Kern-Schale-Nanopartikel in Kathodenkatalysatoren für PEM-Brennstoffzellen

Due the high costs of the platinum based electrodes for oxygen reduction reaction (ORR) in fuel cells the commercial use of proton exchange membrane fuel cells is limited. To overcome this problem we do research on core shell electrocatalysts to improve the kinetics of the ORR and to reduce the necessary platinum amount to a minimum. Furthermore we work on different upscaling methods like chemical or electrochemical deposition methods. Based on that we developed a chemical deposition of copper on carbon support followed by redox exchange reaction with platinum to make Cu_CorePt_shell electrocatalysts. Therefore the copper particles were deposited especially on Vulcan X72 but also on other supports like different CNTs through reductions methods followed by a redox exchange reaction of the upper copper layers with platinum under varying conditions like pH, time, concentrations or heat treatment. We also moved on to enhance the electrochemical deposition of platinum on Cu/C catalysts using the electrochemical slurry reactor (ESR) of our group. In this ESR we exchange some upper layers of copper through the pulse deposition of platinum under the variation of electrolyte, time and concentrations. The obtained Cu@Pt/C electrocatalysts can be characterized by electrochemical methods such as cyclic voltammetry (CV), methanol oxidation (MeOH-Ox.), ORR and CO-oxidation experiments. Morphological and physical properties are determined with X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Furthermore inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray photoelectron spectroscopy (XPS) and special IR-measurements can be done through cooperation partners.