Confinement amorphous cobalt-nickel oxide polyhedral yolk-shell structures for enhanced oxygen evolution performance

Abstract

Multi-scale regulation strategies ranging from electronic behavior regulation to crystal structure modulation to micro-nano structure construction can effectively improve the properties of materials, thereby bringing about significant improvements in performance. In this paper, we successfully constructed (Co1-xNix)3O4 with Ni substitution (x) unique polyhedral yolk-shell structure (PYSSs) electrocatalysts with confined amorphous regions, and achieved a significant improvement in the performance of oxygen evolution reaction (OER). The substitution of Ni can regulate the electronic coupling between metal sites, thereby optimizing the electronic configuration, creating abundant vacancy defects and enhancing the Co 3d-O 2p covalency. Meantime, the creation of confined amorphous regions can further increase the number of oxygen vacancies and unsaturated metal sites. Especially, the construction of the unique PYSSs structure can increase the effective specific surface area, hold the reaction intermediates for deeper reaction, accelerate the infiltration and transport of the electrolyte, prevent the adhesion of bubbles and accelerate the gas diffusion.