  Bimetallic nanoalloys have gained extensive attention due to their tunable
properties and wide range of catalytic applications. However, achieving good
compositional control in nanoalloy catalysts remains a formidable challenge. In
this work, we demonstrate that heat treatment can be used to tune the
composition of Pt-Zn nanoalloy catalysts, leveraging the volatile nature of
zinc to enhance their performance in propane dehydrogenation. Through identical
location (scanning) transmission electron microscopy (IL-(S)TEM) using an
in-situ EM gas cell, as well as other complementary techniques, we observed
that the zinc content of the Pt-Zn nanoalloy particles decreased over time of
the heat treatment under hydrogen. The rate of change depends on the original
composition of the particles, as well as the heat treatment conditions such as
temperature and flow rate. Our experimental results and theoretical
calculations suggest that Zn in the intermetallic phase might be more stable,
providing an opportunity for precise tuning the nanoparticle compositions. This
approach presents a viable strategy for developing better Pt-Zn catalysts for
propane dehydrogenation.
