Cu–Pt Nanocage with 3-D Electrocatalytic Surface as an Efficient Oxygen Reduction Electrocatalyst for a Primary Zn–Air Battery

Abstract

Cu–Pt nanocage (CuPt-NC) intermetallic structures have been prepared by an in situ galvanic displacement reaction. The structures are found to be well organized within the framework demarcated with distinguishing arms, having clear edges and corners with a size of ∼20 nm. The unique nanocage structure possessing large specific surface area and better structural integrity helps to achieve improved electrochemical oxygen reduction reaction activity and stability in alkaline solution in comparison to the commercially available 20 wt % Pt/C. CuPt-NC shows 50 mV positive onset potential shift with significantly higher limiting current in comparison to Pt/C. Interestingly, CuPt-NC has shown 2.9- and 2.5-fold improved mass activity and specific activity, respectively, for ORR at 0.9 V vs RHE in comparison to Pt/C. Moreover, the stability of CuPt-NC has been tested by an accelerated durability test under alkaline conditions. CuPt-NC has been subsequently utilized as the air electrode in a primary Zn–air battery and is found to possess 1.30- and 1.34-fold improved power density and current density at 1 V, respectively, in comparison to the state-of-the-art Pt/C catalyst. In addition, CuPt-NC has shown several hours of constant discharge stability at 20 mA cm–2 with a specific capacity of 560 mAh gZn–1 and energy density of 728 Wh kgZn–1 in the primary Zn–air battery system.