Presence Of ZnO Research Articles

Structure and Electrical Properties of ZnO Nanoparticles Blend with POT-DBSA

In this study, we report on a successful preparation nanocomposites poly (o-toluidine) (POT) doping with dodecylbenzene sulfonate acid (DBSA)/ ZnO by in-situ polymerization of (o-toluidine) monomer using ZnO nanoparticles (the weight ratios OT/ZnO: 1/5%, 1/10%, 1/15%). The composite films have been prepared by using the casting method on different substrate depending on the type of measurement. The surface morphology properties of the prepared samples were studied by the field emission scanning electron microscopy (FESEM). The results of FESEM indicate that ZnO nanoparticles were successfully embedded in the POT via chemical interactions between ZnO and (O-toluidine) monomer and the EDX spectrum showed the presence of element Zn in POT-DBSA/ZnO composites. The crystal structure was measured by x-ray directional and its pattern revealed the presence of ZnO in dopant polymer, in the diffraction patterns of POT-DBSA. The intensity of the peaks was increased as the amount of ZnO nanoparticles increased in POT-DBSA. The typical rectifying behaviour indicated that the formation of a diode observes by the I–V characterization of POT-DBSA/ZnO composites at thin film layer with top Al thin layer contact.

Hybrid Sono-photocatalytic degradation of Acid Brown 14 Using Persulphate and ZnO Nanoparticles: Feasibility and kinetic Study

ABSTRACT Degradation of acid brown 14 (AB14) was studied using ultrasound/ultraviolet for heterogeneous activation of persulphate and ZnO nanoparticle. Various operating parameters including AB14 initial concentration, pH, ZnO dose, anion concentration, ultrasound, as well as ultraviolet synergic effect and scavenging factors were evaluated. The maximum dye removal was observed at a high persulphate concentration, acidic pH, low initial day concentration, and under the simultaneous ultrasound/ultraviolet irradiations plus presence of ZnO. AB14 removal efficiency was elevated from 15% to 75% when ZnO was added as a catalyst. The kinetic study revealed that the experimental data had the best fit with the second-order kinetic model (R2: 0.92) with the rate constant of 0.0025 min−1. The scavenging test indicated that the sulphate radicals were the dominant species during the AB14 degradation. Finally, the high removal efficiency of AB14 (nearly to 100%) suggests that this process is efficient for removal of organic dyes from aqueous solutions.

One-step synthesis of zinc-encapsulated MCM-41 as H2S adsorbent and optimization of adsorption parameters

The nano-sized structure of well-ordered Zn@MCM-41 adsorbent was synthesized through a direct hydrothermal method using CTAB as a structure-directing agent in an ammonia aqueous solution with different amounts of zinc acetylacetonate which were inserted into the structure-directing agent's loop during the synthesis. The XRD, HRTEM, and N2 adsorption-desorption isotherms were used to characterize the prepared ZnO functionalized mesoporous silica samples. As a result, the presence of ZnO in highly-ordered MCM-41's pore was proved as well as maintenance of the ordered mesostructure of MCM-41. The materials were possessed with a high specific surface area (1114-509 m2.g-1) and a large pore diameter (4.03-3.27 nm). Based on the obtained results from the adsorption of H2S gas in a lab-made setup, the Znx@MCM-41 showed the superior ability to increase of ZnO amount up to 7 hours as a breakthrough point.

Saline slag waste as an aluminum source for the synthesis of Zn–Al–Fe–Ti layered double-hydroxides as catalysts for the photodegradation of emerging contaminants

In this work, aluminum extracted from saline slag waste is valorized to create a layered double-hydroxide series containing zinc and various proportions of aluminum/titanium. Materials were synthesized by the co-precipitation method with an Me2+/Me3+ molar ratio of 3:1 and tested for the removal of diclofenac and salicylic acid from water under UV radiation. The incorporation of 5 wt% iron by wet impregnation is evaluated. In addition, another series of zinc, aluminum/iron materials with and without 5 wt% impregnated titanium are tested as catalysts for comparison. Structural characterization and comparison of the two series was performed by powder X-ray diffraction (PXRD), nitrogen adsorption at 77 K, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) measurements. The uncalcinated samples had a typical hydrotalcite structure with a high crystallinity; the presence of ZnO, ZnFe2O4 or Fe3O4 was found after calcination. The specific surface areas of the dried samples ranged from 78 to 199 m2/g, being highest for Zn6Al0.5Ti1.5. Overall, the results showed that the ZnAlTi series were more effective catalysts than ZnAlFe for photodegradation of the emerging contaminants diclofenac and salicylic acid, under UV light at 298 K, considering two concentrations of the organic molecules (5 and 50 μmol/dm3).

