Highly durable Pd metal catalysts for the oxygen reduction reaction in fuel cells; coverage of Pd metal with silicaElectronic supplementary information (ESI) available: Details of experimental method, TEM image, polarization curves for the ORR and CO stripping voltammogram. See DOI: 10.1039/c0cc04055j

Pd cathode catalysts for polymer electrolyte fuel cells have been covered with silica layers a few nanometres thick. The silica-coated Pd catalysts showed high activity and excellent durability for the oxygen reduction under the severe cathode conditions of PEFCs, while Pd catalysts without silica-coating were seriously deactivated under the same conditions. The coverage of Pd metal with silica prevents the diffusion of Pd species out of the silica layers. [ABSTRACT FROM AUTHOR]