Facile fabrication of single-atom catalysts by a plasma-etching strategy for oxygen reduction reaction

Single-atom catalysts (SACs) are one of the most promising candidates for catalyzing various electrochemical reactions, due to their maximum atom utilizations and unique electronic structures. However, the general methods for preparing the SACs usually require complex processes, delicate regulation, and unique properties for the anchoring metals and supports. Herein, for the first time, we developed a facile, highly efficient, and universal plasma-etching strategy to fabricate various single-metal and dual-metal SACs. As an example, prepared Cu-SAC/NC exhibited superb oxygen reduction reaction (ORR) activity and a long period of circulation stability in an alkaline medium. More importantly, Cu-SAC/NC also exhibited an excellent battery performance when implemented as the air-cathode catalyst for assembled zinc-air batteries. Furthermore, density functional theory calculations revealed that pyrrolic-type three-coordinated Cu-po-N₃ sites exhibited considerable stability and a theoretical overpotential of only 0.21 V for the ORR, and were the main active sites for the high performance of the catalyst. This work proposes a facile, general, highly efficient, and controllable strategy for preparing SACs, and it is expected to open new approaches for the practical applications of SACs.