Effective porous carbon electrocatalyst derived from Angelica-offcuts for oxygen reduction reaction

The biomass-based materials hold promising potential to develop high-efficiency, durable, and low-cost electrocatalysts for oxygen reduction reaction (ORR). Herein, Hemin-decorated porous offcuts of Angelica sinensisderived carbon (H-PAC) catalyst was prepared by an activation-adsorption-pyrolysis strategy. The resultant HPAC catalyst displays a high electrocatalytic ORR performance with positive initial potential ( E onset , 0.952 V) and half-wave potential (E1/2, E 1/2 , 0.865 V) in alkaline medium. Additionally, this H-PAC catalyst also shows good longterm stability, with only negatively shifting 13 mV of E 1/2 after 7,500 cycles. The Zn-air battery (ZAB) assembled by H-PAC as air cathode shows a great performance of ZAB, with power density of 142.9 mW cm-2 , specific capacity of 840.4 mA h g-1 at 5 mA cm-2 and 818.2 mA h g-1 at 10 mA cm-2 and charge-discharge cycling of 140 h. This study would provide a good strategy for building hierarchical-porous carbon-based catalyst from renewable biomass-waste in future study.