Layered Molybdenum (Meta)phosphate for Photoreduction of Hexavalent Chromium and Degradation of Methylene Blue under Sunlight Radiance

[Image: see text] 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 [MoO(2)(PO(3))(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 MoO(2)(PO(3))(2) as a photocatalyst for wastewater treatment. The photoreduction of toxic Cr(6+) to Cr(3+) 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. MoO(2)(PO(3))(2) has been shown to complete photoreduction of toxic Cr(6+) to Cr(3+) 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 O(2)(•–), (•)OH, and h(+) can exist and play an important role in methylene blue photodegradation.