Simple Chemical Precipitation Research Articles

Structural, optical, and antibacterial properties of Li-doped ZnO nanoparticles synthesized in water: evidence of incorporation of interstitial Li

The mode of incorporation of lithium (Li) (as substitution or interstitial position) in zinc oxide (ZnO) has its own importance as far as the potential applications of Li-doped ZnO nanoparticles (NPs) are concerned. Fabrication of p-type ZnO-based semiconductors as well as defect engineering-based applications demand substitution of Zn2+ by Li+. However, doping of ZnO by Li with interstitial positions can play an important role in controlling different properties of it. In the present study, we report the successful doping of Li in ZnO NPs up to a Li concentration of 10 mol% employing a simple wet chemical precipitation method in water. Up to a Li concentration of 8 mol%, doping by substitution of Li to the Zn sites has been observed. However, for 10 mol% of Li concentration, doping by incorporation of interstitial sites in addition to the substitution has been confirmed through complementary characterization techniques. The effects of interstitial Li in ZnO on structural, optical, and antimicrobial properties have been studied in detail systematically. For all the cases (structural, optical, and antimicrobial), the properties of Li-doped ZnO NPs have been changed reversibly in the ZnO NPs after the incorporation of interstitial sites by Li as compared to the substitution of Li. For example, the microstrain, band gap, and antimicrobial activity have been found to increase with the increase in Li concentration up to 8 mol%. However, the microstrain, band gap, and antimicrobial activity are found the decrease for 10 mol% of Li as compared to 8 mol% of Li. This study indicated that the different properties of Li-doped ZnO NPs can be controlled suitably as per the requirements for the practical applications of ZnO-based materials.

Rare Earth Doping Engineering Tailoring Advanced Oxygen-Vacancy Co3 O4 with Tunable Structures for High-Efficiency Energy Storage.

Co3 O4 with high theoretical capacitance is a promising electrode material for high-end energy applications, yet the unexcited bulk electrochemical activity, low conductivity, and poor kinetics of Co3 O4 lead to unsatisfactory charge storage capacity. For boosting its energy storage capability, rare earth (RE)-doped Co3 O4 nanostructures with abundant oxygen vacancies are constructed by simple, economical, and universal chemical precipitation. By changing different types of RE (RE=La, Yb, Y, Ce, Er, Ho, Nd, Eu) as dopants, the RE-doped Co3 O4 nanostructures can be well transformed from large nanosheets to coiled tiny nanosheets and finally to ultrafine nanoparticles, meanwhile, their specific surface area, pore distribution, the ratio of Co2+ /Co3+ , oxygen vacancy content, crystalline phase, microstrain parameter, and the capacitance performance are regularly affected. Notably, Eu-doped Co3 O4 nanoparticles with good cycle stability show a maximum specific capacitance of 1021.3Fg-1 (90.78mAhg-1 ) at 2Ag-1 , higher than 388Fg-1 (34.49mAhg-1 ) of pristine Co3 O4 nanosheets. The assembling asymmetric supercapacitor delivers a high energy density of 48.23Whkg-1 at high power density of 1.2kWkg-1 . These findings denote the significance and great potential of RE-doped Co3 O4 in the development of high-efficiency energy storage.

Piezocatalytic degradation of organic dyes and production of H2O2 with hydroxyapatite

