Oxygen reduction reaction (ORR) is an important cathode reaction used in fuel cells and metal-air batteries for renewable energy applications. Platinum (Pt) has been studied extensively as an essential catalytic component to reduce undesired overpotentials observed in ORR. Previous experimental and computational investigations have revealed that once alloyed with first-row transition metals, Pt can show dramatic activity enhancement in ORR catalysis. Recent experiments further indicate that elongated Pt nanostructures are less subject to dissolution, Ostwald ripening and aggregation than the Pt NPs in acidic conditions and may be robust for catalyzing ORR with high activity and durability.Using thermal decomposition of metal pentacarbonyl and/or reduction of metal acetylacetonate in sodium oleate solution of 1-octadecene (ODE) and oleylamine (OAm), we have succeeded in preparing FePt, CoPt or FePtM (M = Cu, Ni) NWs with the desired alloy composition control. Electrochemical studies showed that these NWs were active catalysts for ORR. The specific and mass activities of the 2.5 nm wide FePt NWs reached 1.53 mA/cm2 and 844 mA/mg Pt at 0.9 V (vs. reversible hydrogen electrode, RHE) (0.2 mA/cm2 and 110 mA/mg Pt at 0.95 V) while those of the benchmark Pt catalyst valued at 0.32 mA/cm2 and 155 mA/mg Pt at 0.9 V (0.080 mA/cm2 and 35 mA/mg Pt at 0.95 V). The NWs also demonstrated diameter dependent ORR catalysis, and the 6.3 nm wide FePt NWs showed an even higher specific activity of 3.9 mA cm-2 at 0.9 V and 0.46 mA cm-2 at 0.95 V. These NWs represent a new class of robust catalyst for ORR and may be more applicable in practical fuel cell and other related energy devices.

MPt nanowires as efficient catalysts for oxygen reduction reaction

246th National Meeting (2013)

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