Fabrication of visible light active Mn-doped Bi2WO6-GO/MoS2 heterostructure for enhanced photocatalytic degradation of methylene blue

Abstract

The increase in environmental pollution has led to an increased investigation in the development of novel ternary photocatalytic systems for remediation. These Photocatalytic systems exhibit superior photocatalytic action for the removal of pollutants because of their visible light active bandgaps. A highly effective visible light active ternary heterojunction was fabricated using a hydrothermal method assisted by ultrasonication. Herein, we report the Insitu hydrothermal synthesis of Mn-doped Bi2WO6-GO/ MoS2 photocatalyst, efficiently exhibiting greater photocatalytic activity for the wastewater treatment under solar light. The binary metal sulphide (MoS2) used as a co-catalyst, acted as electron collector and Graphene oxide (GO) as a support material for interfacial electron transfer to and from bismuth tungstate and MoS2. The as-prepared samples were characterized using SEM-EDX, FT-IR, XRD, XPS, and UV-Vis techniques. The bandgap of the novel photocatalyst was found in the visible region (2.2 eV) which helped in suppressing photoinduced electron-hole pairs recombination. The ternary Mn-BMG showed 99% methylene blue removal after 60 minutes of sunlight irradiation at the optimum conditions of pH 8, catalyst dose 50 mg/100ml and initial MB concentration of 10ppm under sunlight irradiation. The Mn-BMG has proved to be an effective sunlight active photocatalyst that can be reused without substantial loss in photocatalytic efficiency.

The Fabrication of Halogen-Doped FeWO4 Heterostructure Anchored over Graphene Oxide Nanosheets for the Sunlight-Driven Photocatalytic Degradation of Methylene Blue Dye

“…In I-FWGO, the stretching peaks of O-W-O and F-O-W shifted due to the iodine doping into the Fe-O lattice [24,25]. The peak intensity in the iodine-doped composite was lower than in the undoped counterpart and pristine FeWO 4 , confirming the successful insertion of dopant species in the host material [23]. FeWO4, with a bandgap of 2.0 eV, belongs to the wolframite family, which shows excellent photocatalytic activity due to various optical, electronic, and ferromagnetic properties [20].…”

“…The characteristic peaks of GO are shown around 1410 cm −1 , 1581 cm −1 , and 1711 cm −1 , which are attributed to COO − , C=C, and C=O stretching vibrations, respectively [22]. In both composites, two characteristic peaks correspond to W-O stretching and O-W-O stretching peaks at 832 cm −1 and 1034 cm −1 [23]. In I-FWGO, the stretching peaks of O-W-O and F-O-W shifted due to the iodine doping into the Fe-O lattice [24,25].…”

Bismuth tungstate Bi2WO6: a review on structural, photophysical and photocatalytic properties

“…117 According to 118 doping with Europium was the primary reason for the high activity of the photocatalyst, rather than changes in band gap absorption properties. Recently, Tahir and his team 119 reported on the in situ hydrothermal engineering of a Mn-doped Bi 2 WO 6 –GO/MoS 2 photocatalyst. They found that the Mn-doped composite had an absorption edge located in the visible zone with a gap energy of 2.2 eV.…”

Investigation of boron-doped graphene oxide anchored with copper sulphide flowers as visible light active photocatalyst for methylene blue degradation

“…A modified version of Hummer’s technique was employed to produce graphene oxide (Fig. S1 ), as previously reported by our research group 42 . Prepared GO was dispersed ultrasonically and mixed in an aqueous solution containing boric acid in a 1:3 ratio, resulting in boron-doped graphene oxide synthesis 43 .…”

“…More dye molecules adsorb to the catalyst surface as the dye concentration rises, thus, the active sites become saturated. Reduced light intensity at the catalyst surface results in less hydroxyl radical production, resulting in less efficient breakdown of methylene blue molecules 42 . A concentration of 15 ppm was found to be the optimum level for BGO-CuS, and 10 ppm was found to be optimum for GO-CuS and CuS.…”