N-doped 3D hierarchical carbon from water hyacinth for high-performance Zn-air batteries

Investigating high-performance, affordable carbon-based catalysts as a reliable replacement for platinum-based catalysts in oxygen reduction processes is essential to addressing the commercialization of metal-air batteries (ORR). In this paper, we provide a two-step pyrolysis method for producing N-doped porous carbon catalysts from water hyacinth. The produced catalysts have enhanced ORR activity, a superior half-wave potential (ΔE1/2 = 0.843 V) as comparison to commercial platinum carbon (ΔE1/2 = 0.83 V), and noteworthy cycling stability after 2000 cycles. Additionally, this catalyst is utilized to create a rechargeable Zn-air battery (ZAB), which performs better than the Pt/C-RuO2 battery already on the market thanks to its high specific capacity (775 mAh g−1) and battery charge/discharge cycle stability (212 h). This finding paves the way for the creation of biomass-derived heteroatom-doped carbon catalysts that are cost-effective, high-performing, and ecologically benign.