Hybridization of cobalt oxide with holey 2D niobium nitride nanosheets to promote oxygen evolution reaction

The control of defect structure and holey morphology has garnered increasing interest owing to its usefulness in regulating the functionalities of nanostructured materials. Here we report a hybridization approach to improve oxygen electrocatalyst performance of metal oxide nanoparticles using holey NbN nanosheets as hybridization matrices. The controlled ammonolysis of exfoliated Nb 6 O 17 monolayers led to the creation of holey NbN nanosheet morphology due to the abundant presence of nitrogen vacancies. Hybridization with holey NbN nanosheets allowed enhancement of the functionalities of hybridized Co 3 O 4 as oxygen evolution electrocatalysts. The introduction of crystal defects into the NbN nanosheets reinforced the interfacial electronic coupling with Co 3 O 4 , maximizing the hybridization effect. The resulting Co 3 O 4 ‐holey NbN nanohybrids delivered outstanding electrocatalyst performance toward the oxygen evolution reaction, which was ascribable to the improvement of charge/mass transports and the promotion of electrocatalysis kinetics.