In situ grown monolayer N-Doped graphene and ZnO on ZnFe2O4 hollow spheres for efficient photocatalytic tetracycline degradation

Herein, ZnFe2O4/ZnO hollow porous spheres (HPS) of the dual-template and self-dissolution design, on which monolayer nitrogen-doped graphene (NG) is in situ grown by chemical vapor deposition, are applied for realizing effective photocatalytic degradation of antibiotics. The constructed photocatalyst possesses a hollow interior for strengthening visible-light absorption ability and offering large surface area, a porous for facilitating rapidly mass transfer capability, a thin shell for shortening the migration distance of photo-generated electrons (e.), tight adhesion for expediting charge separation and mobility, and a monolayer NG cage surface for adsorbing and stimulating activating antibiotics molecules. Benefiting from the novel HPS structure, the prepared ZnFe2O4/NG/ZnO HPS photocatalyst exhibits high activity under visible-light irradiation, currently the largest to the best of our knowledge, which is much enhanced compared with those of the ZnFe2O4/NG/ZnO solid spheres and ZnFe2O4/NG hollow spheres.