Hydroxyapatite (HAP) is a widely available and environmentally friendly material that exhibits excellent biocompatibility and versatile physicochemical properties, hence it has drawn a great deal of recent research interests. However, its piezoelectric properties have not been fully exploited so far. The aim of present work is to develop a facile method to prepare HAP with good piezoelectric activity and explore its potential application in the degradation of organic pollutants and production of H2O2. In present work, the HAP was prepared by a simple chemical precipitation followed by calcination at 200 ℃ in atmospheric condition. The piezocatalytic activity of HAP was investigated by the degradation of organic dyes and the production of H2O2. The factors that affect the piezocatalytic degradation, including the dose of catalyst, dye concentration, temperature, initial pH, and ultrasonic power were systematically studied. In the optimized condition, the degradation rates of 92%, 88%, 86% and 90% are readily obtained for 5 mg/L rhodamine B (RhB), methylene blue (MB), methyl orange (MO) and crystal violet (CV) respectively in 30 min ultrasonic treatment. The reaction mechanism was studied by tree radical tests and electron spin resonance (ESR) spectra and results confirmed that •OH plays the key role in the degradation reaction. The production of H2O2 was also preliminarily evaluated, an accumulated concentration of 152.24 μmol/L H2O2 was achieved in pure water within 30 min. The stability study showed that the HAP can maintain its piezocatalytic performance for at least 4 times of recycle experiments. Thus the HAP obtained from a simple synthetic method has a great potential in the application for wastewater purification and H2O2 production.

Effect of cobalt incorporation on the photocatalytic degradation of brilliant green using SnO2 nanoparticles under visible light irradiation

• Bare and Co-doped nanocrystals of SnO 2 were synthesized by a simple chemical precipitation method. • The result of UV-DRS proposed a band gap narrowing effect on SnO 2 with cobalt doping. • The defects and vacancies induced band gap reduction and increased BET surface area on cobalt doping, have played a vital role in the photochemistry of SnO 2 . Suggested here are a simple chemical precipitation method in order to synthesize bare and various levels of Co doping samples. The harvested samples were tested for their structural, optical, morphological and photocatalytic properties. The optical study shows a decline in the band gap of SnO 2 on 0.075 M of cobalt doping. The tuned band gap of SnO 2 on doping utilizes the visible light for the photodegradation of brilliant green (BG) and recommends the usage of the optimum level of Co-doped SnO 2 in environmental remediation applications.

Effect of silicon or cerium doping on the anti-inflammatory activity of biphasic calcium phosphate scaffolds for bone regeneration.

Biphasic calcium phosphate (BCP) bioceramics composed of hydroxyapatite and β-tricalcium phosphate have attracted considerable attention as ideal bone substitutes for reconstructive surgery, orthopedics, and dentistry, owing to their similar chemical composition to bone mineral and biocompatibility. The addition of trace elements to BCP bioceramics, such as magnesium (Mg), cerium (Ce), and silicon (Si), can alter the physicochemical and biological properties of the resulting materials. To improve the anti-inflammatory activity of a pure BCP scaffold, this study developed a simple wet chemical precipitation and gel-casting method to fabricate microporous BCP scaffolds containing Si or Ce. The BCP scaffolds exhibited interconnected microporous structures with uniform micropores and unequiaxed grains. No changes in the phase composition and microstructure of the scaffolds with the Si or Ce doping were observed. Conversely, Si or Ce doping into the BCP crystal lattice influenced the in vitro biological activity of the scaffolds and the bone-forming ability of the cells cultured on the BCP scaffolds. The results of biological activity assays demonstrated that Ce-BCP promoted cell proliferation and osteogenic differentiation more effectively than the other scaffolds. In particular, Ce-BCP significantly suppressed the expression of bone-active cytokines via the anti-inflammatory and anti-oxidative effects. Therefore, Si- or Ce-doped BCP scaffolds can contribute to providing a new generation of bone graft substitutes.

Fabrication of CuFe2O4/Bi12O17Cl2 photocatalyst with intrinsic p-n junction for highly efficient bisphenol A degradation

The construction and application of novel highly efficient photocatalysts have been the focus in the field of environmental pollutant removal. In this work, a novel CuFe2O4/Bi12O17Cl2 photocatalysts were synthesized by simple hydrothermal and chemical precipitation method. The fabricated CuFe2O4/Bi12O17Cl2 composite exhibited much higher photocatalytic activity than pristine CuFe2O4 and Bi12O17Cl2 in the removal of bisphenol A (BPA) under visible-light illumination, which ascribed to the intrinsic p-n junction of CuFe2O4 and Bi12O17Cl2. The photocatalytic degradation rate of BPA on CuFe2O4/Bi12O17Cl2 with an optimized CuFe2O4 content (1.0 wt.%) reached 93.0% within 30 min. The capture experiments of active species confirmed that the hydroxyl radicals (•OH) and superoxide radicals (•O2−) played crucial roles in photocatalytic BPA degradation process. Furthermore, the possible degradation mechanism and pathways of BPA was proposed according to the detected intermediates in photocatalytic reaction process.

