CN114588894A - Rhodium-based catalyst, and preparation method and application thereof - Google Patents
Rhodium-based catalyst, and preparation method and application thereof Download PDFInfo
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- CN114588894A CN114588894A CN202210287759.7A CN202210287759A CN114588894A CN 114588894 A CN114588894 A CN 114588894A CN 202210287759 A CN202210287759 A CN 202210287759A CN 114588894 A CN114588894 A CN 114588894A
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- 239000010948 rhodium Substances 0.000 title claims abstract description 173
- 229910052703 rhodium Inorganic materials 0.000 title claims abstract description 167
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 title claims abstract description 166
- 239000003054 catalyst Substances 0.000 title claims abstract description 160
- 238000002360 preparation method Methods 0.000 title claims abstract description 35
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Inorganic materials O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims abstract description 46
- 239000002243 precursor Substances 0.000 claims abstract description 44
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 42
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 31
- 150000003283 rhodium Chemical class 0.000 claims abstract description 31
- 239000012266 salt solution Substances 0.000 claims abstract description 31
- 238000010438 heat treatment Methods 0.000 claims abstract description 30
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 17
- 238000000151 deposition Methods 0.000 claims abstract description 11
- 238000002156 mixing Methods 0.000 claims abstract description 11
- 239000000243 solution Substances 0.000 claims description 23
- 239000002245 particle Substances 0.000 claims description 22
- 239000007788 liquid Substances 0.000 claims description 21
- 238000006243 chemical reaction Methods 0.000 claims description 20
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 19
- 238000001704 evaporation Methods 0.000 claims description 18
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 18
- VXNYVYJABGOSBX-UHFFFAOYSA-N rhodium(3+);trinitrate Chemical compound [Rh+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VXNYVYJABGOSBX-UHFFFAOYSA-N 0.000 claims description 16
- 238000000231 atomic layer deposition Methods 0.000 claims description 15
- 238000000227 grinding Methods 0.000 claims description 11
- 238000000034 method Methods 0.000 claims description 11
- 239000012071 phase Substances 0.000 claims description 9
- 229910052814 silicon oxide Inorganic materials 0.000 claims description 8
- 229910021604 Rhodium(III) chloride Inorganic materials 0.000 claims description 6
- 239000007791 liquid phase Substances 0.000 claims description 6
- SONJTKJMTWTJCT-UHFFFAOYSA-K rhodium(iii) chloride Chemical compound [Cl-].[Cl-].[Cl-].[Rh+3] SONJTKJMTWTJCT-UHFFFAOYSA-K 0.000 claims description 6
- 239000002135 nanosheet Substances 0.000 claims description 5
- 239000002077 nanosphere Substances 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 239000004408 titanium dioxide Substances 0.000 claims description 4
- 239000002073 nanorod Substances 0.000 claims description 3
- 238000004321 preservation Methods 0.000 claims description 3
- 239000012808 vapor phase Substances 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims 3
- 230000004048 modification Effects 0.000 abstract description 21
- 238000012986 modification Methods 0.000 abstract description 21
- 230000000694 effects Effects 0.000 abstract description 20
- 230000003197 catalytic effect Effects 0.000 abstract description 15
- 239000002105 nanoparticle Substances 0.000 abstract description 14
- 230000009286 beneficial effect Effects 0.000 abstract description 7
- 230000003647 oxidation Effects 0.000 abstract description 7
- 238000007254 oxidation reaction Methods 0.000 abstract description 7
- 238000003746 solid phase reaction Methods 0.000 abstract description 7
- 238000004873 anchoring Methods 0.000 abstract description 6
- 239000000969 carrier Substances 0.000 abstract description 6
- 230000002195 synergetic effect Effects 0.000 abstract description 6
- 230000032683 aging Effects 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 18
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 14
- 230000005540 biological transmission Effects 0.000 description 10
- 238000003917 TEM image Methods 0.000 description 7
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000001000 micrograph Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 238000004220 aggregation Methods 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
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- 230000002349 favourable effect Effects 0.000 description 2
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- 238000002203 pretreatment Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 150000003624 transition metals Chemical class 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 235000013162 Cocos nucifera Nutrition 0.000 description 1
- 244000060011 Cocos nucifera Species 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- 235000009827 Prunus armeniaca Nutrition 0.000 description 1
- 244000018633 Prunus armeniaca Species 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 230000004931 aggregating effect Effects 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- 230000006315 carbonylation Effects 0.000 description 1
- 238000005810 carbonylation reaction Methods 0.000 description 1
- 238000007385 chemical modification Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
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- 238000000635 electron micrograph Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 238000007210 heterogeneous catalysis Methods 0.000 description 1
- 238000007037 hydroformylation reaction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 229910052809 inorganic oxide Inorganic materials 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910000510 noble metal Inorganic materials 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 241000894007 species Species 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 229910003158 γ-Al2O3 Inorganic materials 0.000 description 1
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- 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
- B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
- B01J23/46—Ruthenium, rhodium, osmium or iridium
- B01J23/464—Rhodium
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- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8628—Processes characterised by a specific catalyst
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- 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
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- 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
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- B01J35/00—Catalysts, in general, characterised by their form or physical properties
- B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
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- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/08—Heat treatment
- B01J37/082—Decomposition and pyrolysis
- B01J37/088—Decomposition of a metal salt
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Abstract
The invention provides a rhodium-based catalyst, a preparation method and an application thereof, wherein the preparation method comprises the following steps: (1) depositing an oxide on the carrier by an atomic layer to obtain a precursor; (2) mixing the precursor obtained in the step (1) with a rhodium salt solution, and carrying out heat treatment to obtain a rhodium-based catalyst; the carrier comprises any one or the combination of at least two of alumina, silica or zirconium dioxide; the support is of a different kind than the oxide. According to the preparation method of the rhodium-based catalyst, the low-content oxide modification layer can be deposited on the atomic layers of different carriers, the oxide modification layer deposited on the atomic layers can generate a synergistic effect with the active component rhodium, and the catalytic activity of the catalyst at low temperature is improved; the oxide modification layer is also beneficial to anchoring atomic-level dispersed rhodium nanoparticles, inhibits the solid-phase reaction of the rhodium nanoparticles and the carrier at high temperature, improves the low-temperature activity of the catalyst and further improves the stability of the catalyst under the high-temperature oxidation condition.
