Sintering-resisting loading type nanometer palladium catalyst and preparing method and application thereof

Abstract

A sintering-resisting loading type nanometer palladium catalyst and a preparing method and application thereof relate to a nanometer metal catalyst. The sintering-resisting loading type nanometer palladium catalyst contains active component acetylacetone palladium and carrier SiO2, and metal Pd occupies 0.5-5.0% of the sintering-resisting loading type nanometer palladium catalyst according to mass percent. The preparing method of the sintering-resisting loading type nanometer palladium catalyst includes steps: (1) SiO2 is selected to serve as the carrier, immersed into nitric acid solution and washed until the pH of SiO2 is 6.5-7.0, and then is dried; (2) Pd (acac) 2 compound is dissolved in acetylacetone or toluene solvents to prepare Pd (acac) 2 solution with mass concentration of Pd to be 0.26-1.04 mg / ml; (3) SiO2 obtained in the step (1) is immersed into the metal salt solution obtained in the step (2), and an initial catalyst is obtained after drying and roasting; and (4) the initial catalyst obtained in the step (3) is subjected to hydrogen gas reduction, and the sintering-resisting loading type nanometer palladium catalyst is finally obtained.

Description

technical field [0001] The invention relates to a nanometer metal catalyst, in particular to a sintering-resistant nanometer Pd catalyst, which is prepared by a simple impregnation method and its application in CO oxidation reaction. Background technique [0002] Supported Pd catalyst is one of the most important metal catalysts, which can be widely used in reactions such as olefin hydrogenation, alcohol oxidation, coupling reaction, automobile exhaust elimination, CO oxidation treatment, etc. The size is closely related, usually the Pd catalyst with smaller particles has better catalytic performance. Okada et al. (Catalysis Today, 2011, doi:10.1016 / j.cattod.2011.08.014) compared the preparation of nano-Pd / SiO by deposition and impregnation methods 2 It was found that the particle size of Pd on the catalyst prepared by the deposition method (3.9nm) was significantly smaller than that of the catalyst prepared by the impregnation method (6~12nm), and the former was more condu...

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Problems solved by technology

Although the catalyst prepared by this method can effectively inhibit the agglomeration of metal particles in a certain temperature range, its high temperature (>700°C) stability) still needs to be improved, and due to the special structure of the encapsulated catalyst, the reactants must first Diffusion passes through the cladding layer to reach the metal active center, and there is a contact problem between the metal active phase and the substrate in the reaction, while PdSiO 2 The preparation process is relatively cumbersome, the preparation cycle is long, and it needs to go through processes such as precipitation, suction filtration, washing, drying, and roasting, so that its industrial application is subject to certain restrictions.

Therefore, it is very difficult and challenging to explore a simple method to prepare highly dispersed, sintering-resistant Pd-supported catalysts.

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