Ferrous-Oxalate-Modified Aramid Nanofibers Heterogeneous Fenton Catalyst for Methylene Blue Degradation

The heterogeneous Fenton system has drawn great attention in recent years due to its effective degradation of polluted water capability without limitation of the pH range and avoiding excess ferric hydroxide sludge. Therefore, simple chemical precipitation and vacuum filtration method for manufacturing the heterogeneous Fenton aramid nanofibers (ANFs)/ferrous oxalate (FeC2O4) composite membrane catalysts with excellent degradation of methylene blue (MB) is reported in the study. The morphology and structure of materials synthesized were characterized by scanning electron microscope (SEM), X-ray energy spectrum analysis (EDS), infrared spectrometer (FTIR), and X-ray diffraction (XRD) equipment. The 10 ppm MB degradation efficiency of composite catalyst and ferrous oxalate (FeC2O4) within 15 min were 94.5% and 91.6%, respectively. The content of methylene blue was measured by a UV-Vis spectrophotometer. Moreover, the dye degradation efficiency still could achieve 92% after five cycles, indicating the composite catalyst with excellent chemical stability and reusability. Simultaneously, the composite catalyst membrane can degrade not only MB but also rhodamine B (RB), orange II (O II), and methyl orange (MO). This study represents a new avenue for the fabrication of heterogeneous Fenton catalysts and will contribute to dye wastewater purification, especially in the degradation of methylene blue.

Facile fabrication of binary BiOCl-Cu2CoSnS4 and ternary BiOCl-Cu2CoSnS4-TiO2 heterojunction nano photocatalyst for efficient sunlight-driven removal of direct blue 71 in an aqueous medium

We report a novel BiOCl-Cu2CoSnS4-TiO2 ternary heterojunction nanocomposite fabricated via a simple chemical precipitation method by anchoring Cu2CoSnS4 and TiO2 on the surface of spherical BiOCl particles using ethylene glycol as a solvent at an ambient temperature (100 °C, 4 h). The as-synthesized BiOCl-Cu2CoSnS4-TiO2 nanocomposite was examined by transmission electron microscopy, UV–visible NIR spectroscopy, X-ray diffraction (XRD), time-resolved fluorescence (TRF), photoluminescence spectroscopy (PL), and N2 adsorption-desorption tests. XRD spectra of BiOCl-Cu2CoSnS4-TiO2 heterojunction show the diffraction peaks corresponding to tetragonal Cu2CoSnS4 nanoparticles and the tetragonal phase of BiOCl. The peaks of TiO2 are not viewed in the XRD pattern of BiOCl-Cu2CoSnS4-TiO2 nanocomposite which may be due to the presence of a low concentration of TiO2 in the composite. PL and time-resolved fluorescence confirm the separation of electron-hole pairs which could aggressively participate in the direct blue 71 dye degradation. The BiOCl-Cu2CoSnS4-TiO2-1 heterojunction degraded 91.48% direct blue 71 under natural sunlight which is higher than the bare BiOCl, Cu2CoSnS4 nanoparticles and TiO2 nanoparticles, and binary BiOCl-Cu2CoSnS4 composite. The electron-hole pair’s separation leads to higher photoactivity driven by the heterojunction interface between BiOCl, Cu2CoSnS4 nanoparticles, and TiO2 nanoparticles. The photogenerated h+, O2•−, and •OH radicals were responsible for the degradation of direct blue 71 over BiOCl-Cu2CoSnS4-TiO2 heterojunction as confirmed by the radical capture experiment.

