Preparation method of Co / m-ZrO2 catalyst for catalyzing hydrogen production by reforming ethanol

Abstract

The invention discloses a preparation method of a monoclinic phase Co / ZrO2 catalyst for hydrogen production through ethanol oxidation reforming. The preparation method comprises the following steps: S1, dissolving Zr (NO3) 4. 5H2O and CO (NH2) 2 in deionized water; s2, transferring the mixed solution in the step S1 into a high-pressure kettle with a polytetrafluoroethylene lining for reaction; s3, filtering and washing the obtained precipitate; s4, drying for a period of time at a certain temperature, and calcining to obtain a ZrO2 carrier; s5, putting the ZrO2 carrier into a Co (NO3) 2 aqueous solution, and carrying out ultrasonic dispersion; s6, after drying, activating treatment is conducted through H2 / Ar mixed gas, and the catalyst for the ESR reaction is obtained. Experimental results show that the monoclinic phase Co / ZrO2 catalyst is rough and porous in surface, uniform in distribution and irregular in particle shape, has higher ethanol conversion rate, hydrogen selectivity and catalytic tolerance, and shows higher C-C bond cracking capacity and catalytic ethanol reforming activity in hydrogen production by ethanol oxidation reforming.

Description

Technical Field

[0001] The present invention relates to a catalyst for hydrogen production by steam reforming of ethanol and a preparation method thereof, and particularly relates to a catalyst with monoclinic zirconia as a carrier and Co as an active component, which is mainly applicable to catalytic steam reforming reaction of ethanol to produce hydrogen and belongs to the field of hydrogen energy. Technical Background

[0002] With the rapid development of the national economy, this continuous improvement has promoted the growth of global energy demand. Although the research and development of new energy have never slowed down, the degree of dependence of human beings on fossil fuels such as coal, oil, and natural gas has not decreased, and traditional fossil fuels are still the main energy sources for the current survival, life, and development of human beings. The rapid economic development has also brought inestimable pollution and damage to the ecological environment, and the extensive use of traditional fossil fuels has made the two major world problems of environmental pollution and energy crisis increasingly severe. Developing hydrogen energy to replace fossil fuels is conducive to alleviating the energy crisis and improving the ecological environment.

[0003] As a very important industrial raw material, product, and ideal clean energy, hydrogen energy is widely used in fields such as petroleum, chemical industry, metallurgy, and fuel cells due to its clean and efficient characteristics. Compared with traditional fossil fuels, hydrogen energy has the following advantages: (1) good combustion performance, rapid ignition, and a wide flammable range when mixed with air; (2) high hydrogen combustion efficiency, and the heat released by hydrogen after complete combustion of the same mass of fuel is about 3 times that of gasoline, 4 times that of alcohol, and 4.5 times that of coal; (3) environmental protection, the product of hydrogen combustion is only water, and zero emission of greenhouse gases can be achieved; (4) less loss, relatively improved safety, and reduced ineffective energy loss. Therefore, it is urgent to develop an environmentally friendly, sustainable, and renewable organic substance for thermochemical hydrogen production. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a preparation method of a Co / m-ZrO2 catalyst for catalytic reforming of ethanol to produce hydrogen. The Co / m-ZrO2 catalyst prepared by this method has a rough and porous surface with uniform distribution and irregular particle shape, and has higher ethanol conversion rate, hydrogen selectivity, and catalytic tolerance, and shows higher C-C bond cleavage ability and catalytic ethanol reforming activity in the oxidative reforming of ethanol to produce hydrogen.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a preparation method of a Co / m-ZrO2 catalyst for catalytic steam reforming of ethanol to produce hydrogen, comprising the following steps:

[0007] S1. Dissolve Zr(NO3)4·5H2O and CO(NH2)2 in deionized water;

[0008] S2. Transfer the mixed solution in S1 to a high-pressure autoclave with a polytetrafluoroethylene liner for reaction;

[0009] S3. Filter and wash the obtained precipitate;

[0010] S4. Dry at a certain temperature for a period of time and then calcine to obtain the ZrO2 support;

[0011] S5. Place the ZrO2 support in an aqueous solution of Co(NO3)2 and disperse it ultrasonically;

[0012] S6. After drying, activate it with a H2 / Ar mixed gas to obtain the catalyst for the ESR reaction.

[0013] Preferably, in step S1, Zr in the mixed solution 4+ is 0.4 mol / L.

[0014] Preferably, in step S2, the reaction vessel is a 100 mL high-pressure autoclave with a polytetrafluoroethylene liner, the reaction temperature is 140 °C, and the reaction time is 4 h.

[0015] Preferably, in step S4, the drying temperature is 80 °C, the calcination temperature is 600 °C,

[0016] the drying time is 12 h, the calcination time is 3 h, and the calcination atmosphere is air.

[0017] Preferably, in step S5, ultrasonically disperse for 0.5 h.

