UV Light Conditions Research Articles

Live Cell Imaging Studies on Orange Emitting Thiazole-Pyridone Azo Fluorophore and Its Latent Fingerprints, Computational, Electrochemical Sensing for Dopamine Detection.

The fluorescent materials have sparked a lot of research interests due to their unique electronic, optical and chemical characteristics. Here, we are intended to present a simple and facile synthesis of novel orange emitting thiazole-pyridone fluorescent tag (TPFT) by a simple diazo coupling reaction and the structural elucidation was carried out by IR, NMR (1H and 13C), UV-Vis, photoluminescence and HR-MS spectrometry. The solvatochromic behaviour of the TPFT offered crucial information about the formation of hydrazone and azo tautomeric forms. The DFT simulations are computed to calculate HOMO-LUMO energy gap (3.028 eV) of TPFT along with MEP and RDG analyses. Comprehensive LFP visualization is revealed under both normal and UV light conditions (365 nm). The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to analyse the electrochemical behaviour of the TPFT-modified glassy carbon electrode (MGCE) and exhibited a lower detection limit of 7.89 × 10-8 M (S/N = 3) with a linear range of 0.5-8.0 μM for DA detection. The live-cell imaging study of TPFT showed a strong blue emission at 453 nm, which generally indicates the existence of fluorescence stability.

γ-Cyclodextrin-metal organic framework as a carrier for trans-N-p-coumaroyltyramine: A study of drug solubability, stability, and inhibitory activity against α-glucosidase.

γ-Cyclodextrin-based metal-organic frameworks (γ-CD-MOF) were successfully synthesized using the solvent diffusion method and applied as carriers for trans-N-p-coumaroyltyramine (N-p-t-CT, NCT) to study the solubability, stability, sustained release and inhibitory activity against α-glucosidase. The solubilization effect of γ-CD-MOF on N-p-t-CT was performed using impregnation (NCT@CD-MOF-1) and co-crystallization (NCT@CD-MOF-2) methods. X-ray diffraction, scanning electron microscope (SEM), fourier transform infrared spectrometer (FTIR), and N2 adsorption/desorption were used to characterize the MOFs before and after loading NCT. The results showed that NCT@CD-MOF-2 had a better solubability for N-p-t-CT, 145.03μg/mg of drug loading capacity could be achieved, and the solubility of NCT@CD-MOF-2 in water was 366 times higher than free N-p-t-CT. In addition, the stabilities of N-p-t-CT under temperature, UV light and pH conditions were greatly improved after encapsulation in γ-CD-MOF. Furthermore, NCT@CD-MOFs had a sustained release of N-p-t-CT over an extended period in vitro due to the primary encapsulation in pore structures. Notably, γ-CD-MOF loaded with N-p-t-CT showed superior inhibitory activity against α-glucosidase compared to free N-p-t-CT. Cytotoxicity studies demonstrated that NCT@CD-MOF-2 had low toxicity in vitro and perfect biocompatibility with HL-7702 cells, and γ-CD-MOF could reduce the toxicity of free N-p-t-CT at higher concentrations.

Unraveling the transition of ZIF-67-on-ZIF-8 core–shell structured dodecahedron formed by an oriented attachment mechanism from type II to step-scheme for enhanced photocatalytic degradation of oxytetracycline hydrochloride

A composite photocatalyst comprising ZIF-67 and ZIF-8 was synthesized using a hydrothermal method. The process entailed the crystallization of ZIF-67 on the ZIF-8 dodecahedron backbone, eschewing the utilization of ligands. The photocatalytic efficiency of the composite ZIF-67-on-ZIF-8 was evaluated through the degradation of oxytetracycline hydrochloride (OTC) under visible and UV light. The results indicated superior OTC degradation compared to pure ZIF-8 and ZIF-67, which might be attributed to the energy level and lattice alignment between ZIF-8 and ZIF-67. This facilitated the separation and transfer of photogenerated electron-hole pairs, thereby suppressing electron-hole complexation. The activation of ZIF-67-on-ZIF-8 with peroxymonosulfate (PMS) resulted in a further enhancement in the degradation efficiency of OTC under both visible and UV light conditions. The optimal effect was observed with the addition of 0.6 mmol of PMS, which resulted in a degradation rate of 95.7 % at 60 min under visible light and 97.01 % at 30 min under UV light. The acceleration of the degradation process and the reduction in the required time were the result of a change in configuration. The study’s originality led to the transformation of the conventional type II heterojunction model into the S-scheme heterojunction model through the modification of the light source, thereby offering a novel perspective for heterojunction design.