Synthesis of ZnO nanoparticles through a simple wet chemical precipitation method

The research on Zinc oxide nanoparticles has become very important on these days due to its unique property and wide range of applications in all the branches of science. In this study, we synthesized ZnO nanoparticles through a simple and cost-effective wet chemical precipitation approach. The XRD spectra revealed the hexagonal wurtzite structure in the prepared ZnO nanoparticles. The UV-Vis absorption peak of the as - prepared ZnO sample was identified at 301.2 nm and was observed to be blue shifted in comparison to the bulk counterpart. The transmittance analysis of the prepared ZnO sample showed very high transmittance to the visible range of light. The widening of the optical band gap was observed in the preparation ZnO sample. The band gap of the synthesized ZnO sample was found to be 3.7943 eV. The theoretical estimation of particle size in the prepared ZnO sample was performed using the Brus model and the particle size was estimated to be 4.38 nm. This study revealed the potential application of prepared ZnO nanoparticles as transparent electrode in solar cell.

Enhanced energy storage density in poly(vinylidene fluoride-hexafluoropropylene) nanocomposites by filling with core-shell structured BaTiO3@MgO nanoparticals

Filling with high dielectric constant inorganic nanoparticles is an effective approach to enhance the energy storage performance of an organic dielectric. However, the dielectric mismatch between ceramic and polymer causes early breakdown, which limits the storage density of ceramic/polymer nanocomposites in the application of dielectric capacitors. Herein, we employed MgO as a buffer barrier to mitigate the mismatched dielectric characteristics among BaTiO3 (BT) nanoparticles and poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) substrate considering its high insulation and medium dielectric constant. The alien oxide was coated on the spherical BT by a simple chemical precipitation process, forming a BaTiO3@MgO (BT@MgO) core-shell nanostructure, which has been carefully examined by TEM and EDS. The BT-MgO heterogeneous interfacial region provides channels for carriers and promotes charge movement, and therefore the dielectric constant and potential shift have been significantly enhanced. The BT@MgO/P(VDF-HFP) nanocomposite with 1 vol% filling ratio delivered a maximum energy density Ud, and the value reaches up to 5.6 J/cm3 that is 40.0 % and 55.6 % greater than that of the host matrix and BT-filled counterpart with the same filler amount. The BT@MgO core-shell nanostructure demonstrates an alternative way to effectively heighten the energy storage performance of ceramic/polymer composite dielectrics.

Effect of Nitrate Doping on the Properties of Chemically Synthesized Calcium Hydroxide Nanoparticles

AbstractCalcium hydroxide has drawn a significant attention of current researchers due to its multifunctional applications in the field of biomedical, catalysis, and culture heritage conservation. In this work, the synthesis of calcium hydroxide was done by using the simple chemical precipitation method. The prepared calcium hydroxide was then doped with the three different concentrations e. g., 4, 7 and 10 Wt. % of calcium nitrate. The entire prepared samples were characterized by the XRD (X‐ray diffraction), FESEM (field emission scanning electron microscope), DTA‐TGA (Thermogravimetric analysis‐ Differential thermal analysis), and UV‐Vis spectroscopy techniques. From the X‐ray diffraction results, it was observed that with increase in calcium nitrate doping the crystallites size decreases from 83 nm to 70 nm. The thermal properties also varied as a function of calcium nitrate doping. Further, the UV‐Vis spectroscopy results showed the increase in optical band gap with increase in calcium nitrate doping. These results are explained in terms of structural, microstructural, thermal, and optical band gap characteristics. Finally, the implication of these results in development of a better material for thermochemical energy storage is discussed.

