Preparation method of highly dispersed nanocatalyst

Abstract

The invention discloses a preparation method of a highly dispersed nanocatalyst. The method comprises the following steps: (1) respectively preparing a metal salt solution and a precipitant solution,continuously dropwise adding the metal salt solution into the precipitant solution under continuous stirring, continuing the stirring, performing a primary low-temperature hydrothermal reaction, filtering, washing and drying the obtained product, performing a secondary low-temperature hydrothermal reaction, and performing filtration and vacuum drying on the obtained reaction product to obtain a metal oxide carrier rich in oxygen vacancies; and (2) loading a noble metal on the metal oxide carrier by adopting an impregnation technology, and performing temperature-programmed reduction in a hydrogen atmosphere to obtain the highly dispersed nanocatalyst. The method has the advantages of low cost, rich and easily available raw materials, mild preparation conditions and strong universality; andthe highly dispersed nanocatalyst prepared by using the oxygen vacancy supported noble metal has the advantages of good catalytic activity, good product selectivity and great potential industrial catalytic application potential.

Description

technical field [0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a preparation method of a highly dispersed nanometer catalyst. Background technique [0002] Highly dispersed nanocatalysts have attracted much attention because of their high utilization of catalytic active components, which can reduce the amount of precious metals and reduce costs. Methods to improve the dispersion of nanocatalysts include: reducing the loading of noble metals, enhancing the support-metal interaction, or using support vacancies to increase the dispersion of active sites. [0003] At present, improving metal dispersion by increasing the concentration of oxygen vacancies on oxide supports has become a research hotspot. Metal oxides are widely used in the field of catalysis as a carrier to support noble metals. Reducible metal oxides such as CeO 2 、TiO 2 , γ-Al 2 o 3 Coordinatively unsaturated Al 3+ It can stabilize the dispersion of...

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Problems solved by technology

[0004] The currently proposed method for generating oxygen vacancies is generally high-temperature and high-pressure calcination under an inert gas or reducing gas atmosphere. For example, the patent publication number CN106824165A discloses a preparation method for a ceria-loaded highly dispersed nanocatalyst. Heat ceria and reducing gas to react at high temperature to obtain ceria with oxygen vacancies; the patent publication number CN107029728 A discloses a method for preparing a photocatalyst copper calcium titanate containing high-density oxygen vacancies. Put the mixed solid powder in a high-temperature tube furnace for high-temperature calcination at 800°C for 6 hours to obtain a material containing oxygen vacancies; the patent publication No. CN106475089A discloses a TiO with oxygen vacancies 2 / WO 3 A preparation method of a visible light catalyst, in which the precursor is calcined at high temperature in air and then reduced with hydrogen to obtain TiO containing oxygen vacancies 2 / WO 3 Photocatalyst: The preparation method reported in the above patent literature has complicated process conditions, high energy consumption and high cost, and the prepared oxygen vacancies are mostly distributed on the surface, so it is difficult to obtain defect-rich materials with uniform and stable morphology distribution

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