Improving the stability of aminated metal-free catalysts is a big challenge in Fenton-like reactions. Herein, trinuclear iron cluster (Fe3 cluster)-protected aminated graphene (Fe3-NH2-GR) is designed by a protective strategy. By protecting with the Fe3 cluster, the lone pair electrons of amino groups are protected and the N content of Fe3-NH2-GR can be fixed steadily. In peroxymonosulfate (PMS)-based Fenton-like reactions with a fixed-bed reactor, the lifetime of Fe3-NH2-GR is two times longer than that of aminated graphene (NH2-GR) under the same conditions. The deactivation kinetics shows that both Fe3-NH2-GR and NH2-GR follow zero-order kinetics and the deactivation rate constants of Fe3-NH2-GR are lower than that of NH2-GR at every period. Moreover, Fe3-NH2-GR still maintains 50% phenol degradation after 40 h rather than being constantly deactivated as NH2-GR. This stable activity is attributed to the formation of -O-NO2, while the N content will be lost in NH2-GR. This protective strategy by the Fe3 cluster provides a reliable method to enhance the efficiency and stability of carbon catalysts in Fenton-like reactions.
Keywords: Fenton-like; aminated graphene; deactivation analysis; protective strategy; stability enhancement.