CN-122006699-A - Graphene-based catalyst and preparation method and application thereof

Abstract

The invention provides a graphene-based catalyst and a preparation method and application thereof, and belongs to the technical field of nitrogen oxide treatment. The catalyst is formed by compounding Graphene Oxide (GO) nano-sheets and Mn-Ce oxide, wherein Mn-Ce is uniformly dispersed on the surface and between layers of GO in the form of nano-particles less than or equal to 50nm. The invention adopts room temperature rheological phase method to prepare, forms the precursor through ultrasonic dispersion and room temperature grinding, and obtains the finished product through washing and drying, and the whole process does not need high temperature calcination, thus the energy consumption is low. The catalyst directly utilizes industrial waste heat to drive denitration reaction, does not need to additionally heat flue gas, reduces the energy consumption cost of industrial denitration, maintains the denitration efficiency of more than 80% after continuous operation in the flue gas containing 10vol% of water vapor, has excellent water resistance stability, is suitable for low-temperature flue gas denitration scenes of industries such as steel, garbage incineration, coking and the like, and realizes pollution reduction and carbon reduction synergistic effect.

Inventors

• CAI LINJIE
• WANG LEI
• MAO DONGSEN
• XUE ZHAOTENG
• XUE HONGYAN
• CAI FUFENG
• YU JUN
• HUANG HOUJIN
• Sam Tang

Assignees

• 上海应用技术大学

Dates

Publication Date

20260512

Application Date

20260108

Claims (10)

1. 1. The graphene-based catalyst is characterized by comprising graphene oxide nano sheets and Mn-Ce oxide compounded with the graphene oxide sheets; wherein the Mn-Ce oxide is a nanoparticle with the particle size less than or equal to 50nm and is uniformly dispersed on the surface and between layers of the graphene oxide nanosheets.
2. 2. The graphene-based catalyst according to claim 1, wherein the particle size of the Mn-Ce oxide is 10-20nm, the specific surface area of the catalyst is 90-170m 2 /g, the pore volume is 0.31-0.41cm 3 /g, and the average pore diameter is 8-13nm.
3. 3. The graphene-based catalyst according to claim 1, wherein the molar ratio of manganese element to cerium element in the catalyst is (3-5) 1, and the mass of the graphene oxide nano-sheets accounts for 0.5-3wt% of the total mass of the catalyst.
4. 4. A preparation method of the graphene-based catalyst according to any one of claims 1 to 3, which comprises the steps of mixing a manganese source and a cerium source, adding graphene oxide dispersion liquid and solid sodium hydroxide, grinding into paste to obtain a graphene oxide composite Mn-Ce nanoparticle precursor, performing centrifugal washing for multiple times to obtain a solid phase product, and drying the solid phase product to obtain the graphene-based catalyst.
5. 5. The method for preparing a graphene-based catalyst according to claim 4, wherein the manganese source is selected from one or two of manganese nitrate and manganese acetate, and the cerium source is selected from one or two of cerium nitrate and cerium acetate.
6. 6. The preparation method of the graphene-based catalyst according to claim 4, wherein the preparation method of the graphene oxide dispersion liquid is characterized in that graphene oxide is placed in absolute ethyl alcohol, ultrasonic treatment is carried out for 30-60min under the power of 200-500W, and the graphene oxide ethanol dispersion liquid is obtained, wherein the ratio of the cerium source to the absolute ethyl alcohol is 8mmol (5-15 mL).
7. 7. The method for preparing a graphene-based catalyst according to claim 4, wherein the grinding is machine grinding, the grinding speed is 300-500rpm, and the grinding time is 30-60min.
8. 8. The method for preparing a graphene-based catalyst according to claim 4, wherein the amount of the solid sodium hydroxide is 11-15 times the amount of the cerium source material.
9. 9. The preparation method of the graphene-based catalyst according to claim 4, wherein the centrifugal washing time is 10-20 min/time, and the washing solvent is a mixed solution of deionized water and absolute ethyl alcohol, and the volume ratio of the deionized water to the absolute ethyl alcohol is 1:1.
10. 10. The use of a graphene-based catalyst according to any one of claims 1-3, wherein the catalyst is used in selective catalytic reduction denitration under the conditions that the flue gas temperature is 50-200 ℃, the simulated flue gas composition is NO 400-600ppm, NH 3 400-600ppm、O 2 3-8%、N 2 is balance gas, and the space velocity is 40000-100000h -1 .

