Platinum-based intermetallic nanocrystalline oxygen reduction catalyst and preparation method thereof

Abstract

The invention belongs to the field of fuel cell cathode materials, and particularly discloses a platinum-based intermetallic nanocrystalline oxygen reduction catalyst and a preparation method thereof.The preparation method comprises the following steps: S1 mixing a platinum salt solution and a reducing agent solution to obtain a mixed solution, reacting the platinum salt in the mixed solution with the reducing agent to obtain platinum nanoparticles and separating the platinum nanoparticles from the mixed solution; and S2 coating a metal oxide on the surface of the platinum nanoparticles to obtain a platinum and metal oxide composite and performing annealing treatment on the platinum and metal oxide composite to obtain the platinum-based intermetallic nanocrystalline oxygen reduction catalyst. The platinum-based intermetallic nanocrystalline oxygen reduction catalyst is used for accelerating the cathode oxygen reduction reaction rate of the fuel cell and has good activity and durability and has simple synthesis process and can effectively regulate and control the size of nanoparticles and is easy to produce in mass.

Description

Technical field [0001] The present invention belongs to the field of fuel cell cathode materials. More specifically, it relates to a platinum-based intermetallic nanocrystalline oxygen reduction catalyst and a preparation method thereof, in particular to a platinum-based intermetallic nanocrystal for accelerating the oxygen reduction reaction rate of a fuel cell cathode. Crystal oxygen reduction catalyst and its preparation method. Background technique [0002] At present, with the rapid development of society, mankind’s demand for energy is expanding. At the same time, the gradual consumption of coal, oil, natural gas and other fossil energy and environmental pollution are urgently needed to be solved. The development of green and pollution-free energy has become a national concern. Focus on the key points. Proton Exchange Membrane Fuel Cell (PEMFC) can convert the chemical energy stored in fuel / oxygen into electrical energy through an electrochemical process. Because there is ...

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Problems solved by technology

In the current research, alloying platinum with transition metals can effectively improve the oxygen reduction catalytic activity of platinum-based catalysts, but there are still problems with its stability: that is, transition metals are prone to dissolution under high temperature, high voltage and acidic conditions. , leading to a decrease in the activity of the catalyst

In addition, since the nanoparticles have to undergo high-temperature annealing to complete the phase transition process, the nanocrystals of these platinum-based intermetallic compounds are currently relatively large in size (usually 10nm in size), and the utilization rate of platinum atoms is low, resulting in relatively low activity and limiting Further applications of this type of catalyst

A large number of studies have shown that as the size of nanoparticles decreases, their electrochemically active area increases sharply, which can greatly increase the utilization rate of platinum atoms, thereby improving the activity of the catalyst; An effective method for agglomeration in the catalyst is to coat the surface of nanoparticles with inert protective layers such as magnesium oxide and silicon oxide, but the introduction of these protective layers requires additional preparation processes, which makes the preparation process of the entire catalyst more complicated and cumbersome, which is not conducive to large-scale, Industrial production

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