[0018] Preferably, in step S6, the drying temperature is 90 °C, the activation temperature is 500 °C, the drying time is 12 h, the activation time is 1 h, and the mixed gas is 5% H2 / Ar (volume fraction).

[0019] The second aspect of the present invention provides the Co / m-ZrO2 catalyst prepared by the above preparation method.

[0020] The third aspect of the present invention provides the application of the above Co / m-ZrO2 catalyst in the reforming of ethanol steam to produce hydrogen.

[0021] The present invention has the following beneficial effects:

[0022] The present invention adjusts Zr in the solution 4+The concentration was changed and the precipitant was altered to adjust the microstructure of Co / ZrO₂, and the Co / ZrO₂ catalyst was obtained. The experimental results show that the obtained Co / m-ZrO₂ not only has a porous surface with uniform distribution and irregular particle shapes, but also has higher ethanol conversion rate, hydrogen selectivity and catalytic tolerance, showing higher C-C bond cleavage ability and catalytic ethanol reforming activity in ethanol reforming for hydrogen production. Description of the Drawings

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 SEM image of 5% Co / m-ZrO₂-140(4) prepared according to the present invention;

[0025] Figure 2 XRD patterns of 5% Co / m-ZrO₂-140(4) prepared according to the present invention and 5% Co / t-ZrO₂-140(4) prepared using CH₃OH as the solvent;

[0026] Figure 3 XRD patterns of the catalysts obtained at the same hydrothermal time of 6 h and different hydrothermal temperatures (140 °C, 160 °C, 180 °C);

[0027] Figure 4 XRD patterns of the catalysts obtained at the same hydrothermal temperature of 140 °C and different hydrothermal times (2 h, 4 h, 6 h);

[0028] Figure 5 Performance graphs of the catalysts 5.0% Co / m-ZrO₂-140(4) and 5.0% Co / t-ZrO₂-140(4) prepared according to the present invention for ethanol reforming for hydrogen production. (Experimental reaction conditions: 101325 Pa, 500 °C, GHSV = 44400 mL·g cat -1 ·h -1 , water / ethanol = 6:1 (molar ratio)).

[0029] Figure 6 Nitrogen adsorption-desorption test results of the catalysts 5.0% Co / m-ZrO₂-140(4) and 5.0% Co / t-ZrO₂-140(4) prepared according to the present invention.

[0030] The present invention is not limited to the above specific embodiments. Those of ordinary skill in the art can make various changes starting from the above concepts without creative efforts, and all such changes fall within the protection scope of the present invention.

Claims

1. A preparation method of a monoclinic Co / ZrO2 catalyst for ethanol catalytic reforming to produce hydrogen, characterized in that, It includes the following steps: S1. Dissolve Zr(NO3)4·5H2O and CO(NH2)2 in deionized water; S2. Transfer the mixed solution in S1 to an autoclave with a polytetrafluoroethylene liner for reaction; S3. Filter and wash the obtained precipitate; S4. Dry for a period of time at a certain temperature and then calcine to obtain a ZrO2 support; S5. Place the ZrO2 support in an aqueous solution of Co(NO3)2 and disperse it by ultrasonic treatment; S6. After drying, obtain the catalyst for the ESR reaction through activation treatment with a H2 / Ar mixed gas; 2. The preparation method of the monoclinic Co / ZrO2 catalyst according to claim 1, characterized in that: In step S1, weigh 4.3 g of Zr(NO3)4·5H2O and 6.0 g of CO(NH2)2 and dissolve them in 25 mL of deionized water.

3. The preparation method of the monoclinic Co / ZrO2 catalyst according to claim 1, characterized in that: In step S2, transfer it to an autoclave with a 100 mL polytetrafluoroethylene liner and react at a temperature of 140 °C for 4 h.

4. The preparation method of the monoclinic Co / ZrO₂ catalyst according to claim 1, characterized in that: In step S4, dry the precipitate after filtration and washing at 80 °C for 12 h, and then calcine it in an air atmosphere at 600 °C for 3 h to obtain a ZrO2 support.

5. The preparation method of the monoclinic Co / ZrO2 catalyst according to claim 1, characterized in that: In step S5, 5.0 g of the ZrO2 support is weighed and placed in 20 mL of a 0.2 mol·L -1 aqueous Co(NO3)2 solution, and ultrasonic dispersion is carried out for 0.5 h.

6. The preparation method of the monoclinic Co / ZrO2 catalyst according to claim 1, characterized in that: In step S6, dry the sample at 90 °C for 12 h and then activate it with a 5% H2 / Ar (volume fraction) mixed gas at 500 °C for 1 h to obtain the catalyst for the ESR reaction.

7. A monoclinic Co / ZrO2 catalyst prepared by the preparation method according to any one of claims 1-7.

8. Use of the monoclinic Co / ZrO2 catalyst according to claim 7 in the oxidative reforming of ethanol to produce hydrogen.

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