Simultaneous modulation of double-coordination shells at cobalt atomic site towards superior oxygen electrocatalysis.

Abstract

Engineering the coordination microenvironment surrounding the single atom sites (SA) presents a great opportunity to enhance their catalytic performance. In this work, we report the rational design of the cobalt SA sites with simultaneous modifications to the double coordination shells of the Co atom. In the first coordination shell, a vacancy is introduced to create the asymmetric Co-N₃-V configuration, where V denotes the vacancy. Meanwhile, phosphorus (P) atoms are doped into the carbon substrate to regulate the local environment of the second shell surrounding the Co site. These simultaneous modifications to the double-shell coordination influence the charge density of the active centers, and ultimately improve their activities. Additionally, the one-dimensional (1D) carbon substrate, that is composed of connected bubbles (BCF), provides a conductive and porous framework that facilitates fast kinetics. Taking these advantages, the Co-N-V/P@BCF catalyst demonstrates exceptional bifunctional oxygen catalytic behavior. Furthermore, the robust mechanical properties of Co-N-V/P@BCF, as evidenced by finite element analysis (FEA), endow the full Zn-air battery (ZAB) with remarkable reliability, flexibility, and stable high-rate long-term performance under diverse operating conditions. Therefore, this work not only offers new insights into regulating the electronic structure of single-atomic sites, but also promotes the development of ZAB for various applications.