Silver-containing catalyst, preparation method and application thereof
阅读说明：本技术 一种含银催化剂及其制备方法与用途 (Silver-containing catalyst, preparation method and application thereof ) 是由 肖松涛 欧阳应根 叶国安 王玲钰 刘协春 于 2019-09-12 设计创作，主要内容包括：本发明属于催化剂技术领域,涉及一种含银催化剂及其制备方法与用途。所述的催化剂包含催化活性物质,所述的催化活性物质包含金属银或其化合物,所述的金属银或其化合物中的银元素由组成和/或丰度较天然有所改变的非放射性同位素构成,其中至少一种非放射性同位素的丰度在天然丰度的基础上改变1/20以上且不低于20％。利用本发明的催化剂及其制备方法与用途,能够使得到的含银催化剂具有更好的催化性能。(The invention belongs to the technical field of catalysts, and relates to a silver-containing catalyst, and a preparation method and application thereof. The catalyst comprises a catalytic active substance, wherein the catalytic active substance comprises metallic silver or a compound thereof, the silver element in the metallic silver or the compound thereof is composed of non-radioactive isotopes of which the composition and/or the abundance is changed from natural abundance, and the abundance of at least one non-radioactive isotope is changed from 1/20 to 20 percent on the basis of the natural abundance. By utilizing the catalyst, the preparation method and the application thereof, the obtained silver-containing catalyst has better catalytic performance.)
1. A silver-containing catalyst characterized by: the catalyst comprises a catalytic active substance, wherein the catalytic active substance comprises metallic silver or a compound thereof, the silver element in the metallic silver or the compound thereof is composed of non-radioactive isotopes of which the composition and/or the abundance is changed from natural abundance, and the abundance of at least one non-radioactive isotope is changed from 1/20 to 20 percent on the basis of the natural abundance.
2. The catalyst of claim 1, wherein:
the catalytic active substance also comprises metallic iron or a compound thereof, and the mass ratio of the metallic silver or the compound thereof to the metallic iron or the compound thereof is 1: 0.1-10;
the iron element in the metallic iron or the compound thereof consists of non-radioactive isotopes, and the composition and/or abundance of various isotopes are the same as or different from those of the natural iron.
3. The catalyst of claim 1, wherein:
the catalytic active substance also comprises metallic copper or a compound thereof, and the mass ratio of the metallic silver or the compound thereof to the metallic copper or the compound thereof is 1: 0.1-10;
the copper element in the metallic copper or the compound thereof consists of nonradioactive isotopes, and the composition and/or abundance of various isotopes are the same as or different from those of the natural isotopes.
4. The catalyst of claim 1, wherein: the catalyst also comprises a catalytic auxiliary substance, and the mass ratio of the catalytic active substance to the catalytic auxiliary substance is 1: 0.1-10.
5. The catalyst of claim 4, wherein: the catalytic auxiliary substance comprises a cocatalyst which is selected from one or more of ruthenium, cobalt, gold, palladium, nickel and rare earth elements.
6. The catalyst of claim 4, wherein: the catalytic auxiliary substance comprises a catalyst carrier which is selected from one or more of active carbon, silicon carbide, aluminum oxide, graphene, silicon dioxide and zeolite.
7. Process for the preparation of a catalyst according to one of claims 1 to 6, comprising the following steps:
(1) preparation of catalytically active material: preparing the catalytic active substance or the compound thereof with changed isotope composition and/or abundance by using an isotope separation method, an isotope mixing method, a nuclear reaction method or an element artificial production method;
(2) preparation of the catalyst: the catalysts are prepared using the respective catalytically active substances or compounds thereof.
8. Use of a catalyst according to any one of claims 1 to 6 for catalysing the reaction of ethylene to ethylene oxide.
9. Use of a catalyst according to any one of claims 1 to 6 for catalysing the methanol oxidation synthesis of formaldehyde.