Description
Technical Field
The invention belongs to the technical field of heterogeneous catalysis, relates to a rhodium-based catalyst, and particularly relates to a rhodium-based catalyst and a preparation method and application thereof.
Background
Nitrogen Oxides (NO)x) Is an environmental pollutant which can cause acid rain and photochemical smog and is one of the main pollutants in the atmosphere. With the improvement of the exhaust emission standard, further research and development are carried out on catalysts with high thermal stability and low-temperature catalytic activity for reducing NOxThe discharge is of great significance. Reduction of NO with CO can remove both components of the flue gas simultaneously and reduce the additional cost of purchasing and transporting the reductant for storage, thus becoming an attractive denitration technology. To date, rhodium-based catalysts have been used for their NOxThe high catalytic activity of the reduction is widely studied and the stability of the catalyst is particularly important when noble metals are used in the active phase of the catalyst. Under the high-temperature oxidation condition, the catalyst carrier and the active components of the nano particles are easy to aggregate and sinter, so that the active surface area is reduced and the catalytic activity is reduced. In the case of rhodium (Rh) -based catalysts, the main factors that lead to the reduction of their activity are sintering aggregation of Rh and solid-phase reaction between Rh and inorganic oxide support after high-temperature aging. Furthermore, in view of the cold start problem, NO is increasedxThe low temperature activity of the reduction catalyst is also of critical importance. In order to enhance the activity and thermal stability of the catalyst, efforts have been made for a long time to increase the intrinsic activity and sintering resistance of the catalyst by changing the interaction of the active component with the support through a chemical modification method, but the catalyst activity and stability are often difficult to balance at the same time.
CN110354852A discloses a supported rhodium-based catalyst, a preparation method thereof and a method for preparing C from synthesis gas2Use in oxygenates. The supported rhodium-based catalyst comprises a main active component and a carrier; wherein the main active component contains rhodium element and manganese element, and the weight percentage of the rhodium element and the manganese element in the supported rhodium-based catalyst is 0.01-20.0 wt%(ii) a The carrier is at least one of silicon oxide, aluminum oxide and titanium oxide. However, the supported rhodium-based catalyst has high rhodium content, so that the cost of the supported rhodium-based catalyst is high, and meanwhile, the supported rhodium-based catalyst obtained by the preparation method has low rhodium dispersion degree and poor metal rhodium utilization rate.
CN106824295A discloses a rhodium-based catalyst, application thereof and a carrier pretreatment method of the rhodium-based catalyst, and specifically, the carrier is impregnated with an organic reagent and then dried to obtain a treated carrier. The invention also provides a rhodium-based catalyst obtained by treating the carrier by the carrier pretreatment method and application of the rhodium-based catalyst in olefin hydroformylation reaction. However, the preparation method of the rhodium-based catalyst adopts a large amount of toxic organic matters, which can cause pollution to the environment,
CN106140156A discloses an activated carbon-supported rhodium-based catalyst, a preparation method thereof and application thereof in the reaction of preparing methyl acetate by carbonylation of methanol, wherein the rhodium-based catalyst consists of two parts of a main active component and a carrier, the main active component is Rh and a transition metal assistant, the transition metal is one or more of Ir, La, Pt, Pd, Ce, Ru, Fe, Co, Ni, Mn and Zr, and the carrier is coconut shell carbon or apricot shell carbon. However, the activated carbon-supported rhodium-based catalyst has poor dispersibility of Rh, resulting in poor stability of the activated carbon-supported rhodium-based catalyst.
The prior rhodium-based catalyst and the preparation method thereof have certain defects, and have the problems of complex preparation method, difficult simultaneous maintenance of higher low-temperature activity and thermal stability of the rhodium-based catalyst and low dispersion degree of rhodium. Therefore, the development of a novel rhodium-based catalyst, a preparation method and application thereof are very important.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide a rhodium-based catalyst and a preparation method and application thereof, the preparation method of the rhodium-based catalyst can deposit low-content oxide modification layers on different carriers by an atomic layer, and the oxide modification layers deposited by the atomic layer can generate a synergistic effect with an active component rhodium, so that the catalytic activity of the catalyst at low temperature is improved; the oxide modification layer is also beneficial to anchoring atomic-level dispersed rhodium nanoparticles, inhibits the solid-phase reaction of the rhodium nanoparticles and the carrier at high temperature, improves the low-temperature activity of the catalyst and further improves the stability of the catalyst under the high-temperature oxidation condition.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a process for the preparation of a rhodium-based catalyst, said process comprising the steps of:
(1) depositing an oxide on the carrier by an atomic layer to obtain a precursor;
(2) mixing the precursor obtained in the step (1) with a rhodium salt solution, and carrying out heat treatment to obtain a rhodium-based catalyst;
the carrier comprises any one or the combination of at least two of alumina, silica or zirconium dioxide; the support is of a different kind than the oxide.
