Preparation method of Pt-pd alloy type catalyst

Abstract

The invention relates to a preparation method of a Pt-pd alloy type catalyst. The preparation method comprises the following steps: (1) dissolving polyoxyethylene-polyoxypropylene segmented copolymer used as a reducing agent and a protecting agent into deionized water to obtain copolymer solution; (2) adding platinum salt solution and palladium salt solution into the copolymer solution obtained in the step (1), reacting while stirring, cooling the reaction system to be at room temperature after finishing the reaction to obtain Pt-Pd alloy nanoparticle sol; and (3) adding an electrical conductive carrier into the Pt-Pd alloy nanoparticle sol in the step (2), stirring to load the Pt-Pd alloy nanoparticle sol on the electrical conductive carrier, separating, washing, and drying to obtain the Pt-Pd alloy type catalyst.

Description

technical field [0001] The invention relates to a preparation method of a Pt-Pd alloy catalyst for a fuel cell. Background technique [0002] With the increasing depletion of fossil energy, environmental pollution and climate change, clean energy has attracted great attention from all over the world. Proton exchange membrane fuel cells have many advantages such as high power density, high energy conversion efficiency, low operating temperature, and no noise pollution, and are considered to be widely used in transportation power sources, backup power sources and other fields. However, the commercialization of proton exchange membrane fuel cells faces the problem of high cost, in which the catalyst occupies a large proportion, because the catalyst uses Pt, and the resource of Pt is limited, so the price is high. In order to reduce the cost of fuel cells, the amount of Pt must be reduced, which requires an increase in the catalytic activity per unit mass of Pt (mass activity),...

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Problems solved by technology

Chinese patent (application number: CN201110300365.2) discloses a method for preparing PdPt core-shell catalysts using ascorbic acid as a reducing agent and Pluronic F127 as a protective agent, but the particle size of the catalyst prepared by this method is relatively large, around 15-30nm , and the Pt shell has a dendritic structure, which is easy to cause corrosion of the catalyst

Chinese patent (application number: CN200310121180.0) discloses a method for preparing Pt-Pd bimetallic catalysts using ethylene glycol as a reducing agent, but when using this method to prepare catalysts with high Pd content, the Pd nanoparticles are very unstable , the prepared catalyst particles are easy to agglomerate, and the catalyst active area is small, which cannot meet the needs of fuel cells.

People such as A. Maghsodi use sodium borohydride as reducing agent to prepare Pt-Pd alloy, although the preparation method is simple, because the speed of sodium borohydride reduction metal ion is faster, it is difficult to control, the particle size of the prepared metal particle is bigger, As a result, the active area of ​​the catalyst is small, which affects the catalytic activity of the catalyst (A. Maghsodi et al. Applied Surface Science, 2011, 257, 6353.)

In addition, polyvinylpyrrolidone (PVP) was used as both a protective agent and a reducing agent in the preparation of Pt-Pd alloys (Lim et al., Angew. Chem.-Int. Edit., 2009, 48, 6304.), however, the adsorption on The removal of PVP on the surface of nanoparticles is very difficult, and the residual PVP will cover the active sites of the catalyst, seriously affecting its catalytic activity (Long, N. V., et al., ColloidPolym. Sci., 2011, 289, 1373.)

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