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Two dimensional ZIF-derived ultra-thin Cu-N/C nanosheets as high performance oxygen reduction electrocatalysts for high-performance Zn-air batteries.
Nanoscale ( IF 6.7 ) Pub Date : 2020-06-11 , DOI: 10.1039/d0nr03495a
Yi Guan 1 , Nan Li 1 , Yongliang Li 1 , Lingna Sun 1 , Yuan Gao 1 , Qianling Zhang 1 , Chuanxin He 1 , Jianhong Liu 1 , Xiangzhong Ren 1
Affiliation  

Bottom-up construction of transition copper–nitrogen–carbon (Cu–N–C) electrocatalysts with high-performance and long-term durability for the oxygen reduction reaction (ORR) still remains a great challenge. Herein, we propose a temperature-controlled synthesis strategy with confinement effect for fabrication of a novel two-dimensional dual-metal (Cu/Zn) zeolitic imidazolate framework material, which presents an ultrathin nanosheet morphology after high-temperature thermal treatment (denoted as Cu–N-UNS). By controlling the reaction temperature as well as regulating the ratio of metal ions and taking advantages of the confinement effect of surfactants, the rationally designed ultra-thin carbon layer not only prevents aggregation of transition Cu particles and avoids direct contact with reactants and electrolyte solutions to enhance the durability of electrocatalysts, but also shortens the electronic transmission path between the active transition metal species and carbon surface. Therefore, the electrocatalyst exhibits excellent electrocatalytic performance for the ORR (E1/2 ≈ 0.898 V), which is superior to those of state-of-the-art benchmark noble-metal electrocatalysts. Moreover, the even distribution of Cu–N–C and existence of N–Cu2+–Cu0 active sites make a great contribution to the electrocatalyst activity. Notably, the Cu–N-UNS used as air electrodes for Zn–air batteries also exhibits a high peak power density of ≈134.7 mW cm−2 at a current density of ≈231.9 mA cm−2 with remarkable durability.

中文翻译:

二维ZIF衍生的超薄Cu-N / C纳米片,作为高性能Zn-air电池的高性能氧还原电催化剂。

自底向上构造具有高性能和氧还原反应(ORR)的长期耐久性的过渡铜-氮-碳(Cu-N-C)电催化剂仍然是一个巨大的挑战。在这里,我们提出了一种具有约束作用的温度控制合成策略,用于制造新型的二维双金属(Cu / Zn)沸石咪唑酸盐骨架材料,该材料在高温热处理后呈现超薄纳米片形态(称为Cu) –N-UNS)。通过控制反应温度以及调节金属离子的比例,并利用表面活性剂的封闭作用,合理设计的超薄碳层不仅可以防止过渡Cu粒子聚集,避免与反应物和电解质溶液直接接触,从而提高了电催化剂的耐久性,而且缩短了活性过渡金属与碳表面之间的电子传递路径。因此,该电催化剂对ORR(E 1/ 2≈0.898 V),优于最先进的基准贵金属电催化剂。此外,Cu–N–C的均匀分布和N–Cu 2+ –Cu 0活性位的存在对电催化剂的活性做出了巨大贡献。值得注意的是,用作Zn-空气电池空气电极的Cu-N-UNS在电流密度≈231.9mA cm -2时,还具有≈134.7mW cm -2的高峰值功率密度,并具有显着的耐久性。
更新日期:2020-07-09
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