阅读说明：本技术 镍基催化剂、制备方法及用途 (Nickel-based catalyst, preparation method and application ) 是由 戴翼虎 杨艳辉 吴月 徐敏 王巧娟 高兴 于 2020-06-18 设计创作，主要内容包括：本发明公开了镍基催化剂、制备方法及用途,该催化剂包括活性组分金属Ni和载体,载体为纯相La<Sub>2</Sub>O<Sub>2</Sub>CO<Sub>3</Sub>或金属掺杂的La<Sub>2</Sub>O<Sub>2</Sub>CO<Sub>3</Sub>。该催化剂选取含有大量中等碱性位点的碳酸氧镧为载体,并负载Ni基催化剂应用于CO<Sub>2</Sub>甲烷化反应,通过Ni-La<Sub>2</Sub>O<Sub>2</Sub>CO<Sub>3</Sub>协同作用,调变相关反应物活化路径、稳定活性金属状态,从而显著促进了CO<Sub>2</Sub>催化加氢反应的热稳定性、活性及选择性。(The invention discloses a nickel-based catalyst, a preparation method and application thereof, wherein the catalyst comprises an active component metal Ni and a carrier, and the carrier is pure-phase La 2 O 2 CO 3 Or La doped with metal 2 O 2 CO 3 . The catalyst selects lanthanum oxycarbonate containing a large amount of medium-alkaline sites as a carrier, and loads a Ni-based catalyst to be applied to CO 2 Methanation by Ni-La 2 O 2 CO 3 The synergistic effect of the two components can modulate the activation path of related reactants and stabilize the state of active metal, thereby obviously promoting CO 2 Thermal stability, activity and selectivity of catalytic hydrogenation reaction.)

1. A nickel-based catalyst characterized by: comprises an active component metal Ni and a carrier, wherein the carrier is pure phase La₂O₂CO₃Or La doped with metal₂O₂CO₃。

2. The nickel-based catalyst according to claim 1, characterized in that: when the carrier is pure phase La₂O₂CO₃When the catalyst is used, the percentage content of Ni in the catalyst is 3-15%.

3. The nickel-based catalyst according to claim 1, characterized in that: when the carrier is metal-doped La₂O₂CO₃When the catalyst is used, the percentage content of Ni in the catalyst is 3-15%.

4. The method for preparing a nickel-based catalyst according to claim 1, wherein:

when the carrier is pure phase La₂O₂CO₃The method comprises the following steps:

(1) taking a mixed aqueous solution of lanthanum nitrate and urea, and carrying out hydrothermal treatment;

(2) washing, filtering, drying and roasting the hydrothermal product obtained in the step (1) to obtain La₂O₂CO₃A carrier;

(3) ultrasonically dispersing nickel nitrate into absolute ethyl alcohol to form precursor solution, and mixing the La prepared in the step (2)₂O₂CO₃Grinding, aging and drying the carrier;

(4) roasting the sample prepared in the step (3);

(5) reducing the sample prepared in the step (4) to obtain La₂O₂CO₃The Ni-based catalyst is loaded on the catalyst,

when the carrier is metal doped with La₂O₂CO₃The method comprises the following steps:

(1)M-La₂O₂CO₃preparation of (M ═ Ce, Y, Zr) support: adding metal salt into absolute ethyl alcohol for ultrasonic dispersion, and reacting with La₂O₂CO₃Mixing, grinding and standing, drying and roasting the obtained product to obtain the carrier M-La₂O₂CO₃；

(2) Ultrasonically dispersing nickel nitrate into absolute ethyl alcohol to form precursor solution, and reacting with M-La₂O₂CO₃Mixing carriers, grinding, aging and drying;

(3) roasting the sample prepared in the step (2);

(4) reducing the sample prepared in the step (3) to obtain M-La₂O₂CO₃Supporting a Ni-based catalyst.

5. The use of the nickel-based catalyst of claim 1 in catalyzing CO₂Application in the process of hydromethanation.

Technical Field

The invention relates to a catalyst, a preparation method and application, in particular to a nickel-based catalyst, a preparation method and application.

Background

Since the industrial revolution, the massive use of fossil energy has led to the CO₂The discharge amount increases year by year. CO 2₂As a greenhouse gas, its excessive emission inevitably exacerbates the greenhouse effect, causing a series of environmental problems. In recent years, CO₂Efficient utilization is appreciated by many, where catalytic hydrogenation of carbon dioxide can produce many high value-added chemicals, e.g., CO₂Direct preparation of olefin, methanol, formic acid and CO₂Methanation, etc., and is therefore considered to be CO₂One of the most efficient ways is utilized. And CO₂The methanation has the advantages of low reaction cost, high speed, less by-products, wide application of the generated methane as fuel in industry and civil use, and the like₂Plays an important role in transformation. From a kinetic point of view, CO₂At the bottom of the energy step, its chemical inertness largely raises the reaction energy barrier and thus hinders the reaction from proceeding. The active catalyst is therefore CO acceleration₂Prerequisites for the reaction to proceed, and such catalysts must possess the ability to activate CO₂The ability of the cell to perform. Is currently used for CO₂Catalysts for methanation reaction are generally metal-based catalysts, wherein active components comprise precious metals (Ru, Rh, etc.) and non-precious metals (Ni, Co), from the industrial production point of view, the precious metal-based catalysts have high catalytic activity, stability and oxidation resistance, but the cost is high, and the precious metal-based catalysts are not suitable for commercial production, while the non-precious metal-based Ni catalysts are widely concerned due to high activity, methane selectivity and low cost. However, Ni-based catalysts in CO₂The methanation reaction process has the phenomena of poor thermal stability and easy sintering, so that the catalytic activity is obviously reduced, and the industrial application is not facilitated. Therefore, improvement of the thermal stability of the Ni-based catalyst is imminent.

