In this study, a novel photocatalytic material heterostructured ZnO-CdO-CuO nanocomposite along with pristine ZnO, CdO, and CuO nanoparticles were synthesized by the facile co-precipitation method. ...The grown nanocomposite was characterized by XRD, FTIR, Raman, SEM, IV, UV–vis and PL techniques. The XRD pattern exhibited the diffraction peaks of ZnO (hexagonal), CdO (cubic) and CuO (monoclinic) with ZnO, CdO, and CuO phases 65%, 16%, and 19%, respectively. The microstructural analysis was carried out using Scherrer plot, W-H and SSP methods. The FTIR and Raman spectra also inveterate the successful formation of ZnO-CdO-CuO. The IV measurements revealed the high electrical response of nanocomposite. The SEM images are shown agglomerated rod-shaped morphology and the elemental analysis also confirmed the higher atomic concentration of Zn. PL spectra shown strong NBE and DLE emissions related to extrinsic defects which could act as the trap centers for charge carriers and enhance photocatalytic activity. The energy bandgap (Eg) was 2.9 eV, specified that the grown nanocomposite could be an excellent photocatalyst. The photocatalytic activity was performed against methylene blue (MB) revealed higher degradation efficiency of 94% as compared to pristine ZnO (60.0%), CdO (41.0%), and CuO (61.0%). The photodegradation of other synthetic dyes i.e. rhodamine-B, methyl orange, and cresol red was also assessed by grown nanocomposite under sunlight, exhibits degradation efficiencies, 87%, 89% and 99% in 100 min illumination, respectively. Furthermore, the species trapping experiment along with the recyclability test was carried out against cresol red dye using the nanocomposite catalyst. A schematic model was also designed to illustrate the photodegradation reaction mechanism.
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•A novel heterostructured ZnO-CdO-CuO nanocomposite was synthesized.•Enhanced photocatalytic activity of nanocomposite against MB dye than pure oxides.•CR dye was degraded more as compared to MB, RhB and MO dye under similar conditions.•The main role of O2*- and HO* radicals in degradation reaction.•The PL spectra shown NBE and DLE were due to intrinsic defects.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Novel tri-phase CuO–MgO–ZnO nanocomposite was prepared using the co-precipitation technique and investigated its physical properties using characterization techniques including XRD, FTIR, Raman, IV, ...UV-vis, PL, and SEM. The application of grown CuO–MgO–ZnO nanocomposite for the degradation of various dyes under sunlight and antibacterial activity against different bacteria were studied. The XRD confirmed the existence of diffraction peaks related to CuO (monoclinic), MgO (cubic), and ZnO (hexagonal) with CuO phase 40%, MgO 24%, and ZnO 36%. The optical energy gap of nanocomposite was 2.9 eV, which made it an efficient catalyst under sunlight. Raman and FTIR spectra have further confirmed the formation of the nanocomposite. SEM images revealed agglomerated rod-shaped morphology. EDX results showed the atomic percentage of a constituent element in this order Cu>Zn>Mg. PL results demonstrate the presence of intrinsic defects. The photocatalytic activity against methylene blue (MB), methyl orange (MO), rhodamine-B (RhB), cresol red (CR), and P-nitroaniline (P-Nitro) dyes has shown the excellent degradation efficiencies 88.5%, 93.5%, 75.9%, 98.8%, and 98.6% at 5 ppm dye concentration and 82.6%, 83.6%, 64.3%, 93.1%, and 94.3% at 10 ppm dye concentration in 100 min, respectively, under sunlight illumination. The higher degradation is due to the generation of superoxide and hydroxyl radicals. The recyclability test showed the reusability of catalyst up to the 5th cycle. The antibacterial activity against
Escherichia coli
,
Klebsiella pneumoniae
,
Proteus Vulgaris
,
Staphylococcus aureus
, and
Pseudomonas aeruginosa
