Energy storage devices like metal-air batteries exhibiting high energy density are considered globally as a promising sustainable energy solution. However, the practical application of the metal-air battery is limited by the use of the high-cost Pt/C + RuO2 catalyst to catalyze sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air cathode. Therefore, developing a low-cost and highly efficient bifunctional oxygen electrocatalyst is crucial for the advancement of next-generation metal-air batteries. Herein, we have optimized a promising strategy for developing a robust and low-cost bifunctional oxygen electrocatalyst by synthesizing highly crystalline Co3O4-embedded nitrogen-doped carbon sheets from ZIF-9 through a simple wet chemical method. The key finding of this study was the water-induced phase transition of the ZIF-9 (I) to ZIF-9 (III) phase with a completely different structure and morphology, enabling the formation of highly crystalline Co3O4-embedded nitrogen-doped carbon sheets. Z9-CoNCS-1.0G catalyst, prepared through this wet chemical method by incorporating 1 g of glucose, has demonstrated excellent bifunctional performance that rivaled the commercial Pt/C + RuO2 catalysts. This study offers a promising pathway for developing highly crystalline Co3O4 embedded in nitrogen-doped carbon from ZIF-9, which can serve as a highly efficient bifunctional oxygen electrocatalyst.
Somasundharam et al. (Fri,) studied this question.