Gas-solid phase reaction double-noble metal catalyst and preparation method thereof

Abstract

The invention provides an Ag-Ru / needle-shaped alpha-alumina noble metal catalyst for gas-solid phase reaction and a preparation method thereof. Porous silicon is used as a template, the surface is coated with aluminum oxide and roasted, the silicon template is removed through fluorine gas to obtain silver or silver fluoride / needle-shaped alpha-aluminum oxide, an Ag active component is attached tothe tip end of the needle-shaped aluminum oxide, Ru is dispersed on the surface of a catalyst carrier, and the catalyst has excellent selectivity and conversion rate for reaction for preparing benzaldehyde through dehydrogenation and oxidation of benzyl alcohol.

Description

technical field [0001] The invention relates to a double noble metal catalyst for gas-solid phase reaction and a preparation method thereof, which belongs to the field of catalyst carrier preparation, and is especially suitable for the field of gas-solid phase reaction of benzyl alcohol dehydrogenated to produce benzaldehyde. [0002] technical background [0003] At present, the "green" production processes of benzaldehyde mainly include toluene oxidation, reduction and direct oxidation of benzyl alcohol. Among them, the toluene oxidation method has the defects of low product yield and many by-products, which limit its industrial application, while the reduction method has no market competitiveness due to the high production cost of the hydrogenation reduction process. The direct oxidation of benzyl alcohol has a good application prospect due to its high atom economy, simple process and environmental friendliness. In recent years, the research on the catalytic oxidation rea...

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Problems solved by technology

[0007] However, the above-mentioned catalysts all face the following problems: (1) The catalyst carrier is a molecular sieve structure, the preparation process is complicated, and the process requirements are high, and it is difficult to obtain a uniform and effective molecular sieve carrier; (2) The active components need to be prepared on the catalyst carrier Afterwards, it is loaded, that is, the catalyst carrier must have a very high specific surface area to ensure that the active components are highly dispersed on the surface of the catalyst carrier; (3) For gas-solid phase reactions, although mesoporous is conducive to the active components Dispersion, but it seriously affects the mass transfer of gas. In short, the active components are dispersed on the mesoporous surface, but it is difficult for the reactants to enter the mesopores and react with the active sites, which eventually leads to low catalytic activity; (4) from In terms of crystal form, α-alumina has stronger catalytic activity than γ-alumina, but because the specific surface area of ​​α-alumina is much lower than that of γ-alumina, the utilization rate of α-alumina is reduced; (5) Acupuncture-shaped alumina is currently prepared and used in the gas-solid phase reaction of benzyl alcohol dehydrogenation to benzaldehyde; (6) The catalytic activity and selectivity of single noble metals need to be improved

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