A structural unique 1D-MoO3@3D-WO3 nanohybrid for stable and reusable photocatalytic conversion of hexavalent chromium in aqueous medium

Abstract A novel hybrid of binary metal oxide (1D-MoO3@3D-WO3) nanocomposite synthesized via a simple hydrothermal followed by greener way of ultrasonic assisted method. The synthesized MoO3@WO3 was properly characterized by sophisticated instrumental techniques like XRD, FT-IR, XPS, SEM, TEM, UV-DRS and EDX with mapping analysis. This hybrid nanocatalyst exhibited an increased photocatalytic efficiency towards reduction of toxic Cr(VI) in aqueous solutions compared to those of pure MoO3 and WO3 under visible illumination. The superior photoreduction performance of MoO3@WO3 was ascribed to the formation of heterojuction with suitable band gap alignments. After 25 min irradiation, we found that 97.6 % of toxic Cr(VI) was effectively removed. The reduction percentage and kinetic rate constant were found to be 97.6% and 0.367 min-1, respectively. The various reduction parameters were optimized such as pH, Cr(VI) concentration and catalyst weight percentage. Finally, we suggested the photocatalytic electron transfer mechanism, durability and reproducibility of our MoO3@WO3 nanomaterials. Our results may offer an improved system for reduction of toxic pollutants and other photocatalytic applications.