Diffuse Reflectance Measurements Research Articles

Tunable Optical Properties and Relaxor Behavior in Ni/Ba Co-Doped NaNbO3 Ceramics: Pathways Toward Multifunctional Applications

In this study, Ni/Ba co-doped NaNbO3 ceramics (NBNNOx) were synthesized using a solid-state method to explore the effects of Ni2+ and Ba2+ ion substitution on the structural, optical, and dielectric properties of NaNbO3. X-ray diffraction (XRD) confirmed that the ceramics retained an orthorhombic structure, with crystallinity improving as the doping content (x) increased. Significant lattice distortions induced by the Ni/Ba co-doping were observed, which were essential for preserving the perovskite structure. Raman spectroscopy revealed local structural distortions, influencing optical properties and promoting relaxor behavior. Diffuse reflectance measurements revealed a significant decrease in band gap energy from 3.34 eV for undoped NaNbO3 to 1.08 eV at x = 0.15, highlighting the impact of co-doping on band gap tunability. Dielectric measurements indicated relaxor-like behavior at room temperature for x = 0.15, characterized by frequency-dependent anomalies in permittivity and dielectric loss, likely due to ionic disorder and structural distortions. These findings demonstrate the potential of Ni/Ba co-doped NaNbO3 ceramics for lead-free perovskite solar cells and other functional devices, where tunable optical and dielectric properties are highly desirable.

Breaking Barriers in Chalcogenide Perovskite Synthesis: A Generalized Framework for Fabrication of BaMS3 (M═Ti, Zr, Hf) Materials

AbstractChalcogenide perovskites have garnered increasing attention as stable, non‐toxic alternatives to lead halide perovskites. However, their conventional synthesis at high temperatures (>1000 °C) has hindered widespread adoption. Recent studies have developed low‐to‐moderate temperature synthesis methods (<600 °C) using reactive precursors, yet a comprehensive understanding of the pivotal factors affecting reproducibility and repeatability remains elusive. This study delineates the critical factors in the low‐temperature synthesis of BaMS3 (M═Zr, Hf, Ti) compounds and presents a generalized framework. Innovative approaches are developed for synthesizing BaMS3 compounds using this framework involving organometallics for solution deposition. The molecular precursor routes, employing metal acetylacetonates to generate soluble metal–sulfur bonded complexes and metal–organic compounds to produce soluble metal‐thiolate, metal‐isothiocyanate, and metal‐trithiocarbonate species, are demonstrated to yield carbon‐free BaMS3. These methods have achieved the most contiguous films of BaZrS3 and BaHfS3 using solution deposition to date. Furthermore, a hybrid solution processing method involving stacking sputter‐deposited Zr and solution‐deposited BaS layers is employed to synthesize a contiguous, oxygen‐free BaZrS3 film. The diffuse reflectance measurements indicate a direct bandgap of ≈ 1.85 eV for the BaZrS3 films and ≈ 2.1 eV for the BaHfS3 film under investigation.

Production of GeOx Films at Different Oxygen Flow Rates and Different Annealing Temperatures and Examination of Energy Band Gaps using Kubelka Munk Method

In this study, GeOx films were grown on silicon substrates using the Radio Frequency (RF) Magnetron Sputtering method at different oxygen flow rates and annealing temperatures. The films were produced at a substrate temperature of 250°C and a working pressure of 13 mTorr. Subsequently, the films were annealed at temperatures of 300°C, 500°C, 600°C, 700°C, 900°C, and 1000°C. Total and diffuse reflection measurements were performed to investigate the optical properties of the films. Energy band gaps were determined using diffuse reflection measurements and they were calculated using the Kubelka-Munk method. It was observed that the energy band gap increased with increasing oxygen ratio. Additionally, annealing temperatures were found to cause changes in the energy band gaps.

Orientation of Co2+ and Cu2+ ions introduced L-type zeolite observed with a magnetic field

L-type zeolite with Co2+ and Cu2+ ions in 3d-transition-metal ions were prepared via ion exchange. The suspension containing these zeolite was used for slip-casting under a 12 T magnetic field applied perpendicular to the substrate surface, resulting in an orientation parallel to the c-axis for Co-L and an orientation vertical to the c-axis for Cu-L. The orientation behavior was strongly affected by the magnetocrystalline anisotropy of the L-type zeolite introduced by Co2+ and Cu2+ ions. X-ray absorption fine structure and diffuse-reflectance measurements indicated that the introduced Co2+ and Cu2+ ions formed six-coordinated hydration complexes in the zeolite structure. These hydrated complexes have a distorted octahedral structure. The results suggest that the stable direction of the magnetic moment of the hydration complex at site B of L-type zeolite depends on the strain direction. The Co2+ and Cu2+ hydration complexes have different strain directions, and the difference in orientation is speculated to be due to the different stable directions of the magnetic moment within the zeolite.

