Silver鈥揅opper Nanoalloy Catalyst Layer for Bifunctional Air Electrodes in Alkaline Media

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• 作者：Xiaoqiang Wu ; Fuyi Chen ; Yachao Jin ; Nan Zhang ; Roy L. Johnston
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：7
• 期：32
• 页码：17782-17791
• 全文大小：636K
• ISSN：1944-8252

文摘

A carbon-free and binder-free catalyst layer composed of a Ag鈥揅u nanoalloy on Ni foam was used as the air cathode in a zinc鈥揳ir battery for the first time. The Ag鈥揅u catalyst was prepared using pulsed laser deposition. The structures of the catalysts were found to consist of crystalline Ag鈥揅u nanoalloy particles with an average size of 2.58 nm embedded in amorphous Cu films. As observed in the X-ray photoelectron spectra, the Ag 3d core levels shifted to higher binding energies, whereas the Cu 2p core levels shifted to lower binding energies, indicating alloying of the silver and copper. Rotating disk electrode measurements indicated that the oxygen reduction reaction (ORR) proceeded through a four-electron pathway on the Ag₅₀Cu₅₀ and Ag₉₀Cu₁₀ nanoalloy catalysts in alkaline solution. Moreover, the catalytic activity of Ag₅₀Cu₅₀ in the ORR is more efficient than that of Ag₉₀Cu₁₀. By performing charge and discharge cycling measurements, the Ag₅₀Cu₅₀ catalyst layer was confirmed to have a maximum power density of approximately 86.3 mW cm^鈥? and an acceptable cell voltage at 0.863 V for current densities up to 100 mA cm^鈥? in primary zinc鈥揳ir batteries. In addition, a round-trip efficiency of approximately 50% at a current density of 20 mA cm^鈥? was also obtained in the test.