10. Use of a catalyst according to one of claims 1 to 6 for catalyzing a rhodamine B degradation reaction.
Technical Field
The invention belongs to the technical field of catalysts, and relates to a silver-containing catalyst, and a preparation method and application thereof.
Background
Catalyst materials and catalytic technology are one of the fundamental and critical materials and technologies for the development of the chemical industry today. In modern industry, the production value produced by catalytic technology accounts for about 30% of the total value of national economy.
Noble metal catalysts have unique activity and are of great importance in the field of catalysis, with silver-based catalysts being a representative of noble metal catalysts.
Ag in silver-based catalysts is the cheapest noble metal. The silver catalyst is relatively cheap and has good hydrogenation activity, and due to the advantages of good catalytic activity, high mechanical strength, insensitivity to poison, good thermal conductivity and the like, the silver catalyst is not only applied to hydrogenation of various unsaturated hydrocarbons, but also is a good catalyst in certain conversion processes such as dehydrogenation, oxidative dehalogenation, desulfurization and the like, and is a unique industrial catalyst for preparing ethylene oxide by directly oxidizing ethylene. And the silver catalyst has low preparation cost and is easy to obtain, and has potential in industrial application prospect.
Since the silver-based catalyst was successfully applied in the 30 th of the 20 th century, the silver-based catalyst has been greatly developed in the aspects of active components, addition of auxiliaries, selection of carriers, preparation methods, application and the like through development of more than 80 years. Especially in the application field, the method is expanded from the initial chemical production field to the environmental protection and medicine field. With the application of computer simulation technology in the field of catalyst research, the research mode of silver-based catalysts is gradually changed from a mode relying on experiments alone to a mode combining experiments and computer simulation.
Currently, a large number of researchers worldwide are working on developing new silver-based catalysts to improve their catalytic activity, selectivity, and lifetime, and the main studies include:
1) ethylene direct oxidation to ethylene oxide
The direct oxidation of ethylene over silver catalysts is currently the only technique for the production of EO. The world EO/EG production technology is mainly monopolized by three companies of Shell, SD and Dow in the United states (Dow chemical combines UCC company in 2001), and the company of Japan catalyst, BASF in Germany, Snam in Italy also has own patent technology. The production capacity of the worldwide EO production device adopting the Shell, SD and Dow three major technologies accounts for more than 90 percent of the total EO production capacity. During the epoxidation of ethylene to ethylene oxide, the feed ethylene consumes about 7/10 of the overall ethylene oxide production cost. Obviously, the key to improving the economic benefit of ethylene oxide production is to reduce the consumption of raw material ethylene, and the performance of the catalyst plays a crucial role in reducing the consumption of ethylene, so the development and use of a high-selectivity and high-conversion catalyst is the most effective method for saving production cost and improving benefit.
2) Preparation of formaldehyde by methanol oxidation
Davilin changed the activity of the electrolytic silver catalyst by using organic halide in 1999, and researches show that a small amount of organic halide CH is added3I can improve the catalytic activity of the electrolytic silver catalyst. The characterization experiments such as X-ray photoelectron spectroscopy, scanning electron microscope and the like find a small amount of CH3The I interacts with the surface of the electrolytic silver catalyst to form silver iodide microcrystals with special structures, and the microcrystals increase the specific surface area of the catalyst and improve the formaldehyde conversion rate.
3) Silver-containing photocatalyst
The silver-based visible light photocatalyst is large in number, and can be roughly classified into three-element composition and multi-element composition from the element type composition. The catalyst composed of three elements mainly takes Ag and O as fixed constituent elements, and the other element is changeable or has different proportions among the three elements; the catalysts composed of multiple elements are synthesized by a solid phase method or an ion exchange method, as their name implies, with 4 or more elements.
