Abstract Due to its good electronic conductivity and large specific surface area, multiwalled carbon nanotube (MWCNT) has been proven a good platform for the further fabrication of efficient oxygen reduction reaction (ORR) catalysts. In this work, the nanocomposite of NiFe layered double hydroxides (NiFe-LDHs) and MWCNT was synthesized by the direct coating of MWCNT with NiFe-LDH nanoparticles (NPs) under ultrasonic assistance. It was found out that MWCNT can be easily dispersed in the NiFe-LDH suspension. The dispersed MWCNT was simultaneously coated with NiFe-LDH NPs via the electrostatic interaction between the negatively charged MWCNT and positively charged NiFe-LDH NPs. The obtained nanocomposite (NiFe-LDH/MWCNT) exhibits tube-like structure and good dispersity in polar solvents such as ethanol and water. Further investigation shows that NiFe-LDH/MWCNT possesses excellent ORR activity with 4e-route selectivity, suggesting the synergistic effect between NiFe-LDH and MWCNT. Moreover, NiFe-LDH/MWCNT exhibited improved catalytic capability and durability than commercial Pt/C catalysts.

中文翻译：

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NiFe层状双氢氧化物超声辅助涂层多壁碳纳米管以改善电催化氧还原

摘要 多壁碳纳米管（MWCNT）具有良好的导电性和大的比表面积，已被证明是进一步制备高效氧还原反应（ORR）催化剂的良好平台。在这项工作中，NiFe 层状双氢氧化物 (NiFe-LDHs) 和 MWCNT 的纳米复合材料是通过在超声波辅助下用 NiFe-LDH 纳米粒子 (NPs) 直接涂覆 MWCNT 来合成的。结果表明，MWCNT 可以很容易地分散在 NiFe-LDH 悬浮液中。通过带负电的 MWCNT 和带正电的 NiFe-LDH NPs 之间的静电相互作用，分散的 MWCNT 同时被 NiFe-LDH NPs 包覆。所得纳米复合材料（NiFe-LDH/MWCNT）具有管状结构，在乙醇和水等极性溶剂中具有良好的分散性。进一步研究表明，NiFe-LDH/MWCNT 具有优异的 ORR 活性和 4e 路线选择性，表明 NiFe-LDH 和 MWCNT 之间存在协同效应。此外，NiFe-LDH/MWCNT 表现出比商业 Pt/C 催化剂更高的催化能力和耐久性。