A kind of nanometer metal or metal alloy catalyst and preparation method thereof

Abstract

The invention relates to a graphene airgel-supported nano-metal or metal alloy catalyst and a preparation method thereof, which belongs to the field of nano-material application and catalytic technology, and is characterized in that: graphene oxide and metal compounds are used as precursors, and a continuous reduction method is adopted , to obtain small-sized nano-metal and nano-metal alloy particles loaded three-dimensional porous graphene airgel catalyst. In the catalyst, the types of nano-metals and nano-metal alloys are selected from: Pt, Au, Ag, Pd, Ru, Rh, Pb, Fe, Co, Ni, Ir, Cu, etc.; the types and proportions can be arbitrarily matched. The size of the nanoparticles is about 2-6 nm, and they are evenly distributed on the graphene sheet. At the same time, graphene is assembled into a three-dimensional porous airgel structure with an average pore size of 1-2 microns, which can have a high specific surface area, high electron transport and mass transport rate, and prevent the agglomeration of graphene and nanoparticles. The composite material has excellent catalytic performance, and the components of the catalyst can be selected according to different needs.

Description

technical field [0001] The invention relates to a graphene airgel-loaded nano-metal or metal alloy catalyst and a preparation method thereof, belonging to the technical field of nano-material application and catalysis. Background technique [0002] Nano-noble metals platinum (Pt), gold (Au), silver (Ag), palladium (Pd) are very active catalysts, widely used in various chemical reactions including hydrogenation, NO reduction, CO oxidation and organic small molecule oxidation reactions , oxygen reduction, etc. Not only that, but Pt and Pd are also the most important catalysts for fuel cells; with the continuous development of industry and technology, the importance of clean energy has become increasingly prominent. This is not only a challenge to energy technology, but also brings energy science. to a huge impetus. [0003] Proton exchange membrane fuel cell (PEMFC), as a new type of energy device, has many advantages such as low operating temperature, no pollution, high spec...

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Problems solved by technology

The mechanism is as follows: using graphene oxide as a precursor, after being modified by the positively charged organic electrolyte reagent PDDA, the surface of graphene oxide is positively charged, which can electrostatically adsorb some negatively charged metal ion precursors (here if using There is no need to use PDDA to modify the positively charged metal ion precursor), then use ultrasonic reduction method, add an appropriate amount of strong reducing agent under ultrasonic conditions for reduction, then add ascorbic acid, and after constant temperature and heat preservation, three-dimensional graphene water can be formed. The composite material of gel-loaded nanoparticles can be obtained after freeze-drying or supercritical CO2 drying to obtain three-dimensional graphene airgel-loaded nano-metal and alloy catalysts; here, PDDA is used to regulate the distribution of nanoparticles, and its The dosage has a great influence on the formation of three-dimensional materials. After a certain value, the three-dimensional graphene structure cannot be formed. The pre-reduction of a strong reducing agent under ultrasonic conditions can play two roles. One: it can be reduced to obtain more active metals. Alloys, such as Pt-Fe, Pt-Co, Pt-Ni, Pt-Cu, etc.; second: to obtain nanoparticles with smaller sizes. Similarly, the amount of strong reducing agent also plays a key role in the formation of three-dimensional graphene , beyond a certain amount, high quality cannot be obtained, or a three-dimensional graphene structure cannot be formed

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