Sun Xiaoling, Gong Qiaojuan, Liang Yunxia, Wu Mingjie, Xu Nengneng, Gong Pengni, Sun Shuhui, Qiao Jinli
College of Chemistry and Materials Science, Shanxi Normal University, 1 Gongyuan Street, Linfen 041000, China.
Department of Applied Chemistry, Yuncheng University, 1155 Fudan West Street, Yuncheng 044000, China.
ACS Appl Mater Interfaces. 2020 Aug 26;12(34):38202-38210. doi: 10.1021/acsami.0c10734. Epub 2020 Aug 14.
Rational synthesis of bifunctional electrocatalysts with high performance and strong durability is highly demanded rechargeable metal-air battery. In this work, ZIF-derived CoS/C coated with conductive graphene nanosheet (CoS/GN) was synthesized by a simple solvothermal method and formed a stable double-carbon structure. As expected, the prepared CoS/GN catalyst exhibits a high catalytic activity (Δ: 0.88 V) and long-term durability toward both oxygen reduction reaction and oxygen evolution reaction (ORR and OER), which is even superior to the Pt/C + Ir/C mixture (0.91 V). In addition, the Zn-air battery with the CoS/GN catalyst showed higher power density (186 mW cm) and more stable charge-discharge cycling performances (2000 cycles) than the Pt/C + Ir/C (118 mW cm). Based on these analysis results, the favorable catalytic performance of ORR/OER should be illustrated by the following reasons: (i) large specific surface area and unique mesoporous structure, providing abundant active sites; (ii) good conductivity, accelerating the electrons transfer; and (iii) the unique stable "double-carbon" structures (metal-S-C-C), preventing the agglomeration of metal sulfide, building new quick transfer pathway, and forming the strong electron coupling ability and synergistic effect.
高性能且耐久性强的双功能电催化剂的合理合成是可充电金属空气电池的迫切需求。在这项工作中，通过简单的溶剂热法合成了涂覆有导电石墨烯纳米片的ZIF衍生的CoS/C（CoS/GN），并形成了稳定的双碳结构。正如预期的那样，制备的CoS/GN催化剂对氧还原反应和析氧反应（ORR和OER）均表现出高催化活性（Δ：0.88 V）和长期耐久性，甚至优于Pt/C + Ir/C混合物（0.91 V）。此外，具有CoS/GN催化剂的锌空气电池比Pt/C + Ir/C（118 mW cm）表现出更高的功率密度（186 mW cm）和更稳定的充放电循环性能（2000次循环）。基于这些分析结果，ORR/OER的良好催化性能应由以下原因说明：（i）大比表面积和独特的介孔结构，提供丰富的活性位点；（ii）良好的导电性，加速电子转移；（iii）独特稳定的“双碳”结构（金属-S-C-C），防止金属硫化物团聚，建立新的快速转移途径，并形成强电子耦合能力和协同效应。
