Abstract
Noble metal, semiconductor, or metal-free nanomaterials have shown promising applicability as potential photocatalyst materials. A one-step process has been established for the synthesis of layered molybdenum (meta)phosphate [MoO2(PO3)2] using a solvothermal method. The nanopowders were characterized by X-ray diffraction (XRD), UV-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), infrared spectroscopy (IR), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL), surface area analysis (Brunauer-Emmett-Teller (BET)), electron spin resonance (ESR), and high-resolution transmission electron microscopy (HRTEM). Through this study, we demonstrate the use of MoO2(PO3)2 as a photocatalyst for wastewater treatment. The photoreduction of toxic Cr6+ to Cr3+ by layered molybdenum (meta)phosphate is investigated using formic acid as a scavenger. This catalyst has also been used for photodegrading organic dyes like methylene blue. MoO2(PO3)2 has been shown to complete photoreduction of toxic Cr6+ to Cr3+ in 6 min and achieved 78% degradation efficiency for methylene blue in 36 min. The reactive species trapping experiments revealed that the key active species like O2 •-, •OH, and h+ can exist and play an important role in methylene blue photodegradation.