bacteria with the zone of inhibition 30, 31, 30, 30, and 30 mm, respectively, was achieved.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Novel photocatalytic and antibacterial material Zn0.9Ce0.05M0.05O (M = Er, Y, V) nanocrystals were synthesized via a facile co-precipitation technique and characterized by different analytical ...techniques. XRD confirmed the incorporation of Ce, Er, Y, and V, that without modifying the basic ZnO hexagonal wurtzite structure affects strongly structural properties. The Scherrer, W–H, and SSP methods were used to calculate different microstructural parameters using XRD data. The optical energy bandgap was found to be decreased in all co-doped samples (3.14–2.82 eV) calculated from UV–vis spectra by employing different methods. The effect of dopants ions on the optical properties of ZnO was also studied in detail. The FTIR spectrum inveterate the existence of Zn–O, and Zn-M–O (M = Ce, Er, Y, V) vibrational mode that further confirmed the incorporation of dopants ions. The photocatalytic performance of the grown products was evaluated under sunlight illumination against methylene blue (MB) dye. The antibacterial activity was performed against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa bacteria. The co-doped nanocrystals have shown enhanced photocatalytic and antibacterial activity as compared to Ce-doped ZnO but the Ce–V co-doped ZnO shown the highest activity. The influence of different operational parameters such as the amount of catalyst, the concentration of dye, and pH of the solution on photocatalytic activity of Ce–V co-doped ZnO nanocrystal was also studied and discussed in detail. The radical trapping experiments were also performed to identify the active species involved in photodegradation reaction. The recyclability test exhibited that Ce–V co-doped ZnO catalyst has high stability and can be reused up to the 6th cycles. Furthermore, a possible photocatalytic mechanism was also proposed for the photodegradation of MB dye.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Novel Zn0.90Co0.10O and Zn0.90Co0.05M0.05O (M=Ca, Ba, Cr, Pb) nanocrystals were synthesized by co-precipitation method and studied its structural, optical and electrical properties along with their ...photocatalytic activity. The XRD confirmed that Ca, Ba, Cr, and Pb have been incorporated without modifying ZnO hexagonal wurtzite structure. The microstructural parameters were calculated using Scherrer, W–H, and SSP methods. FTIR confirmed the existence of Zn–O vibrational modes. UV–vis spectra used to calculate the energy bandgap by using Tauc’s plot, Energy equation, Vegard’s law, and Derivative method. Optical parameters such as Urbach energy, refractive index, dielectric constant, extinction coefficient and optical conductivity were also studied. The IV measurements demonstrated that electrical conductivity was increased significantly by co-doping. The photocatalytic activity for the decolorization of methylene blue (MB) and methyl orange (MO) dyes under sunlight revealed the highest degradation efficiency for co-doped nanocrystals against MB as compared to MO in 100min illumination. The grown nanocrystals are propitious sunlight driven photocatalyst to eradicate organic toxins.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Water pollution poses a significant threat to both human health and ecosystem integrity. Chemical pollutants such as dyes and pesticides affect the water quality and endanger aquatic life. Among the ...methods for water purification from organic pollutants, photodegradation is certainly a valid technique to decrease such contaminants. In this work, pristine NiO, ZnO, and NiO-ZnO photocatalysts were synthesized by the homogeneous co-precipitation method. X-ray diffraction confirms the formation of a photocatalyst consisting of ZnO (Hexagonal) and NiO (Cubic) structures. The crystalline size was calculated by the Scherrer formula, which is 19 nm for the NiO-ZnO photocatalyst. The band gap measurements of the prepared samples were obtained using the Tauc Plot, equation which is 2.93 eV, 3.35 eV and 2.63 eV for NiO, ZnO, and NiO-ZnO photocatalysts, respectively. The photocatalytic performance of NiO-ZnO nanocomposite was evaluated through the degradation of Methylene Blue and Nile Blue dyes under sunlight, and Bentazon herbicide under a UV light. Photocatalyst degradation efficiency was 95% and 97% for Methylene Blue and Nile Blue in 220 min under sunlight while a degradation of 70% for Bentazon after 100 min under UV light source was found.