Characterization of polycrystalline bulk ferroelectric ZnSnS3 synthesized by hydrothermal method for photovoltaic application

ZnSnS3, a newly theoretically predicted ferroelectric material which shows promising properties for solar cell and photovoltaic applications, was successfully grown in our laboratory by hydrothermal method. The high intensity x-ray diffraction pattern from the (211), (101̅), (200), (210), (310), (320), and (321̅) planes reveal the crystalline character of the trigonal ZnSnS3 phase. The microstructural property and elemental distribution were evaluated using SEM and TEM studies. Diffuse reflectance measurement at room temperature shows a direct bandgap of 2.62 eV along with a high energy direct transition of 3.13 eV. Two broad photoluminescence peaks at various temperatures (4–300 K) were also detected around (2.61–2.73 eV) and (3.04–3.11 eV). The emission characteristics are explained considering the shallow donor level to valence band transitions. Raman study elucidates that the synthesized ZnSnS3 possess a good number of Raman active bands. A phase transition from the ferroelectric to non-ferroelectric phase of ZnSnS3 is observed around 330 °C in DSC and dielectric measurements. The P-E measurement showed that the material is ferroelectric in nature with saturation polarization value of 21.85μC/cm2. The current-voltage characteristics showgood photovoltaic response of the fabricated Ni/ZnSnS3/Ni device in the visible range indicating its application in PV devices and photodetector.

Optimization of structure, optical, magnetic, and radiation shielding properties of ZnO@xSrFe12O19 nanocomposites

In this work, the pristine ZnO, SrFe12O19 (SFO), and their nanocomposites (ZnO/x SFO: x = 1, 3 and 5%) were synthesized by co-precipitation and sonomechanical method. The x-ray diffraction data validate the preparation of ZnO, SFO, and nanocomposite samples with high phase purity. The optical band gap was calculated from UV–vis-NIR diffuse reflectance measurements, and it was modified by increasing SFO content. Adding 1, 3, and 5 wt% of SFO to the ZnO matrix showed ferromagnetic characteristics for the nanocomposites with a squareness ratio of around 0.49, which considered these nanocomposites as a magnetic semiconductor suitable for digital memory and spintronic applications. Additionally, the radiation shielding features of the prepared samples were evaluated. The shielding parameters for the studied samples were obtained using the Phy-X/PSD program. The fast neutron removal cross-section of SFO was 0.094 cm−1, the highest among the investigated samples, while the composites had similar values, about 0.083 cm−1. The results indicated that the γ--ray attenuation ability and the values of exposure buildup factor for the prepared samples were close. Therefore, ZnO, SFO, and their nanocomposites compared to stationary shielding materials (SMs), can be candidates for applications where radiation protection is needed.

Dependency of crossover point on absorption changes in bilayer diffusion reflection measurements.

A better understanding of diffusion reflection (DR) behavior may allow it to be used for more noninvasive applications, including the development of in vivo non-damaging techniques, especially for medical topical diagnosis and treatments. For a bilayer opaque substance where the attenuation of the upper layer is larger than the attenuation of the lower layer, the DR crossover point ( ) is location where the photons coming from the bottom layer start affecting the DR. We aim to study the dependency of the on absorption changes in different layers for constant scattering and top layer thickness. Monolayer and bilayer optical tissue-like phantoms were prepared and measured using a DR system. The results were compared with Monte Carlo simulations. There is an agreement between the experiments and the simulations. correlates with the square root of the absorption coefficient ratio of the lower layer to the top layer. The experimental findings support and validate the theoretical prediction describing the dependency of the on the square root of the ratio of the layers' absorption coefficients. In addition, a secondary breaking point is suggested to be observed experimentally at the entrance to the noise area.

Flux Crystal Growth, Structure, and Optical Properties of LiLa3Ti2S3O6: An Oxysulfide Phase Derived from K2NiF4-Type Structure.