Characterization and Photocatalytic Activity of Er2Ti2O7 Prepared by Sol-Gel Method

In this article, the erbium nitrate pentahydrate (Er(NO3)3·5H2O), tetrabutyl titanate (C16H36O4Ti), glacial acetic acid (CH3COOH), and anhydrous ethanol (C2H5OH) were used as the main raw materials. The Er2Ti2O7 was successfully prepared by the sol-gel method. The structure and morphology of the samples were characterized by thermogravimetric-differential thermal analyzer (TG-DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT­IR). The 10 mg/L methyl orange solution was used as a simulated pollutant under UV light conditions. The effects of different temperatures and light times on the photocatalytic performance of the Er2Ti2O7 samples were investigated. The results showed that the pure Er2Ti2O7 samples could be successfully prepared by calcination in the temperature range of 750–1000 °C. The average grain size of Er2Ti2O7 was about 20–60 μm, and the photocatalytic performance of Er2Ti2O7 samples calcined at 900 °C was the best. When the illumination time is 90 min, the degradation rate of methyl orange reaches to about 100%. The preparation of Er2Ti2O7 by the sol-gel method is a kind of ultraviolet light photocatalyst with wide application prospects.

Aging and Small-sized Particles Release Characteristics of Tire Microplastics in Various Environmental Media

In recent years, research on microplastics has mostly focused on thermoplastic materials, and there is a lack of research on the pollution status and environmental behavior of tire microplastics, a type of rubber elastomers. In order to investigate the aging and small-sized particles release characteristics of tire microplastics in various environmental media, the aging process of two different tire microplastics, one for cars and the other for electric bicycles, was simulated in dry and aquatic environments under laboratory conditions. The results showed that the tire microplastics would be aged after 30 d of UV illumination, which was manifested by the roughness of the surface and the appearance of cracks and flaking. The Fourier infrared spectra showed that the carbonyl index of the surface also increased. In addition, tire microplastics released a large number of small sub-micron particles under the influence of UV illumination and hydrodynamic action, and the number of particles released from car tire microplastics in aquatic environments reached 694.8 million particles per milliliter of solution at 30 d of the UV light condition, among which 694.6 million particles with a particle size of less than 1 μm were released, which was approximately 100 times of that in the dark condition. The study showed that tire microplastics in aquatic environments were more susceptible to aging and released more small particles under light conditions and that car tire microplastics released more small particles than electric bicycle tire microplastics, posing ecological and environmental risks.

Synthesis and characterization of X (X = Ni or Fe) modified BaTiO3 for effective degradation of Reactive Red 120 dye under UV-A light and its biological activity

For the sustainable advancement of industrial expansion that is environmentally conscious, harmful dyes must be removed from wastewater. Untreated effluents containing colors have the potential to harm the ecosystem and pose major health risks to people, animals, and aquatic life. Here, we have fabricated Ni or Fe modified with BaTiO3 materials and effectively utilized them for Reactive Red 120 (RR 120) dye degradation under UV-A light. The synthesized materials were characterized, and their structural, and photo-physical properties were reported. Phase segregation was not present in the XRD pattern, as evidenced by the absence of secondary phase peaks linked to iron, nickel, or oxides. Low metal ion concentrations may be the cause of this, and the presence of those elements was confirmed by XPS measurements. The Raman spectra of the BaTiO3/Ni and BaTiO3/Fe samples show a widened peak at 500 cm−1, which suggests that Ni or Fe are efficiently loaded onto the BaTiO3. RR 120 dye photodegradation under UV light conditions was effectively catalyzed by BaTiO3/Fe, as evidenced by its superior performance in the UV irradiation technique over both BaTiO3 and BaTiO3/Ni. Compared to bare BaTiO3, both metal-modified materials efficiently degraded the RR 120 dye. Acidic pH facilitated the degradation process, which makes sense given that the heterogeneous photo-Fenton reaction was the mechanism of degradation along with BaTiO3 sensitization. High-acidity sewage can be dangerous and carcinogenic, and conventional biological treatment methods are not appropriate for managing it. In the current investigation, it may be used to treat color effluents with extremely low pH levels. Additionally, the ability of the produced nanocomposites to inhibit the growth of twenty pathogens was examined, along with two fungi, fifteen Gram-negative Bacilli (GNB), one Gram-positive Bacilli (GPB), and two Gram-positive Cocci (GBC).

