Harnessing Zn-volatility for compositional tuning in PtZn nanoalloy catalysts

Abstract

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-STEM) using an in situ gas cell, as well as other complementary techniques, we observed that the zinc content of the Pt-Zn nanoalloy particles can be tuned via heat treatment under hydrogen. The extent of change appeared to be influenced by experimental details such as the original composition of the particles, as well as heat treatment conditions such as temperature and flow rate. Our experimental results, supported by theoretical calculations, suggest that Zn volatilization can be controlled when the alloys reach certain compositions such as the intermetallic phase. This approach offers a new strategy for developing better Pt-Zn catalysts.