Codeposition of electroless Ni-P/ZnO nano composites and evaluation of corrosion resistance of the coatings

Codeposition of nano ZnO with Ni-P coatings was carried out on 99% pure copper substrates. The ZnO nano particles were prepared by simple Sol-Gel method using Zinc acetate dihydrate as precursor. The particle size of the same was found to be <100 nm. The process optimization for codeposition of nano ZnO with Ni-P coatings was carried out by varying the composition of nano ZnO particles using ultrasonicator. An adherent and uniform coating of Ni-P/ZnO was obtained. Presence of ZnO in the coatings was confirmed by EDAX. Surface morphology of the coatings was studied by SEM which shows the smooth homogenous surface in Ni-P/ZnO composite coating. Corrosion resistance of the coatings was evaluated by Salt spray test and Galvanostatic Polarization method using 5% NaCl solution. Corrosion resistance of the Ni-P and Ni-P/ZnO nano composite coatings were compared. Incorporation of nano ZnO in the coatings found to enhance the corrosion resistance and microhardness of the coatings.

AuAg/ZnO nanocatalyst for CO2 valorization and H2 and CO electrochemical production

A controllable composition and morphology AuAg/ZnO catalyst, prepared by an easily scalable method, was, for the first time, explored for the electrocatalytic reduction of CO2. It was found that the composition of the bimetallic alloy contributes to the overall CO2 reduction performance. In particular, as also demonstrated by density functional theory calculations, CO production increases, decreasing the Au content in the catalyst alloy. The experimental investigation reveals that the products are H2 and CO, which production rate increases in the presence of ZnO, up to a Faradic efficiency of 94.7 % at 0.4 V. On the other hand, controlling the oleic acid covering it is possible to modulate the surface properties allowing to obtain, at 0.6 V, H2/CO ratios equal to 1.1 and 1.9 for nanocatalysts thermally treated for 2 and 5 h, respectively.

Photocatalytic Properties and Preparation of Nano-ZnO by Thermal Decomposition Based on ZIF-8

Using Zn(NO3)2·2H2O, 2-methylimidazole and CH3COONa·3H2O as main raw materials and methanol as solvent, ZIF-8 samples were prepared by hydrothermal reaction at 120 °C. And ZnO was obtained by calcination ZIF-8 in muffle furnace at 600 °C. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and thermos gravimetry-differential scanning calorimetry (TG-DSC). The photocatalytic activity of ZnO was investigated by methyl orange which was used as simulated sewage. The results show that the prepared ZnO is irregular, average grain size is about 80 nm, and the band gap width is 3.12 eV. Under UV-light, the degradation rate of 10 mg/L methyl orange is more than 70% in the presence of ZnO, while the degradation rate of methyl orange by commercial P25 is only 40%. The photocatalytic experiments show that the as-prepared ZnO has much higher photocatalytic activity than the commercial P25 photocatalyst. The ZnO is a kind of green photocatalyst which has a wide application prospect in the field of photocatalysis.

Antibiofilm Action of ZnO, SnO2 and CeO2 Nanoparticles Towards Grampositive Biofilm Forming Pathogenic Bacteria

