Method for preparing metal-oxide compound nano catalyst by molecular layer deposition

Abstract

The invention discloses a method for preparing a metal-oxide compound nano catalyst by molecular layer deposition. The method comprises the following steps: placing a sample loaded with a metal A precursor into a reaction cavity of molecular layer deposition equipment; feeding a precursor of B, multivariate isocyanate and polyamine into the cavity in sequence to generate layer-by-layer monomolecular layer reaction, and covering a compound of the precursor of A by a B-containing organic-inorganic compound membrane; growing layer by layer, changing the cycle number to adjust the thickness of a B-polyurea hybrid membrane; and removing an organic part of the compound by thermal treatment, reducing to realize high-dispersion mixing of the metal A and nano particles of an oxide B, and forming an interface with a large number of metals A and oxides B. The obtained metal-oxide interface controllable material is higher in performance in catalytic hydrogenation, catalytic oxidation and the like. The method is easy to operate, and the interface site can be adjusted according to the deposition cycle number.

Description

technical field [0001] The invention relates to a method for preparing a metal-oxide nanometer composite catalyst by molecular layer deposition. Background technique [0002] The activity and selectivity of heterogeneous catalysts depend on the structure of the catalyst. Bimetallic catalysts have been fully utilized in multimolecular reactions such as catalytic oxidation, catalytic hydrogenation, and catalytic coupling. By introducing the second element oxide or simple substance into the first metal catalyst to form an interface structure, the stability of the first metal nanoparticles can be improved, or the selectivity of the catalyst can be improved. How to design and control the metal-metal oxide interface is the focus of researchers from all over the world. [0003] Using traditional methods (such as co-precipitation, impregnation, chemical vapor deposition, etc.) to obtain metal-metal oxide nanocatalysts, it is difficult to control the uniformity of particle size and...

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Problems solved by technology

The porous film-coated nanoparticles obtained by heat treatment after MLD film deposition on the metal surface have high stability, (T.D.Gould, A.Izar, A.W.Weimer, J.L.FalconerandJ.W.Medlin, ACSCatal.,2014,4, 2714), but the porous membrane occupies the active sites of the metal particles, leading to a decrease in its catalytic performance

In addition, the decomposition temperature of the organic part of the currently known MLD films is mostly as high as 600-900 °C, which is not suitable for controlling the uniformity and interfacial structure of the resulting oxide nanoparticles.

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