Edge-rich Co/N-doped 3D nanosheet stacked carbon as an efficient dual-function electrocatalyst for rechargeable Zn-air battery

The development of high-efficiency oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) dual-function electrocatalysts based on transition metal and nitrogen co-doped carbon material is vital to the development of rechargeable Zn-air battery. In this work, dual-function oxygen electrocatalysts of 2D graphene-like (NC) and 3D nanosheet stacked carbon (CNC) derived from Zn-based zeolite-like metalorganic frameworks were prepared from the complex of imidazole-4, 5-dicarboxylic acid (4,5-Imdc) with only zinc nitrate (4,5-Imdc-Zn) or zinc and cobalt nitrate (4,5-Imdc-ZnCo). Morphology and catalytic activity of NC and CNC were studied in detail. After high temperature calcination, 4,5-Imdc-Zn developed into a 2D graphene-like structure (NC). While derivative of 4,5-Imdc-ZnCo appears a 3D nanosheet stacked (CNC) structure induced by a “pinning effect” of the existing Co ions. With increased defects, edges and Co-Nx active sites compared to NC, CNC shows more excellent electrocatalytic activity.