The ability to form biofilm and produce several virulence factors has caused numerous human pathogens to become tremendously resistant towards traditional antibiotic treatments, thus, new alternative strategies are urgently in demand. One of the strategies that have recently been developed involves the application of metallic Nanoparticles (NPs). Up to the present, promising results in terms of antimicrobial and antibiofilm activities have been observed in a wide range of metal NPs. The present study has selected three metal oxides such as ZnO, SnO2 and CeO2 NPs to comparatively investigate their antibiofilm and antibacterial properties against two Gram-positive human pathogens, which are Listeria monocytogenes and Staphylococcus aureus. The anti-biofilm activities of ZnO, SnO2 and CeO2 NPs against S. aureus and L. monocytogenes were assayed by crystal violet staining and confirmed by microscopic visualization using SEM. The synthesis of amyloid protein by S. aureus and exopolysaccharide by L. monocytogenes in the presence of ZnO, SnO2 and CeO2 NPs was evaluated by Congo red assay. Results have shown that ZnO, SnO2 and CeO2 NPs effectively inhibited biofilm formation of both L. monocytogenes and S. aureus. The microscopic analysis also confirmed the antibiofilm activity of these NPs. It was also found that only ZnO NPs inhibited cell growth as well as the production of amyloid protein in S. aureus. Overall, these results indicated that ZnO, SnO2 and CeO2 NPs can be considered as potential agents for treating the infections caused by L. monocytogenes and S. aureus, especially those associated with biofilm formation. Based on the present study, further studies are required to understand their mechanisms at both phenotypic and molecular levels, as well as their in vivo cytotoxicity, thereby enabling the applications of these metal oxide NPs in biomedical fields and food industry.

Photoelectrocatalytic Degradation of Methylene Blue Using ZnO Nanorods Fabricated on Silicon Substrates.

ZnO nanorods were grown on silicon (Si) substrates by two techniques: (i) Chemical Bath Deposition (CBD) and (ii) a CBD seed layer combined with Carbothermal Reduction Vapor Phase Transport (CTR-VPT). The structured ZnO nanorods were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle measurments. The photoelectrochemical property of ZnO nanorods were analyzed by linear voltammetry under UV-ABC light excitation. Using the ZnO nanorod samples as photoanodes, the removal of methylene blue (MB) as a representative organic compound was studied by the photoelectrocatalytic (PEC) technique applying a potential (E) of 0.6 V. For comparison purposes, experiments were performed under the same conditions using photocatalysis (PC), direct photolysis and using samples of pure Si (support material) as working electrodes in PEC. XRD analyses of ZnO prepared by both methods showed the expected ZnO wurtzite phase and a preferred c-axial orientation in the growth of the nanorods. The presence of ZnO was further confirmed by XPS and contact angle measurements showed that ZnO grown by CBD (ZnO/CBD) had a slightly hydrophobic behavior while ZnO grown by CTR-VPT (ZnO/CTR-VPT) is hydrophilic. Both ZnO sample types were shown to be photoactive, with ZnO/CBD showing higher resultant photocurrent compared to ZnO/CTRVPT. For the degradation of MB 53% of the compound was removed using ZnO/CBD as a working electrode, while using the ZnO/CTR-VPT electrode led to a removal of 43% of MB. However, direct photolysis alone removed 39% of the MB. The lower removal of MB using ZnO/CTR-VPT samples was related to surface dissociation during the degradation process. The results show that ZnO nanorods prepared by the CBD techique are a promising photoelectrode for PEC applications. Our data also indicate that CTR-VPT-grown nanorods produce uniform nanorod arrays, but this uniform nanostructure deposit does not lead to any increase in PEC activity.

Plant Mediated Synthesis, Characterization of Zinc Oxide Nanoparticles using Simarouba glauca and its Antibacterial Activities

Development of Nano biotechnology through green route is generating interest for researchers towards the production of eco-friendly and cost effective nanoparticles. In this regard, making use of floral parts for the nano particles synthesis has advantages such as cost effective, biocompatible and safe discharge. Using Simarouba glauca aqueous leaf extract, Zinc oxide nanoparticles (ZnO NPs) were synthesized from 1mM solution of Zinc nitrate. The presence of ZnO was confirmed at 340nm in Ultraviolet-visible (UV-Vis) spectroscopy and at 533-860cm-1 in Fourier transform infrared spectroscopic (FTIR) analysis. Further morphological phase identification was carried out by Transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. Elemental confirmation and its quantitative measurement were performed by X-ray fluorescence spectroscopy (XRF) and energy-dispersive X-ray analysis spectroscopy (EDAX) Anti-bacterial activities exhibited inhibition against the bacterial strains Bacillus cereus CI 2106 (Gram-positive) and Klebsiella pneumonia ATCC 27736 (Gram-negative) at minimum concentrations.

