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@ARTICLE{Beermann:842560,
      author       = {Beermann, Vera and Gocyla, Martin and Kühl, Stefanie and
                      Padgett, Elliot and Schmies, Henrike and Goerlin, Mikaela
                      and Erini, Nina and Shviro, Meital and Heggen, Marc and
                      Dunin-Borkowski, Rafal and Muller, David A. and Strasser,
                      Peter},
      title        = {{T}uning the {E}lectrocatalytic {O}xygen {R}eduction
                      {R}eaction {A}ctivity and {S}tability of
                      {S}hape-{C}ontrolled {P}t–{N}i {N}anoparticles by
                      {T}hermal {A}nnealing − {E}lucidating the {S}urface
                      {A}tomic {S}tructural and {C}ompositional {C}hanges},
      journal      = {Journal of the American Chemical Society},
      volume       = {139},
      number       = {46},
      issn         = {1520-5126},
      address      = {Washington, DC},
      publisher    = {American Chemical Society},
      reportid     = {FZJ-2018-00779},
      pages        = {16536 - 16547},
      year         = {2017},
      abstract     = {Shape-controlled octahedral Pt–Ni alloy nanoparticles
                      exhibit remarkably high activities for the electroreduction
                      of molecular oxygen (oxygen reduction reaction, ORR), which
                      makes them fuel-cell cathode catalysts with exceptional
                      potential. To unfold their full and optimized catalytic
                      activity and stability, however, the nano-octahedra require
                      post-synthesis thermal treatments, which alter the surface
                      atomic structure and composition of the crystal facets.
                      Here, we address and strive to elucidate the underlying
                      surface chemical processes using a combination of ex situ
                      analytical techniques with in situ transmission electron
                      microscopy (TEM), in situ X-ray diffraction (XRD), and in
                      situ electrochemical Fourier transformed infrared (FTIR)
                      experiments. We present a robust fundamental correlation
                      between annealing temperature and catalytic activity, where
                      a ∼25 times higher ORR activity than for commercial Pt/C
                      (2.7 A mgPt–1 at 0.9 VRHE) was reproducibly observed upon
                      annealing at 300 °C. The electrochemical stability,
                      however, peaked out at the most severe heat treatments at
                      500 °C. Aberration-corrected scanning transmission electron
                      microscopy and energy-dispersive X-ray spectroscopy (EDX) in
                      combination with in situ electrochemical CO stripping/FTIR
                      data revealed subtle, but important, differences in the
                      formation and chemical nature of Pt-rich and Ni-rich surface
                      domains in the octahedral (111) facets. Estimating trends in
                      surface chemisorption energies from in situ electrochemical
                      CO/FTIR investigations suggested that balanced annealing
                      generates an optimal degree of Pt surface enrichment, while
                      the others exhibited mostly Ni-rich facets. The insights
                      from our study are quite generally valid and aid in
                      developing suitable post-synthesis thermal treatments for
                      other alloy nanocatalysts as well.},
      cin          = {ER-C-1 / PGI-5 / IEK-3},
      ddc          = {540},
      cid          = {I:(DE-Juel1)ER-C-1-20170209 / I:(DE-Juel1)PGI-5-20110106 /
                      I:(DE-Juel1)IEK-3-20101013},
      pnm          = {143 - Controlling Configuration-Based Phenomena (POF3-143)},
      pid          = {G:(DE-HGF)POF3-143},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:29019692},
      UT           = {WOS:000416496400025},
      doi          = {10.1021/jacs.7b06846},
      url          = {https://juser.fz-juelich.de/record/842560},
}