Description

Graphene-based catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of nitrogen oxide treatment, in particular to a graphene-based catalyst and a preparation method and application thereof. Background Nitrogen oxide (NO x) is used as an atmospheric pollutant, is one of main gases for aggravating greenhouse effect, can damage stratosphere ozone structure, and is a key precursor substance for forming acid rain and haze. Among the existing denitration technologies, a Selective Catalytic Reduction (SCR) technology using ammonia as a reducing agent is widely used for emission control of coal-fired power plants, industrial boilers, and the like due to its high maturity and excellent denitration efficiency. At present, the traditional denitration catalyst (such as V 2O5-WO3/TiO2) has excellent performance in a medium-high temperature section (300-400 ℃) and obviously reduced activity under the condition of being lower than 200 ℃, and is difficult to meet increasingly strict emission standards. In the exploration of a plurality of non-vanadium-based low-temperature SCR catalysts, manganese-cerium (Mn-Ce) based composite oxides have great potential, and the manganese oxide and the cerium oxide are compounded, so that a remarkable synergistic effect can be generated, and higher NO x conversion efficiency can be realized in a low-temperature range. However, the trend toward large-scale industrial applications of manganese-cerium based catalysts still faces key challenges, such as their generally limited specific surface area, resulting in underexposure of active sites, limiting effective contact and mass transfer efficiency of reactant molecules. Thus, simultaneously increasing the activity and selectivity of the manganese cerium composite oxide catalytic low temperature NH 3 -SCR reaction remains a significant challenge. Disclosure of Invention Aiming at the defects of the prior art, the primary aim of the invention is to provide a graphene-based catalyst which is a Graphene Oxide (GO) composite Mn-Ce oxide denitration catalyst, and the catalyst has excellent ultralow Wen Tuoxiao activity, good water resistance stability and unique microstructure. The second aim of the invention is to provide a preparation method of the catalyst, which has simple process, mild condition and no need of high-temperature calcination, and remarkably reduces the preparation energy consumption and cost. The third purpose of the invention is to provide the application of the catalyst in the field of low-temperature denitration, in particular to the application of the catalyst in ultralow-temperature denitration by utilizing industrial waste heat, so as to realize the dual benefits of energy consumption reduction and pollutant emission reduction. GO is regarded as a carrier or functional aid with great prospect in the field of catalysis because of its extraordinary physicochemical properties as a carbon nanomaterial with a unique two-dimensional structure. GO has a higher specific surface area, and the surface of the lamellar layer is rich in various oxygen-containing functional groups (such as carboxyl-COOH, hydroxyl-OH and the like). The synergistic optimization effect of the structure, the electron and the surface property introduced by GO provides a brand-new idea and opportunity for solving the bottlenecks of activity, stability and the like of the manganese-cerium-based catalyst in low-temperature SCR application. It is noted that most of the current catalyst preparation processes often rely on high temperature calcination treatments, and the room temperature rheological phase reaction laws employed in the present invention avoid this limitation. The room temperature rheological phase reaction process is to prepare compound or material with solid-liquid rheological mixture as reaction system in room temperature environment, and the method includes mixing solid reactants in proper molar ratio, adding water or other solvent to regulate the system state and form solid-liquid rheological modification. Compared with the conventional solution reaction system, the chemical reaction rate, the product nucleation and the growth rate under the system all show new characteristics, and the characteristics provide a new path which is mild, energy-saving and simple and convenient to operate for the green and efficient preparation of the catalyst. The aim of the invention can be achieved by the following technical scheme: One of the purposes of the invention is a graphene-based catalyst, which comprises graphene oxide nano-sheets and Mn-Ce oxide compounded with the graphene oxide sheets; the Mn-Ce oxide is a nanoparticle with the particle size less than or equal to 50nm, and is uniformly dispersed on the surface and the interlayer of the graphene oxide nanosheet without obvious agglomeration. Further, the particle size of the Mn-Ce oxide is 10-20nm, the specific surface area of the cataly