Synthesis and characterization of Fe2O3 doped ZnO supported on clinoptilolite for photocatalytic degradation of metronidazole

ABSTRACT ZnO/Fe2O3/Clinoptilolite photocatalyst was synthesized through sol–gel method. The photocatalyst was characterized by XRD, XRF, EDX, FE-SEM, FT-IR, BET and UV–VIS DRS analyses. According to the XRD, FT-IR, and EDX results, the presence of ZnO and Fe2O3 was confirmed on the clinoptilolite surface. Based on the XRF results, the molar ratio of Fe3+/ZnO in the photocatalyst was obtained as 0.06. The FE-SEM results confirmed stabilization of ZnO/Fe2O3 on the clinoptilolite surface. Based on the BET results, the surface area and pore volume for the photocatalyst were obtained as 291.35 m2/g and 0.23 cm3/g, respectively. According to the UV–VIS DRS results, the band gap energy of the photocatalyst was measured as 3.38 eV. The performance of the synthesized photocatalyst in degrading metronidazole from contaminated water, as one of the most widely used antibiotics in pharmaceutical industries, was evaluated by response surface methodology. Operational factors including pH (4–10), metronidazole concentration (1–100 mg/l), irradiation time (45–180 min), photocatalyst concentration (0.5–2 g/l), and H2O2 concentration (25–100 mg/l) were investigated. The optimal values of the factors in degrading 99% of the contaminant were as follows: irradiation time = 90 min, photocatalyst concentration = 1 g/l, pH = 10, H2O2 concentration = 40 mg/l, and MNZ concentration = 60 mg/l.

Enhanced photocatalytic performance of Cu2O nano-photocatalyst powder modified by ball milling and ZnO

In this paper, a ball milled Cu2O-ZnO nano-photocatalyst with good photocatalytic performance in visible light range was prepared. Effect of ZnO presence and ball milling of Cu2O on the structure, microstructure, optical properties and photocatalytic performance were studied. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), high resolution transmission electron microscopy (HRTEM), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) analysis and UV–Vis spectrophotometer were used as characterization techniques. FESEM results indicated that ball milling of Cu2O changed the morphology of Cu2O-ZnO composite. The uniform formation of ZnO particles with average size of 30 nm over the Cu2O surface was observed. The formation of p-n heterostructure with good contact between Cu2O and ZnO nanoparticles was found by HRTEM image. Ball milling of Cu2O promotes visible light absorption and reduction band gap to 1.9 eV in Cu2O-ZnO photocatalyst. Intensity of PL spectra for the ball milled Cu2O-ZnO photocatalyst was obviously lower. Ball milled Cu2O-ZnO photocatalyst shows the highest photocatalytic activity and degradation efficiency of 98% was obtained for 2 mg/L methylene blue (MB) solution after 240 min. The kinetics of the photodegradation was followed the Langmuir-Hinshelwood (L-H) model and degradation rates were decreased by increase of MB concentration. In the case of ball milled Cu2O and presence of ZnO, the MB degradation kinetics was two times faster.

Photodegradation of 2, 4, 5, 6-Tetrachloroisophthalonitrile (Chlorothalonil) by Visible and Ultraviolet Light in the Presence of ZnO and TiO2

photocatalytic degradation of fungicides (chlorothalonil) in suspension aqueous solution with semiconductors (tio­2, zno) and without semiconductor has been investigated. the influence of different parameters such as light sources, the concentration of fungicides, type of semiconductors and temperature were studied by uv-visible spectrophotometer at 232 and 254 nm. the degradation reaction order spectra of chlorothalonil were determined which first order at 232 nm and second order at 254 nm. in addition, the rate constant, arrhenius factor and energy of activation can be estimated for both peaks. moreover, conductivity of chlorothalonil has been recorded during the photo-degradation and the rate of reaction also has been determined that dependent on product formation.

