Investigation on the Photodegradation Performance of S‐Rich g‐C 3 N 4 /MnO 2 Composites for Efficient Removal of Hazardous Dyes From Aqueous Phase

Investigation on the Photodegradation Performance of S‐Rich g‐C 3 N 4 /MnO 2 Composites for Efficient Removal of Hazardous Dyes From Aqueous Phase P. Varun Prasath Department of Chemistry SRM Valliammai Engineering College Kattankulathur India S. M. Muba Shera Department of Chemical Engineering A.C. Tech Campus Anna University Guindy Chennai India K. Suganandam Department of Chemistry Velammal College of Engineering and Technology Madurai Tamil Nadu India G. Kalaiarasi Department of Chemistry and Centre for Material Chemistry Karpagam Academy of Higher Education (Deemed to be University) Coimbatore India S. Sudhakar Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences Saveetha University Chennai India K. Ravichandran KREA University Sri City Andra Pradesh India A. Kosiha Department of Chemistry, School of Basic Science, Vels Institute of Science Technology & Advanced Studies (VISTAS) (Deemed to be University) Chennai India https://orcid.org/0000-0002-3548-4055 ABSTRACT

Sulfur (S)‐rich g‐C 3 N 4 /α‐MnO 2 (α‐MnO 2 /GCN‐S) heterojunction was synthesized using a simple hydrothermal technique, which was effectively utilized for the photodegradation of methylene blue and congo red dyes under visible light illumination. The results of the characterization analysis suggest that the α‐MnO 2 /GCN‐S composite exhibits a high crystalline nature and the heterojunction successfully formed between g‐C 3 N 4 and α‐MnO 2 demonstrates an effective photocatalytic agent for selected hazardous dyes. According to the obtained findings, α‐MnO 2 /GCN‐S composite exhibited outstanding visible light absorption when compared with pure g‐C 3 N 4 and α‐MnO 2 under visible light irradiation. The enhanced photocatalytic performance of the α‐MnO 2 /GCN‐S can be attributed to the effective separation of electron–hole pairs facilitated by g‐C 3 N 4 , along with the improved visible light absorption properties of the S‐doped α‐MnO 2 . The findings indicate that the α‐MnO 2 /GCN‐S composite demonstrates exceptional photocatalytic performance, achieving degradation efficiencies of 91% and 92% for congo red and methylene blue in 30 and 60 min, respectively. On the other hand, the pristine form of GCN‐S and α‐MnO 2 exhibited lower degradation rates of 51% and 55% for congo red, and 67%, 69% for methylene blue, respectively. These results highlight the capability of α‐MnO 2 /GCN‐S composites to efficiently eliminate harmful dyes from aqueous solutions.
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