Atomically-dispersed Fe-N-x and C-S-C ordered mesoporous carbons as efficient catalysts for the oxygen reduction reaction in a microbial fuel cell

摘要

An efficient catalyst (Fe/S-N/C) possessing abundant ordered mesoporous was synthesized via a facile strategy, in which the active Fe-N-x and C-S-C species exhibited atomic dispersion. Attributing to its well-developed porosity, the total pore volume and specific surface area of Fe/S-N/C catalyst reach 0.556 cm(3) g(-1) and 980.9 m(2) g(-1) respectively. Electron microscopy results reveal the uniform dispersion of atomic Fe-N-x and C-S-C in this catalyst, which has inherited a polyhedral morphology derived from ZIF-8. X-ray spectroscopy measurements further validate that the Fe/S-N/C composite can provide abundant and highly efficient active sites for ORR. The atomic ratio of nitrogen is 4.28%, with high relative concentrations of the active pyridinic N and Fe-N-x. Furthermore, the Fe/S-N/C catalysts demonstrate significant ORR activity in the practical application of MFC devices. Based on a high open circuit potential (0.674 V) and maximum power density (1436.42 mW m(-2)) of the MFC device which uses the Fe/S-N/C as air-cathode catalyst, the Fe/S-N/C displays better catalytic activity than commercial 20% Pt/C catalyst. This investigation provides a new strategy to design an effective, low-cost ORR catalyst for MFC devices. (C) 2020 Elsevier B.V. All rights reserved.