LAUSR

Abstract ZnO/Ag2O photocatalysts with heterostructure were synthesized by a green and effective mechanochemical method. The preparation process was taken in solid state at room temperature with a short grinding time. The as-made products showed a high degree of crystallinity without post-calcination treatment. Such synthetic method does not involve any organic solvents and the reaction matrix can be recycled. The as-prepared ZnO/Ag2O samples show excellent photocatalytic activity and photostability for degradation of different organic dyes under visible light. The content of Ag2O plays an important role in the photocatalytic activity, which can be tuned by the precursor AgNO3. The photodegradation rate constant (k) of the optimal ZnO/Ag2O sample under visible light is nearly 0.1004 min−1 for methylene blue (MB), 0.063 min−1 for rhodamine B (RHB) and 0.07 min−1 for methyl orange (MO), which are much better than the pure ZnO (0.0075 min−1). The enhancement of the visible light photocatalytic activity could be attributed to the heterojunction interfaces induced by the match of crystal lattice and energy band between the Ag2O and ZnO. The Ag2O generates the excited-state electrons under visible light irradiation. The excited electrons on Ag2O could directly transfer to the conduction band (CB) of ZnO, making ZnO/Ag2O present remarkable visible light photocatalytic activity.