Novel CoO Nanoparticles/Nitrogen-Doped Carbon Composites with Extraordinary Catalytic Activity for Oxygen Evolution Reaction (OER).

Herein, CoO nanoparticles/nitrogen-doped carbon (CoO/NPC) composites with different structures were prepared via a facile method. Structure control was achieved by the rational morphology design of ZIF-67 precursors, which were then pyrolyzed in air to obtain CoO/NPC composites. When applied as catalysts for the oxygen evolution reaction (OER), the M-CoO/NPC composites derived from the flower-like ZIF-67 showed superior catalytic activities than those derived from the rhombic dodecahedron and hollow spherical ZIF-67. The former M-CoO/NPC composite displayed a small over-potential of 0.3 V, low onset potential of 1.41 V, small Tafel slope of 83 mV dec, and a desirable stability. (94.7% OER activity was retained after 10 h.) The excellent performance of the flower-like M-CoO/NPC composite in the OER was attributed to its favorable structure.