Rapid Laser-Induced Highly Dispersed and Ultrafine N-Doped Graphene-Wrapped FeCo2O4 Nanoparticles for Nearly 100% Utilization and Conversion of Peroxymonosulfate into Singlet Oxygen

Currently, catalysts with core-shell structures have an important role in catalytic performance and practical applications, but how to simplify the preparation method and a reasonable explanation of the activation mechanism are still lacking. In this work, we obtained highly dispersed and ultrafine laser-induced nitrogen-doped graphene-wrapped iron cobaltate (LI-FeCo2O4@NDG) catalysts by one-step carbonization of iron cobalt metal-organic framework (FeCo-MOF) precursors using a CO2 laser annealing technique under ambient conditions. An LIFeCo2O4@NDG/peroxymonosulfate (PMS) system achieved a rapid degradation of sulfamethoxazole (SMX) with 92.2% degradation efficiency in 6 min. Meanwhile, LI-FeCo2O4@NDG exhibited low metal leaching (Co, 0.155 mg/L; Fe, 0.008 mg/L) and a high reaction rate constant (k = 0.413 min-1). Most importantly, the ability of the catalyst could achieve nearly 100% utilization and conversion of PMS to singlet oxygen (1O2). The activation mechanism may be explained that the electron pool and interfacial electric field formed by the LI-FeCo2O4@NDG with the core-shell structure could accelerate the electron supply and transfer to the PMS, facilitating the activation of PMS self-decomposition to produce more 1O2. Overall, this work is expected to open a new avenue for the construction of core-shell structures and a new insight for revealing its activation mechanism of PMS.