The support of the present invention comprises any one or a combination of at least two of alumina, silica or zirconia, and typical but non-limiting combinations include a combination of alumina and silica, a combination of silica and zirconia, a combination of alumina and zirconia, or a combination of alumina, silica and zirconia.
According to the preparation method of the rhodium-based catalyst, the low-content oxide modification layer can be deposited on the atomic layers of different carriers, the oxide modification layer deposited on the atomic layers can generate a synergistic effect with the active component rhodium, and the catalytic activity of the catalyst at low temperature is improved; the oxide modification layer is also beneficial to anchoring atomic-level dispersed rhodium nanoparticles, inhibits the solid-phase reaction of the rhodium nanoparticles and the carrier at high temperature, improves the low-temperature activity of the catalyst and further improves the stability of the catalyst under the high-temperature oxidation condition.
Preferably, the morphology of the alumina, silica or zirconia of step (1) is independently any one of or a combination of at least two of nanocubes, nanosheets, nanospheres or nanorods, respectively, typical but non-limiting combinations include combinations of nanocubes and nanosheets, combinations of nanosheets and nanospheres, combinations of nanospheres and nanorods, or combinations of nanocubes, nanosheets and nanospheres.
Preferably, the oxide in step (1) comprises any one or a combination of at least two of alumina, silica, zirconia, titania or lanthanum trioxide, and typical but non-limiting combinations include a combination of alumina and silica, a combination of silica and zirconia, a combination of zirconia and titania, a combination of titania and lanthanum trioxide, a combination of alumina, silica and zirconia, or a combination of alumina, silica, zirconia and titania.
Preferably, the mass ratio of the support to the oxide in step (1) is (93-49990): 5, and may be, for example, 93:5, 100:5, 200:5, 500:5, 800:5, 1000:5, 3000:5, 5000:5, 8000:5, 10000:5, 20000:5, 30000:5, 40000:5, 42000:5, 45000:5, 47000:5, 49000:5 or 49990:5, but is not limited to the recited values, and other values not recited within the range of values are also applicable.
Preferably, the carrier in the step (1) has an average particle diameter of 5-100 nm and a specific surface area of 80-200 m2/g。
The carrier of step (1) is defined to have an average particle diameter of 5 to 100nm, and may be, for example, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm or 100nm, but is not limited to the recited values, and other values not recited within the range of the values are also applicable; when the average particle size of the carrier is smaller, the distribution of active components of the catalyst is facilitated, and the catalytic activity is improved, but when the average particle size of the carrier is smaller, the preparation cost of the carrier is increased, and the cost is not controlled; when the average particle diameter of the carrier is too large, the distribution of the catalyst active component is not favorable, resulting in a decrease in the catalyst activity.
The invention defines the steps(1) The specific surface area of the carrier is 80-200 m2Per g, may be, for example, 80m2/g、90m2/g、100m2/g、110m2/g、120m2/g、130m2/g、140m2/g、150m2/g、160m2/g、170m2/g、180m2/g、190m2(ii)/g or 200m2In the following description,/g is not limited to the values listed, but other values not listed in the numerical range are equally applicable.
Preferably, the atomic layer deposition in step (1) includes vapor phase atomic layer deposition and/or liquid phase atomic layer deposition.
According to the invention, the ultralow-content oxide modification layer is modified on the surface of the carrier by adopting a vapor atomic layer deposition and/or liquid atomic layer deposition method, and the oxide can be dispersed on the carrier more uniformly by the vapor atomic layer deposition and the liquid atomic layer deposition, so that the stability of the rhodium-based catalyst is improved.
Preferably, the rhodium salt solution of step (2) comprises a rhodium nitrate solution and/or a rhodium trichloride solution.
The rhodium salt solution is preferably a rhodium nitrate solution, and rhodium nitrate is decomposed at high temperature and does not generate residual impurities in the rhodium-based catalyst.
Preferably, the rhodium salt solution of step (2) has a concentration of 0.01mol/L to 0.1mol/L, for example, 0.01mol/L, 0.012mol/L, 0.015mol/L, 0.018mol/L, 0.02mol/L, 0.03mol/L, 0.04mol/L, 0.05mol/L, 0.06mol/L, 0.07mol/L, 0.08mol/L, 0.09mol/L, or 0.1mol/L, but not limited to the recited values, and other values not recited in the recited values are also applicable; when the concentration of the rhodium salt solution is higher, the particle size of the active component is larger, and the catalytic activity is reduced; when the concentration of the rhodium salt solution is too low, the rhodium-based catalyst cannot be successfully prepared.
Preferably, the solid-to-liquid ratio of the precursor to the rhodium salt solution in the step (2) is (10-500): 1, and the unit of the solid-to-liquid ratio is g/mL.
