Estudo da inserção de grafeno em catalisadores de PtSn para a oxidação de etanol

Abstract

Fuel cells are portable electrochemical converters that generate electricity using renewable fuels and can act as high-efficiency energy sources. When fed with ethanol, they lose performance due to electrode poisoning. To mitigate this problem, noble metals are used in the electrodes in addition to the addition of elements to the electrocatalysts, increasing the production cost while the problem persists. Thus, this study seeks to increase the efficiency of ethanol oxidation by modifying the carbon support with graphene, where the metallic phase is anchored, and to verify its influence on the general catalysis process. Electrocatalysts with carbon-graphene hybrid support were synthesized in different proportions, and a physical mixture of graphene with the carbon-supported electrocatalyst was prepared. Hybrid supported electrocatalysts showed higher electrochemical activity and stability in ethanol oxidation compared to carbon supported electrocatalyst, with an increase of 132% in alkaline medium. In the physical mixture, the addition of graphene generated a 10% decrease in the amount of metallic phase needed, obtaining the same performance as the pure electrocatalyst. While in acidic medium, in addition to the 10% decrease, the physical mixture exhibited a much superior performance to the pure electrocatalyst. The results showed that the influence of graphene depends on its interaction with the electrocatalyst, while promoting an increase in the performance of ethanol oxidation.