Synthesis of oxygen-rich carbon materials as metal-free catalysts for oxygen reduction reaction in seawater electrolyte

Compared to conventional aqueous metal-air batteries, seawater batteries provide a promising strategy for the sustainable energy conversion and storage systems. However, the intricate ionic environment of seawater, in particular, Cl significantly restraint the oxygen reduction reaction (ORR) activity of the catalysts. Herein, mesoporous carbon materials with abundant oxygen-containing functional groups were simply fabricated as the cost-effective catalysts from the biowaste Ginkgo biloba, exhibiting prominent stability and ORR activity with a 4e path selectivity up to 92 % in seawater electrolyte. Structure characterization and ORR experimental results indicated the ORR performance was significantly modulated by the C-O-C in carbon matrix, and the synergistic of C-O-C and N-containing configuration may further enhance the dissociation of O-O of *OOH, resulting in an optimized 4e path selectivity. Additionally, the Ginkgo biloba derived catalysts displayed an overpotential of 580 mV for at 10 mA/cm2 more negative than that of the previously reported commercial Ir/C in seawater electrolyte. This study highlights the synthesis of sustainable and cost-effective catalysts for seawater batteries, offering a strategy for designing metal-free catalysts of seawater battery, and promoting the advancement of sustainable energy conversion and storage technologies.