title: Surface-Regulated Nano-SnO2/Pt3Co/C Cathode Catalysts for Polymer Electrolyte Fuel Cells Fabricated by a Selective Electrochemical Sn Deposition Method.
abstract: We have achieved significant improvements for the oxygen reduction reaction activity and durability with new SnO2-nanoislands/Pt3Co/C catalysts in 0.1 M HClO4, which were regulated by a strategic fabrication using a new selective electrochemical Sn deposition method. The nano-SnO2/Pt3Co/C catalysts with Pt/Sn = 4/1, 9/1, 11/1, and 15/1 were characterized by STEM-EDS, XRD, XRF, XPS, in situ XAFS, and electrochemical measurements to have a Pt3Co core/Pt skeleton-skin structure decorated with SnO2 nanoislands at the compressive Pt surface with the defects and dislocations. The high performances of nano-SnO2/Pt3Co/C originate from efficient electronic modification of the Pt skin surface (site 1) by both the Co of the Pt3Co core and surface nano-SnO2 and more from the unique property of the periphery sites of the SnO2 nanoislands at the compressive Pt skeleton-skin surface (more active site 2), which were much more active than expected from the d-band center values. The white line peak intensity of the nano-SnO2/Pt3Co/C revealed no hysteresis in the potential up-down operations between 0.4 and 1.0 V versus RHE, unlike the cases of Pt/C and Pt3Co/C, resulting in the high ORR performance. Here we report development of a new class of cathode catalysts with two different active sites for next-generation polymer electrolyte fuel cells.
authors.forename: Kensaku
authors.initials: K
authors.lastname: Nagasawa
authors.forename: Shinobu
authors.initials: S
authors.lastname: Takao
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Nagamatsu
authors.forename: Gabor
authors.initials: G
authors.lastname: Samjeské
authors.forename: Oki
authors.initials: O
authors.lastname: Sekizawa
authors.forename: Takuma
authors.initials: T
authors.lastname: Kaneko
authors.forename: Kotaro
authors.initials: K
authors.lastname: Higashi
authors.affiliation: Faculty for Integrated Arts and Sciences, The University of Tokushima , Minamijosanjima, Tokushima 770-8502, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Japan Synchrotron Radiation Research Institute , SPring-8, Sayo, Hyogo 679-5198, Japan.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Uruga
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Iwasawa