Ultrasonic synthesis of high fluorescent C-dots and modified with CuWO4 nanocomposite for effective photocatalytic activity

Prasad, P. Reddy; Naidoo, Eliazer Bobby

doi:10.1016/j.molstruc.2015.05.043

Cited by 32 publications

(9 citation statements)

References 35 publications

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“…According to Pourmortazavi et al . and Reddy Prasad and Naidoo the PL emission of CuWO 4 crystal is due to the electronic transitions within complex structure of WO 4 2– anion molecular as well as by the trapping and recombination of photoinduced electrons and holes in the semiconductor, conversely CuWO 4 crystal is a crystalline solid compiled with interconnected (…[WO 6 ]–[CuO 6 ]–[WO 6 ]…) clusters.…”

Section: Resultsmentioning

confidence: 99%

Structural and Optical Properties of Triclinic CuWO₄ Prepared by Solid‐State Reaction Technique

Yadav

Sinha

2019

Macromolecular Symposia

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Copper tungstate CuWO 4 ceramic is prepared by solid-state reaction route at 850°C for 3 h. The X-ray diffraction (XRD) study proves that the synthesized composition possesses a monophasic triclinic structure with space group P1. The structural analysis (crystal symmetry and unit cell parameters) is investigated systematically using Rietveld refinement of the XRD patterns. Scanning electron microscope analysis of the sintered ceramics reveals the formation of dense microstructure with non-uniform grains. The 16 active vibrational modes are observed in Raman spectra from 100 to 1000 cm −1 . UV-vis absorption spectra revealed a direct allowed transition with band gap E g = 2.23 eV. The photoluminescence (PL) emission spectra show intense yellow emission at room temperature. These results suggest the applications of CuWO 4 as photocatalysts, photoanodes, and phosphors.

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Section: Resultsmentioning

confidence: 99%

Structural and Optical Properties of Triclinic CuWO₄ Prepared by Solid‐State Reaction Technique

Yadav

Sinha

2019

Macromolecular Symposia

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“…In the last years, the experimental results previosly reported in the literature [26,53,70] have explained the key factors or variables responsible for PL properties of CuWO 4 crystals. Pourmortazavi et al [26,70] and, ReddyPrasad and Naidoo [53] described the PL emission of these crystals with the electronic transitions within complex structure of WO 2À 4 anion molecular as well as by the trap- (Fig. 3).…”

Section: Photoluminescence Propertiesmentioning

confidence: 98%

“…Currently, the scientific studies on the electronic properties of pure and doped CuWO 4 have been mainly focused on the photocatalytic (PC) degradation of organic dyes (Rhodamine B, eosin yellow dye and methylene blue) under ultraviolet and visible light [53][54][55], magnetic [56][57][58][59], photoelectrochemical water splitting [60][61][62][63][64], visible and solar-assisted water splitting [65,66], photoanode for solar water oxidation [67,68], electrical transport [69], and photoluminescence (PL) [24,53,70]. An important point to be considered is that the theoretical studies [16,[71][72][73][74][75], performed by means of ab initio calculations based on the density-functional theory (DFT) for the electronic structure of CuWO 4 crystals, have shown that the conduction band (CB) of this oxide is composed of 3d orbitals (Cu atoms) and 5d orbitals (W atoms), while the valence band (VB) is formed of 2p orbitals (O atoms).…”

Section: Introductionmentioning

confidence: 99%

Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals

Souza

Sczancoski

Nogueira

et al. 2017

Ultrasonics Sonochemistry

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Copper tungstate (CuWO) crystals were synthesized by the sonochemistry (SC) method, and then, heat treated in a conventional furnace at different temperatures for 1h. The structural evolution, growth mechanism and photoluminescence (PL) properties of these crystals were thoroughly investigated. X-ray diffraction patterns, micro-Raman spectra and Fourier transformed infrared spectra indicated that crystals heat treated and 100°C and 200°C have water molecules in their lattice (copper tungstate dihydrate (CuWO·2HO) with monoclinic structure), when the crystals are calcinated at 300°C have the presence of two phase (CuWO·2HO and CuWO), while the others heat treated at 400°C and 500°C have a single CuWO triclinic structure. Field emission scanning electron microscopy revealed a change in the morphological features of these crystals with the increase of the heat treatment temperature. Transmission electron microscopy (TEM), high resolution-TEM images and selected area electron diffraction were employed to examine the shape, size and structure of these crystals. Ultraviolet-Visible spectra evidenced a decrease of band gap values with the increase of the temperature, which were correlated with the reduction of intermediary energy levels within the band gap. The intense photoluminescence (PL) emission was detected for the sample heat treat at 300°C for 1h, which have a mixture of CuWO·2HO and CuWO phases. Therefore, there is a synergic effect between the intermediary energy levels arising from these two phases during the electronic transitions responsible for PL emissions.

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“…By comparison, the band structures of semiconductors can be manipulated far more easily. Visible‐light‐responsive semiconductors with tunable bandgaps, such as nitrogen‐doped ZnO (N‐ZnO), Fe 3 O 4 , CuWO 4 , CdS, and various bismuth‐based semiconductors, have been coupled with CDs and the photocatalytic properties of the resulting heterostructures investigated.…”

Section: Photocatalytic Degradationmentioning

confidence: 99%

Smart Utilization of Carbon Dots in Semiconductor Photocatalysis

et al. 2016

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Efficient capture of solar energy will be critical to meeting the energy needs of the future. Semiconductor photocatalysis is expected to make an important contribution in this regard, delivering both energy carriers (especially H ) and valuable chemical feedstocks under direct sunlight. Over the past few years, carbon dots (CDs) have emerged as a promising new class of metal-free photocatalyst, displaying semiconductor-like photoelectric properties and showing excellent performance in a wide variety of photoelectrochemical and photocatalytic applications owing to their ease of synthesis, unique structure, adjustable composition, ease of surface functionalization, outstanding electron-transfer efficiency and tunable light-harvesting range (from deep UV to the near-infrared). Here, recent advances in the rational design of CDs-based photocatalysts are highlighted and their applications in photocatalytic environmental remediation, water splitting into hydrogen, CO reduction, and organic synthesis are discussed.

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Ultrasonic synthesis of high fluorescent C-dots and modified with CuWO4 nanocomposite for effective photocatalytic activity

Cited by 32 publications

References 35 publications

Structural and Optical Properties of Triclinic CuWO₄ Prepared by Solid‐State Reaction Technique

Structural and Optical Properties of Triclinic CuWO₄ Prepared by Solid‐State Reaction Technique

Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals

Smart Utilization of Carbon Dots in Semiconductor Photocatalysis

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Ultrasonic synthesis of high fluorescent C-dots and modified with CuWO4 nanocomposite for effective photocatalytic activity

Cited by 32 publications

References 35 publications

Structural and Optical Properties of Triclinic CuWO4 Prepared by Solid‐State Reaction Technique

Structural and Optical Properties of Triclinic CuWO4 Prepared by Solid‐State Reaction Technique

Structural evolution, growth mechanism and photoluminescence properties of CuWO4 nanocrystals

Smart Utilization of Carbon Dots in Semiconductor Photocatalysis

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Product

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Structural and Optical Properties of Triclinic CuWO₄ Prepared by Solid‐State Reaction Technique

Structural and Optical Properties of Triclinic CuWO₄ Prepared by Solid‐State Reaction Technique