In this article, ternary oxide NiO-CdO-ZnO nanocomposite along with pure NiO, CdO and ZnO were prepared by the homogeneous co-precipitation method. The XRD pattern confirmed the formation of ...nanocomposite with NiO (cubic)–CdO (cubic)–ZnO (hexagonal). The volume fractions were 38% NiO, 6% CdO and 56% ZnO phase in nanocomposite determined by direct comparison method. Crystallite size and lattice strain were calculated using Scherrer plot, Williamson-Hall and Size-Strain plot methods. The UV–vis was used to study optical properties such as bandgap (Eg), refractive index (n), extinction coefficient (k), optical conductivity (σopt) and dielectric constants (εr, εi). FTIR and Raman analyses have confirmed the successful formation of NiO-CdO-ZnO nanocomposite. The current-voltage measurements revealed that nanocomposite has high electrical response. SEM images shown that nanocomposite has roughly spherical morphology and EDX described that Zn has higher concentration than Ni and Cd. PL spectra of nanocomposite demonstrated the emission bands associated with new energy levels induced by defects. The photocatalytic activity of grown nanocomposite against rhodamine B (RhB) and methylene blue (MB) dyes under sunlight revealed high degradation efficiency 99% for RhB and 98% for MB in 60 and 90 min illumination respectively, indicated that grown nanocomposite is a propitious sunlight-driven photocatalyst to eliminate organic toxins.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
The log-aesthetic curve (LAC) is a family of aesthetic curves with linear logarithmic curvature graphs (LCGs). It encompasses well-known aesthetic curves such as clothoid, logarithmic ...spiral, and circle involute. LAC has been playing a pivotal role in aesthetic design. However, its application for functional design is an uncharted territory, e.g. the relationship between LAC and fluid flow patterns may aid in designing better ship hulls and breakwaters. We address this problem by elucidating the relationship between LAC and flow patterns in terms of streamlines at a steady state. We discussed how LAC pathlines form under the influence of pressure gradient via Euler's equation and how LAC streamlines are formed in a special case. LCG gradient ($\alpha $) for implicit and explicit functions is derived, and it is proven that the LCG gradient at the inflection points of explicit functions is always 0 when its third derivative is nonzero. Due to the complexity of the parametric representation of LAC, it is almost impossible to derive the general representation of LAC streamlines. We address this by analyzing the streamlines formed by incompressible flow around an airfoil-like obstacle generated with LAC having various shapes, ${\alpha _r} = \ \{ { - 20,{\rm{\ }} - 5,{\rm{\ }} - 1,{\rm{\ }} - 0.5,{\rm{\ }} - 0.15,{\rm{\ }}0,{\rm{\ }}1,{\rm{\ }}2,{\rm{\ }}3,{\rm{\ }}4,{\rm{\ }}20} \}$, and simulating the streamlines using FreeFem++ reaching a steady state. We found that the LCG gradient of the resultant streamlines is close to that of a clothoid. When the obstacle shape is almost the same as that of a circle ($\alpha \ = \ 20$), the streamlines adjacent to the obstacles have numerous curvature extrema despite nearing steady state. The flow speed variation is the lowest for $\alpha \ = \ - 1.43$ and gets higher as $\alpha$ is increased or decreased from $\alpha \ = \ - 1.43$.
Graphical Abstract
Graphical Abstract
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•Novel direct dual-Z-scheme ZnO-Er2O3-Yb2O3 heterostructured nanocomposite synthesized by simple co-precipitation method.•Photocatalytic and antibacterial application study.•The ...effect of several operational parameters on photocatalytic activity was studied.•The conventional hetero-junction scheme and direct dual-Z-scheme were proposed to elaborate the photocatalytic mechanism.