Fluorescent sensor based on thiourea capped Mn doped ZnS quantum dots for the sensing of Cu2+ ions in water

In the present study the utilization of a simple, rapid, and highly effective “turn-off” fluorescent sensor based on thiourea capped manganese doped zinc sulphide quantum dots for the detection of Cu2+ ions in water is described for the first time. The quantum dots are prepared by a simple and facile chemical precipitation method. The developed quantum dots are characterized by UV–vis., FT-IR, photoluminescence, XRD, and TEM techniques. The doping by manganese is confirmed by a peak at 598 nm in the PL spectrum. The sensor exhibit high sensitivity and selectivity towards copper ion at pH 9 with a limit of detection of 20.75 nM. The obtained results are also reasonable in real sample analysis.

Effect of different in situ temperatures on the crystallinity and optical properties of green synthesized 8-hydroxyquinoline zinc by saffron extract

In this research, bis (8-hydroxyquinoline) zinc (ZnQ2) nanoparticles were synthesized by the saffron extract method in a water environment at room temperature using a simple chemical precipitation method. Based on this technique, saffron was utilized as a surfactant due to its non-toxicity and being environmentally friendly. The existence of C-H bonds in the compound of saffron makes it an appropriate material for the green synthesis of ZnQ2 nanoparticles. These kinds of bounds cause reduce the rate of agglomeration of ZnQ2 nanoparticles while of the synthesis process. In this project, the ZnQ2 nanoparticles were synthesized using saffron non-toxic surfactant in different temperatures. The temperature effects from room temperature to 200 °C were considered on the crystal structure of ZnQ2 nanoparticles and their effect on optical properties, an in-situ HT-XRD instrument has been used. The functional groups of the compound, structural, morphology, and fluorescence properties of ZnQ2 nanoparticles were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), photoluminescence (PL) spectroscopy, and Ultraviolet-visible spectroscopy (UV-Vis). According to the results, XRD analysis confirmed the crystalline nature of the synthesized ZnQ2 nanoparticles by the saffron extract. The same bounds were achieved at various temperatures and also with the increase in temperatures of synthesis at 200°C sizes and band gaps were altered from 3.4 nm to 2.5 nm. Therefore, the ZnQ2 nanoparticles are one of the best green materials for replacing transferred electrons materials in optical devices. In conclusion, with utilizing the green materials, Because of reduction the intensity of surface trap and absorption is reduced and the PL of ZnQ2 in the 50°C have reached to 20000. This could be an excellent perspective for using green materials in the organic light-emitting diode and other electronic-optical devices.

SYNTHESIS AND CHARACTERIZATION OF STRUCTURAL AND OPTICAL PROPERTIES OF NI-DOPED ZINC SULFIDE NANOPARTICLES

The band-gaps of wide band gap metal sulfide semiconductors such as ZnS, are significantly reduced when doped with transition metal ions Ni2+.The new composite materials offer promising and versatile applications in spintronic devices, solar cells and other optoelectronic devices, and in photonics etc. It has led to substantial modifications in methods of synthesis for ZnS nanoparticles. In this research work, we have synthesized ZnS nanoparticles via simple chemical precipitation method. ZnS nanoparticles have been characterized using UV-visible spectra and Raman spectroscopy. For morphological studies we have used scanning electron microscopy (SEM). The optical band gap has been evaluated from UV-vis-nir absorption spectrum of the particles. Raman spectroscopy is used to study the rotational, vibrational and other modes of the sample, as we are interested to reveal properties of nanoclusters treating as those as nano-molecules. We correlate the variations in properties with their structures. Our investigations confirm formation of large single crystals (nanomolecules) yielding resonant Raman peaks. It is further confirmed from SEM images of the samples. Nanoparticles have special properties other than bulk. Their surface energy contributions are entirely different from their bulk counterparts and play dominant role in its stability. Thus, we assign a special phase for them as “Nanophase”. The phenomenon of nano-cluster (aggregates) formation of nickel atoms via nucleation is also confirmed for high doping concentrations of nickel, which results into inverse trend for band-gap.

