Method for preparing oxygen reduction catalyst from biomass and product

Abstract

The invention discloses a method for preparing an oxygen reduction catalyst from biomass and a product. The method comprises the following steps: S1, mixing biomass with a transition metal salt solution I, and performing freeze-drying to obtain a mixture I; S2, pyrolyzing the mixture I in an inert atmosphere to obtain a core-shell structure material with transition metal nanoparticles wrapped by agraphite carbon layer; S3, dispersing the core-shell structure material into a volatile organic solvent, adding a nitrogen-containing organic matter and a transition metal salt solution II, performing mixing and drying to obtain a mixture II; and S4, pyrolyzing the mixture II in an inert atmosphere so as to grow nitrogen-containing carbon nanofibers on the surface of the core-shell structure material, and washing, filtering and drying the nitrogen-containing carbon nanofibers to obtain the required oxygen reduction catalyst. The sea urchin-shaped oxygen reduction catalyst can be prepared, hasdeveloped porosity, high nitrogen content and stable metal active sites, and has good activity and durability in the aspect of oxygen reduction catalysis.

Description

technical field [0001] The invention belongs to the field of preparation of biomass-based carbon materials, and more specifically relates to a method and product for preparing an oxygen reduction catalyst from biomass, in particular to a method for preparing a nitrogen-rich carbon catalyst coated with metal alloy nanoparticles by utilizing biomass. Background technique [0002] Metal-air battery is a device that can continuously convert chemical energy into electrical energy. Metal-air battery has the advantages of high conversion efficiency and convenient use. Especially in recent years, the research and development and commercialization of hydrogen energy vehicles have attracted extensive attention. , while noble metal (including platinum, palladium, ruthenium, etc.) catalysts are usually used in the cathode oxygen reduction process in batteries, and their high cost, limited resources and poor durability restrict the further development of batteries. Therefore, there is an...

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Problems solved by technology

This method has several disadvantages: 1) the raw material applicability is narrow, only suitable for a small amount of nitrogen-rich biomass (nitrogen N>3wt.%); 2) the precipitation of nitrogen during high-temperature carbonization leads to the reduction of active sites, while Low-temperature carbonization, the degree of carbonization is too low, and the conductivity is too poor, so the contradiction between conductivity and active sites brings technical difficulties; 3) It is difficult to quantitatively control the nitrogen content on the surface of carbon products, and more importantly, the form of nitrogen (Pyridine, pyrrole, G nitrogen, nitrogen oxide) are even more unpredictable, unable to be prepared in a directional manner, resulting in unstable catalytic activity; 4) The inherent structure of biomass macromolecules is difficult to graphitize. Amorphous carbon often has the disadvantage of poor cycle stability in terms of catalytic performance

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