New PtRu alloy colloids as precursors for fuel cell catalysts

We describe the preparation and characterization of new PtRu alloy colloids that are suitable as precursors for fuel cell catalysts. The new, simplifi ed preparation method, which uses an organometallic compound both for reduc tion and as colloid stabilizer, leads to a PtRu colloid possessing lipophil ic surfactant stabilizers. These can easily be modified to show hydrophilic properties. Prior to electrochemical measurements the surfactant shell is removed by reactive annealing in O-2 and H-2, Comparing the electrocatalyti cal activity of the Vulcan-supported colloids with that of a differently pr epared PtRu colloid investigated recently and with a commercially available PtRu catalyst, we found practically identical activities with respect to C O and CO/H-2 oxidation, Activities of similar order of magnitude were found also for methanol oxidation. The results demonstrate the high potential of the new organometallic preparation scheme for the synthesis of colloid pre cursors for bimetallic catalysts, especially if it is considered that varia tions in the alloy composition can easily be realized using the colloidal p reparation method. (C) 2000 Academic Press.