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

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 [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.

Facile fabrication of a Z-scheme g-C3N5/Gd-MOF/silver nanocube composite as a new generation visible light active photocatalyst for abatement of persistent toxic pollutants

“…11 In such cases, low molecular weight organic acids are used as hole scavengers to enhance the reduction of Cr 6+ . 12,13 Such additional implementation or presence of organic acids may further change the pH of water during realtime applications. On the other hand, neomycin is a broadspectrum aminoglycoside antibiotic that works by attaching to bacterial ribosomes and preventing protein synthesis, making it effective against all positive and negative aerobic bacilli.…”