Construction of core-shell Fe3O4@GO-CoPc photo-Fenton catalyst for superior removal of tetracycline: The role of GO in promotion of H2O2 to •OH conversion

A novel core-shell structured Fe3O4@GO-CoPc magnetic catalyst, which is with magnetite (Fe3O4) as the core, graphene oxide (GO) as the interlayer and cobalt-phthalocyanine (CoPc) as the shell, was successfully prepared and used as a heterogeneous photo-Fenton catalyst for tetracycline (TC) degradation in this work. The core-shell structure of the catalyst was confirmed by XRD, FTIR, SEM and TEM. BET and magnetic hysteresis loops mea-surements indicated that Fe3O4@GO-CoPc catalyst owned large specific surface area and could be easily recovered under an external magnetic field. Meanwhile, the experimental results of TC degradation demon-strated that the photo-Fenton efficiency of Fe3O4@GO-CoPc was excellent. When the reaction time was 120 min, TC could be degraded almost completely in the photo-Fenton system with Fe3O4@GO-CoPc. The high photo-Fenton catalytic activity of Fe3O4@GO-CoPc could be resulted from the effective transfer of photo-generated electrons between CoPc and Fe3O4 by GO. Moreover, the main reaction species, center dot OH, O-2 center dot-, O-1(2) and h(+), were verified by the analysis of active species in this system. Finally, the mechanism analyses and quantitative analysis results of active species indicated that the introduction of GO accelerated the cycle between Fe(II) and Fe(III) as well as improved the effective utilization of H2O2 (the efficiency of conversion of H2O2 to center dot OH).

Automated summary

A novel core-shell structured Fe3O4@GO-CoPc magnetic catalyst with excellent photo-Fenton catalytic activity was successfully prepared. The effective transfer of photo-generated electrons between CoPc and Fe3O4 by GO was found to be the key factor contributing to the high catalytic activity. The analysis of active species further confirmed the reaction mechanism.