cs9b05202_si_001.pdf (27.7 MB)
Structural Screening and Design of Platinum Nanosamples for Oxygen Reduction
journal contribution
posted on 2020-03-11, 19:45 authored by Kevin Rossi, Gian Giacomo Asara, Francesca BalettoNanocatalyst-by-design
promises to empower the next generation
of electrodes for energy devices. However, current numerical methods
consider individual and often geometrical closed-shell nanoparticles,
neglecting how the coexistence of several and structurally diverse
isomers in a sample affect the activity of the latter. Here, we present
a multiscale numerical approach to calculate, in a fast and high-throughput
fashion, the current density and mass activity of individual isomers,
as well as predict the activity of morphologically diverse but size-selected
samples. We propose specific design rules of platinum nanosamples
for the electrochemical reduction of molecular oxygen, identifying
the size range up to 5.5 nm as the one where isomerization of individual
nanoparticles and the morphological composition of the sample cannot
be neglected. We confirm a peak of the activity of defected and concave
polyhedra at 2–3 nm while spherical but amorphous isomers become
the most active in the range of 3–5 nm, with an astonishing
mass activity of 2.7 A/mg. We provide a possible explanation to rationalize
the discrepancies in the measured mass activity of size-selected samples,
in terms of the different distributions of Pt isomers in each specimen.