Ultrathin cobalt pyrophosphate nanosheets with different thicknesses for Zn-air batteries

Two dimensional (2D) ultrathin nonprecious metal based catalysts show excellent electrocatalytic activities, due to the larger surface areas, more catalytic sites and more interconnected electron-transfer access than their bulk counterparts. Here, we synthesized cobalt pyrophosphate (Co₂P₂O₇) nanosheets with different thickness by a simple and efficient one-step hydrothermal process. The catalytic performance of the obtained Co₂P₂O₇ was investigated via diverse electrochemical measurement. Due to the unique 2D structure and the flexible coordination of pyrophosphate group, the as-prepared Co₂P₂O₇ catalyst had excellent electrocatalytic performance and good stability, which could rank among the most active nonprecious metal catalysts for oxygen evolution reaction and oxygen reduction reaction. In addition, the ultrathin Co₂P₂O₇ nanosheets exhibited good performance as the air cathode catalyst for zinc air batteries.