Surface engineering of ZIF-L renders multidoped leaf-like porous carbon nanosheets for highly efficient oxygen reduction reaction in both alkaline and acidic media

Abstract

Despite significant progress in developing zeolitic imidazolate frameworks (ZIFs)-derived carbon materials, the crafting of 2D porous carbon catalyst derived from ZIFs with outstanding oxygen reduction reaction (ORR) performance still remains challenge. Herein, we propose on a facile and robust strategy to create leaf-like porous carbon nanosheets (denoted Co,Zn/N,S-LPCS) derived from the surface engineering of ZIF-L with trithiocyanuric acid (TCA) for highly efficient ORR electrocatalyst. By optimizing Co/Zn ratio and TCA amount, the core-shelled ZIF-LCo/Zn@TCA composite is first synthesized. Sequentially, the pyrolysis of ZIF-LCo/Zn@TCA yields Co,Zn/N,S-LPCS with hierarchical porosity and large specific surface area. The resulting Co,Zn/N,S-LPCS electrocatalyst exhibits higher ORR performance than the counterparts of Co,Zn/NC (no TCA) and Co/N,S-LPCS (no Zn). Most importantly, the half-wave potential (E1/2) of Co,Zn/N,S-LPCS is 30 mV larger than Pt/C in alkaline electrolyte, and close to Pt/C in acidic electrolyte. Notably, the long-time stability and anti-methanol property of the Co,Zn/N,S-LPCS largely outperform Pt/C. The Co,Zn/N,S-LPCS-based primary Zn-air battery displays a specific capacity of 808.9 mA h g−1Zn and a power density of 106 mW cm−2. The remarkable performance of the Co,Zn/N,S-LPCS electrocatalyst stems from the synergetic effect of multi-doping, hierarchical porosity, large specific surface area and 2D leaf-like architecture.