Li Xiaofang, Ma Dong-Dong, Cao Changsheng, Zou Ruqiang, Xu Qiang, Wu Xin-Tao, Zhu Qi-Long
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences (CAS), Fuzhou, 350002, China.
Beijing Key Laboratory for Theory and Technology of Advanced Battery Materials, Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing, 100871, China.
Small. 2019 Aug;15(35):e1902218. doi: 10.1002/smll.201902218. Epub 2019 Jul 11.
Controllable synthesis of ultrathin metal-organic framework (MOF) nanosheets and rational design of their nano/microstructures in favor of electrochemical catalysis is critical for their renewable energy applications. Herein, an in situ growth method is proposed to prepare the ultrathin NiFe MOF nanosheets with a thickness of 1.5 nm, which are vertically inlaid into a 3D ordered macroporous structure of NiFe hydroxide. The well-designed composite delivers an efficient electrocatalytic performance with a low overpotential of 270 mV at a current density of 10 mA cm and stable electrolysis as long as 10 h toward the electrochemical oxygen evolution reaction, much superior to the state-of-the-art RuO electrocatalyst. A comprehensive analysis demonstrates that the excellent performance originates from the desirable combination of the highly exposed active centers in the ultrathin bimetallic MOF nanosheets, effective electron conduction between MOF nanosheets and ordered macroporous hydroxide, and efficient mass transfer across the hierarchically porous hybridization. This study sheds light on the exploration of powerful protocols to gain diverse high-performance MOF nanosheets and may open a perspective to achieve their efficient electrocatalytic performance.
可控合成超薄金属有机框架（MOF）纳米片并合理设计其纳米/微观结构以利于电化学催化，对于其在可再生能源领域的应用至关重要。在此，提出了一种原位生长方法来制备厚度为1.5 nm的超薄NiFe MOF纳米片，这些纳米片垂直镶嵌在氢氧化镍铁的三维有序大孔结构中。精心设计的复合材料在电流密度为10 mA cm时具有270 mV的低过电位，展现出高效的电催化性能，并且在电化学析氧反应中能够稳定电解长达10 h，远优于目前最先进的RuO电催化剂。综合分析表明，优异的性能源于超薄双金属MOF纳米片中高度暴露的活性中心、MOF纳米片与有序大孔氢氧化物之间有效的电子传导以及跨多级多孔杂化结构的高效传质的理想组合。这项研究为探索获得各种高性能MOF纳米片的有力方案提供了思路，并可能为实现其高效电催化性能开辟一个新的视角。
