A Highly Durable Platinum Nanocatalyst for Proton Exchange Membrane Fuel Cells: Multiarmed Starlike Nanowire Single Crystal

Abstract

Ein neuer Stern unter den Katalysatoren: Mehrarmige sternförmige Pt‐Nanodrähte auf Kohlenstoffträger (siehe SEM‐Bild) sind aktive und stabile Elektrokatalysatoren für Protonenaustauschmembran‐Brennstoffzellen. Diese neuartige Nanostruktur ist weitaus aktiver und haltbarer als der gegenwärtig eingesetzte, kommerzielle Pt/C‐Katalysator mit Pt‐Nanopartikeln.

High‐Performance Nanofiber Fuel Cell Electrodes

“…More importantly, the mass activity of ES01 at 0.9 V with a cathode feed of pure oxygen was 0.23 A mg Pt À1 , which is twice that for Decal04. It should be noted that: (i) the measured ECSA and mass activity for Decal04 are very close to literature data, [8,[25][26][27] thus confirming the accuracy of data collection and analysis in the present study; and (ii) the measured MEA cathode mass activity of 0.23 A mg Pt À1 matches that for 3M Corporation's nanostructured thin-film whisker material [28] and thus is among the highest activities reported in the open literature.…”

FePt and CoPt Nanowires as Efficient Catalysts for the Oxygen Reduction Reaction

“…[16] The enhancement in both ORR activity and stability observed in FePt NWs arises very likely from the Pt topmost atoms arranged along a long NW facet, as well as from the strong interaction between the NWs and the carbon support, which hinders NW dissolution, Ostwald ripening, and aggregation. [8,10,11] The thicker (6.3 nm) FePt NWs showed even better specific ORR catalysis. These NWs were synthesized by growing FePt over the preformed 2.5 nm Fe 56 Pt 44 NWs (Experimental Section).…”

“…Nonetheless, the present FePt NWs have the highest specific activity for the ORR among all reported elongated Pt-based ORR catalysts. [8,10,11] The mass activity of Fe 20 Pt 80 NWs is 844 mA mg À1 Pt, exceeding the DOE 2015 target at 440 mA mg À1 Pt (DOE = U.S. Department of Energy). [16] The enhancement in both ORR activity and stability observed in FePt NWs arises very likely from the Pt topmost atoms arranged along a long NW facet, as well as from the strong interaction between the NWs and the carbon support, which hinders NW dissolution, Ostwald ripening, and aggregation.…”

“…[4] Previous computational and experimental investigations have revealed that once alloyed with first-row transition metals, such as Fe, Co, and Ni, Pt alloy thin films and nanoparticles (NPs) can show dramatic activity enhancement in ORR catalysis, [5,6] especially when the Pt-skin structure is formed on the surface of MPt. [7] This enhancement is believed to originate from the downshift of the d-band center of Pt in the alloy structure; this downshift results in a decrease of the bonding strength between Pt and the oxygenated species (often called blocking species or spectators) and an increased number of available Pt sites for oxygen adsorption.[5] Recent experiments also indicate that elongated Pt nanostructures are less subject to dissolution, Ostwald ripening, and aggregation than the Pt NPs in acidic conditions, [8][9][10][11] and that they may be robust for catalyzing the ORR with high activity and durability.Herein, we report an advanced organic-phase synthesis of thin FePt and CoPt alloy nanowires (NWs) for enhanced catalysis of the ORR. Different from the previous approach to FePt NPs [12] and FePt NWs, [13] the current synthesis through decomposition of metal pentacarbonyl and reduction of platinum acetylacetonate, [Pt(acac) 2 ], was performed in sodium oleate solution of 1-octadecene (ODE) and oleylamine (OAm).…”

Plasma nitriding induced growth of Pt-nanowire arrays as high performance electrocatalysts for fuel cells

“…Among various novel nanostructures, one-dimensional (1D) single-crystal Pt-nanowires have been demonstrated as an excellent new type of fuel cell electrocatalysts due to their excellent catalytic activity and stability induced by non-isotropy structures and special surface properties1617181920. The synthesis of single-crystal Pt-nanowires has also been demonstrated by Xia et al1117 and Sun et al162122 with wet chemical process. However, due to the strict synthesis process required for the delicate control of Pt reduction kinetics, a large-area direct fabrication of uniform Pt nanowires on electrodes remains a grand challenge for practical applications182324.…”