Nanopartículas de platina suportadas em quitosana para aplicação como catalisadores em células a combustível

Abstract

The limitation of energy resources and the increase in energy consumption favor research into alternative energy generation systems. In this sense, fuel cells (CaC) represent an approach to generating clean energy. Over the years, cells that use alcohols as fuel, called DAFCs (Direct Alcohol Fuel Cells), have emerged. Selective oxidation of alcohols to aldehydes or acids by an electrochemical approach is useful in synthetic chemistry. The alcohols that have been most studied for this purpose are methanol and ethanol. These cells have numerous advantages, such as no need to store or generete hydrogen through hydrocarbon reforming. Currently, studies have focused on the application of catalytic materials with low platinum content in order to reduce their operating costs. Platinum nanoparticles (PtNPs) have high surface area, high melting point (1769˚C) and good resistance to corrosion and chemical attacks. These nanoparticles are efficient in a series of electrochemical reactions, being one of the best catalysts for breaking C─H and O─H bonds at the potentials of interest in the operation of fuel cells. The dissertation deals with the study of the green synthesis route mediated by guarana extract (Paullinia cupana) to obtain platinum nanoparticles, with the aim of using them in the production of electrocatalysts supported on chitosan and active carbon, to promote the oxidation of ethanol in DEFC (Direct Ethanol Fuel Cell) type cells. Chitosan was extracted from shells of caranguejo vermelho (Dilocarcinus pagei), a species very common in the Amazon region. The results indicate that the electrocatalysts synthesized with the obtained nanoparticles, Pt/C and Pt/Q, can promote the oxidation of ethanol, however the current densities were low.