Xiao Yao, Guo Beibei, Zhang Jing, Hu Chun, Ma Ruguang, Wang Deyi, Wang Jiacheng
School of Science, Xihua University, Chengdu, 610039, China.
Dalton Trans. 2020 May 7;49(17):5730-5735. doi: 10.1039/d0dt00976h. Epub 2020 Apr 22.
The development of low-cost bifunctional catalysts for replacing precious metal Pt-group electrocatalysts is highly desirable but remains challenging in the energy conversion and storage field. Metal-organic frameworks (MOFs) with a large specific surface area and a controllable pore structure provide a great opportunity to prepare bifunctional catalysts, but their low activity in oxygen electrocatalysis hinders their applications. Herein, we rationally design and fabricate a bimetallic ZnCo-zeolite imidazole framework@graphene oxide (ZnCo-ZIF@GO) hybrid electrocatalyst through a simple in situ growth of a bimetallic ZIF on graphene oxide nanosheets. The obtained ZnCo-ZIF@GO hybrid displays superior electrocatalytic activities toward both the ORR and OER in alkaline solution compared to the pure ZnCo-ZIF. The outstanding bifunctional electrocatalytic performance is attributed to the synergy and strong interaction between the ZnCo-ZIF and GO, enhanced ionic conductivity, and hierarchical porosity. A rechargeable Zn-air battery (ZAB) assembled using ZnCo-ZIF@GO as the air cathode displays excellent charge and discharge performance, high energy density, and cycling stability, demonstrating its great potential as an advanced bifunctional electrocatalyst in the field of energy conversion and storage.
开发低成本双功能催化剂以替代贵金属铂族电催化剂在能量转换和存储领域备受期待，但仍具有挑战性。具有大比表面积和可控孔结构的金属有机框架（MOF）为制备双功能催化剂提供了绝佳机会，但其在氧电催化方面的低活性阻碍了它们的应用。在此，我们通过在氧化石墨烯纳米片上简单原位生长双金属沸石咪唑框架，合理设计并制备了一种双金属ZnCo-沸石咪唑框架@氧化石墨烯（ZnCo-ZIF@GO）混合电催化剂。与纯ZnCo-ZIF相比，所获得的ZnCo-ZIF@GO混合物在碱性溶液中对氧还原反应（ORR）和析氧反应（OER）均表现出优异的电催化活性。出色的双功能电催化性能归因于ZnCo-ZIF与GO之间的协同作用和强相互作用、增强的离子导电性以及分级孔隙率。使用ZnCo-ZIF@GO作为空气阴极组装的可充电锌空气电池（ZAB）表现出优异的充放电性能、高能量密度和循环稳定性，证明了其作为能量转换和存储领域先进双功能电催化剂的巨大潜力。