Development and Validation of Stability Indicting HPLC Method for the Separation and Simultaneous Analysis of Timolol, Dorzolamide and Latanoprost Inophthalmic formulations

The present work is intended to establish a simple, precise and sensitive stability indicating HPLC method for the separation and simultaneous quantification of timolol, dorzolamide and latanoprost in pharmaceutical formulations. The separation of analytes was achieved on Spherisorb ods2 C18 (250mm × 4.6mm; 5µ)as stationary phase, methanol, acetonitrile and phosphate buffer (pH 5.2) in 55:45:05 (v/v) as mobile phase at 1.0 mL/min and UV detection at 239nm. In this condition, well resolved, retained peaks were identified at 3.45 min fortimolol, 2.66min for dorzolamideand 5.43min for latanoprost. The method reports 0.313µg/mL, 1.25µg/mL and 0.003µg/mL for timolol, dorzolamide and latanoprost respectivelyas LOD that proves that the method have enough sensitivity levels for the detectionanalytes in samples. The method passes all the validation parameters as per the guidelines proved that the method was valid. The method can shows very less % degradation in various stress studies such as acidic, base, peroxide, thermal and UV light conditions and can effectively separate various stress degradation compounds and confirms the stability indicating nature of the method. The method applicability was assessed by analysing the drug content in ophthalmic drops and reports the % assay of be 98.48, 99.37 and 98.32% for timolol, dorzolamide and latanoprost respectively. Based on the results, it can be concluded that the method can adequately suitable for the separation and quantification of timolol, dorzolamide and latanoprost and hence can be applicable for the routine analysis of timolol, dorzolamide and latanoprostin single or any combined ophthalmic formulations.

Sensitive and validated UPLC-MS/MS method for the identification and characterization of forced degradation products for felodipine

AbstractA rapid, stability indicating reverse phase liquid chromatographic method was developed for the determination of purity of Felodipine in active pharmaceutical substance form in the presence of its impurity and its degradation products. To develop the method which is also compatible to liquid chromatographic mass spectroscopic technique. The developed method is also used to determine the assay of Felodipine in bulk drug form. The drug is subjected to various stress conditions like acidic, basic, oxidation, UV light and thermal conditions. Considerable degradation was observed during base hydrolysis. Two degradation products were identified. The Waters Acquity UPLC BEH C18, 2.1 × 100 mm, 1.7 µm Column was used to achieve chromatographic separation. The gradient conditions, diluent and injection volume were optimized to achieve the acceptable resolution between impurities and its degradation products from Felodipine and to get good peak shapes. The masses were determined for main compound and its identified degradation products. Further, the characterization studies for main compound and its degradation products were performed using LCMSMS Q-TOF.

