A 3D hierarchical electrocatalyst: Core–shell Cu@Cu(OH)₂ nanorods/MOF octahedra supported on N-doped carbon for oxygen evolution reaction

Cu-based materials are seldom reported as oxygen evolution reaction (OER) electrocatalysts due to their inherent electron orbital configuration, which makes them difficult to adsorb oxygen-intermediates during OER. Reasonably engineering the hierarchical architectures and the electronic structures can improve the performance of Cu-based OER catalysts, such as constructing multilevel morphology, inducing the porous materials, improving the Cu valence, building heterostructures, doping heteroatoms, etc. In this work, copper-1,3,5-benzenetricarboxylate (HKUST-1) octahedra in-situ grow on the Cu nanorod (NR)-supported N-doped carbon microplates, meanwhile an active layer of Cu(OH)₂ forms on the surface of the original conductive Cu NRs. The octahedral HKUST-1, serving as a spacer between the microplates, greatly improves the porosity and increases the available active sites, facilitating the mass transport and electron transfer, thus resulting in greatly enhanced OER performance.