Coordination regulated cobalt-based electrocatalysts for electrochemical water splitting

Currently, electrochemical water splitting is recognized as the most efficient key technology for producing hydrogen. However, it faces the challenges such as sluggish reaction kinetics, low energy conversion efficiency and poor cycling stability, limiting its practical applications. Therefore, developing efficient and inexpensive electrocatalysts is urgently needed. Cobalt-based electrocatalysts own outstanding electronic orbital structure and low-cost metallic element so that it stimulates the intense interest of researchers and has been extensively developed as electrocatalysts. However, cobalt-based electrocatalysts expose several drawbacks such as low conductivity, limited intrinsic catalytic activity, and less active site. Intensive efforts have been made to optimize the electrocatalytic activity of cobalt-based electrocatalysts, such as doping, vacancy optimization, interface modulation, structural engineering, multi-active site design, promotion of active phases, nanohybridization, and self-supporting architectures, etc. In this work, we summarize these efforts and discuss the influence of electron structure regulation, active site quantity, and carrier/material transfer efficiency on the catalytic performance of cobalt-based materials. And also, the challenges and prospects of cobalt-based catalysts are addressed.