A 3d Flower-Like Cu-Based Hierarchical Composite and its Derivatives for Efficient Oxygen Evolution Reaction

Nowadays, extensive attention has been driven to copper-based materials, while seldom reports are about electrocatalysis of water for oxygen evolution reaction (OER) due to their inherent electron orbital configuration, which make them difficult to absorb oxygen intermediates during OER process. To improve the efficiency of the Cu-based electrocatalysts, great efforts have been made to design the hierarchical architectures, optimize the electronic structures and configure the multidimensional structures. Herein, we developed a novel Cu-based composite with a unique three-dimensional (3D) nanoflower-like hierarchical structure assembled by 2D nanosheets (denoted as Cu-NF), using zeolitic imidazolate framework-67 (ZIF-67) as precursor via facile Cu ion etching, followed by self-assembly strategy. Through controllable low-temperature calcination under N2 atmosphere, a series of Cu-NF derivatives are produced, with the retained original morphology. The material obtains at 300 °C shows the best OER performance, with smallest overpotential of 347 mV in 1.0 mol L-1 KOH for OER. This work provides a simple synthetic strategy for the fabrication of a 3D Cu-based superstructure and its derivatives shows potentials as electrocatalysts for OER.