Structural disordering of de-alloyed Pt bimetallic nanocatalysts: the effect on oxygen reduction reaction activity and stability

TY - JOUR

T1 - Structural disordering of de-alloyed Pt bimetallic nanocatalysts

T2 - the effect on oxygen reduction reaction activity and stability

AU - Spanos, Ioannis

AU - Dideriksen, Knud

AU - Kirkensgaard, Jacob Judas Kain

AU - Jelavic, Stanislav

AU - Arenz, Matthias

PY - 2015

Y1 - 2015

N2 - Platinum bimetallic alloys are well-known for their ability to catalyze the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). PtxCo1-x colloidal nanoparticles were synthesized with varying initial Pt : Co ratios, but constant size to investigate how the initial metal composition affects their electrocatalytic performance. The results show that upon contact with acid environment the Co leaches out of the particles leading to almost identical compositions, independent of the initial differences. Surprisingly the data show a clear trend in ORR activity, although the PtxCo1-x nanoparticles almost completely de-alloy during acid leaching, i.e. under reaction conditions in a fuel cell. To scrutinize the resulting particle structure after de-alloying we used pair distribution function (PDF) analysis and X-ray diffraction (XRD) gaining insight into the structural disorder and its dependence on the initial metal composition. Our results suggest that not only the ORR activity, but also the corrosion resistance of the synthesized NPs, are dependent on the structural disorder resulting from the de-alloying process.

AB - Platinum bimetallic alloys are well-known for their ability to catalyze the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). PtxCo1-x colloidal nanoparticles were synthesized with varying initial Pt : Co ratios, but constant size to investigate how the initial metal composition affects their electrocatalytic performance. The results show that upon contact with acid environment the Co leaches out of the particles leading to almost identical compositions, independent of the initial differences. Surprisingly the data show a clear trend in ORR activity, although the PtxCo1-x nanoparticles almost completely de-alloy during acid leaching, i.e. under reaction conditions in a fuel cell. To scrutinize the resulting particle structure after de-alloying we used pair distribution function (PDF) analysis and X-ray diffraction (XRD) gaining insight into the structural disorder and its dependence on the initial metal composition. Our results suggest that not only the ORR activity, but also the corrosion resistance of the synthesized NPs, are dependent on the structural disorder resulting from the de-alloying process.

U2 - 10.1039/c4cp04264f

DO - 10.1039/c4cp04264f

M3 - Journal article

C2 - 25537262

SN - 1463-9076

VL - 17

SP - 28044

EP - 28053

JO - Physical chemistry chemical physics : PCCP

JF - Physical chemistry chemical physics : PCCP

IS - 42

ER -