Single crystals of a new titanium oxysulfide, LiLa3Ti2S3O6, were grown from a KI molten salt. Single-crystal X-ray diffraction analysis revealed that LiLa3Ti2S3O6 crystallizes in the space group Pnma with lattice parameters of a = 11.7319(4) Å, b = 3.94787(14) Å, and c = 20.6885(6) Å. In this structure, the one-dimensional chains of corner-sharing TiO5S octahedra are further corner-linked via equatorial and apical oxygen atoms to form unique corrugated two-dimensional perovskite-type layers in the ab plane with one octahedral thickness. These layers were intervened along the c-axis by the LaS rock-salt layers corrugated concomitantly with the perovskite-type layers, and LiO2S2 tetrahedral chains were located between these two types of two-dimensional layers. LiLa3Ti2S3O6 can be viewed as a modified K2NiF4-type structure with TiO5S octahedral layers stacked in a zigzag manner along the c axis. The oxysulfide has a direct-type band gap of 1.85 eV, based on UV-vis-NIR diffuse reflectance measurements. First-principles calculations showed that the conduction band minimum mainly consists of Ti 3d orbitals, and the valence band maximum consists of S 3p, O 2p, and Li 2s orbitals. The electronic structures near the Fermi level are similar to those of the structurally related photocatalytic oxysulfides Y2Ti2S2O5 and La5Ti2CuS5O7.

A non-contact solid particle moisture sensor based on near-infrared spectroscopy technology

The detection of moisture content in solid particles has important applications in fields such as biological research, coal mine production, and medicine. This article develops a non-contact solid particle moisture sensor (NcSPMS). NcSPMS uses the multi-light source detection method based on the principle of diffuse reflection absorption to detect the moisture content of solid particles with different particle sizes, distributions and colors. Firstly, the stacked LED light source structure (SLED-LSS) was designed to achieve illumination of LED light source for measurement (M-LED) and the LED light source for reference (R-LED) at the same position and exit angle, eliminating the influence of irregular particle size and distribution on diffuse reflected light intensity. Secondly, the stacked LED array light source structure (SLEDA-LSS) was designed to improve the detection light intensity and enable NcSPMS to detect the moisture content of solid particles of different colors. Thirdly, modulated light technology is used for the transmission of moisture content information. Two modulation frequencies were set to modulate the measurement light source and reference light source, and different intensities of square wave currents were determined to drive the M-LED and R-LED to improve detection accuracy. Fourthly, the FFT-KF data processing method was designed to effectively extract the information of diffuse reflection measurement light intensity. Finally, the function expression of moisture content was obtained through cubic fitting, and the detection of moisture content by NcSPMS was achieved. In order to verify the effectiveness of NcSPMS, the NcSPMS control system was designed. The experimental results show that compared with SLED-LSS, SLEDA-LSS improves measurement accuracy; the different current pairs driving M-LED and R-LED affect the measurement accuracy of NcSPMS; NcSPMS can detect the moisture content of white, yellow, green, red, and black sand particles, with the detection range of 0.10–11.00 %. The relative uncertainty obtained by applying NcSPMS to the detection of nickel ore particles is 4.37 %.

Enhancement of visible-light photocatalysis of TiO2 via nanocomposite incorporating with Fe(III) species

This paper introduces a novel approach for the synthesis of photocatalytic nanocomposites via a fast reaction occurring at ambient conditions between the strong base NaOH and FeCl3 solution to obtain a fresh precipitate of Fe(OH)3 in the presence of TiO2 nanoparticles. FE-SEM analysis revealed a restructured state of TiO2 particles on the surface of colloidal Fe(OH)3. Solid-phase studies, including XRD and FT-IR, indicated a phase transformation from Fe(OH)3 to γ-Fe2O3 during the formation of the nanocomposite. UV–Vis diffuse reflectance measurements confirmed a significant reduction in the band gap of the synthesized composite, indicating its potentials as a photocatalyst under visible light irradiation. Another advantage of this composite type is its rapid sedimentation ability within minutes, facilitating post-processes such as phase separation and catalyst reuse on a large scale, which are challenging in the case of TiO2 nanoparticles. Inducing photocatalysis under visible light, the efficiency in degrading persistent colorants was demonstrated through a case study of indigo carmine (IC), which exhibited a threefold improvement in degradation efficiency for the case of the nanocomposite compared to the original TiO2. Indeed, the IC degradation process was studied in consideration of various factors such as Fe/Ti ratio in the catalyst, illumination time, colorant concentration, catalyst dosage, and pH of the environment. Additionally, mineralization studies confirmed the oxidation of IC to CO2 rather than the formation of potentially toxic intermediates. Furthermore, the stability of the catalyst was examined through six cycles of reuse.

