Nano-metal or metal alloy catalyst and preparing method thereof

Abstract

The invention relates to a graphene aerogel-supported nano-metal or metal alloy catalyst and a preparing method thereof and belongs to the technical field of nanometer material application and catalysis. The preparing method is characterized by comprising the following steps: using graphene oxide and a metal compound as precursors, and obtaining a catalyst with small-size nano-metal and nano-metal alloy particles supported by a three-dimensional porous graphene aerogel by a continuous reduction process. In the catalyst, the varieties of the nano-metal and the nano-metal alloy are selected from Pt, Au, Ag, Pd, Ru, Rh, Pb, Fe, Co, Ni, Ir, Cu and the like; the varieties can be matched at will by any mixing ratio; the nanometer particles are about 2-6nm in size and uniformly distributed on a graphene sheet layer. Meanwhile, the graphene is assembled into a three-dimensional porous aerogel structure, the average size of pore diameters is 1-2 micrometers, high specific area, high electron transmission rate and high mass transmission rate can be obtained, and the agglomeration of the graphene and the nanometer particles is prevented. The composite has excellent catalytic performance, and the components of the catalyst can be selected according to different requirements.

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...

AI Technical Summary

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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