Efficient ORR electrocatalytic activity of peanut shell-based graphitic carbon microstructures
By Yanling Wu, Yanli Chen, Huiqiu Wang, Chiming Wang, Ansheng Wang, Shuai Zhao, Xiyou Li, Daofeng Sun and Jianzhuang Jiang
Published in Journal of Materials Chemistry A
2018
Abstract
A hierarchical microporous graphitic carbon material intrinsically doped with sulfur and extrinsically doped with dual cobalt species [Co3O4 and Co(PO3)2, termed as CoOP] nanoparticles was prepared from a sustainable waste biomass, peanut shell, with CO2 gas as the activating agent through a thermal-reduction method. The resulting CoOP@bio-C exhibits an overall superior ORR catalytic activity, stability and resistance to methanol crossover in alkaline media to commercial Pt/C, with onset and half-wave potentials of 0.91 and 0.81 V in 0.1 M KOH, a limiting current density of −5.7 mA cm−2, and a small Tafel slope of 57 mV dec−1, representing the best result among the biomass-based carbon electrocatalysts. In particular, comparative studies reveal the significant effect of the work function of corresponding catalytic materials on the ORR electrocatalysis. Dual-doped CoOP@bio-C with a work function of 5.42 eV, closer to that of Pt (5.65 eV), displays much better electrocatalytic activity than single-doped Co3O4@bio-C, single-doped Co(PO3)2@bio-C and bio-C-800 catalysts with work functions of 8.35, 6.61 and 5.02 eV, respectively, due to its good adsorption nature to O2 and desorption nature to the reaction intermediates. The present result will be surely helpful for the design and synthesis of biomass resource-based ORR catalysts with great application potential.