Zhang Chaoqi, Yuan Ling, Liu Chao, Li Zimeng, Zou Yingying, Zhang Xinchan, Zhang Yue, Zhang Zhiqiang, Wei Guangfeng, Yu Chengzhong
School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200241, P. R. China.
College of Chemical Engineering, Fuzhou University, Fuzhou 350002, P. R. China.
J Am Chem Soc. 2023 Apr 12;145(14):7791-7799. doi: 10.1021/jacs.2c11446. Epub 2023 Mar 10.
Metal-organic frameworks (MOFs) with highly adjustable structures are an emerging family of electrocatalysts in two-electron oxygen reduction reaction (2e-ORR) for HO production. However, the development of MOF-based 2e-ORR catalysts with high HO selectivity and production rate remains challenging. Herein, an elaborate design with fine control over MOFs at both atomic and nano-scale is demonstrated, enabling the well-known Zn/Co bimetallic zeolite imidazole frameworks (ZnCo-ZIFs) as excellent 2e-ORR electrocatalysts. Experimental results combined with density functional theory simulation have shown that the atomic level control can regulate the role of water molecules participating in the ORR process, and the morphology control over desired facet exposure adjusts the coordination unsaturation degree of active sites. The structural regulation at two length scales leads to synchronous control over both the kinetics and thermodynamics for ORR on bimetallic ZIF catalysts. The optimized ZnCo-ZIF with a Zn/Co molar ratio of 9/1 and predominant {001} facet exposure exhibits a high 2e selectivity of ∼100% and a HO yield of 4.35 mol g h. The findings pave a new avenue toward the development of multivariate MOFs as advanced 2e-ORR electrocatalysts.
具有高度可调节结构的金属有机框架（MOFs）是用于生产H₂O₂的两电子氧还原反应（2e-ORR）中新兴的一类电催化剂。然而，开发具有高H₂O₂选择性和产率的基于MOF的2e-ORR催化剂仍然具有挑战性。在此，展示了一种在原子和纳米尺度上对MOFs进行精细控制的精心设计，使著名的Zn/Co双金属沸石咪唑框架（ZnCo-ZIFs）成为优异的2e-ORR电催化剂。实验结果与密度泛函理论模拟表明，原子水平的控制可以调节参与ORR过程的水分子的作用，对所需晶面暴露的形貌控制可调节活性位点的配位不饱和程度。在两个长度尺度上的结构调控导致对双金属ZIF催化剂上ORR的动力学和热力学的同步控制。优化后的Zn/Co摩尔比为9/1且主要暴露{001}晶面的ZnCo-ZIF表现出约100%的高2e选择性和4.35 mol g⁻¹ h⁻¹的H₂O₂产率。这些发现为开发多元MOFs作为先进的2e-ORR电催化剂开辟了一条新途径。
