Ni-mnox doped oxide catalyst, its preparation method and application

Abstract

The application belongs to the field of catalytic oxidation removal of CO, and provides a Ni-MnOx doped oxide catalyst. The Ni-MnOx doped oxide catalyst is prepared by aerosol high-temperature decomposition of a nickel-containing compound and a manganese-containing compound. The application adopts base metal doping, high-temperature reaction, nano engineering and interface reaction to realize low-temperature gasification of carbonates on the surface of the catalyst, release active sites, achieve 100% conversion of CO into CO2 at 25-800 DEG C, and 82% conversion of CO into CO2 at -20 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of catalytic oxidation for CO removal, specifically relating to a Ni-MnOx doped oxide catalyst, its preparation method, and its application. Background Technology

[0002] The purification of CO-containing gas generally involves using a precious metal catalyst to oxidize CO into CO2 at room temperature or low temperature.

[0003] The document with patent number CN107519871B provides a "method for preparing an AuAg@SiO2 nanocatalyst for catalytic oxidation of CO", which uses noble metals Au and Ag to prepare AuAg alloy particle cores and SiO2 as the outer shell of the catalyst. This catalyst can convert all CO into CO2 at 70℃.

[0004] The document with patent number CN113117693A provides "a Pd-Cu / TiO2 bimetallic catalyst for catalytic oxidation of CO and its preparation method and application", and the catalytic temperature of the Pd-Cu / TiO2 bimetallic catalyst for catalytic oxidation of CO is 20-120℃.

[0005] The document with patent number CN108126708A provides "a CO room temperature oxidation catalyst", the active component of which is nano-gold, the auxiliary agent is one or more of Fe2O3, MnO2, CuO, Co2O3, CeO2 and NiO, and the support is γ-Al2O3, which can oxidize CO 100% at 55℃.

[0006] The document with patent number CN 111266116 A provides "Supported Nanoscale Polymetallic Catalysts and Preparation Methods and Their Applications in CO Oxidation", in LaCo 1-x-y-z Pt x Ru y Pd z Under the catalytic action of O3 / SiO2 supported nano-polymetallic catalyst, the CO conversion rate is 80% at 350℃ and 100% at 400℃.

[0007] Patent CN 110876943 A discloses "Oxide-Modified Pt-Co Bimetallic Catalyst and Preparation Method Thereof and Its Application in CO Oxidation," which uses an oxide-modified Pt-Co bimetallic catalyst for CO oxidation. At 380℃, LaCo... 0 .99 Pt 0 .01 O3 catalyzes 100% CO conversion.

[0008] The document with patent number CN 113597339 A discloses a "low-temperature CO oxidation catalyst," which relates to a low-temperature carbon monoxide (LT) catalyst for reducing exhaust emissions from lean-burn engines. CO oxidation catalyst composition. LT The CO oxidation catalyst composition comprises an oxygen storage component (OSC), a first platinum group metal (PGM) component, and a promoter metal, wherein the OSC is impregnated with the first PGM component and the promoter metal, and LT The CO oxidation catalyst composition can effectively oxidize carbon monoxide (CO) and hydrocarbons (HC) under cold start conditions.

[0009] Patent document CN 113877605 A discloses "a catalyst for low-temperature CO oxidation and its preparation method." This catalyst comprises Pt as the active component, a transition metal element M2 oxide, and an alkali metal element M1, where M2 is selected from one or more of Mn, Mo, Fe, and Ni. Pt accounts for 0.1% of the total mass of the catalyst. 2wt%, M1 element accounts for 1% of the total mass of the catalyst. 10wt%. Pt was first prepared by co-precipitation using M1OH or M12CO3 as precipitants. M1 A basic mixture of M2 was then processed at high temperature to prepare Pt / M1. M2 catalyst. This catalyst exhibits high CO catalytic oxidation activity and stability in various characteristic atmospheres (such as hydrogen-rich, carbon dioxide-rich, and sulfur-containing atmospheres), and shows good application potential in CO elimination scenarios such as fuel cells, vehicle exhaust, and low-temperature methanol wash exhaust. The catalyst evaluation conditions are: reaction pressure at atmospheric pressure, and reactant gas containing 85% CO. 2+ 14.6% He + 0.1% CO + The catalyst was packed with 0.3% H2 (80 mL / min) and air (5 mL / min), with a catalyst loading volume of 1 mL and a space velocity of 5000 h⁻¹. –1 The lowest temperature at which the catalyst achieves a CO catalytic oxidation conversion rate of 99% is 50℃.

