title: Highly Durable Supportless Pt Hollow Spheres Designed for Enhanced Oxygen Transport in Cathode Catalyst Layers of Proton Exchange Membrane Fuel Cells.
abstract: Supportless Pt catalysts have several advantages over conventional carbon-supported Pt catalysts in that they are not susceptible to carbon corrosion. However, the need for high Pt loadings in membrane electrode assemblies (MEAs) to achieve state-of-the-art fuel cell performance has limited their application in proton exchange membrane fuel cells. Herein, we report a new approach to the design of a supportless Pt catalyst in terms of catalyst layer architecture, which is crucial for fuel cell performance as it affects water management and oxygen transport in the catalyst layers. Large Pt hollow spheres (PtHSs) 100 nm in size were designed and prepared using a carbon template method. Despite their large size, the unique structure of the PtHSs, which are composed of a thin-layered shell of Pt nanoparticles (ca. 7 nm thick), exhibited a high surface area comparable to that of commercial Pt black (PtB). The PtHS structure also exhibited twice the durability of PtB after 2000 potential cycles (0-1.3 V, 50 mV/s). A MEA fabricated with PtHSs showed significant improvement in fuel cell performance compared to PtB-based MEAs at high current densities (>800 mA/cm2). This was mainly due to the 2.7 times lower mass transport resistance in the PtHS-based catalyst layers compared to that in PtB, owing to the formation of macropores between the PtHSs and high porosity (90%) in the PtHS catalyst layers. The present study demonstrates a successful example of catalyst design in terms of catalyst layer architecture, which may be applied to a real fuel cell system.
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.|University of Science and Technology (UST) , Daejeon, 305-350, Republic of Korea.
authors.forename: Didem C
authors.initials: DC
authors.lastname: Dogan
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.|University of Science and Technology (UST) , Daejeon, 305-350, Republic of Korea.
authors.forename: Seonghun
authors.initials: S
authors.lastname: Cho
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.
authors.forename: Sun-Mi
authors.initials: SM
authors.lastname: Hwang
authors.affiliation: Korea Basic Science Institute (KBSI) , Daejeon, 305-806, Republic of Korea.|Department of Energy Science, Sungkyunkwan University (SKKU) , Suwon, 440-746, Republic of Korea.
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.affiliation: Korea Basic Science Institute (KBSI) , Daejeon, 305-806, Republic of Korea.
authors.forename: Hwanuk
authors.initials: H
authors.lastname: Guim
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yang
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.
authors.forename: Seok-Hee
authors.initials: SH
authors.lastname: Park
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.|University of Science and Technology (UST) , Daejeon, 305-350, Republic of Korea.
authors.forename: Gu-Gon
authors.initials: GG
authors.lastname: Park
authors.affiliation: Fuel Cell Laboratory, Korea Institute of Energy Research (KIER) , Daejeon, 305-343, Republic of Korea.|University of Science and Technology (UST) , Daejeon, 305-350, Republic of Korea.
authors.forename: Sung-Dae
authors.initials: SD
authors.lastname: Yim
keywords: MEA; PEMFC; catalyst layer; durability; oxygen transport; supportless Pt