The solid-to-liquid ratio of the precursor to the rhodium salt solution is limited to (10-500): 1, and can be, for example, 10:1, 20:1, 30:1, 50:1, 70:1, 100:1, 150:1, 200:1, 300:1, 400:1 or 500:1, but the invention is not limited to the recited values, and other values not recited in the numerical range are also applicable; when the mass ratio of the current precursor to the rhodium salt solution is higher, the rhodium salt solution and the precursor cannot be fully mixed, so that rhodium can only be adhered to part of the precursor; when the mass ratio of the precursor to the rhodium salt solution is low, the dispersity of the active components of the catalyst is reduced, and the catalytic activity of the catalyst is reduced.
Preferably, the heat treatment in step (2) includes temperature increase and heat preservation in an air atmosphere.
Preferably, the heating rate of the temperature rise is 5-10 ℃/min, and the end point temperature is 300-600 ℃.
The present invention limits the heating rate of 5 ℃/min to 10 ℃/min, for example, 5 ℃/min, 6 ℃/min, 7 ℃/min, 8 ℃/min, 9 ℃/min or 10 ℃/min, but the present invention is not limited to the values listed, and other values not listed in the range of the values are also applicable.
Preferably, the time for the heat preservation is 3 to 6 hours, for example, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the heat treatment in step (2) further comprises evaporating to dryness before warming, wherein the evaporating temperature is 20-50 ℃, for example, 20 ℃, 22 ℃, 25 ℃, 27 ℃, 30 ℃, 32 ℃, 35 ℃, 37 ℃, 40 ℃, 42 ℃, 45 ℃, 47 ℃ or 50 ℃, but is not limited to the recited values, and other unrecited values in the range of the values are also applicable.
The evaporation temperature is limited to be 20-50 ℃, when the evaporation temperature is higher, the solvent in the rhodium salt solution is quickly volatilized, and the dispersibility of rhodium in the prepared rhodium-based catalyst is poor, so that the performance of the rhodium-based catalyst is poor; when the temperature for evaporating is low, the solvent in the rhodium salt solution needs a long time to volatilize, and the preparation efficiency of the rhodium-based catalyst is low.
Preferably, the heat treatment of step (2) further comprises grinding between evaporating and raising the temperature.
Preferably, as a preferred technical solution of the preparation method of the first aspect, the preparation method comprises the steps of:
(1) depositing an oxide on a carrier through a gas-phase atomic layer deposition and/or a liquid-phase atomic layer deposition, wherein the mass ratio of the carrier to the oxide is (93-49990): 5, and obtaining a precursor;
(2) mixing the precursor obtained in the step (1) with a rhodium salt solution with the concentration of 0.010-1 mol/L, wherein the solid-to-liquid ratio of the precursor to the rhodium salt solution is (10-500): 1, the unit of the solid-to-liquid ratio is g/mL, evaporating to dryness at 20-50 ℃, grinding, heating to 300-600 ℃ at the heating rate of 5-10 ℃/min, and preserving heat for 3-6 h to obtain the rhodium-based catalyst;
the carrier comprises any one or the combination of at least two of alumina, silica or zirconium dioxide; the support is of a different kind than the oxide.
In a second aspect, the present invention provides a rhodium-based catalyst obtained by the preparation method of the first aspect.
Preferably, the mass fraction of the carrier is 93-99.98 wt%, the mass fraction of the oxide is 0.01-5 wt%, and the mass fraction of the rhodium is 0.01-2 wt%.
The present invention defines a mass fraction of the carrier as 93 to 99.98 wt%, and for example, 93 wt%, 93.5 wt%, 94 wt%, 94.5 wt%, 95 wt%, 95.5 wt%, 96 wt%, 96.5 wt%, 97 wt%, 97.5 wt%, 98 wt%, 98.5 wt%, 99 wt%, 99.5 wt%, 99.9 wt%, or 99.98 wt%, but is not limited to the recited values, and other values not recited within the range of values are also applicable.
The present invention defines an oxide mass fraction of 0.01 to 5 wt%, and for example, it may be 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.07 wt%, 0.1 wt%, 0.15 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, or 5 wt%, but is not limited to the recited values, and other non-recited values within the range of values are also applicable.
In a third aspect, the invention provides a use of a rhodium-based catalyst as described in the second aspect for a CO-SCR reaction.
Compared with the prior art, the invention has the following beneficial effects:
according to the preparation method of the rhodium-based catalyst, the low-content oxide modification layer can be deposited on the atomic layers of different carriers, the oxide modification layer deposited on the atomic layers can generate a synergistic effect with the active component rhodium, and the catalytic activity of the catalyst at low temperature is improved; the oxide modification layer is also beneficial to anchoring atomic-level dispersed rhodium nanoparticles, inhibits the solid-phase reaction of the rhodium nanoparticles and the carrier at high temperature, improves the low-temperature activity of the catalyst and further improves the stability of the catalyst under the high-temperature oxidation condition.
Drawings
Figure 1 is an XRD diffractogram of the rhodium-based catalysts of example 1 and comparative example 1.
Figure 2 is an XRD diffractogram of the rhodium-based catalysts of example 1 and comparative example 1 after high temperature aging.
Fig. 3 is a transmission electron micrograph of the rhodium-based catalyst in comparative example 1.
Fig. 4 is a transmission electron micrograph of the rhodium-based catalyst of comparative example 1 after high temperature aging.