[0010] Due to the scarcity and high cost of precious metal resources, the development of efficient base metal catalysts has become necessary.

[0011] The document with patent number CN1554480A provides "Preparation of CuO / CeO2 catalyst and its application in CO oxidation". The CuO / CeO2 catalyst is prepared by a combination of sol-gel method and impregnation method. The mass ratio of CuO is in the range of 3.78%-15.12%, and the CO conversion rate is 100% above 140℃.

[0012] The document with patent number CN105396587A provides a "composite copper oxide catalyst for removing trace amounts of CO and its preparation method and application," which, under the action of a CuO / CuAl2 / C catalyst, achieves a reaction at 90℃ for 5000 h. –1 At air velocity, CO can be reduced from 2.2 ppm to 16 ppb.

[0013] Patent CN114345357A discloses "a method for preparing an isothermal methanation catalyst". Through the synergistic effect of multiple metal components such as Cu, Zn, Ce, Zr, Mo, Mn, and La, a modified mesoporous alumina support is prepared using a hydrothermal treatment process. Subsequent drying, calcination, and tableting processes yield a precursor with good specific surface area and pore size, and excellent heat and mass transfer performance. A bimetallic Ni is used. Ce was used as the active component to prepare the catalyst. Under conditions of 250~400℃, the CO conversion rate reached over 99.0%.

[0014] Patent number CN115704097A, entitled "Preparation method and application of a diatomic catalyst with an M1M2-support structure," describes a diatomic catalyst whose active center comprises two metal atoms, M1 and M2, spaced L apart. The metals M1 and M2 may be the same or different and are independently selected from one of the following: Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Ru, Rh, Pd, Ir, Pt, Ag, and Au. The support is a carbon-based support or a metal oxide. The catalyst preparation method involves loading a binuclear complex as a precursor onto a support and then pyrolyzing it at high temperature under an inert atmosphere.

[0015] The document with patent number CN114206781A provides "nickel composite hydroxide, positive electrode active material with nickel composite hydroxide as precursor and preparation method thereof". The nickel composite hydroxide contains Ni, Co and one or more added metal elements M selected from the group consisting of Mn, Al, Fe and Ti. The nickel composite hydroxide is a precursor of positive electrode active material for non-aqueous electrolyte secondary batteries. The preparation method includes the following steps: a neutralization reaction step, wherein an aqueous solution containing at least Ni salt, Co salt and the salt of the added metal element, an aqueous solution containing an ammonium ion donor and a pH adjuster are mixed in a reaction tank, and a co-precipitation reaction is carried out in the mixed liquid to obtain crude nickel composite hydroxide.

[0016] In existing technologies, CO oxidation conversion requires high temperatures, involves complex catalyst preparation processes, and incurs high costs. Summary of the Invention

[0017] This invention provides a catalyst that can achieve 100% CO conversion in the temperature range of 25℃ to 800℃, and 82% CO2 conversion even at -20℃.

[0018] The Ni-MnOx doped oxide catalyst was prepared by high-temperature aerosol decomposition of nickel-containing and manganese-containing compounds.

[0019] Furthermore, the atomic ratio of nickel (Ni) to manganese (Mn) is greater than or equal to 0.01 and less than or equal to 1.

