Graphitic carbon nitride/SmFeO₃ composite Z-scheme photocatalyst with high visible light activity

In this work, novel heterostructured photocatalysts associating graphitic carbon nitride (g-CN) and SmFeO₃ were prepared via a mixing-ultrasonication process. Structural, optical and morphological characterizations demonstrate that the interfacial junction between g-CN and SmFeO₃ is well established for all g-CN/SmFeO₃ composites prepared with g-CN:SmFeO₃ weight ratio of 20:80, 50:50 and 80:20. The g-CN/SmFeO₃ (80:20) composite exhibits the highest photocatalytic activity for the degradation of pollutants like the Orange II dye and the tetracycline hydrochloride antibiotic under visible light irradiation. This high photocatalytic activity originates from the enhanced light absorption over the whole visible region compared to pure g-CN and from the improved separation and transfer of photogenerated electron/hole pairs as demonstrated by photoluminescence and photocurrent measurements. A Z-scheme charge carrier transfer mechanism was demonstrated for the photocatalytic reactions. The g-CN/SmFeO₃ (80:20) catalyst was also demonstrated to be stable and can be reused up to six times without significant alteration of the activity.