Structure and Local Reactivity of Supported Catalyst/Nafion® Layers studied by in-situ STM

Kurzfassung

The electrodes are crucial components for fuel cells, since this is where the electrochemical reactions take place. In order to provide an insight into the structure/activity relationships of the rather complex electrodes, a high-resolution measuring technique, based on a scanning tunneling microscope operating in an electrochemical cell, has been developed. The structure of the electrode surface can be imaged from the microscale to the nanoscale, under conditions quite close to those in a working fuel cell. The relative reactivity is measured by using the STM tip as a sensor electrode for the ORR. Here, the first results of the surface structure of the electrode materials are presented, as well as measurements of the local reduction current, related to the oxygen reduction reaction, giving a relative measure for the local reactivity.