In situ generation and efficient activation of H2O2 for pollutant degradation over CoMoS2 nanosphere-embedded rGO nanosheets and its interfacial reaction mechanism.

Graphical abstract Highlights • Mo S C and Mo O Co electron transfer bridges are successfully constructed on CMS-rGO NSs. • CMS-rGO NSs possesses the function of generating and activating H 2 O 2 synchronously. • CMS-rGO NSs shows very high Fenton-like activity for degradation of pollutants. • Dye pollutants can directly act as electron donors for CMS-rGO NSs. Abstract Consumption of additional H 2 O 2 is necessary in classical Fenton catalysis. Herein, we report a novel and special nanocatalyst consisting of CoMoS 2 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 2 O 2 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 2 nanospheres are uniformly embedded in the rGO nanosheets through Mo S C 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 Mo O Co 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 2 is efficiently reduced to HO 2 /O 2 − around the electron-rich Mo center, and HO 2 /O 2 − is further reduced to H 2 O 2 around the Co center. The generated H 2 O 2 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 2 O 2 generation-activation and pollutant degradation through constructing electron transfer bridges over the surface of catalysts. [ABSTRACT FROM AUTHOR]