Tuning the surface structure of PtCo nanocatalysts with high activity and stability toward oxygen reduction

Abstract

Herein, we prepare various types of PtCo nanocatalysts with Pt skin structure for oxygen reduction reaction (ORR) in acidic electrolyte by utilizing post-treatments such as acid leaching, additional Pt reduction (PtCo-Pt (chem)), and thermal annealing (PtCo-Pt (annealed)). The physical and electrochemical properties of these catalyst were analyzed and compared to commercial Pt/C. The Pt skin structure nanocatalysts exhibited approximately improved catalytic activity by 2-fold compared with commercial Pt/C catalysts owing to the optimization of d-band center of Pt by alloying effect with Co. Furthermore, the accelerated degradation test (ADT) was conducted under harsh condition and the Pt skin structure nanocatalysts displayed the superior ORR activity to initial performance of commercial Pt/C in spite of low loading amount of Pt. The causes of enhancement in long-term durability were investigated through several analysis after ADT subsequently. In particular, it is confirmed that the Pt skin structure of PtCo-Pt (chem) has contributed to improvement of durability by hindering dissolution of Co like as "nano-shield". (C) 2019 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.