Solar Light-Driven Photocatalytic Degradation of Methylene Blue by Mesoporous g-C3N4@BiOCl hybrid

Abstract

Photocatalytic degradation of noxious pollutants has emerged as the most appealing technique to minimize water pollution. Here a facile approach has been developed for the construction of g-C3N4@BiOCl hybrid with varying weight ratios by the conglomeration of g-C3N4 nanosheets with BiOCl in-situ. The successful formation, uniform distribution and thermal stability of the hybrid were verified by XRD, XPS, EDX, elemental mapping and TGA analysis. FESEM and HRTEM images displayed that BiOCl platelets are well-covered with g-C3N4 nanosheets. The optical properties were evaluated by UV-DRS and PL spectroscopy which confirmed that the hybrid has a low band gap and low recombination rate, facilitating charge-separation. BET analysis revealed that 3:1 g-C3N4@BiOCl had the highest surface area (107 m 2 /g) with m esopores. To evaluate the photocatalytic performance of the catalyst, methylene blue ( MB) was degraded in natural sunlight. The 3:1 g-C3N4@BiOCl hybrid manifested the best performance (degrading 94.8% of MB with very high rate constant (0.0301 min-1). Effect of pH and catalyst concentration on the photodegradation was also investigated. Trapping experiments revealed that O2•- was the major reactive species in the photodegradation mechanism. The catalyst was reused for MB degradation showing 76% efficiency even after 5 consecutive-cycles. A comparative study was done with catalysts in the literature suggesting that the synthesized nanocomposite acts as one of the best photocatalyst for degradation of hazardous contaminants.