Figure 5 is a transmission electron micrograph of a high angle annular dark field of the rhodium-based catalyst of comparative example 1.
Figure 6 is an image of a high angle annular dark field transmission electron microscope of the rhodium-based catalyst of comparative example 1 after high temperature aging.
Fig. 7 is a transmission electron micrograph of the rhodium-based catalyst in example 1.
FIG. 8 is a transmission electron micrograph of the rhodium-based catalyst of example 1 after high temperature aging.
Figure 9 is a transmission electron micrograph of a high angle annular dark field of the rhodium-based catalyst of example 1.
Figure 10 is an electron micrograph of a high angle annular dark field transmission electron micrograph of the rhodium-based catalyst of example 1 after high temperature aging.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
Example 1
This example provides a rhodium-based catalyst comprising alumina (Al)2O3) Zirconium dioxide (ZrO)2) And rhodium; in percentage by mass, the mass fraction of the aluminum oxide is 98 wt%, the mass fraction of the zirconium dioxide is 0.05 wt%, and the mass fraction of the rhodium is 1.95 wt%.
The preparation method of the rhodium-based catalyst comprises the following steps:
(1) the average particle diameter is 50nm, and the specific surface area is 130m2Depositing zirconium dioxide on the aluminum oxide by a gas-phase atomic layer, wherein the mass ratio of the aluminum oxide to the zirconium dioxide is 9800:5, and obtaining a precursor;
(2) and (2) mixing the precursor obtained in the step (1) with a rhodium nitrate solution with the concentration of 0.1mol/L, wherein the mass ratio of the precursor to the rhodium nitrate solution is 40:1, the unit of solid-to-liquid ratio is g/mL, evaporating to dryness at 40 ℃, grinding, heating to 550 ℃ at the heating rate of 7.5 ℃/min, and preserving heat for 4.5 hours to obtain the rhodium-based catalyst.
Example 2
This embodiment provides a rhodium-based catalyst comprising alumina, titania, and rhodium; in percentage by mass, the mass fraction of the alumina is 98.5 wt%, the mass fraction of the titanium dioxide is 0.1 wt%, and the mass fraction of the rhodium is 1.4 wt%.
The preparation method of the rhodium-based catalyst comprises the following steps:
(1) the average particle diameter is 30nm, and the specific surface area is 160m2Depositing titanium dioxide on the alumina per gram by a gas phase atomic layer, wherein the mass ratio of the alumina to the titanium dioxide is 4925:5, and obtaining a precursor;
(2) and (2) mixing the precursor obtained in the step (1) with a rhodium nitrate solution with the concentration of 0.5mol/L, wherein the mass ratio of the precursor to the rhodium nitrate solution is 200:1, the unit of solid-to-liquid ratio is g/mL, evaporating to dryness at 30 ℃, grinding, heating to 450 ℃ at the heating rate of 9 ℃/min, and preserving heat for 4 hours to obtain the rhodium-based catalyst.
Example 3
This example provides a rhodium-based catalyst comprising silicon oxide, lanthanum oxide, and rhodium; by mass percent, the mass fraction of the silicon oxide is 96 wt%, the mass fraction of the lanthanum oxide is 3.5 wt%, and the mass fraction of the rhodium is 0.5 wt%.
The preparation method of the rhodium-based catalyst comprises the following steps:
(1) the average particle diameter is 80nm, and the specific surface area is 95m2Depositing oxide on the silicon oxide of per gram by a gas phase atomic layer, wherein the mass ratio of the silicon oxide to the lanthanum oxide is 137:5, and obtaining a precursor;
(2) and (2) mixing the precursor obtained in the step (1) with a rhodium nitrate solution with the concentration of 0.05mol/L, wherein the mass ratio of the precursor to the rhodium nitrate solution is 70:1, the unit of solid-to-liquid ratio is g/mL, evaporating to dryness at 35 ℃, grinding, heating to 400 ℃ at the heating rate of 6 ℃/min, and keeping the temperature for 5 hours to obtain the rhodium-based catalyst.
Example 4
This embodiment provides a rhodium-based catalyst comprising zirconium dioxide, aluminum oxide, and rhodium; the mass fraction of the zirconium dioxide is 99.98 wt%, the mass fraction of the aluminum oxide is 0.01 wt%, and the mass fraction of the rhodium is 0.01 wt%.
The preparation method of the rhodium-based catalyst comprises the following steps:
(1) the average particle diameter is 5nm, the specific surface area is 200m2Depositing aluminum oxide on/g zirconium dioxide by a liquid-phase atomic layer, wherein the mass ratio of the zirconium dioxide to the aluminum oxide is 49990:5, and obtaining a precursor;
(2) and (2) mixing the precursor obtained in the step (1) with a rhodium trichloride solution with the concentration of 0.01mol/L, wherein the mass ratio of the precursor to the rhodium trichloride solution is 400:1, the unit of solid-to-liquid ratio is g/mL, evaporating to dryness at 20 ℃, grinding, heating to 300 ℃ at the heating rate of 5 ℃/min, and preserving heat for 6 hours to obtain the rhodium-based catalyst.
Example 5
This example provides a rhodium-based catalyst comprising alumina, lanthanum oxide, and rhodium; in percentage by mass, the mass fraction of the alumina is 93 wt%, the mass fraction of the lanthanum oxide is 5 wt%, and the mass fraction of the rhodium is 2 wt%.
