析氧
化学
催化作用
过电位
化学工程
钴
氢氧化物
浸出(土壤学)
纳米技术
无机化学
材料科学
物理化学
电化学
电极
生物化学
环境科学
土壤科学
工程类
土壤水分
作者
Yong Wang,Yongzhi Zhao,Luan Liu,Wanjun Qin,Sijia Liu,Juping Tu,Yadong Liu,Yunpu Qin,Jianfang Liu,Haoyang Wu,Deyin Zhang,Aimin Chu,Baorui Jia,Xuanhui Qu,Mingli Qin,Junmin Xue
摘要
The oxygen evolution reaction (OER) plays a vital role in renewable energy technologies, including in fuel cells, metal-air batteries, and water splitting; however, the currently available catalysts still suffer from unsatisfactory performance due to the sluggish OER kinetics. Herein, we developed a new catalyst with high efficiency in which the dynamic exchange mechanism of active Fe sites in the OER was regulated by crystal plane engineering and pore structure design. High-density nanoholes were created on cobalt hydroxide as the catalyst host, and then Fe species were filled inside the nanoholes. During the OER, the dynamic Fe was selectively and strongly adsorbed by the (101̅0) sites on the nanohole walls rather than the (0001) basal plane, and at the same time the space-confining effect of the nanohole slowed down the Fe diffusion from catalyst to electrolyte. As a result, a local high-flux Fe dynamic equilibrium inside the nanoholes for OER was achieved, as demonstrated by the Fe57 isotope labeled mass spectrometry, thereby delivering a high OER activity. The catalyst showed a remarkably low overpotential of 228 mV at a current density of 10 mA cm-2, which is among the best cobalt-based catalysts reported so far. This special protection strategy for Fe also greatly improved the catalytic stability, reducing the Fe leaching amount by 2 orders of magnitude compared with the pure Fe hydroxide catalyst and thus delivering a long-term stability of 130 h. An assembled Zn-air battery was stably cycled for 170 h with a low discharge/charge voltage difference of 0.72 V.
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