纳米笼
材料科学
纳米反应器
电催化剂
微型多孔材料
电化学
催化作用
化学工程
纳米技术
功率密度
碳纤维
氧气
电极
有机化学
纳米颗粒
化学
复合材料
物理化学
工程类
功率(物理)
物理
复合数
量子力学
作者
Xiannong Tang,Yuanhao Wei,Weijuan Zhai,Yun Wu,Ting Hu,Kai Yuan,Yiwang Chen
标识
DOI:10.1002/adma.202208942
摘要
Abstract As key parameters of electrocatalysts, the density and utilization of active sites determine the electrocatalytic performance toward oxygen reduction reaction. Unfortunately, prevalent oxygen electrocatalysts fail to maximize the utilization of active sites due to inappropriate nanostructural design. Herein, a nano‐emulsion induced polymerization self‐assembly strategy is employed to prepare hierarchical meso‐/microporous N/S co‐doped carbon nanocage with atomically dispersed FeN 4 (denoted as Meso/Micro‐FeNSC). In situ scanning electrochemical microscopy technology reveals the density of available active sites for Meso/Micro‐FeNSC reach to 3.57 × 10 14 sites cm −2 , representing more than threefold improvement compared to micropore‐dominant Micro‐FeNSC counterpart (1.07 × 10 14 sites cm −2 ). Additionally, the turnover frequency of Meso/Micro‐FeNSC is also improved to 0.69 from 0.50 e − site −1 s −1 for Micro‐FeNSC. These properties motivate Meso/Micro‐FeNSC as efficient oxygen electroreduction electrocatalyst, in terms of outstanding half‐wave potential (0.91 V), remarkable kinetic mass specific activity (68.65 A g −1 ), and excellent robustness. The assembled Zn–air batteries with Meso/Micro‐FeNSC deliver high peak power density (264.34 mW cm −2 ), large specific capacity (814.09 mA h g −1 ), and long cycle life (>200 h). This work sheds lights on quantifying active site density and the significance of maximum utilization of active sites for rational design of advanced catalysts.
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