4) Catalytic hydrogenation reaction
The tourmaline researches the catalytic performance of a silver-based catalyst prepared by using aluminum oxide as a carrier in the selective methanation reaction of CO. The specific preparation process of the catalyst comprises the following steps: the precursor 20% Ag/Al is prepared by ammonium carbonate precipitation method2O3Then, the ruthenium ion solution (Ru/Al-1/100) was ultrasonically impregnated, followed by calcination at 400 ℃ for 2 hours to obtain a sample in an oxidized state of 1% RuO3-20％AgO/Al2O3Reducing the sample at 400 ℃ for 2h to obtain 1 percent RuO3-20％AgO/Al2O3A catalyst. After the catalyst is prepared, the catalyst is used in the selective methanation reaction of CO. The experimental results show that the CO selectivity is higher than 50% when the reaction temperature is 220 ℃.
5) Catalytic reforming reaction
Zhang Chuan, et al, used a pH-raising process to impregnate different contents of silver onto montmorillonite (MMT), calcined and formed at 600, 700 and 800 ℃ respectively, and studied the effect of Ag/MMT catalyst for hydrogen production by Glycerol Steam Reforming (GSR). The experimental results demonstrate that the 700 ℃ calcined catalyst has better activity than the 600 and 800 ℃ calcined catalysts. The catalyst calcined at 700 c with a silver content of 19.89% had the best activity, with a glycerol conversion of 85% at 600 c and a hydrogen selectivity of 76%. The conversion rate of glycerin increases with the temperature increase at 400-600 ℃.
6) Catalytic methane partial oxidation reaction
Ma Sheng et Al examined alpha-Ag/gamma-Al on a continuous flow fixed bed device2O3The influence of the catalyst preparation method and the reaction space velocity on the methanation reaction of carbon monoxide. The catalyst prepared by the grinding and mixing reduction method has higher activity, and n (H) in n (CO)2) 1:3, normal pressure, 593K and space velocity of 2500h-1alpha-Ag/gamma-Al with w (Ag) of 15% prepared by grinding, mixing and reducing method under reaction condition2O3The selectivity of the catalyst for catalyzing CO to synthesize methane reaches over 65 percent, and the conversion rate of carbon monoxide is close to 80 percent.
7) Catalytic cracking reaction
The industrial application of YN-1 type silver catalyst pyrolysis gasoline C9+ fraction selective hydrogenation equipment was studied by Chaihai, et al. The result shows that the YN-1 series silver catalyst is used for hydrogenating C9+ fraction raw materials with colloid content of more than 100 mg/100 ml and bromine value of more than 5g Br/100g, can use reaction temperature rise of more than 90 ℃, and has the advantages of high low-temperature activity, good stability and large gel holding amount.
Disclosure of Invention
It is a primary object of the present invention to provide a silver-containing catalyst that is capable of having better catalytic performance.
To achieve this object, in a basic embodiment, the present invention provides a silver-containing catalyst comprising a catalytically active material, the catalytically active material comprising metallic silver or a compound thereof, the elemental silver of the metallic silver or the compound thereof being composed of a non-radioactive isotope whose composition and/or abundance is changed from natural, wherein the abundance (mass percentage content) of at least one non-radioactive isotope is changed by 1/20 or more and not less than 20% based on the natural abundance (natural abundance of elemental silver isotope: 51.84% for Ag-107 and 41.86% for Ag-109).
In a preferred embodiment, the present invention provides a silver-containing catalyst, wherein:
the catalytic active substance also comprises metallic iron (the natural abundance of iron isotope is 5.8 percent of Fe-54, 91.72 percent of Fe-56, 2.2 percent of Fe-57 and 0.28 percent of Fe-58) or a compound thereof, and the mass ratio of metallic silver or the compound thereof to metallic iron or the compound thereof is 1: 0.1-10;
the iron element in the metallic iron or the compound thereof consists of non-radioactive isotopes, and the composition and/or abundance of various isotopes are the same as or different from those of the natural iron.
