Microwave-assisted hydrothermal synthesis of Ag2Mo1-xWxO4 (x = 0, 0.25, 0.50, 0.75 and 1 mol%) heterostructures for enhanced photocatalytic degradation of organic dyes

Neto, N. F. Andrade; Lima, Anderson Barbosa; Bomio, M. R. D.; Motta, F. V.

doi:10.1016/j.jallcom.2020.156077

Cited by 13 publications

(11 citation statements)

References 33 publications

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“…The indexation for all diffraction peaks detected in the XRD pattern agrees with the alpha phase (α-Ag 2 WO 4 ) of silver tungstate with an orthorhombic ( P 21 n ) structure and four molecules for the unit cell for both samples . The well-defined broad line and intensity for all diffraction peaks indicate a high crystallinity degree and order/disorder at a short and long range . Moreover, the diffraction peaks of silver tungstate polymorphs (β-Ag 2 WO 4 and/or γ-Ag 2 WO 4 ), metallic silver nanoparticles (Ag 0 ), silver tungstate, or copper tungstate are absent, confirming the high purity of these materials .…”

Section: Resultssupporting

confidence: 71%

“…In Figure b, we can observe that there was a notable shift for the plan (002) at 2θ of 30.24° (α-Ag 2 WO 4 ) to 30.40° (α-Ag 1.98 Cu 0.02 WO 4 ), an intensity decrease for diffraction peak at 2θ = 31.62 (231 plan), and a shift for the plan (400) from 33.14° (α-Ag 2 WO 4 ) to 32.90° (α-Ag 1.98 Cu 0.02 WO 4 ). These changes for diffraction pattern of α-Ag 1.98 Cu 0.02 WO 4 in comparison with the XRD pattern of pure silver tungstate are indicative of successful solid solution substitution of silver atoms by copper atoms in the orthorhombic unit cell of silver tungstate. ,, …”

Section: Resultsmentioning

confidence: 84%

“…Several applications are reported for silver tungstate microcrystals, mainly related to the alpha phase. In this context, we can highlight photocatalytic, − antimicrobial, , and fungal properties in addition to applications in semiconductor technology as capacitors, light-emitting devices (LEDs), and gas sensors . These applications are intrinsically dependent on the obtaining methods, particle size and morphology, doping elements, and crystalline defects. ,,− Also, the optical band gap near 3.1 eV for pure silver tungstate (α-Ag 2 WO 4 ) is a factor that limits the photocatalytic applications to the ultraviolet region.…”

Section: Introductionmentioning

confidence: 99%

“…In this context, we can highlight photocatalytic, − antimicrobial, , and fungal properties in addition to applications in semiconductor technology as capacitors, light-emitting devices (LEDs), and gas sensors . These applications are intrinsically dependent on the obtaining methods, particle size and morphology, doping elements, and crystalline defects. ,,− Also, the optical band gap near 3.1 eV for pure silver tungstate (α-Ag 2 WO 4 ) is a factor that limits the photocatalytic applications to the ultraviolet region. To change the photon absorption region from UV to visible light, the investigation of structural, optical, and photocatalytic properties of silver tungstate as solid solutions (Ag 2– x M x WO 4 ), where M is the transition metal, has been recently reported.…”

Section: Introductionmentioning

confidence: 99%

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Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

et al. 2021

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We initially reported the synthesis, characterization of structural, optical, morphological, and photocatalytic properties of Ag 1.98 Cu 0.02 WO 4 solid solution in this work. The results were compared with the same characterizations performed in pure silver tungstate. Both materials exhibited an orthorhombic structure, with a high degree of crystallinity and purity. Although, a small number of copper atoms in the orthorhombic unit cell of Ag 1.98 Cu 0.02 WO 4 were detected by changes in the X-ray diffraction peak intensity and shift in peak positions corroborates with changes observed in micro-Raman active modes. The decrease in the optical band gap, α-Ag 2 WO 4 (3.05 ± 0.03 eV) to α-Ag 1.98 Cu 0.02 WO 4 (2.93 ± 0.01 eV), determined by diffuse reflectance spectroscopy, confirms the insertion of intermediate levels between valence and conduction bands that could be associated with the Jahn−Teller effect of copper. Field-emission scanning electron microscopy images show several rod-like microcrystals for α-Ag 2 WO 4 , while there are heterogeneous microcrystals for Ag 1.98 Cu 0.02 WO 4 solid solution with an inherent polyhedral shape. The highest photocatalytic performance of α-Ag 1.98 Cu 0.02 WO 4 in the degradation of RhB molecules under visible blue light-emitting device irradiation was achieved at the end of 120 min, therefore 10.61 times faster than pure α-Ag 2 WO 4 and 37.77 times than the photolysis experiment. Through the photocatalytic experiments using the scavenger radicals, the contribution of holes (h + ), singlet oxygen ( 1 O 2 ), superoxide radicals (O 2•− ), and hydroxyl radicals ( • OH) were evaluated, where the holes (h + ), singlet oxygen ( 1 O 2 ), and superoxide radicals (O 2•− ) show the main contribution in the photocatalytic degradation of the RhB molecules to colorless organic compounds, carbon dioxide (CO 2 ), and water (H 2 O).

