Hollow and porous NiCo2O4 nanospheres for enhanced methanol oxidation reaction and oxygen reduction reaction by oxygen vacancies engineering

A new three-dimensional (3D) hollow NiCo2O4 nanoparticle with interconnected hierarchically porous structure and abundant oxygen vacancies was successfully constructed by a facile template-free solvothermal approach and followed by an annealing treatment. The obtained catalyst demonstrates remarkable performance as bifunctional electrocatalytic for both MOR and ORR in alkali. [Display omitted] •A new three-dimensional (3D) hollow NiCo2O4 nanoparticle with interconnected hierarchically porous structure was successfully constructed.•Oxygen vacancies-rich of NiCo2O4 can be manufactured by a simple annealing treatment.•The porous NiCo2O4 with high oxygen vacancies (Vo) exhibits outstanding activities for both MOR and ORR show that defect-dependent. The rational designing morphology and regulating active sites of catalyst is crucial to promoting catalytic performances. Herein, a series of controllable hollow NiCo2O4 nanoparticles with interconnected hierarchically porous structure and abundant oxygen vacancies were successfully constructed by a simple template-free solvothermal method and followed by heat treatment. The obtained hollow and porous NiCo2O4 exhibit interesting oxygen vacancies (Vo) defect-dependent activity, where the NiCo2O4-450-Vo show the outstanding performance in the methanol oxidation reaction (MOR) as well as the oxygen reduction reaction (ORR) with four electron reaction pathway in alkaline solution. This work may pave a facile pathway to design the hollow and porous NiCo2O4 nanospheres with the adjustable oxygen vacancies defect to accelerate various electrochemical reactions in fuel cells and other applications.