The preparation method of the rhodium-based catalyst comprises the following steps:
(1) the average particle diameter is 100nm, and the specific surface area is 80m2Depositing lanthanum sesquioxide on per gram of aluminum oxide by a liquid phase atomic layer, wherein the mass ratio of the aluminum oxide to the lanthanum sesquioxide is 93:5, and obtaining a precursor;
(2) and (2) mixing the precursor obtained in the step (1) with a rhodium trichloride solution with the concentration of 1mol/L, wherein the mass ratio of the precursor to the rhodium trichloride solution is 240:1, the unit of solid-to-liquid ratio is g/mL, evaporating to dryness at 50 ℃, grinding, heating to 600 ℃ at the heating rate of 10 ℃/min, and preserving heat for 3 hours to obtain the rhodium-based catalyst.
Example 6
This embodiment provides a rhodium-based catalyst comprising alumina, silica, zirconia, and rhodium; the mass fraction of the aluminum oxide is 53 wt%, the mass fraction of the aluminum oxide is 46 wt%, the mass fraction of the zirconium dioxide is 0.07 wt%, and the mass fraction of the rhodium is 0.93 wt%.
The preparation method of the rhodium-based catalyst comprises the following steps:
(1) the average particle diameter is 45nm, and the specific surface area is 148m2Depositing zirconium dioxide on a mixture of aluminum oxide and silicon oxide in a vapor-phase atomic layer mode, wherein the mass ratio of the aluminum oxide to the silicon oxide in the mixture is 53:46, and the mass ratio of the mixture to the zirconium dioxide is 9900:7 to obtain a precursor;
(2) and (2) mixing the precursor obtained in the step (1) with a rhodium nitrate solution with the concentration of 0.08mol/L, wherein the mass ratio of the precursor to the rhodium nitrate solution is 90:1, the unit of solid-to-liquid ratio is g/mL, evaporating to dryness at 35 ℃, grinding, heating to 500 ℃ at the heating rate of 8 ℃/min, and keeping the temperature for 5 hours to obtain the rhodium-based catalyst.
Example 7
This example provides a rhodium-based catalyst, which is the same as in example 1 except that the mass ratio of alumina to zirconia in step (1) is 50: 5.
Example 8
This example provides a rhodium-based catalyst, which is the same as example 1 except that the mass ratio of alumina to zirconia in step (1) is 60000: 5.
Example 9
This example provides a rhodium-based catalyst having an average particle size of 2nm and a specific surface area of 280m, except that in step (1), alumina was used2The rest of the process was the same as in example 1 except for the amount of/.
Example 10
This example provides a rhodium-based catalyst having an average particle size of 150nm and a specific surface area of 65m, except that in step (1), alumina was used2The rest of the process was the same as in example 1 except for the amount of/.
Example 11
This example provides a rhodium-based catalyst, which was the same as in example 1 except that the concentration of the rhodium nitrate solution in step (2) was 0.005 mol/L.
Example 12
This example provides a rhodium-based catalyst, which was the same as in example 1 except that the concentration of the rhodium nitrate solution in step (2) was 0.2 mol/L.
Example 13
This example provides a rhodium-based catalyst, which is the same as that of example 1 except that the solid-to-liquid ratio of the precursor to the rhodium salt solution is 5:1, and the unit of the solid-to-liquid ratio is g/mL.
Example 14
This example provides a rhodium-based catalyst, which is the same as that of example 1 except that the solid-to-liquid ratio of the precursor to the rhodium salt solution is 800:1, and the unit of the solid-to-liquid ratio is g/mL.
Comparative example 1
The present comparative example provides a rhodium-based catalyst, the preparation method of which comprises the following steps: the average particle diameter is 50nm, and the specific surface area is 130m2Alumina in a ratio of 0.1 mol/L/gMixing the rhodium nitrate solution, wherein the mass ratio of the alumina to the rhodium nitrate solution is 60:1, evaporating to dryness at 40 ℃, grinding, heating to 550 ℃ at the heating rate of 7.5 ℃/min, and keeping the temperature for 4.5 hours to obtain the rhodium-based catalyst.
Comparative example 2
This comparative example provides a rhodium-based catalyst identical to that of example 1 except that the zirconium dioxide was replaced with an equivalent mass of alumina.
