Ordering-dependent dealloying dynamics and catalytic advancements in PtCo nanoalloys for oxygen reduction reaction

Abstract

The dealloying dynamics of PtCo nanoparticles depending on the degree of order were studied in this study to understand the structure-activity/stability relation in nanoalloy catalysts comprehensively. The ordering degree of the catalysts was controlled by adjusting the heat treatment conditions while adopting a carbon shell which makes getting an identical PtCo nanoalloy catalyst, except for the degree of order, possible. Subsequently, the influence of the extent of dealloying on activity and stability, based on the degree of order, was investigated. The findings revealed a contrasting trend between activity and stability depending on the degree of order following the dealloying process. The mass activity (MA) of the dealloyed LO-PtCo@NCL/CB, which is considered the most promising in terms of both activity and stability, was 1.118 A mgpt-1 4.3 times higher than that of Pt/C at 0.259 A mgpt-1. Remarkably, H2-air PEMFCs employing dealloyed LO-PtCo@NCL/CB reached a high power density of 1.206 W cm-2 with a cathode loading of 0.075 mgpt cm-2. Additionally, the negligible cell voltage loss was achieved at 0.8 A cm-2 and 1.5 A cm-2 after a 30,000 cycles durability test surpassing the Department of Energy's durability targets. Furthermore, the scalability of the process for mass production was also validated.