V2O5 based nanocomposites with MOF and rGO for the adsorption and photocatalytic degradation of methylene blue dye

In the present work, vanadium pentoxide-metal organic framework (V2O5-MIL 125 MOF) and vanadium pentoxide-reduced graphene oxide (V2O5-rGO) nanocomposites were successfully synthesized using a facile low-temperature hydrothermal treatment. These nanocomposites were used as photocatalysts to study the adsorption capacity and photocatalytic degradation of methylene blue (MB) dye in an aqueous solutions, under dark and UV light conditions. The influence of adsorption on dye removal and its isotherm revealed that both the nanocomposites follow the Freundlich isotherm. The kinetics of adsorption indicated pseudo-second-order behaviour. V2O5-MIL 125 MOF and V2O5-rGO exhibited maximum dye adsorption capacities of 62 and 24 mg/g, respectively. The optimal values for maximum photocatalytic degradation were determined, and the mechanism of degradation was verified using radical scavengers. A 125 W high-pressure mercury vapour light was employed as the light source for all dye degradation studies. Maximum degradation was obtained at neutral conditions (pH 7.4) of the solution, ambient temperature (30±2˚C), and an initial dye concentration of 10 ppm. The synthesized photocatalysts V2O5-MIL 125 MOF and V2O5-rGO exhibited maximum degradation of 87% within 270 min and 82% within 300 min of UV light exposure, respectively. The adsorption and photocatalytic effects of V2O5-MIL 125 MOF and V2O5-rGO were also compared with pure vanadium pentoxide (V2O5), revealing superior activity in both cases.

A colorimetry-enhanced tri-functional film with high stability by polyphenol-anthocyanin co-pigmentation/conjugate: New prospect for active intelligent food packaging

A highly stable “tannin-anthocyanin conjugated” trifunctional active intelligent film was developed by incorporating bilberry anthocyanins (BA) as an indicator and tannin acids (TA) as a co-pigment into a sodium alginate-carrageenan polysaccharide matrix (SC-BA/TA). The doping of TA conferred outstanding antioxidant (DPPH scavenging rate > 90%) and antibacterial properties to the film, particularly effective against S. aureus. The SC-BA/TA films effectively blocked UV rays (close to 0%, effectively impeding most UVA, as well as nearly all UVC and UVB) within the range of 200–320 nm. The TA-BA co-pigment effect significantly improved the anthocyanins' storage and color stability (retention rate > 70% under UV and natural light conditions). TA forms conjugate with anthocyanins by π-π stacking and hydrogen bonding interactions with co-pigmentation rate increases of 10.5% and 11.0% for pH 2 and pH 3, respectively. The film exhibited good responsiveness to volatile amines within 4 min, and offered real-time monitoring of beef freshness, as indicated by visualizing color changes (from red to dark yellow color). Furthermore, the integration of the film's RGB value with beef quality via a smartphone App effectively reduces the variability in visual recognition among individuals. To sum up, composite films based on the “tannin-anthocyanin conjugate” approach hold great potential in the field of food freshness monitoring, opening new possibilities for the development of highly stable active smart packaging films.

A multifunctional Eu-MOF with multi-color and proton conduction switching and its anti-counterfeiting applications

Lanthanide metal-organic frameworks (Ln-MOFs) have exhibited remarkable capabilities in color change, luminescence, proton conduction through the strategic modification of metal nodes, organic ligands and channels or pores. By modifying the electron-deficient bipyridinium to contain carboxylic acid moieties and coordinating them with the luninescent Eu3+ ion, a unique and versatile Eu-MOF has been synthesized. Under UV light conditions, the complex shows an obvious color change from colorless to blue, which is due to the formation of viologen radicals after photoinduced electron transfer (PIET) process. As we all know, the changed color is caused by the alteration of absorption intensity, ultimately impacting its luminescence as well. Thus, the bright and strong red fluorescence of this complex is quenched upon continuous UV light irradiation, which may be attributed to intramolecular energy transfer from the excited state of the europium ion to the colored state of the CV ligand. Based on the control of multiple colors of the complex, the designed encryption model can realize multiple anti-counterfeiting of real numbers. In addition, the conductivity of this compound increases significantly after UV illumination, showing excellent photo-modulated proton conductivity. In short, our work has proposed a multifunctional bipyridinium-based Ln-MOF with photochromism, photo-switchable photoluminescence and proton conduction, which offers valuable insights for the creation of versatile switchable materials based on MOFs.