Investigation on Bovine Serum Albumin (BSA) binding efficiency and antibacterial activity of ZnO nanoparticles

Biomolecule-NPs interaction is extremely important in various biomedical applications especially for assessing the macrostructural effects of nanoparticles on proteins. We prepared ZnO nanoparticles (ZnO NPs) of average dimension, ~11 nm, using citrus lemon extract assisted green synthetic strategy. The binding interaction with Bovine Serum Albumin (BSA) was monitored from changes in inherent fluorescent emission characteristics of BSA and synchronized emission spectra of component fluorophores in presence of ZnO NPs.Molecular docking studies conducted to analyse the binding sites and associated parameters. Here in the sample possess very strong interaction with BSA. Comparison of binding constant with similar studies indicates the superior performance of ZnO NPs developed using lemon fruit extract. Molecular docking studies disclosed the mode of interactions and the negative value of binding models indicates a worthy and feasible interaction. Antibacterial activity of ZnO NPs was tested against K. pneumoniae, S. aureus, E. coli and P. mirabilis bacterial pathogens. The zone of inhibition and minimum inhibitory concentration and minimum bactericidal concentrations were also determined. The developed ZnO NPs exhibits antibacterial activity against the studied pathogens.

Electrochemistry Studies of Hydrothermally Grown ZnO on 3D-Printed Graphene.

A three-dimensional (3D) printer was utilised for the three-dimensional production of graphene-based pyramids and an efficient hydrothermal procedure for ZnO growth. In particular, the 3D-printed graphene pyramids were forwarded in Pyrex glass bottles with autoclavable screw caps filled with 50 mL of an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine for 1 h at 95 °C; sufficient enough time to deposit well-dispersed nanoparticles. X-ray diffraction patterns were in accordance with a Raman analysis and presented the characteristic peaks of graphite along with those of wurtzite ZnO. Different positions on the sample were tested, confirming the uniform dispersion of ZnO on graphene pyramids. From the electrochemical studies, it was found that the charging and discharging processes are affected by the presence of ZnO, indicating one well-defined plateau for each process compared to the previously reported bare graphene pyramids. In total, the material shows a value of 325 mAh g−1, a capacitance retention factor of 92% after 5000 scans, and a coulombic efficiency of 100% for the first scan that drops to 85% for the 5000th scan. This excellent performance is the result of the effect of ZnO and graphene that combines two Li+ accommodation sites, and the contribution of graphene pyramids, which provides more available sites to favor lithium storage capacity. Hence, this anode may be a promising electrode material for lithium-ion batteries.

Antibacterial Activities of Zinc Oxide Nanostructures with Different Structures

We report on antibacterial activities of Zinc oxide (ZnO) with different structures. Fast furrier transform infrared spectroscopy ZnO nanostructures showed peaks in the range between 450–600 cm-1 indicating the successful growth through the presence of Zn-O stretching. On the other hand, impurities such as zinc complexes might be present due to the appearance of peaks at 1110 cm-1, 1390 cm-1 and 1506 cm-1. Furthermore, SEM images revealed that nanorods and sea-urchin like nanostructures are present in the produced ZnO nanostructures. Nanorods exhibit a better antibacterial response than the sea-urchin like structure. The change in structural morphology along with its purity has greatly influenced the area of bacterial inhibition zone during antibacterial testing.

Impact of biosolids, ZnO, ZnO/biosolids on bacterial community and enantioselective transformation of racemic–quizalofop–ethyl in agricultural soil

The effects of biosolids, ZnO, and ZnO/biosolids on soil microorganism and the environmental fate of coexisting racemic–quizalofop–ethyl (rac-QE) were investigated. Microbial biomass carbon in native soil, soil/biosolids decreased by 62% and 52% in the presence of ZnO (2‰, weight ratio). The soil bacterial community structure differed significantly among native soil, soil/biosolids, soil/ZnO, and soil/biosolids/ZnO based on a principal co-ordinate analysis (PCoA) of OTUs and one-way ANOVA test of bacterial genera. Chemical transformation caused by ZnO only contributed 4% and 3% of the overall transformation of R-quizalofop-ethyl (R-QE) and S-quizalofop-ethyl (S-QE) in soil/ZnO. The inhibition effect of ZnO on the initial transformation rate of R-QE (rR-QE) and S-QE (rR-QE) in soil only observed when enantiomer concentration was larger than 10 mg/kg. Biosolids embedded with ZnO (biosolids/ZnO) caused a 17%–42% and 22%–38% decrease of rR-QE and rS-QE, although rR-QE and rS-QE increased by 0%–17% and 22%–58% by the addition of biosolids. The results also demonstrated that the effects of biosolids on agricultural soil microorganism and enantioselective transformation of chiral pesticide was altered by the embedded nanoparticles.

