | 中国科学技术大学 | The preparation method of CeO 2 supporting high-dispersion nano catalyst |
| CN108855071A (en) * | 2018-07-12 | 2018-11-23 | 杭州晟睿新材料有限公司 | A kind of preparation method and applications of cerium oxide support type high-dispersion nano catalyst |
| CN111135822A (en) * | 2018-11-06 | 2020-05-12 | 中国科学院大连化学物理研究所 | Application of high-dispersion noble metal supported catalyst in hydrogenation of aromatic nitro compound |
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| CN102091626A (en) * | 2010-12-31 | 2011-06-15 | 南京工业大学 | Catalyst for catalytic hydrogenation of p-nitrophenol and preparation method thereof |
| CN106824165A (en) * | 2017-04-17 | 2017-06-13 | 中国科学技术大学 | The preparation method of CeO 2 supporting high-dispersion nano catalyst |
| CN108855071A (en) * | 2018-07-12 | 2018-11-23 | 杭州晟睿新材料有限公司 | A kind of preparation method and applications of cerium oxide support type high-dispersion nano catalyst |
| CN111135822A (en) * | 2018-11-06 | 2020-05-12 | 中国科学院大连化学物理研究所 | Application of high-dispersion noble metal supported catalyst in hydrogenation of aromatic nitro compound |
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Application publication date: 20200925 |