Light and Humidity Dual-Responsive Anti-Counterfeiting Films Based on Hydrogen-Bonded Cholesteric Liquid Crystal Polymers with Spiropyran.

There is still significant room for improvement when combining structural color with fluorescence patterns in dual anti-counterfeiting and dynamic anti-counterfeiting labels. In this study, we achieved significant breakthroughs under dual anti-counterfeiting conditions by using the structural color properties of the hydrogen-bonded cholesteric liquid crystal (HBCLC) and combining them with the fluorescence dye spiropyran (SP) to create anti-counterfeiting patterns. The anti-counterfeiting label can only display storage information after meeting the conditions of humidity and ultraviolet light (UV) and has the functions of dynamic encryption and repeated reading. We adjusted the center of the reflection band of the HBCLC film to transition from red to infrared under 40-90% relative humidity (RH) conditions and used it as a background film to draw anti-counterfeiting patterns with SP. Since these fluorescence dyes can switch between merocyanine (MC) (red) and SP (colorless) under UV and visible light conditions, when combined with the HBCLC, orthogonal dynamic encryption was achieved. Additionally, with the adsorption of SP, the reflection band of HBCLC films under the same humidity range increased from around 160 nm to around 260 nm, greatly improving the sensitivity to humidity changes. Furthermore, under UV conditions, it can still emit red fluorescence, demonstrating a polymorphic encryption feature, which greatly increased the complexity of the anti-counterfeiting pattern with significant significance to dynamic anti-counterfeiting and information storage.

In vitro analyses of cerium oxide nanoparticles in degrading anthracene/fluorene and revealing the antibiofilm activity against bacteria and fungi

A sol-gel method was used to synthesize the cerium dioxide nanoparticles. The nanoparticles formed were then characterized with UV–visible spectrophotometry, Fourier Transform Infrared Spectrophotometer (FTIR), SEM-EDAX, XRD, and Dynamic Light Scattering (DLS). The UV–visible absorbance at 282 nm and characteristic peak at 600-4000 cm−1 provided insight into the formation of cerium dioxide nanoparticles using a chemical method. SEM analysis and EDAX analysis confirmed nanoparticle formation and elements within the nanoparticles based on their irregular morphology. The hydrodynamic size obtained from the DLS analysis was 178.4 nm and the polydispersity was 0.275 nm. Furthermore, XRD results confirmed the crystalline nature of cerium dioxide nanoparticles. Using batch adsorption as a method, the effect of concentration of Polycyclic Aromatic Hydrocarbons (PAH), adsorbent concentration, pH, and irradiation source was investigated. Under UV light conditions, 10 μg/mL cerium dioxide nanoparticle at pH 5 degraded 2 μg/mL of PAH (anthracene and fluorene). Consequently, the synthesized cerium dioxide nanoparticles were effective photocatalysts. For anthracene and fluorene, kinetic studies showed the degradation process followed pseudo-second-order kinetics and Freundlich isotherms. Cerium oxide also exhibited significant antimicrobial and antibiofilm activity against bacteria and fungi. As a result, the cerium dioxide nanoparticle has proved to be a highly effective photocatalytic tool for the degradation of PAHs and exhibits strong antimicrobial activity.

Lutein-loaded glycosylated zein nanoparticles-Preparation, characterization, and stability in functional drink

In order to improve its carrying and delivery performance, zein was glycosylated with chitosan oligosaccharide (COS) by Maillard reaction to prepare glycosylated zein conjugates (GLCZ), and lutein was encapsulated within GLCZ for fabricating GLCZ-LUT nanoparticles. The results revealed the encapsulation efficiency of lutein loaded in zein (Z-LUT) was greatly increased from 69.33% to 85.75% when zein was modified with COS at a mass ratio of 1:3. The GLCZ-LUT nanoparticles presented unique spherical nanostructures, larger particle sizes (260–380nm), increased zeta potential (−22.4 to −27.5 mv), and superior polydispersity (PDI <0.2). Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) confirmed that lutein was combined and encapsulated better by the Maillard-modified zein, and hydrogen bonding, electrostatic interactions, and hydrophobic interactions were the driving forces for formation of combined nanoparticle structures. Moreover, GLCZ-LUT showcased enhanced solubility, in vitro release, and antioxidant capacity of lutein. The stability of lutein under thermal, storage, and UV-light conditions in functional drinks was also significantly improved by GLCZ. The glycosylated COS/zein system, developed through the Maillard reaction, emerges as a leading contender for efficient lutein delivery in functional beverages.