Pectin Based Graft Copolymer–ZnO Hybrid Nanocomposite for the Adsorptive Removal of Crystal Violet

In this work we report the comparative study of the dye adsorption behavior of a Pectin-based terpolymer gel, pectin-graft-(poly(2-acrylamido-2-methyl-1-propane sulfonic acid)-co-acrylamide) (Pec-g-poy(AMPS-co-AAm)) and its nanocomposite with ZnO, (Pec-g-poy(AMPS-co-AAm)/ZnO) from aqueous solutions. Both the hydrogel systems have been synthesized using microwave irradiation technique through free radical polymerization. Swelling behavior of the systems was studied in buffer solutions of pH ranging from 1.2 to 13 and maximum swelling was observed in neutral medium. The equilibrium swelling of parent gel was found to be 28.12 g/g whereas it was 16.54 in the case of nanocomposite. Cationic dye, crystal violet, is employed to assess the adsorption efficiency of the gel samples from aqueous solutions. The influence of initial dye concentration was investigated. A maximum adsorption of 329 and 568 mg/g has been observed for the parent gel and the nanocomposite respectively. The presence of ZnO is observed to enhance the adsorption capacity of Pec-g-poy(AMPS-co-AAm) gel considerably. The kinetic studies revealed a second order adsorption process with high rate of initial adsorption in the case of the nanocomposite when compared to the parent gel and the isotherm studies reveals that the adsorption process fits well into Langmuir model. The evaluation of thermodynamic parameters indicated the adsorption process to be exothermic and spontaneous. Desorption studies under acidic condition showed that almost 96% of the adsorbed dye molecules could be desorbed to the stripping solution of pH 1.2 which support the use of these hydrogel systems for the repeated use as adsorbents for cationic dyes.

Tuning crystallization and hydrolytic degradation behaviors of poly(lactic acid) by using silver phosphate, zinc oxide and their nano-hybrids

ABSTRACTThe promising potential of silver phosphate (Ag3PO4) nanoparticles is shown in improving the properties of polylactic acid (PLA) by preparing PLA/Ag3PO4, PLA/ZnO and PLA/Ag3PO4/ZnO nanocomposites. The dispersion quality of nanoparticles was significantly improved once the nano-hybrids were used. It was found that Ag3PO4 acts as efficient nucleating agents in the solution-induced crystallization. Generally, ZnO was not as efficient as Ag3PO4 in improving the PLA crystallinity. Hydrolytic degradation experiments revealed that Ag3PO4 could notably retard the degradation process while it was accelerated in the presence of ZnO. Therefore, Ag3PO4 and ZnO would be desirable for long- and short-life biological applications, respectively.

Investigation of Novel Low Melting Phosphate Glasses Inside the Na2O–K2O–ZnO–P2O5 System

Phosphate glasses containing different concentrations of zinc oxide inside the (1 − x)(NaPO3–KPO3)–xZnO system (0 ≤ x ≤ 50 mol%) have been prepared using the conventional melt quenching technique. The prepared glasses were transparent, bubble-free and colourless. Their density, molar volume, glass transition temperature, and structural properties using infrared and Raman spectroscopies are investigated. As the content of ZnO increases, the density increases while the molar volume decreases. The composition dependence of Tg shows a minimum for the glass (x = 20 mol%). Structural approach realized by IR and Raman spectroscopies reveals that zinc ions occupy different sites in the glassy-network, mainly modifier sites and middle phosphate network in low-zinc and high-zinc glasses, respectively. The introduction of ZnO in the network induces some structural rearrangements through the conversion of metaphosphate structural units to pyrophosphate ones. It is also highlighted that the presence of ZnO in the glassy matrix allows the transformation of some P–O–P and P=O bonds to P–O–Zn linkages. From the UV–Visible absorption studies, the values of the optical band gap, Eg, and Urbach energy, ΔE, were evaluated. The optical band gap is found to depend on the glasses composition. Eg and ΔE show a minimum and a maximum respectively, for the glass (x = 20 mol%).