High temperature aging tests were conducted with the rhodium-based catalysts described in examples 1-14 and comparative examples 1 and 2, the high temperature aging test method comprising: placing the rhodium-based catalyst in a muffle furnace at 1050 ℃ for 10min to obtain an aged rhodium-based catalyst;
x-ray diffractometrically measuring the X-ray patterns of the rhodium-based catalysts of example 1 and comparative example 1, as shown in fig. 1; measuring the X-ray patterns of the rhodium-based catalysts in the example 1 and the comparative example 1 after high-temperature aging by using an X-ray diffractometer, as shown in figure 2, and observing the appearances of the rhodium-based catalysts and the rhodium-based catalysts in the comparative example 1 after high-temperature aging by using a transmission electron microscope, as shown in figures 3 and 4; observing the transmission electron microscope images of the rhodium-based catalyst and the rhodium-based catalyst in the comparative example 1 by a scanning transmission electron microscope, wherein the images of the high-angle annular dark field transmission electron microscope images are shown in figures 5 and 6; observing the appearances of the rhodium-based catalyst and the rhodium-based catalyst after high-temperature aging in example 1 by using a transmission electron microscope, as shown in fig. 7 and 8; observing the high-angle annular dark-field transmission electron microscope images of the rhodium-based catalyst and the rhodium-based catalyst after high-temperature aging in example 1 by using a scanning transmission electron microscope, as shown in figures 9 and 10;
the rhodium-based catalysts described in examples 1-14 and comparative examples 1 and 2 were used for CO denitration reactions: loading rhodium-based catalyst into a fixed bed test bed, introducing test gas, testing at specified temperature, detecting components in tail gas by an online mass spectrometer, and calculating NOxConversion rate; wherein, the test airspeed 60000h-1The test gas composition was 1000ppm of NO and 1000ppm of CO, and the equilibrium gas was Ar, and the NO conversion rates of the rhodium-based catalyst at 150 ℃, 200 ℃, 250 ℃ and 300 ℃ were measured, respectively. The NO conversion rates for CO-SCR denitration of rhodium-based catalysts at different reaction temperatures are shown in table 1; different reaction temperaturesThe NO conversion of CO-SCR denitration after high temperature aging of the lower rhodium-based catalyst is shown in table 2.
TABLE 1
TABLE 2
From tables 1, 2 and FIGS. 1-10, we can see:
(1) the rhodium-based catalysts obtained in examples 1 to 6 have a high NO conversion rate in CO-SCR denitration, and the rhodium-based catalysts have a high NO conversion rate in CO-SCR denitration after high-temperature aging, and have a low phase transition degree after high-temperature aging; according to the preparation method of the rhodium-based catalyst, the low-content oxide modification layer can be deposited on the atomic layers of different carriers, the oxide modification layer deposited on the atomic layers can generate a synergistic effect with the active component rhodium, and the catalytic activity of the catalyst at low temperature is improved; the oxide modification layer is also beneficial to anchoring atomic-level dispersed rhodium nanoparticles, inhibits the solid-phase reaction of the rhodium nanoparticles and the carrier at high temperature, improves the low-temperature activity of the catalyst and further improves the stability of the catalyst under the high-temperature oxidation condition.
(2) As can be seen from the comparison of example 1 with examples 7 and 8, the mass ratio of the carrier to the oxide according to the present invention affects the NO conversion rate, and the higher or lower mass ratio of the carrier to the oxide causes the NO conversion rate to decrease; after the carrier is modified by the atomic layer deposition oxide, the low-temperature activity of the catalyst is obviously improved, and the proper oxide modification layer can effectively improve the low-temperature activity of the catalyst.
(3) As can be seen from a comparison of example 1 with examples 9 and 10, the average particle size of the support according to the present invention affects the NO conversion; when the average particle size of the carrier is smaller, the distribution of active components of the catalyst is facilitated, and the catalytic activity is improved, but when the average particle size of the carrier is smaller, the preparation cost of the carrier is increased, and the cost is not controlled; when the average particle diameter of the carrier is too large, the distribution of the catalyst active component is not favorable, resulting in a decrease in the catalyst activity.
(4) As can be seen from the comparison between example 1 and examples 11 and 12, the concentration of the rhodium salt solution of the invention affects the NO conversion rate, and when the concentration of the rhodium salt solution is higher, the particle size of the active component is larger, and the catalytic activity is reduced; when the rhodium salt solution is at a low concentration, the rhodium-based catalyst may not be successfully prepared.
(5) As can be seen from the comparison between example 1 and examples 13 and 14, the mass ratio of the precursor to the rhodium salt solution of the present invention affects the NO conversion rate, and when the mass ratio of the precursor to the rhodium salt solution is higher, the rhodium salt solution and the precursor cannot be sufficiently mixed, so that only part of the precursor can be adhered with rhodium; when the mass ratio of the precursor to the rhodium salt solution is low, the dispersity of the active components of the catalyst is reduced, and the catalytic activity of the catalyst is reduced.
(6) As can be seen from the comparison of example 1 with comparative example 1, no significant peaks of Rh and Zr species were observed in the XRD diffractogram due to the high dispersibility and low crystallinity of rhodium and oxide on the surface of the support; after aging at high temperature, part of gamma-Al2O3The rhodium-based catalyst being ald-deposited with oxide has a lower degree of phase transition than the rhodium-based catalyst without ald-deposited oxide, the ald-deposited oxide on the support being capable of inhibiting phase transition of the support at high temperatures; from the transmission electron microscope picture and the high-angle annular dark field transmission electron microscope picture, the carrier and the active component rhodium of the rhodium-based catalyst without the atomic layer deposited with the oxide are seriously aggregated, and the aggregation degree of the carrier and the active component rhodium of the rhodium-based catalyst with the atomic layer deposited with the oxide is obtainedThe improvement that Rh nano particles are still highly uniformly dispersed on a carrier even after being aged at 1050 ℃, and oxide deposited in an atomic layer in the rhodium-based catalyst with the oxide deposited in the atomic layer can effectively anchor and maintain the rhodium metal particles dispersed in an atomic level and inhibit the rhodium particles from aggregating at high temperature; the NO conversion rate of the rhodium-based catalyst with the oxide deposited on the atomic layer is higher than that of the rhodium-based catalyst without the oxide deposited on the atomic layer, the rhodium-based catalyst with the oxide deposited on the atomic layer shows excellent ageing resistance after high-temperature ageing treatment, the activity of the catalyst still keeps higher activity even after the catalyst is aged in air at 1050 ℃, and the activity and the thermal stability of the rhodium-based catalyst can be effectively improved by using the oxide modified carrier; in addition, the synthesis strategy of the invention has good expansibility, and different types of oxides can be modified on different supports to meet the needs of the reaction.