Non-destructive spectroscopic diagnostic tools for the assessment of the mechanical strength of 3D-printed PLA

Polylactic acid (PLA) is a biodegradable and biocompatible thermoplastic that is commonly used in 3D printing. Despite being widely utilized, PLA is susceptible to degradation by both UV light and hydrothermal conditions. This study investigated the effects of 3D printing temperature, UV light exposure, and hydrothermal aging on the properties of PLA. Samples were 3D printed at temperatures of 190, 205, 220 and 235 °C. The specimens were then aged under UV light and thermal cycling or hydrothermally at 80 °C for up to 6 weeks. The aged materials were then characterized using X-ray diffraction (XRD), thermos-gravimetric analysis (TGA), microscopy, mechanical testing, and ultimately Raman spectroscopy.Results showed that the PLA cristallinity increases with aging time in both hydrothermal and under UV exposure conditions, while mechanical strength decreases. Additionally, the UV exposure caused the formation of monomers and oligomers on the outermost layers. Printing temperature was shown to play only a minor role in the determination of the chemophysical properties of the 3D printed components, with faster degradation occurring on samples printed at higher temperatures, which also resulted in higher amounts of monomer when exposed to UV light for 6 weeks.The relative intensities of specific regions of the Raman spectra obtained on the aged samples could be successfully correlated with both the mechanical strength and chemo-physical properties such as the decomposition temperature. The algorithms developed in this study enable non-destructive analysis of PLA components, allowing for the determination of the extent of structural degradation due to environmental aging and the expected residual mechanical resistance.

Nitrogen and Phosphorus Co-Doped Carbon Dots for the Growth Promotion of Water Spinach

Carbon dots have received much attention due to their unique physicochemical properties and diverse applications in bioimaging, optoelectronic devices, catalysis, and agriculture. Here, in this work, we report a simple hydrothermal synthesis of nitrogen and phosphorus−doped carbon dots (N, P−CDs). The optical and physical properties of the synthesized N, P−CDs are analyzed using systematical spectroscopy and electrical characterization. The synthesized N, P−CDs show strong photoluminescence at 626 nm and demonstrate high stability under UV light and other conditions. Moreover, we incorporate the synthesized N, P−CDs into water spinach by root spraying and leaf spraying. It is found that N, P−CDs could effectively promote the growth of water spinach by accelerating the photosynthetic rate, and increasing the content of total phenols, anthocyanins, and flavonoids in water spinach.

Study on electronic transport performance of Ag-ZnO film by photoassisted conductive atomic force microscopy

Purpose The purpose of this paper is to study the electronic transport performance of Ag-ZnO film under dark and UV light conditions. Design/methodology/approach Ag-doped ZnO thin films were prepared on fluorine thin oxide (FTO) substrates by sol-gel method. The crystal structure of ZnO and Ag-ZnO powders was tested by X-ray diffraction with Cu Kα radiation. The absorption spectra of ZnO and Ag-ZnO films were recorded by a UV–visible spectrophotometer. The micro electrical transport performance of Ag-ZnO thin films in dark and light state was investigated by photoassisted conductive atomic force microscope (PC-AFM). Findings The results show that the dark reverse current of Ag-ZnO films does not increase, but the reverse current increases significantly under illumination, indicating that the response of Ag-ZnO films to light is greatly improved, owing to the formation of Ohmic contact. Originality/value To the best of the author’s knowledge, the micro electrical transport performance of Ag-ZnO thin films in dark and light state was firstly investigated by PC-AFM.

