Spin polarization induced by atomic strain of MBene promotes the ·O2– production for groundwater disinfection

Superbugs in groundwater are posing severe health risks through waterborne pathways. An emerging approach for green disinfection lies at photocatalysis, which levers the locally generated superoxide radical (·O₂^-) for neutralization. However, the spin-forbidden feature of O₂ hinders the photocatalytic generation of active ·O₂^-, and thus greatly limited the disinfection efficiency, especially for real groundwater with a low dissolved oxygen (DO) concentration. Herein, we report a class of strained Mo_4/3B_2-xT_z MBene (MB) with enhanced adsorption/activation of molecular O₂ for photocatalytic disinfection, and find the strain induced spin polarization of In₂S₃/Mo_4/3B_2-xT_z (IS/MB) can facilitate the spin-orbit hybridization of Mo sites and O₂ to overcome the spin-forbidden of O₂, which results in a 16.59-fold increase in ·O₂^- photocatalytic production in low DO condition (2.46 mg L^-1). In particular, we demonstrate an In₂S₃/Mo_4/3B_2-xT_z (50 mg)-based continuous-flow-disinfection system stably operates over 62 h and collects 37.2 L bacteria-free groundwater, which represents state-of-the-art photodisinfection materials for groundwater disinfection. Most importantly, the disinfection capacity of the continuous-flow-disinfection system is 25 times higher than that of commercial sodium hypochlorite (NaOCl), suggesting the practical potential for groundwater purification.