(7) It is understood from the comparison between example 1 and comparative example 2 that the same carrier and oxide cause a decrease in NO conversion, and that the same carrier and oxide eliminate the modification of the carrier by the oxide, failing to improve the activity and thermal stability of the rhodium-based catalyst.
In conclusion, the preparation method of the rhodium-based catalyst provided by the invention can deposit the low-content oxide modification layer on the atomic layer on different carriers, and the oxide modification layer deposited on the atomic layer can generate a synergistic effect with the active component rhodium, so that the catalytic activity of the catalyst at low temperature is improved; the oxide modification layer is also beneficial to anchoring atomic-level dispersed rhodium nanoparticles, inhibits the solid-phase reaction of the rhodium nanoparticles and the carrier at high temperature, improves the low-temperature activity of the catalyst and further improves the stability of the catalyst under the high-temperature oxidation condition.
The above description is only for the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the protection scope and the disclosure of the present invention.
Claims (10)
1. A method of preparing a rhodium-based catalyst, the method comprising the steps of:
(1) depositing an oxide on the carrier by an atomic layer to obtain a precursor;
(2) mixing the precursor obtained in the step (1) with a rhodium salt solution, and carrying out heat treatment to obtain a rhodium-based catalyst;
the carrier comprises any one or the combination of at least two of alumina, silica or zirconium dioxide; the support is of a different kind than the oxide.
2. The preparation method according to claim 1, wherein the morphologies of the alumina, silica or zirconia of step (1) are each independently any one of or a combination of at least two of nanocubes, nanosheets, nanospheres or nanorods;
preferably, the oxide in step (1) comprises any one of alumina, silicon oxide, zirconium dioxide, titanium dioxide or lanthanum oxide or a combination of at least two of the above.
3. The preparation method according to claim 1 or 2, wherein the mass ratio of the carrier to the oxide in the step (1) is (93-49990): 5;
preferably, the carrier in the step (1) has an average particle diameter of 5-100 nm and a specific surface area of 80-200 m2/g。
4. The production method according to any one of claims 1 to 3, wherein the atomic layer deposition in step (1) is performed by vapor phase atomic layer deposition and/or liquid phase atomic layer deposition.
5. The production method according to any one of claims 1 to 4, wherein the rhodium salt solution of step (2) comprises a rhodium nitrate solution and/or a rhodium trichloride solution;
preferably, the concentration of the rhodium salt solution in the step (2) is 0.01-0.1 mol/L;
preferably, the solid-to-liquid ratio of the precursor to the rhodium salt solution in the step (2) is (10-500): 1, and the unit of the solid-to-liquid ratio is g/mL.
6. The production method according to any one of claims 1 to 5, wherein the heat treatment of step (2) includes temperature elevation and heat retention in an air atmosphere;
preferably, the temperature rise rate of the temperature rise is 5-10 ℃/min, and the end point temperature is 300-600 ℃;
preferably, the heat preservation time is 3-6 h;
preferably, the heat treatment in the step (2) further comprises evaporating before heating, wherein the evaporating temperature is 20-50 ℃;
preferably, the heat treatment of step (2) further comprises grinding between evaporating and raising the temperature.
7. The method according to any one of claims 1 to 6, characterized in that it comprises the steps of:
(1) depositing an oxide on a carrier through a gas-phase atomic layer deposition and/or a liquid-phase atomic layer deposition, wherein the mass ratio of the carrier to the oxide is (93-49990): 5, and obtaining a precursor;
(2) mixing the precursor obtained in the step (1) with a rhodium salt solution with the concentration of 0.010-1 mol/L, wherein the solid-to-liquid ratio of the precursor to the rhodium salt solution is (10-500): 1, the unit of the solid-to-liquid ratio is g/mL, evaporating to dryness at 20-50 ℃, grinding, heating to 300-600 ℃ at the heating rate of 5-10 ℃/min, and preserving heat for 3-6 hours to obtain the rhodium-based catalyst;
the carrier comprises any one or the combination of at least two of alumina, silica or zirconium dioxide; the support is of a different kind than the oxide.
8. A rhodium-based catalyst, characterized in that it has been obtained by a process according to any one of claims 1 to 7.
9. The rhodium-based catalyst according to claim 8, wherein the mass fraction of the carrier is 93 to 99.98 wt%, the mass fraction of the oxide is 0.01 to 5 wt%, and the mass fraction of rhodium is 0.01 to 2 wt%, in terms of mass percentage.
10. Use of a rhodium-based catalyst as claimed in claim 8 or 9 in a CO-SCR reaction.
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| CN107262093A (en) * | 2017-06-23 | 2017-10-20 | 福州大学 | A kind of methane catalytic combustion catalyst and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116116405A (en) * | 2022-11-04 | 2023-05-16 | 佛山东佛表面科技有限公司 | Single-atom cluster type noble metal integral type silk screen catalyst for CO reduction of NO |
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| CN114588894B (en) | 2023-06-16 |
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