Influence of Cerium and Nickel Co-Doping on ZnO Nanostructures for Electrochemical Behavior of H2O2 Sensing Applications

The present paper reports facile synthesis by simple chemical precipitation method for Zinc Oxide (ZnO) nanoparticles with cerium (Ce) and nickel (Ni) co-doped ZnO nanocrystals. The different optimum conditions are analyzed in dual metallic (Ce/Ni) nanoparticles doped with ZnO nanoparticles. Successful incorporation of cerium and nickel is predicted with X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Additionally, optical effects were studied as-prepared active materials by UV-Visible reflectance (UV-Vis-DRS) and photoluminescence (PL) measurements at room temperature. In addition, morphology investigations of the scanning electron microscope (SEM) and transmission electron microscope (TEM) are conducted. The results of electrochemical studies reveal that the co-doped product exhibits a higher H2O2 sensing response, with 46.21 μA/μM.cm2 for Ce/Ni-doped ZnO, which can use potentially for future biomedical applications.

Synthesis and characterization of pristine and strontium-doped zinc oxide nanoparticles for methyl green photo-degradation application

Herein we describe an effective route for the degradation of methyl green (MG) dye under visible light illumination by pristine and strontium (Sr)-doped zinc oxide (ZnO) photocatalysts (synthesized by the simple chemical precipitation method). The x-ray diffraction structural analysis has confirmed that both photocatalysts exhibit the hexagonal wurtzite structure; without any additional phase formation in Sr-doped ZnO, in particular. The optical properties of the synthesized photocatalysts have been investigated using UV–vis absorption spectroscopy in the wavelength range of 250–800 nm. Through Tauc’s plot, the slight decrease from 3.3 to 3.2 eV in band gap energy has been elucidated (in the case of Sr-doped ZnO), which has been further confirmed by the quenching in the intensity of Photoluminescence (PL) emission spectrum. This may be due to sub-band level formation between valence and conduction band, caused by the impregnation of Sr2+ ions into ZnO host. The morphological study has also been performed using Field Emission Scanning Electron Microscope, which indicates nanoparticles (NPs) based surface texture for both photocatalysts. During the photocatalytic activity study, after 30 min irradiation of visible light, ∼65.7% and ∼84.8% photocatalytic degradation of MG dye has been achieved for pristine and Sr-doped (2 wt%) ZnO photocatalysts, respectively. The rate of photocatalytic reaction (K) has been observed to be ∼0.06399 min−1 for Sr-doped (2 wt%), whereas nearly half magnitude ∼0.03403 min−1 has been observed for pristine ZnO, respectively. The significantly improved photodegradation activity may be ascribed to the relatively broader optical absorption capability, surface defects and the enhanced charge separation efficiency of the Sr-doped ZnO photocatalyst.

Synthesis of chitosan/SnO2 nanocomposites by chemical precipitation for enhanced visible light photocatalytic degradation efficiency of congo red and rhodamine-B dye molecules

Tin oxide (SnO2) nanoparticles (NPs) as well as SnO2/chitosan(CS) nanocomposites (NCs) were successfully synthesized by a simple chemical precipitation technique and their photocatalytic degradation ability against congo red (CR) and Rhodamine-B (Rh-B) were subsequently evaluated. The crystallinity and surface morphology of the materials were evaluated using X-ray diffraction analysis and transmission electron microscopy (TEM), respectively. The TEM images revealed that nanosized SnO2 NPs were successfully obtained and were homogeneously distributed within the CS matrix. The CS/SnO2 NCs were exposed to Rh-B dye molecules, resulting in 95% degradation within 60 min, which was significantly higher than for SnO2 NPs. On the other hand, CS/SnO2 NCs were found to degrade 98% of CR dye molecules within 40 min of visible light irradiation, which was also significantly shorter than for SnO2 NPs. The CR dye molecules experienced significantly better levels of photodegradation parameters than Rh-B. The present study demonstrates the potential of CS/SnO2 NCs in the area of environmental remediation of organic dye-based water pollutants.