[0020] Furthermore, the atomic ratio of nickel (Ni) to manganese (Mn) is greater than or equal to 0.3 and less than or equal to 0.75.

[0021] Furthermore, the Ni-MnOx doped oxide catalyst is a hollow spherical shell composed of 10-100 nanometer spheres arranged in a circle. The shell can be open or closed, and the outer diameter of the shell is between 100 nanometers and 10 micrometers.

[0022] One object of the present invention is to provide a method for preparing Ni-MnOx doped oxide catalysts.

[0023] The preparation method of this Ni-MnOx doped oxide catalyst includes the following steps:

[0024] S1: Atomizes an aqueous solution containing nickel and manganese compounds. The mist is carried into the insulated pipe by an inert gas, and the water vaporizes to generate an aerosol containing small solid particles of nickel nitrate and manganese nitrate.

[0025] S2: The aerosol is introduced into the high-temperature decomposition tube along with the inert gas and decomposes into nickel and manganese oxide. The nickel is doped into the manganese oxide lattice to form partially or completely doped Ni-MnOx doped oxide solid products.

[0026] S3: The Ni-MnOx doped oxide solid product enters the water absorption bottle along with the inert gas. After being absorbed by water, it is separated by high-speed centrifugation and dried to obtain the Ni-MnOx doped oxide catalyst.

[0027] Furthermore, the temperature of the insulated pipe is 60-70℃, and the temperature of the high-temperature decomposition pipe is 500-800℃.

[0028] Furthermore, the temperature of the insulated pipe is 70℃, and the temperature of the high-temperature decomposition pipe is 600℃.

[0029] Furthermore, the drying temperature is 80°C, and the drying time is 12 hours. One object of this invention is to provide the application of the Ni-MnOx doped oxide catalyst described above in CO oxidation.

[0030] Furthermore, the application includes the purification of CO-containing gas, the preparation of high-purity oxygen, and the oxidation of CO generated from the combustion of ore fuels.

[0031] This invention employs base metal doping, high temperature, nanoengineering, and interface to achieve low-temperature gasification of carbonates on the catalyst surface, releasing active sites and achieving 100% conversion of CO to CO2 at 25℃-800℃, and 82% conversion to CO2 at -20℃. Attached Figure Description

[0032] Figure 1 The present invention provides a method for preparing Ni-MnOx doped oxide catalysts;

[0033] Figure 2 The apparatus for preparing Ni-MnOx doped oxide catalysts provided in Example 1;

[0034] Figure 3 Electron micrograph of Ni-MnOx doped oxide catalyst with Ni / (Ni+Mn) 0.5 provided for implementation 1;

[0035] Figure 4 Transmission electron microscope image of the Ni-MnOx doped oxide catalyst with nickel / (nickel Ni+manganese Mn) 0.5 provided in Example 1;

[0036] Figure 5 The XRD pattern of the Ni-MnOx doped oxide catalyst with a nickel ratio of Ni / (Ni+Mn) of 0.5 provided in Example 1;

[0037] Figure 6 A graph showing the relationship between CO conversion and reaction temperature for Ni-MnOx doped oxide catalysts with different Ni / (Ni+Mn) atomic ratios provided for Example 1;

[0038] Figure 7 The graph shows the relationship between the 90% CO conversion rate and the atomic ratio of Ni-MnOx doped oxide catalysts with different Ni / (Ni+Mn) atomic ratios provided for Example 1. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but this should not be construed as limiting the scope of the present invention.

[0040] The temperature of a chemical reaction is controlled by the desorption of carbonates from the catalyst surface. This invention employs base metal doping, high-temperature reaction, nanoengineering, and interfacial reaction to achieve low-temperature vaporization of surface carbonates, releasing active sites and achieving 100% conversion of CO to CO2 at temperatures ranging from 25℃ to 800℃.

[0041] This invention provides an apparatus for preparing Ni-MnOx doped oxide catalysts.

