Morphology control and electronic tailoring of Co_xA_y (A = P, S, Se) electrocatalysts for water splitting

As a crucial route for the development of clean and sustainable energy systems, electrochemical water splitting has received much attention. Designing high-performance electrocatalysts for this process is extremely desirable to lower its overpotential and make practical applications possible. Over the past years, owing to the exploitation of novel preparation strategies, advanced characterization approaches, and insightful theoretical calculations, the rational design of numerous Co_xA_y (A = P, S, Se)-based materials with excellent electrocatalytic water-splitting behavior has been demonstrated. In particular, the catalytic properties of these Co_xA_y (A = P, S, Se)-based materials highly depend on their structural/electronic modulation. This article summarizes recent efforts and progress in regulating their electronic and morphological structures toward the performance optimization. Phase control, defect engineering, nanostructure construction, heteroatom doping, and composite engineering, are introduced to optimize electronic configurations, increase active sites, and enhance the conductivity, etc. Moreover, the underlying activity-structure relationships behind the boosted catalytic behavior of these Co_xA_y (A = P, S, Se)-based materials are discussed in detail. Lastly, a perspective on the exploration of Co_xA_y (A = P, S, Se)-based electrocatalysts in the future is presented. This review provides insights into the investigation of emerging materials in energy chemistry.