Microfluidic fabrication of size-controlled nanocarriers with improved stability and biocompatibility for astaxanthin delivery

Improving the stability of astaxanthin (AST) is a vital way to enhance its oral bioavailability. In this study, a microfluidic strategy for the preparation of astaxanthin nano-encapsulation system was proposed. Thanks to the precise control of microfluidic and the rapid preparation ability of the Mannich reaction, the resulting astaxanthin nano-encapsulation system (AST-ACNs-NPs) was obtained with average sizes of 200 nm, uniform spherical shape and high encapsulation rate of 75%. AST was successfully doped into the nanocarriers, according to the findings of the DFT calculation, fluorescence spectrum, Fourier transform spectroscopy, and UV–vis absorption spectroscopy. Compared with free AST, AST-ACNs-NPs showed better stability under the conditions of high temperature, pH and UV light with<20% activity loss rate. The nano-encapsulation system containing AST could significantly reduce the hydrogen peroxide produced by reactive oxygen species, keep the potential of the mitochondrial membrane at a healthy level, and improve the antioxidant ability of H2O2-induced RAW 264.7 cells. These results indicated that microfluidics-based astaxanthin delivery system is an effective solution to improve the bioaccessibility of bioactive substances and has potential application value in food industry.

Surface-Related Factors Affecting the Photocatalytic Process of Semiconductor Oxides: Ceria and Titania

Nanoparticles of CeO2, with rod-, and cubic-morphology, were synthesized by hydrothermal method and compared with commercial polyhedral ceria particles. Comparison of the synthesized CeO2 with the commercial powder revealed the influence of its defectivity with the absorption edge energy. The defectivity of CeO2 has also been determined in correlation with the photocatalytic performance of CeO2 per unit particles area, under narrow band UV-light (LED) condition. Analysis of the photocatalytic performance of the synthesized and commercial CeO2, as well as the reference TiO2 powder, revealed an enhancement in the decolorization of methylene blue dye (MB) with pH. The improvement in photocatalysis was associated with the surface charge condition of CeO2 particles, which controls the adsorption of molecules during the process. Furthermore, it was observed that the highly negative surface charge of cubic-morphology CeO2 favored the decolorization of MB, despite the low BET surface area. The photoelectrochemical study of ceria electrodes revealed a low photopotential compared to that of TiO2, the impact of which leads to a worse photocatalytic performance of CeO2 compared to TiO2.

Investigation of efficient photoconduction and enhanced luminescence characteristics of Ce-doped ZnO nanophosphors for UV sensors.

This study involves the single-step, mass-scale productive synthesis, photoconduction, and luminescence characteristics of pure and cerium rare-earth-ion-doped ZnO (CZO) nanophosphors with different Ce concentrations (Ce: 0, 2, 4, 6, and 8wt.%) synthesized using the solid-state reaction method. The synthesized nanophosphors were characterized for their structural, morphological, optical, and photoconductivity (PC) properties using X-ray diffraction (XRD), field-effect scanning electron microscopy (FE-SEM), energy dispersive spectroscopy, Fourier-transform infrared (FT-IR), photoluminescence (PL), and PC measurements. The sharp diffraction peaks of XRD results exhibit the formation of crystalline hexagonal wurtzite ZnO nanostructures. The decrease in diffraction peak intensities of CZO with an increase in Ce concentrations signifies the deterioration of the ZnO crystal. FE-SEM images exhibit the good crystalline quality of nanophosphors composed of spherical- and elongated-shaped nanoparticles that are distributed consistently on the surface. The energy dispersive X-ray pattern of the 4wt.% Ce-doped ZnO (CZO4 ) sample confirms the doping of Ce in ZnO. The presence of chemical bonds and functional groups corresponds to transmittance peaks established using FT-IR spectroscopy. Deconvoluted PL spectra show two major emission peaks, one in the UV region, which is near-band-edge, and the other in the visible region ranging from ~456 to 561 nm. In PC studies, current-voltage (I-V) and current-time (I-T) characteristics, that is, rise/decayin current under dark as well as UV light conditions, are also investigated. Efficient photoconduction is observed in CZO samples. The obtained results indicate the suitability to luminescent and photosensor applications.