Amorphous calcium phosphate nanoparticles allow fingerprint detection via self-activated luminescence

Herein, stable activator-free photoluminescent nanoparticles based on amorphous calcium phosphate (ACP) were obtained for the first time, and their performance for latent fingerprint imaging was investigated. ACP nanoparticles with irregular rounded shape and diameters in 10–40 nm range were prepared by a rapid and simple chemical precipitation followed by heat treatment at 400 °C for 4 h. Notably, diffuse reflectance spectroscopy, photoluminescence excitation and emission measurements reveal a high density of localized energy states within the wide optical band gap of heat-treated ACP (Eg = 5.25–5.42 eV). This behavior allowed the excitation of ACP in near-ultraviolet region (λexc = 450 nm, 2.75 eV), leading to an intense defect-related broadband (490–890 nm) photoluminescence emission centered at 540 nm (2.30 eV), 50 times more intense than untreated nanoparticles. The effect of lattice shrinkage due to structural water elimination, the presence of ionic vacancies (VCa and VO in PO43-) and carbonate groups (CO32-), on the luminescent properties of ACP were discussed in detail, as well as investigated after aqueous-mediated ACP crystallization into hydroxyapatite (HA). ACP nanoparticles were non-cytotoxic, as determined by MTT assay in Human Dermal Fibroblast neonatal (HDFn) cell line, with cell viabilities superior to 95% in all tested concentrations (20–320 μg/mL), after incubation for 24 and 48 h. Latent fingerprint images were obtained using the ACP nanoparticles under near-ultraviolet irradiation (λexc = 450 nm) in tweezers and LCD smartphone and successfully validated by the Integrated Automated Fingerprint Identification System used by Scientific Police in Spain. The present results evidenced that the new luminescent ACP nanoparticles are safe to be used and agree with the forensic requirements for future legal actions.

Room-temperature growth optimization and PL characteristic of polytype h/α-MoO3 thin films by chemical precipitation method

In this study, MoO3 thin films were coated using a simple chemical precipitation technique at room temperature, without using an autoclave or other complex equipment. Films were deposited on precoated MoO3 seed layers prepared by spray pyrolysis on glass substrates. The effects of the seed layer growth conditions and pH value of the precipitation method’s solution on the characteristics of MoO3 films were investigated. The Raman and X-ray diffraction techniques showed that MoO3 films have grown in mixed hexagonal (h) and orthorhombic (α) crystal structures and the scanning electron microscope verified that the samples’ surface was covered of both hexagonal micro rods and lamellar micro belts. The XRD patterns indicated that the crystallinity was significantly improved using a seed layer sprayed under lower carrier gas pressure, and lower pH value of the precipitation method’s solution. The UV–Visible spectra showed that using seed layers prepared at higher carrier gas pressure decreases the bandgap of the films prepared by precipitation, due to the incorporation of more oxygen vacancies. The photoluminescence studies showed that the film deposited at a higher solution’s pH value has higher PL intensity, which indicates that this sample is a suitable candidate for optoelectronic applications.

Ultrasensitive and Selective Electrochemical Detection of Dopamine Based on CuO/PVA Nanocomposite-Modified GC Electrode

At present, the determination of dopamine (DA) is enormously necessary for the human body. Since then, it has played a crucial role in the brain that affects mood, sleep, memory, learning, and concentration. Dopamine insufficiency is a threat to human health. Dopamine recognition is important to avoid this problem. Copper oxide (CuO) nanoparticles are one of the potentials which can be used in the detection of dopamine level in the sample. In this work, CuO was synthesized by a simple chemical precipitation technique and modified by polyvinyl alcohol (PVA) as a capping agent. The nanomaterials manufactured are used for the detection of dopamine in 0.1 M PBS medium at room temperature. The CuO/PVA-modified electrode shows better electrocatalytic activity than CuO/GCE (glassy carbon electrode). The constructed dopamine biosensor of copper oxide-PVA nanocomposites also has extraordinary selectivity, stability, sensitivity (183.12 μA mM-1 cm-2), and a minimum level detection limit of 0.017 μM, is inexpensive, and has minimal effort and rapid detection of dopamine.