[0042] The apparatus for preparing Ni-MnOx doped oxide catalysts includes an ultrasonic atomization assembly, a carrier gas assembly, a heating assembly, a water absorption bottle, and a delivery assembly. The ultrasonic atomization assembly includes a glass bottle and an ultrasonic atomizer housed within it, which atomizes the liquid contained in the bottle. The carrier gas assembly includes a rotor flowmeter that introduces carrier gas into the glass bottle at a set flow rate. The heating assembly includes a tube furnace and an electric furnace temperature controller, which controls the reaction temperature within the tube furnace. The water absorption bottle contains water to absorb the product carried by the carrier gas. The mixture of water and product is centrifuged at high speed to obtain a solid product, which is then dried in a drying oven to obtain the Ni-MnOx doped oxide catalyst product. The delivery assembly includes an insulation tube, an insulation temperature controller, a high-temperature decomposition tube, and an exhaust pipe. The insulation tube delivers the carrier gas and atomized liquid to the high-temperature decomposition tube of the tube furnace. After the reaction is complete, the carrier gas and product are passed into the water absorption bottle through the exhaust pipe. The water absorption bottle contains water, and the product is absorbed in the water absorption bottle. The carrier gas is then discharged through the exhaust pipe. The insulation temperature controller is used to maintain the temperature of the insulation tube.

[0043] Based on the above device, see [link / reference] Figure 1 This invention provides a method for preparing Ni-MnOx doped oxide catalysts.

[0044] S1: An aqueous solution of nickel nitrate and manganese nitrate is atomized by an ultrasonic atomizer. The mist is carried into a heat-insulated (60-70℃) pipe by nitrogen gas. The liquid in the mist vaporizes in the heat-insulated pipe to generate an aerosol containing small solid particles of nickel nitrate and manganese nitrate.

[0045] S2: The aerosol is introduced into a high-temperature (500-800℃) decomposition tube along with nitrogen gas, where it decomposes into nickel and manganese oxide. Furthermore, nickel is doped into the manganese oxide lattice to form partially or completely doped Ni-MnOx doped oxide solid products.

[0046] S3: The Ni-MnOx doped oxide solid product and nitrogen gas enter the water absorption bottle. After the Ni-MnOx doped oxide solid product is absorbed by water, it is separated by high-speed centrifugation and dried in a drying oven to obtain the Ni-MnOx doped oxide catalyst.

[0047] Nitrogen can be replaced with other inert gases.

[0048] The temperature of a chemical reaction is controlled by the desorption of carbonates from the catalyst surface. This invention employs base metal doping, high-temperature reaction, nanoengineering, and interfacial reaction to achieve low-temperature vaporization of carbonates on the catalyst surface, releasing active sites and achieving 100% conversion of CO to CO2 at 25°C, and 82% conversion to CO2 at -20°C.

[0049] Example 1

[0050] like Figure 2 As shown, an apparatus 1 for preparing a Ni-MnOx doped oxide catalyst includes an ultrasonic atomizing component, a carrier gas component, a heating component, a water absorption bottle 31, and a conveying component. The ultrasonic atomizing component includes a glass bottle 11 and an ultrasonic atomizer 12 disposed within the glass bottle 11. The carrier gas component includes a rotor flow meter. The heating component includes a tube furnace 21 and an electric furnace temperature controller. The conveying component includes an insulation tube 41, a quartz tube 42 (high-temperature decomposition tube), an insulation controller, and a discharge tube.

[0051] The parameters of the above instruments are shown in the table below:

[0052] Table 1

[0053]

[0054] Based on the Ni-MnOx doped oxide catalyst preparation apparatus 1 and the Ni-MnOx doped oxide catalyst preparation method provided above, a series of Ni-MnOx doped oxide catalysts with different Ni / (Ni+Mn) atomic ratios were prepared.

