Fuel cells are promising electrochemical devices for energy conversion but, until now, there are important challenges to be overcome such as the catalyst poisoning by CO adsorption. This molecules appears during direct oxidation reaction of methanol ( or any other common small organic molecule used) and as contaminant when the fuel is hydrogen. Due to its strong interaction with the Pt surface, CO adsorbed molecules block the active sites and, then, decreases the fuel cell efficiency. The most common proposition to increase the electrocatalyst acitivity is to use Pt alloys which can be prepared by electrodeposition. In our laboratory, we are developing a different approach: the use of metallic multilayers as catalysts. In this approach, each layer has thickness of some nanometers and, as described in the literature, important changes in the electronic structure of the materials, i.e., the density of states at the Fermi level or its energy value or even the format of the electronic energy bands could occur. Although we have observed important increase in the electrocatalytic acitivity for the oxidation of small organic molecules, there is not in the literature any mechanistic explanation for the observed effect. Therefore, this research plan aims at the investigation of CO and ethanol oxidation over such heterostructured materials using in situ infra-red spectroscopy to improve the knowledge of this nanostructured samples.
News published in Agência FAPESP Newsletter about the scholarship: