Graphitic carbon nitride modified by 5-sulfonic-8-hydroxyquinoline and Fe (III) ions as visible-light photocatalyst to efficiently reduce nitroaromatic compounds

Abstract

In this study, a new graphitic carbon nitride (CN) catalyst was synthesized by combining 5-sulfonic-8-hydroxyquinoline (SQ) and Fe (III) ions. Photocatalysis reduction of nitroaromatic compounds was employed to evaluate the catalytic performance of the synthesized catalyst. Compared to the pristine CN, the optimized CN-SQ-2-Fe photocatalyst showed enhanced absorption in visible light region, which promoted photogenerated charge transfer and separation. Herein, we also developed a green and efficient photocatalysis route to convert nitrophenols (NPs) into aminophenols (APs) using CN-SQ-2-Fe photocatalyst. The visible light, separation of photogenerated charges and carrier transportation of the optimized sample CN-SQ-2-Fe were significantly improved in comparison with the pristine CN and the modified samples of CN-Fe and CN-SQ-2. Accordingly, the CN-SQ-2-Fe showed a high conversion (96%) of p-nitrophenol (p-NP) to p-aminophenol (p-AP) under visible light irradiation for 2 h and possessed high photocatalytic durability. Different NP compounds were also studied under the condition of photocatalysis reduction and demonstrated high conversion (>97%). Finally, a possible mechanism was proposed for the photocatalytic reduction of p-NP by CN-SQ-2-Fe. This work provides an effective approach to prepare graphitic carbon nitride (CN) modified by 5-sulfonic-8-hydroxyquinoline (SQ) and Fe (III) ions, which is a potential visible light driven photocatalyst for the reduction of nitrobenzene derivatives.