Fabrication of magnetic FeO@SiO@BiOCO/rGO composite for enhancing its photocatalytic performance for organic dyes and recyclability.

A novel magnetic FeO@SiO@BiOCO/rGO composite comprising of uniform core-shell-structured FeO@SiO@BiOCO microspheres mounted on reduced graphene oxide (rGO) sheets was successfully fabricated by using a facile hydrothermal method. The adsorption-desorption isotherm of FeO@SiO@BiOCO/rGO belonged to type IV with an H4-type hysteresis loop. The specific surface areas and magnetization saturation value (M) of FeO@SiO@BiOCO/rGO (x = 0.15 g) were 102.12 m/g and 25.4 emu/g, respectively. FeO@SiO@BiOCO/rGO (x = 0.15 g) exhibited remarkable photocatalytic degradation activity and mineralization effect for MO and decolorization performance for the mixed solution of MO, Rh B, and MB. MO degradation by FeO@SiO@BiOCO/rGO conformed to a first-order kinetic reaction, and the corresponding k value was 0.05553 min. A suitable amount of rGO in FeO@SiO@BiOCO/rGO could decrease the energy band gap, inhibit the recombination of photo-induced electron/hole (e/h) pair, and broaden and enhance the response of the catalyst to visible light, thereby enhancing the visible-light catalytic degradation of organic dyes. The active species produced in the photocatalysis included •O, •OH, and h, with •O being the dominant active species. The as-prepared photocatalyst also showed excellent magnetic separation performance and stability. Results show that the as-prepared FeO@SiO@BiOCO/rGO composite is a promising photocatalyst with considerable application potential in organic dyes removal.