Carbon-Supported W@Pt Nanoparticles with a Pt-Enriched Surface as a Robust Electrocatalyst for Oxygen Reduction Reactions

摘要

A carbon-supported surface-platinum-enriched tungsten nanoparticles (W@Pt/C) is successfully prepared via a replacement method. X-ray diffraction results verify that the prepared tungsten (W) nanoparticles are amorphous and that platinum (Pt) particles have been successfully placed onto the surface. Transmission electron microscopy shows that the surfaceplatinum- enriched tungsten (W@Pt) nanoparticles are uniformly dispersed on the surface of the carbon support and have an average size of only 1.9 nm. Energy-dispersive X-ray spectroscopy reveals that the Pt and W elements are evenly distributed on the surface of the catalyst. Electrochemical measurements confirm that the as-prepared catalyst exhibits an enhanced catalytic activity for oxygen reduction reaction (ORR) in comparison with commercial catalyst (JM Pt/C). Furthermore, the mass activity of the W@Pt/C catalyst at a potential of 0.9 V/ RHE is 2.1 times higher than that of Pt/C (JM). Importantly, the ORR durability of the catalyst is greatly improved as compared to Pt/C (JM). This result may be due to the fact that the mean particle size of the W@Pt/C remains nearly constant during an accelerated durability test. Based on these results, the W@Pt/C maybe a promising cathode catalyst for use in fuel cells.