[0055] The experimental parameters were as follows: N2 flow rate: 0.8 L / min; water: 50 mL; insulation tube temperature: 70 °C; tube furnace temperature: 600 °C; centrifugation: 100,000 rpm for 5 minutes; drying temperature: 80 °C for 12 hours.

[0056] Catalysts with different doping ratios were prepared using purchased liquid manganese nitrate (50%wtMn(NO3)3) and solid nickel nitrate (Ni(NO3)2·6H2O) as raw materials, according to the amounts added as shown in Table 2.

[0057] Table 2

[0058]

[0059] The morphology and composition of Ni-MnOx doped oxide catalysts with Ni / (Ni+Mn) 0.5 were characterized.

[0060] 1. Images of Ni-MnOx doped oxide catalysts with a nickel / (Ni+Mn) ratio of 0.5 obtained using scanning electron microscopy are shown below. Figure 3 .

[0061] Results analysis:

[0062] The catalyst consists of open and closed hollow spheres with particle sizes ranging from tens of nanometers to 5 micrometers. The sphere walls are composed of solid spheres ranging from a few nanometers to tens of nanometers.

[0063] 2. Images of the Ni-MnOx doped oxide catalyst with a nickel / (Ni+Mn) ratio of 0.5 obtained by transmission electron microscopy are shown below. Figure 4 .

[0064] Results analysis:

[0065] from Figure 4 The crystallographic stripes A of NiO and B of Mn2O3 are clearly visible in the electron microscope image. The image also shows blurred areas C within the crystallographic stripes, indicating the presence of lattice defects.

[0066] 3. XRD analysis of Ni-MnOx doped oxide catalyst with Ni / (Ni+Mn) 0.5 is shown in [reference needed]. Figure 5 .

[0067] The presence of nickel oxide as the main peak on the Ni / (Ni+Mn)0.5 catalyst indicates that manganese, which is smaller than nickel atoms, has been incorporated into the nickel oxide framework.

[0068] The above results indicate that the nickel-Ni / (nickel-Ni+manganese-Mn)0.5Ni-MnOx doped oxide catalyst is a mixture of NiO, Mn2O3, and Mn-doped NiO, and exhibits lattice defects. These mixtures are composed of hollow spheres ranging from hundreds of nanometers to 5 micrometers in size.

[0069] Example of effect 1

[0070] The catalytic oxidation performance of a series of Ni-MnOx doped oxide catalysts with different doping ratios prepared by the apparatus and method of Example 1 was evaluated using a flow-through fixed-bed reactor.

[0071] Reaction conditions: 1% CO, 10% O2, N2 equilibrium gas, Ni-MnOx doped oxide catalyst amount 0.2 g, total flow rate 100 mL / min, and space velocity per unit mass 30000 mL / (g·h).

[0072] The relationship between CO conversion and reaction temperature for Ni-MnOx doped oxide catalysts with different Ni / (Ni+Mn) atomic ratios is shown in the figure. Figure 6 .

[0073] Results analysis: From room temperature (25℃) to 800℃, the CO conversion rate of Ni-MnOx doped oxides with Ni / (Ni+Mn) atomic ratios ranging from 0.33 to 0.5 was 100%. Other Ni-MnOx doped oxides with Ni / (Ni+Mn) atomic ratios also achieved 100% CO conversion above 150℃. The CO conversion rate was also 82% at -20℃.

[0074] The temperatures (T0) at which Ni-MnOx doped oxide catalysts with nickel (Ni) / (nickel (Ni) + manganese (Mn)) atomic ratios of 0, 0.15, 0.25, 0.33, 0.4, 0.5, 0.7, and 0.75, prepared using the apparatus and method of Example 1, achieve a 90% CO conversion. 90 A curve was plotted between the atomic ratios of nickel (Ni) and manganese (Mn), see [reference needed]. Figure 7 .

