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 LI-FeCo2O4@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.