Zehl, G.; Dorbandt, I.; Schmithals, G.; Radnik, J.; Wippermann, K.; Richter, B.; Bogdanoff, P.; Fiechter, S.: Preparation of carbon supported Ru-Se based catalysts and their electrochemical performance in DMFC cathodes. ECS Transactions 3 (2006), p. 1261-1270
10.1149/1.2356245
Abstract:
Ruthenium catalysts were prepared employing aqueous solutions of ruthenium salts as precursors to obtain 2 nm sized metal particles homogeneously dispersed on a CO2-activa¬ted carbon support after annealing in hydrogen at 200 °C. Selenium treatment was per¬form¬ed pouring the reduced product into a H2SeO3 or a SeCl4 solution prior to reduction in hydrogen at 300 °C and 800 °C. RuSex clusters have been formed which convert into a RuSexOy cluster after exposure to air. The presence of selenium in the cluster surface leads to a significant stabilisa¬tion against oxi¬dation of the metallic core and enables a highly selective catalytic activity towards the oxygen reduction reaction. The highest current density in RDE experi¬ments was observed for a carbon supported Ru(25wt%)Se(6wt%) catalyst. Varying metal loading, PTFE and NAFION content in the cathode layer of a DMFC-MEA structure, best results were obtained using a metal loading of 1 mg/cm2 obtaining power densities of 20 mW/cm2 at a cell voltage of 0.4 V in a single cell