Protective Strategy to Boost the Stability of Aminated Graphene in Fenton-like Reactions

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.