Synthesis of coral like WO3/g-C3N4 nanocomposites for the removal of hazardous dyes under visible light

Abstract In this work, the novel coral like WO3/g-C3N4 nanocomposites were prepared via a wet chemical process. The samples using various mass ratios (1:1. 1:3, 3:1) of WO3 and g-C3N4 were prepared under the same conditions. The photocatalysts were characterized by using various techniques including N2 sorption, energy dispersion spectroscopy (EDS), X-ray and photoelectron spectroscopy (XPS), which confirmed the homogeneous combination of WO3 with g-C3N4. Furthermore, the high-resolution transmission electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM) were used for analyzing the coral like morphology of the synthesized samples. The photocatalysts were used for the removal of important industrial dyes, methylene blue (MB), as well as remazol brilliant red X-3BS (RbX) under the visible light source. The synergistic effect of the semiconductors (WO3 and g-C3N4) was proved to be beneficial for accelerating electron-hole separation. The synthesized WO3/g-C3N4 -1:1 catalyst exhibited the highest photocatalytic performance in comparison to pure g-C3N4, WO3, and other synthesized catalysts for the degradation of dyes. The highest rate constants of 0.0419 min−1 and 0.0365 min−1 were obtained for MB and RbX removal by WO3/g-C3N4-1:1 catalyst which is almost 34 times superior as compared to pure WO3 (0.0012 min−1). Furthermore, the catalysts showed good stability along with efficient degradation efficiency after multiple cyclic runs. The Z-scheme photocatalytic mechanism along with reactive species (from scavenger studies) was well explained for the degradation of dyes using WO3/g-C3N4 composites.