In situ constructing Co/Co-Ox/Co-Nx diverse active sites on hollow porous carbon spheres derived from Co-MOF for efficient bifunctional electrocatalysis in rechargeable Zn-air
In situ constructing Co/Co-Ox/Co-Nx diverse active sites on hollow porous carbon spheres derived from Co-MOF for efficient bifunctional electrocatalysis in rechargeable Zn-air
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DOI：
10.1016/j.mtphys.2023.101209
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发表时间：
2023-09
影响因子：
11.5
通讯作者：
Song Xue;Junfeng Qin;Xiaohua Zhang;Xinqing Guo;Min Hong;Wuhua Liu;Cuicui Du;Jinhua Chen
中科院分区：
文献类型：
--
作者：
Song Xue;Junfeng Qin;Xiaohua Zhang;Xinqing Guo;Min Hong;Wuhua Liu;Cuicui Du;Jinhua Chen
富土、耐用、高效的氧还原反应(ORR)和析氧反应(OER)双功能电催化剂对锌空气电池的广泛应用具有重要意义。然而，由于活性中心单一，传统的商用基准催化剂通常只在两个反应(ORR或OER)中的一个反应中表现出选择性活性，难以满足双功能催化的要求。开发在单一催化剂上实现不同活性中心的高效氧电催化剂并了解其内部协同反应活性仍然是一个挑战。本文以富氧的Co-MOF为前驱体，在三聚氰胺存在下，通过裂解法制备了具有多种本征活性中心(包括Co-Nx和Co-Ox种)和金属Co纳米颗粒共存的球形中空多孔碳基复合材料(S-Co/CoC)。由于催化剂具有较大的比表面积、良好的导电性、丰富的各种本征活性中心以及活性中心之间的电子相互作用和氧物种在催化剂表面的吸附/脱附过程，S-Co/CoC对ORR和OER都表现出良好的电催化活性，其ORR半波电位为0.81nV，OER电位为1.53nV(与10 mA/cm−2时的RHE相比)，提供了0.72nV的微小可逆电位差，优于商用贵金属催化剂和报道最多的钴基ORR/OER催化剂。组装的S-Co/CoC基锌空气二次电池的峰值功率密度高达101.7 mW/cm−2，为构建高性能的锌空气二次电池双功能催化剂提供了一种有意义的策略。
Earth-rich, durable, and efficient bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is vitally important for the wide application of zinc-air batteries in the future. However, due to the single active site, traditional commercial benchmark catalysts typically exhibit selective activity in only one of the two reactions (ORR or OER), making it difficult to meet the dual functional catalytic requirements. Developing efficient oxygen electrocatalysts that achieve diverse active sites on a single catalyst and understanding their internal synergistic reaction activity remain a challenge. Herein, spherical hollow porous carbon matrix composites (s-Co/CoNC) with the coexistence of diverse intrinsic active sites including Co-Nxand Co-Oxspecies and metal Co nanoparticles were prepared by pyrolysis with oxygen-enriched Co-MOFs as precursor in the presence of melamine. Owing to the combined advantages of the catalyst including the great specific surface area, good conductivity, abundant diverse intrinsic active sites towards ORR and OER, and the electronic interaction among active sites and the optimized the adsorption/desorption process of oxygen species at the catalyst surface, s-Co/CoNC exhibits desirable electrocatalytic activity for both ORR and OER with an ORR half-wave potential of 0.81 V, an OER potential of 1.53 V(vs. RHE at 10 mA cm−2), providing a small reversible potential difference of 0.72 V, superior to the commercial noble-metal catalysts and the most reported cobalt based ORR/OER catalysts. The assembled s-Co/CoC-based rechargeable Zn-air batteries possess high peak power density of 101.7 mW cm−2. This work provides a significant strategy for constructing high-performance dual functional catalysts for secondary Zn-air batteries.