In this work, a novel antibacterial and photocatalytic material ZnO-Er2O3-Yb2O3 heterostructured nanocomposite was synthesized by facile co-precipitation technique. The antibacterial activity was performed against S. aureus and E. coli bacteria. The ZOI showed the nanocomposite has higher activity antibacterial against E. coli. The direct optical energy bandgap was 2.9 eV, specified it as a proficient photocatalyst under sunlight illumination. The grown nanocomposite degraded 99.7% MB dye in 40 min under sunlight irradiation. The effect of several operational parameters including catalyst dose, dye concentrations, pH of reaction along with reusability and radical trapping experiment was also studied. The conventional hetero-junction scheme and direct Z-scheme were also proposed to elaborate the photocatalytic mechanism.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The homogeneous precipitation method was used to synthesis ZnO, NiO nanoparticles and ZnO–NiO nanocomposites with and without surfactants, sodium dodecyl sulphate (SDS) and hexamethylenetetramine ...(HMT) to alter the composition of nanocomposites. The grown samples were annealed at 300 °C and 600 °C for 2 h to convert the hydroxides into their oxides. To investigate the effect of different composition on the crystal growth, particle size, morphology, structural and optical properties of nanocomposite, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy (UV), Raman spectroscopy and Scanning electron microscopy (SEM) were employed. X-ray quantitative phase analysis was used to estimate the volume fractions of ZnO and NiO phases in grown nanocomposites. The percentage of ZnO phase is more than NiO phase in all nanocomposites and strongly depends on composition. The structural parameters like lattice constants (a, c), bond-length (l), unit cell volume (v), density (ρ), d-spacing (d), strain (ε) and dislocation density (δ) of ZnO, NiO and ZnO–NiO nanocomposites were calculated. The Scherrer, Williamson-Hall and Size-Strain analysis were used to calculate the crystallite size and lattice strain. The optical parameters such as optical absorption coefficient (α), bandgap (Eg), skin depth (δ), optical density (Dopt), extinction coefficient (k), refractive index (n), optical conductivity (σopt) and dielectric constants (εr, εi) were studied from UV–vis spectra. The nanocomposites grown in this study provide an opportunity of band tuning for better functional performance for device fabrication compared to the basic metal oxides. FTIR characteristic peaks and Raman fundamental optical phonon modes confirmed the formation of ZnO, NiO and ZnO–NiO nanocomposites. SEM analysis revealed that ZnO–NiO nanocomposites have different surface morphology by adding different surfactants.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Novel tri-phase ZnO-Yb2O3–Pr2O3 heterostructured nanocomposite was synthesized by the co-precipitation technique, and its application as an efficient antibacterial agent and photocatalyst were ...studied. The grown sample was characterized by XRD, FTIR, Raman, UV–vis, IV, and SEM to explore the structural, optical, electrical, and morphological properties. The XRD pattern revealed the presence of diffraction peaks related to ZnO (hexagonal), Yb2O3 (cubic) and Pr2O3 (hexagonal) in the nanocomposite. The microstructural parameters were calculated using Scherrer plot, W–H and SSP methods. The optical energy bandgap was 2.8 eV determined from UV–vis spectroscopy, specified that it could be used as a proficient photocatalyst under sunlight illumination. The FTIR spectrum confirmed the presence of characteristics vibrational bands associated with the Zn–O, Pr–O, and Yb–O bond vibrations at 463, 535 and 562 cm−1, respectively. The Raman spectrum exhibits the fundamental optical phonon modes related to ZnO, Yb2O3 and Pr2O3 in the nanocomposite, confirmed the successful formation of the nanocomposite. IV measurement showed the high electrical conductivity of grown nanocomposite. SEM images revealed that nanocomposite has a porous type morphology with high agglomeration. The antibacterial activity was performed against S. aureus (G-positive) and E. coli (G-negative) bacteria. The zone of inhibition (ZOI) shown that the nanocomposite has the highest activity against S. aureus with a ZOI 31 mm. The photocatalytic activity of the ZnO-Yb2O3–Pr2O3 nanocomposite was carried out for the degradation of MB dye under sunlight irradiation, revealed 99.8% degradation in 60 min. The effect of several operational parameters such as catalyst dose, dye concentrations, pH of reaction along with reusability and radical trapping experiments were performed and discussed in detail. A possible schematic model was proposed to elaborate the photocatalytic mechanism. Furthermore, this work introduces a novel material to enhance the photocatalytic and antibacterial activity for environmental and biomedical application.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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