Tofu-derived nitrogen-doped mesoporous carbon materials as metal-free catalyst for oxygen reduction reaction

Abstract

Nitrogen dope mesoporous carbon materials are widely used in the designing of oxygen reduction reaction (ORR) catalysts. How to prepare nitrogen-doped carbons (NC) with broad mass transfer path and preserve abundant ORR active nitrogen functionalities is still a great challenge. Here, nitrogen-doped mesoporous carbon materials are obtained through simply pyrolysis a mixture of renewable biomass (tofu) and ZnCl2. Owing to the effective chemical activation effect during carbonization, the optimal NC could present high porosity (high surface area of 1062 m2 g−1, large pore volume of 0.97 cm3 g−1) and high nitrogen content (7.74 wt%). Benefit from the rich of nitrogen functionalities to create abundant active sites and the well-developed mesoporous structure (high mesopore area 825 m2 g−1 and dual mesopore system with mesopore in both 3 nm and 30 nm) to guarantee fast mass transport and electron transfer, the obtained NC could serve as fine metal-free ORR catalyst, accelerating oxygen reduction reaction via high efficient 4e− oxygen reduction pathway. And more important, NC showed higher stability than commercial Pt/C (20 wt%), which highlight its great potential in the designing of electrocatalyst.