Catalyst and preparation method of coated catalyst

Abstract

The invention provides a preparation method of a coated catalyst. The catalyst comprises a molybdenum-based compound core structure and an outer coated silicon dioxide shell structure, wherein the molybdenum-based compound core structure is one or more of molybdenum disulfide, molybdenum carbide and molybdenum nitride. The method comprises the following steps: step A, acquiring a powdery molybdenum-based compound core structure; step B, uniformly mixing the powdery molybdenum-based compound with a dispersing agent, adding alkali for adjusting the pH value, a surfactant and ethyl orthosilicate,carrying out solid-liquid separation after reaction, washing and drying the obtained solid to obtain a precursor of the coated catalyst, and roasting the precursor at the temperature of 600-1000 DEGC to obtain the coated catalyst, wherein the dispersing agent comprises one or more of deionized water, ethanol and polyvinylpyrrolidone. The preparation process is simple and convenient, raw materials are easy to obtain, the microwave catalytic hydrogen sulfide direct decomposition activity is high, and the stability is good.

Description

technical field [0001] The invention belongs to the technical field of waste gas treatment containing hydrogen sulfide, and in particular relates to a preparation method of a coated catalyst and the catalyst. Background technique [0002] Hydrogen sulfide (H 2 S) is a colorless and highly toxic gas with a pungent smell of rotten eggs at low concentrations. It naturally exists in crude oil, natural gas, volcanic gases, hot springs and some lakes, and is also derived from by-products of industrial manufacturing. Such as petroleum refining, natural gas purification, coal mining, paper mills, leather factories, etc. It will not only cause serious corrosion to the transportation pipeline, but also bring a huge burden to the environment, and also pose a serious threat to human health. Therefore, in terms of hydrogen sulfide treatment, national regulations also impose strict requirements on related industries. [0003] At present, the main method for industrially treating hydrog...

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Problems solved by technology

[0003] At present, the main method for industrially treating hydrogen sulfide waste gas is the Claus process, which is to incompletely oxidize hydrogen sulfide to generate water and sulfur, so that sulfur can be recovered, but hydrogen resources are wasted, because hydrogen sulfide waste gas cannot be recovered It is completely oxidized, and the tail gas is also accompanied by the generation of sulfur dioxide. Direct discharge into the atmosphere will cause secondary pollution. Therefore, it is very meaningful to find an effective way to directly decompose hydrogen sulfide into sulfur and hydrogen.

[0004] In recent years, there are many shortcomings in the method of directly decomposing hydrogen sulfide to generate hydrogen and sulfur: excessive energy consumption, expensive materials, low catalyst decomposition efficiency and easy deactivation, harsh decomposition reaction conditions, etc., for example: Furhad et al. Directly decompose hydrogen sulfide without adding a catalyst. It is found that the conversion rate of hydrogen sulfide is 35.6% at a temperature of 1200°C and a pressure of 0.1Mpa. The rate can reach 65.8%. Although this process realizes the direct decomposition of hydrogen sulfide, the required temperature is too high and consumes a lot of energy; Zhao et al. used pulsed corona discharge plasma reactor to explore the direct decomposition of hydrogen The minimum energy consumption of each hydrogen sulfide molecule is 17 eV, but it cannot handle the high concentration of hydrogen sulfide gas, which also limits the industrial application; Ma Guijun et al. 2+ When doped into ZnS, the decomposition rate of hydrogen sulfide can reach 17 μmol / h, but the catalyst is easily deactivated, the utilization rate of visible light is extremely low, and the decomposition efficiency is not high

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