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

et al. 2021

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“…The change in the stability of different phases by the compositional change can be observed in different materials. Andrade Neto et al 20 . showed that as the W 6+ cation is added in high concentrations in the Ag 2 MoO 4 structure, the formation of Ag 2 WO 4 starts and, as the amount of W 6+ increases, this becomes the most stable phase in growth.…”

Section: Resultsmentioning

confidence: 99%

Antimicrobial and electrical properties of ce‐ and ni‐doped zns nanoparticles obtained by a sonochemical method

Neto

Oliveira

Corrêa

et al. 2021

Int J Applied Ceramic Tech

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In this work, cerium-and nickel-codoped ZnS nanoparticles were obtained by a sonochemical method for 20 min. The nanoparticles were characterized by X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), and microscopy electronic transmission (MET). The electrical properties are estimated through I-V curves and the antimicrobial activity was analyzed against E. coli (gram-negative) and S. aureus (gram-positive) bacteria using the diffusion disk methodology. The diffractograms indicate the obtaining of cubic structure ZnS for the pure sample, whereas the doped samples present the cubic and hexagonal structures of the ZnS. The bandgap reduced from 3.60 to 3.52 eV, for pure and codoped samples. I-V curves indicate an increase in resistivity with doping, being more evident for samples containing cerium. Antimicrobial activity increased as doping occurred, where the codoped sample showed the best results. Even for the low amount of dopant (1 mol%), the antimicrobial activity can be increased by about 50% for the codoped sample, compared to the pure ZnS. Thus, it is known that the doping of ZnS with cerium and nickel provides the stabilization of the hexagonal metastable phase, which acts to restrict electronic mobility and, consequently, improves the antimicrobial response of the material.

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Experimental and Theoretical Correlation of Modulated Architectures of β-Ag2MoO4 Microcrystals: Effect of Different Synthesis Routes on the Morphology, Optical, Colorimetric, and Photocatalytic Properties

Lopes

Nolêto

Vieira

et al. 2022

J Inorg Organomet Polym

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In this paper, the effect of different synthesis methods, such as controlled precipitation (CP), sonochemical (SC), hot solution ion injection with fast cooling, and conventional hydrothermal (CH) in obtaining beta-disilver molybdate (β-Ag 2 MoO 4 ) are explained in details. X-ray diffraction patterns, Rietveld refinement data, cluster modeling, micro-Raman, and Fourier transform infrared spectroscopies confirmed that all β-Ag 2 MoO 4 crystals have a spinel-like cubic structure, space group (Fd 3 m), and symmetry point group (O 7 h ). Field emission scanning electron microscopy (FE-SEM) images showed that through different synthetic routes, it is possible to obtain monophasic crystals, such as regular/irregular polyhedrons (cubes, cuboctahedron, trapezohedron, rhombic dodecahedron), potatoes, and non-uniform. The crystal shape observed experimentally was modeled based on Rietveld refinement data and FE-SEM images obtained by KrystalShaper. First-principles quantum mechanical calculations based on density functional theory were employed to modulate the surfaces of the material and to obtain their surface energy (E surf ) values. From these E surf values in association with the Wulff construction, the evolution of the crystals shape was achieved correlating with the experimental results when different synthesis methods are used. Ultraviolet-Visible (UV-Vis) spectroscopy measurements in absorbance mode showed three main absorptions (280, 310, and 340 nm), while the UV-Vis analyses in diffuse reflectance mode showed a tail of energy absorption in the UV spectrum range (3.25 eV and 3.3 eV). The quantitative data from the colorimetric analysis indicated that the β-Ag 2 MoO 4 crystals are desirable for developing inorganic pigments with a beige to brown shade. Photocatalytic assays were performed using four lamps: UV-C, UV-B, UV-A, and visible light. The β-Ag 2 MoO 4 crystals prepared by the CP method showed a higher degradation rate at 85.12% for the rhodamine B dye solution under 240 min exposure to UV-C light.

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Microwave-assisted hydrothermal synthesis of Ag2Mo1-xWxO4 (x = 0, 0.25, 0.50, 0.75 and 1 mol%) heterostructures for enhanced photocatalytic degradation of organic dyes

Cited by 13 publications

References 33 publications

Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

Antimicrobial and electrical properties of ce‐ and ni‐doped zns nanoparticles obtained by a sonochemical method

Experimental and Theoretical Correlation of Modulated Architectures of β-Ag2MoO4 Microcrystals: Effect of Different Synthesis Routes on the Morphology, Optical, Colorimetric, and Photocatalytic Properties

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Microwave-assisted hydrothermal synthesis of Ag2Mo1-xWxO4 (x = 0, 0.25, 0.50, 0.75 and 1 mol%) heterostructures for enhanced photocatalytic degradation of organic dyes

Cited by 13 publications

References 33 publications

Ag2–xCuxWO4 Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

Ag2–xCuxWO4 Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

Antimicrobial and electrical properties of ce‐ and ni‐doped zns nanoparticles obtained by a sonochemical method

Experimental and Theoretical Correlation of Modulated Architectures of β-Ag2MoO4 Microcrystals: Effect of Different Synthesis Routes on the Morphology, Optical, Colorimetric, and Photocatalytic Properties

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Product

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Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation

Ag_2–xCu_xWO₄ Solid Solution: Structure, Morphology, Optical Properties, and Photocatalytic Performance in the Degradation of RhB under Blue Light-Emitting Device Irradiation