In situ generation and efficient activation of H 2 O 2 for pollutant degradation over CoMoS 2 nanosphere-embedded rGO nanosheets and its interfacial reaction mechanism

Consumption of additional H O is necessary in classical Fenton catalysis. Herein, we report a novel and special nanocatalyst consisting of CoMoS nanosphere-embedded, reduced graphene oxide (rGO) nanosheets (CMS-rGO NSs). This nanocatalyst was discovered to have an impressive reactivity for in situ generation and synchronistical activation of H O in different active centers, yielding fast and efficient degradation of the pollutants. The reaction rate is ∼21 times higher than that of conventional Fenton catalysts. The characterization shows that countless flower-like CoMoS nanospheres are uniformly embedded in the rGO nanosheets through MoSC bonding bridges in CMS-rGO NSs, which leads to activation of the π electrons and their transfer from rGO to the metal centers (π → M). The formed MoOCo further leads to a distribution of orientations of the electrons around the metal centers due to the different electronegativity of Mo and Co. During the reaction, the dissolved O is efficiently reduced to HO /O around the electron-rich Mo center, and HO /O is further reduced to H O around the Co center. The generated H O is finally reduced to OH for degrading dyes in the electron-rich metal (Mo or Co) centers of CMS-rGO NSs. The dye pollutants also act as electron donors, and they are directly degraded in the electron-poor π-center of CMS-rGO NSs, which promote the electron transfer cycle and achieve electron gain-loss balance. This discovery provides a new strategy for H O generation-activation and pollutant degradation through constructing electron transfer bridges over the surface of catalysts.