[0075] Results analysis:

[0076] A nickel (Ni) / (nickel (Ni) + manganese (Mn)) atomic ratio in the range of 0.25-0.71 can significantly reduce the CO oxidation temperature. With an atomic ratio in the range of 0.33-0.5, over 90% of CO can be oxidized to CO2 at temperatures below room temperature (25°C). Specifically, when the nickel (Ni) / (nickel (Ni) + manganese (Mn)) ratio is 0.5, T... 90 At -10℃, 82% is converted into CO2 even at -20℃.

[0077] Because the Ni-MnOx doped oxide catalyst provided by this invention catalyzes the efficient oxidation of CO to CO2 within a temperature range of -20 to 800°C under oxygen-containing conditions, this invention provides an application of the Ni-MnOx doped oxide catalyst in CO oxidation, particularly in the following three aspects:

[0078] (1) Purification of CO-containing air at room temperature (25℃) or below zero. CO is produced by the combustion of hydrocarbons. By catalytically oxidizing the gas in the indoor space, the toxic and harmful CO is converted into non-toxic and harmless CO2.

[0079] (2) Preparation of high-purity oxygen. Pure oxygen contains trace amounts of CO, which is difficult to remove. The CO in oxygen is converted into CO2 by the Ni-MnOx doped oxide catalyst provided by this invention, and then adsorbed by CO2 adsorption materials, such as alumina, to achieve CO removal and preparation of high-purity oxygen.

[0080] (3) Oxidation of CO in the combustion products of hydrocarbon fuels (such as gasoline engines, diesel engines, etc.).

[0081] The oxidation of CO using Ni-MnOx doped oxide catalysts can achieve 100% CO conversion under various conditions. When the gas is anhydrous and the gas temperature ranges from 25℃ to 800℃, 100% CO to CO2 conversion can be achieved, with 82% conversion even at -20℃. When the gas contains water, 100% CO to CO2 conversion can also be achieved at temperatures between 150℃ and 800℃.

Claims

1. A Ni-MnOx doped oxide catalyst characterized in that, Prepared by aerosol pyrolysis of a nickel-containing compound and a manganese-containing compound; the atomic ratio of nickel Ni / (nickel Ni+manganese Mn) is greater than or equal to 0.01 and less than or equal to 1; The preparation method of the Ni-MnOx doped oxide catalyst comprises the following steps: S1: atomizing an aqueous solution of a nickel-containing compound and a manganese-containing compound, and bringing the mist into a heat preservation pipeline via an inert gas, so that water vapor is generated to form an aerosol containing solid small particles of nickel nitrate and manganese nitrate; S2: the aerosol is introduced into a high-temperature decomposition pipeline with the inert gas, and is decomposed into nickel and manganese oxide, the nickel is doped into the manganese oxide lattice to form a partially or fully doped Ni-MnOx doped oxide solid product; S3: the Ni-MnOx doped oxide solid product is introduced into a water absorption bottle with the inert gas, and after being absorbed by water, high-speed centrifugal separation is performed, and after drying, the Ni-MnOx doped oxide catalyst is obtained; The temperature of the heat preservation pipeline is 60-70℃, and the temperature of the high-temperature decomposition pipeline is 500-800℃; The Ni-MnOx doped oxide catalyst is a hollow spherical shell composed of 10-100 nm spherical arrangements, the shell is open or closed, and the shell outer diameter is between 100 nm and 10 microns.

2. The Ni-MnOx doped oxide catalyst of claim 1, wherein, The atomic ratio of nickel Ni / (nickel Ni+manganese Mn) is greater than or equal to 0.3 and less than or equal to 0.

75.

3. The Ni-MnOx doped oxide catalyst of claim 1, wherein, The temperature of the heat preservation pipeline is 70℃, and the temperature of the high-temperature decomposition pipeline is 600℃.

4. The Ni-MnOx doped oxide catalyst of claim 1, wherein, The drying temperature is 80℃, and the drying time is 12 hours.

5. The application of the Ni-MnOx doped oxide catalyst in CO oxidation according to claim 1.

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