TY - JOUR
T1 - In situ electrochemical grazing incidence small angle X-ray scattering: From the design of an electrochemical cell to an exemplary study of fuel cell catalyst degradation
AU - Bogar, Marco
AU - Khalakhan, Ivan
AU - Gambitta, Alessandro
AU - Yakovlev, Yurii
AU - Amenitsch, Heinz
PY - 2020/11/30
Y1 - 2020/11/30
N2 - Nowadays, electrochemistry has a considerable technological impact, involving fuel cells, super capacitors and batteries. These devices are based on complex architectures, which complicates monitoring their evolution in situ under operating conditions to reveal the reasons for reduced lifetime and performances. Here, we present a design of a multipurpose electrochemical cell for grazing incidence small and wide angle X-ray scattering (GISAXS and GIWAXS) where the environment for operating conditions can be recreated. We focus on proton exchange membrane fuel cells (PEMFCs) which operational conditions are simulated by means of potentiodynamic-based accelerated stress tests, applied to a thin film of Pt nanoparticles representing a model system of a benchmark catalyst. Two different upper potentials are used to mimic fuel cell operating conditions: at 1.0 V
RHE the catalyst film preserves its initial morphology, while at 1.5 V
RHE (simulating fuel cell start-up/shut-down cycles) significant coarsening has been observed. The initial dimension of the Pt particles of 4.0 nm increases to 8.7 nm due to the predominant process of coalescence and final Ostwald ripening. In parallel, the distance between the particles increases, the catalyst film (9 nm thick) becomes thinner at first and exhibit a higher roughness at the end.
AB - Nowadays, electrochemistry has a considerable technological impact, involving fuel cells, super capacitors and batteries. These devices are based on complex architectures, which complicates monitoring their evolution in situ under operating conditions to reveal the reasons for reduced lifetime and performances. Here, we present a design of a multipurpose electrochemical cell for grazing incidence small and wide angle X-ray scattering (GISAXS and GIWAXS) where the environment for operating conditions can be recreated. We focus on proton exchange membrane fuel cells (PEMFCs) which operational conditions are simulated by means of potentiodynamic-based accelerated stress tests, applied to a thin film of Pt nanoparticles representing a model system of a benchmark catalyst. Two different upper potentials are used to mimic fuel cell operating conditions: at 1.0 V
RHE the catalyst film preserves its initial morphology, while at 1.5 V
RHE (simulating fuel cell start-up/shut-down cycles) significant coarsening has been observed. The initial dimension of the Pt particles of 4.0 nm increases to 8.7 nm due to the predominant process of coalescence and final Ostwald ripening. In parallel, the distance between the particles increases, the catalyst film (9 nm thick) becomes thinner at first and exhibit a higher roughness at the end.
KW - Fuel cells
KW - Electrochemistry
KW - Grazing incidence small angle X-ray scattering
KW - Ostwald ripening
KW - Nanoparticles
KW - Catalyst layer
UR - http://www.scopus.com/inward/record.url?scp=85092319106&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2020.229030
DO - 10.1016/j.jpowsour.2020.229030
M3 - Article
SN - 0378-7753
VL - 477
JO - Journal of Power Sources
JF - Journal of Power Sources
M1 - 229030
ER -