In addition to the active metal component, the selected support and its surface properties also significantly affect the catalytic performance and stability. Karelovic A, Karim W, et al found that the structure and properties at the support-dominated metal-support interface determine the stability, activity, and selectivity of the catalyst. The catalytic performance is regulated by virtue of the metal-carrier interface by virtue of the additive and carrier characteristics. For example, both Ni-based catalysts when supportedIn SiO₂CO on a support₂Less hydrogenation activity, but in CeO₂And MgO exhibit higher CO on these supports₂Methanation reactivity, due to CeO₂Isobasic oxides contain a moderately basic site, and dissociate H₂The metallic Ni site of (2) is required to be adjacent to the interface and is responsible for activating CO₂The basic sites of the carrier generate synergistic effect, and the necessity of a metal-carrier interface is highlighted. However, these oxide catalysts do not satisfy high activity, selectivity and stability at the same time. A number of related patents have also been published in recent years. Chinese patent CN101733104A discloses a CO-containing catalyst₂Catalyst for methanation reaction of synthetic gas is prepared from one or more of Ni, Mo and Ru as active component and Al₂O₃、MgO、TiO₂Or ZrO₂Adding Be or Ca as carrier and metal assistant. However, it does not provide a stable result, and the catalyst preparation process is cumbersome, and the use of various metals and noble metal elements increases the preparation cost. Chinese patent CN104148065A discloses a method for CO₂The methanation catalyst is prepared by using noble metal Ru or Rh as active component, using alkaline metal as adjuvant and CeO₂、ZrO₂The catalyst is a carrier, and the synthesized catalyst uses noble metal, various metal additives and carriers, so that the production cost is overhigh, the preparation process is complex, and the catalyst is not suitable for large-scale synthesis application.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a catalyst with high activity, selectivity and stability.

It is another object of the present invention to provide a method for preparing the catalyst with high activity, selectivity and stability.

A final object of the invention is to provide the use of said highly active, selective and stable catalysts.

The technical scheme is as follows: the invention provides a nickel-based catalyst, which comprises an active component metal Ni and a carrier, wherein the carrier is pure-phase La₂O₂CO₃Or La doped with metal₂O₂CO₃。

Further, when the carrier is pure phase La₂O₂CO₃When the catalyst is used, the percentage content of Ni in the catalyst is 3-15%.

Further, when the carrier is La doped with metal₂O₂CO₃When the catalyst is used, the percentage content of Ni in the catalyst is 3-15%.

The preparation method of the nickel-based catalyst,

when the carrier is pure phase La₂O₂CO₃The method comprises the following steps:

(1) taking a mixed aqueous solution of lanthanum nitrate and urea, and carrying out hydrothermal treatment;

(2) washing, filtering, drying and roasting the hydrothermal product obtained in the step (1) to obtain La₂O₂CO₃A carrier;

(3) ultrasonically dispersing nickel nitrate into absolute ethyl alcohol to form precursor solution, and mixing the La prepared in the step (2)₂O₂CO₃Grinding, aging and drying the carrier;

(4) roasting the sample prepared in the step (3);

(5) reducing the sample prepared in the step (4) to obtain La₂O₂CO₃Loading Ni base catalyst, when the carrier is metal doped La₂O₂CO₃The method comprises the following steps:

(1)M-La₂O₂CO₃preparation of (M ═ Ce, Y, Zr) support: adding metal salt into absolute ethyl alcohol for ultrasonic dispersion, and reacting with La₂O₂CO₃Mixing, grinding and standing, drying and roasting the obtained product to obtain the carrier M-La₂O₂CO₃；

(2) Ultrasonically dispersing nickel nitrate into absolute ethyl alcohol to form precursor solution, and reacting with M-La₂O₂CO₃Mixing carriers, grinding, aging and drying;

(3) roasting the sample prepared in the step (2);

(4) reducing the sample prepared in the step (3) to obtain M-La₂O₂CO₃Supporting a Ni-based catalyst.

The nickel-based catalyst is used for catalyzing CO₂Application in the process of hydromethanation.

Has the advantages that: the invention selects lanthanum oxycarbonate containing a large amount of medium-alkalinity sites as a carrier, and loads a Ni-based catalyst to be applied to CO₂The methanation reaction and the preparation process are simple. By Ni-La₂O₂CO₃The synergistic effect of the two components can modulate the activation path of related reactants and stabilize the state of active metal, thereby obviously promoting CO₂Thermal stability, activity and selectivity of catalytic hydrogenation reaction. The invention adopts hydrothermal and incipient wetness impregnation methods to respectively prepare the carrier and the Ni-based catalyst with stable performance. Carrier La₂O₂CO₃Plays a positive role in regulating and controlling the dispersion and the state of Ni in the reaction, thereby inhibiting the sintering of Ni. The preparation method has the advantages of simple preparation process, low cost and good repeatability, and is suitable for industrial large-scale production.

Drawings

FIG. 1 shows Ni/La₂O₂CO₃An activity profile of the catalyst;

FIG. 2 shows Ni/La₂O₂CO₃A stability profile of the catalyst;

FIG. 3 shows Ni/La₂O₂CO₃XRD pattern of the catalyst;

FIG. 4 shows Ni/M-La₂O₂CO₃XRD pattern of (a).

Detailed Description