Layered Metal–Organic Framework-Derived Metal Oxide/Carbon Nanosheet Arrays for Catalyzing the Oxygen Evolution Reaction

The oxygen evolution reaction (OER) in water splitting plays a critical role in some clean energy production systems. Transition-metal oxides as one of the most common OER electrocatalysts have been widely explored; however, their activity is limited by low electrical conductivity, slow mass transfer, and inadequate active sites. Herein, we develop a feasible strategy in which layered two-dimensional metal–organic frameworks (2D MOFs) act as templates to construct metal oxide/carbon (MOx/C, M = Co, Ni, and Cu) nanosheet arrays for the OER. Because of improved conductivity and more exposed active sites afforded by their 2D structures with rich hierarchical pores and the incorporation with porous carbon, these 2D MOF-derived MOx/C arrays present high electrocatalytic activities and good durability. Particularly, Co3O4/CBDC, NiO/CBDC, and Cu2O/S–CTDC exhibit low overpotentials of 208, 285, and 313 mV at the current density of 10 mA cm–2, respectively, outperforming all previously reported corresponding metal oxide-based catalysts.