In a preferred embodiment, the present invention provides a silver-containing catalyst, wherein:
the catalytic active substance also comprises metallic copper (the natural abundance of copper element isotopes is 69.17 percent and 30.83 percent, namely Cu-63) or a compound thereof, and the mass ratio of the metallic silver or the compound thereof to the metallic copper or the compound thereof is 1: 0.1-10;
the copper element in the metallic copper or the compound thereof consists of nonradioactive isotopes, and the composition and/or abundance of various isotopes are the same as or different from those of the natural isotopes.
In a preferred embodiment, the present invention provides a silver-containing catalyst, wherein the catalyst further comprises a catalytic auxiliary substance, and the mass ratio of the catalytically active substance to the catalytic auxiliary substance is 1: 0.1-10.
In a more preferred embodiment, the present invention provides a silver-containing catalyst, wherein the catalytic auxiliary material comprises a promoter selected from one or more of ruthenium, cobalt, gold, palladium, nickel, and rare earth elements.
In a more preferred embodiment, the present invention provides a silver-containing catalyst, wherein the catalytic auxiliary material comprises a catalyst carrier selected from one or more of activated carbon, silicon carbide, alumina, graphene, silica and zeolite.
The second purpose of the invention is to provide the preparation method of the silver-containing catalyst, so that the silver-containing catalyst can be better prepared, and the prepared silver-containing catalyst has better catalytic performance.
To achieve this object, in a basic embodiment, the present invention provides a method for producing the above silver-containing catalyst, comprising the steps of:
(1) preparation of catalytically active material: preparing the catalytic active substance or the compound thereof with changed isotope composition and/or abundance by using an isotope separation method, an isotope mixing method, a nuclear reaction method or an element artificial production method;
(2) preparation of the catalyst: the catalysts are prepared using the respective catalytically active substances or compounds thereof.
Isotope separation methods can be mainly divided into chemical methods and physical methods, wherein the chemical methods include amalgam exchange methods, ion exchange chromatography, extraction methods and the like; physical methods include electromagnetic methods, molten salt electrolysis methods, electron transfer, molecular distillation, laser separation, and the like (see: Yangzhou, Zeng's title, stable isotope separation, atomic energy Press, first edition 1989, full book, especially page 23).
The isotope mixing method is to mix isotopes with different abundances to prepare isotopes with specified abundances, and mix the isotopes uniformly by a roller or the like.
The nuclear reaction method is a method of bombarding a nuclear nucleus with particles generated by a reactor or an accelerator, and mainly includes primary decay of (n, γ), (n, p), (n, d) (n,2n), (n, f), and target nuclides (see (U.S.) c.b. moore, eds. laser photochemical and isotope separation, atomic energy press, first edition 1988, full book, especially page 18) can be generated by combining the (n, p), (n, d), (n,2n) reaction and the secondary reaction (p, n), (p, d), (t, n), (t, 2 n).
The element artificial production method is to produce a new nuclide by nuclear fission or nuclear fusion (see (U.S.) Benedict (Benedict, M.) and the like, nuclear chemical engineering, atomic energy press, first edition 2011, full book, especially page 169).
A third object of the present invention is to provide the use of the above silver-containing catalyst to enable better catalytic performance.
To achieve this object, in a basic embodiment, the present invention provides the use of the above silver-containing catalyst for catalyzing the reaction of ethylene to ethylene oxide.
To achieve this object, in a basic embodiment, the present invention provides the use of the above silver-containing catalyst for catalyzing the reaction of methanol oxidation to formaldehyde.
To achieve this object, in a basic embodiment, the present invention provides the use of the above silver-containing catalyst for catalyzing a rhodamine B degradation reaction.
The invention has the beneficial effects that the silver-containing catalyst and the preparation method and the application thereof can ensure that the obtained silver-containing catalyst has better catalytic performance.
Detailed Description
The following examples further illustrate specific embodiments of the present invention.