Parameters of differential equations in four-flux and two-flux models approximated for scattering and absorption results on solar thermal collector black paints

Abstract The intrinsic and extrinsic scattering and absorption coefficients of a thin black paint substrate used as a solar thermal collector, deposited on a thick glass substrate, were obtained in an approximated single-layer method, using the new solved equations recently determined from the collimated and diffuse differential equations of the four-flux model, for the intrinsic coefficients, and considering the differential equations of the two-flux model with total light intensities, for the extrinsic coefficients. In a first step, the optical constants were determined from the measurements of regular transmittance and specular reflectance, fitting them to the collimated transmittance and reflectance solutions of the four-flux model. In a second step, the intrinsic coefficients were obtained from the diffuse transmittance and reflectance measurements, considering four forward scattering ratios (for collimated and diffuse light intensities and for forward and backward light directions) and two average crossing parameters (for forward and backward light directions). In a third step, the extrinsic coefficients were obtained, using the new solved equations recently determined considering the total differential equations as the sum of the collimated and diffuse differential equations. Due to the approximated single-layer method, a simple rule of three was applied to the intrinsic and extrinsic results, relating the extinction coefficients calculated from the optical constants to those calculated from the collimated differential equations. The same external and internal diffuse interface reflectance was observed by integrating the collimated interface reflectance up to the critical angle of total internal reflection.

Optimization of Electrospray Deposition Conditions of ZnO Thin Films for Ammonia Sensing.

This study focuses on the influence of electrospray deposition parameters on the morphology, topography, optical and sensing properties of ZnO films deposited on gold electrodes of quartz crystal resonators. The substrate temperature, precursor feed rate and emitter's voltage were varied. Zinc acetate dehydrate dissolved in a mixture of deionized water, ethanol and acetic acid was used as a precursor. The surface morphology and average roughness of the films were studied by scanning electron microscopy (SEM) and 3D optical profilometry, respectively, while the optical properties were investigated by diffuse reflectance and photoluminescence measurements. The sensing response toward ammonia was tested and verified by the quartz crystal microbalance (QCM) method. The studies demonstrated that electrospray deposition parameters strongly influence the surface morphology, roughness and gas sensing properties of the films. The deposition parameters were optimized in order for the highest sensitivity toward ammonia to be achieved. The successful implementation of the electrospray method as a simple, versatile and low-cost method for deposition of ammonia-sensitive and selective ZnO films used as a sensing medium in QCM sensors was demonstrated and discussed.

Optical and dielectric features of PVC/ZnCo2O4/MWCNTs/TBAI polymers for optoelectronic and energy storage applications

Zinc cobalt oxide is considered a highly desirable substance for use in a wide range of applications, particularly supercapacitors. In this study, polyvinyl chloride/zinc cobalt oxide/multi-walled carbon nanotubes/x wt % tetrabutylammonium iodide (PVC/ZnCo2O4/MWCNTs/x wt % TBAI) composite polymers were fabricated using casting and hydrothermal approaches. The resulting composites were then analyzed to determine their structure, optical properties, and dielectric characteristics. The structure of ZnCo2O4 and PVC/ZnCo2O4/MWCNTs/x wt.% TBAI were studied using the X-ray diffraction technique. The morphologies of doped polymer were investigated using SEM technique. The impact of ZnCo2O4/MWCNTs/x wt.% TBAI filler samples on the linear and nonlinear optical properties of PVC polymer has been analyzed through UV diffused reflectance measurements. The doped samples could serve as effective shields against ultraviolet radiation across different wavelengths (UVA, UVB, UVC) and a highly effective material for absorbing solar energy in solar cells. The lowest optical energy gap values are attained (3.77, 3.03) and (3.32, 2.55) eV for the direct and indirect optical band gaps in PVC/ZnCo2O4/MWCNTs/3 wt% TBAI polymer, respectively. The largest refractive index value at 600 nm was observed in the doped polymer with 6 wt% TBAI. The fluorescence emission spectra and dielectric properties of the PVC/ZnCo2O4/MWCNTs/x wt.% TBAI polymers are also studied. The highest electrical dielectric constant was achieved in the ZnCo2O4/MWCNTs/9 wt% TBAI polymer. It follows that the PVC/ZnCo2O4/MWCNTs/x wt % TBAI has the ability to open up new possibilities for use in optoelectronic devices.

The SPECTRAL Perfusion Arm Clamping dAtaset (SPECTRALPACA) for video-rate functional imaging of the skin

Spectral imaging has the potential to become a key technique in interventional medicine as it unveils much richer optical information compared to conventional RBG (red, green, and blue)-based imaging. Thus allowing for high-resolution functional tissue analysis in real time. Its higher information density particularly shows promise for the development of powerful perfusion monitoring methods for clinical use. However, even though in vivo validation of such methods is crucial for their clinical translation, the biomedical field suffers from a lack of publicly available datasets for this purpose. Closing this gap, we generated the SPECTRAL Perfusion Arm Clamping dAtaset (SPECTRALPACA). It comprises ten spectral videos (∼20 Hz, approx. 20,000 frames each) systematically recorded of the hands of ten healthy human participants in different functional states. We paired each spectral video with concisely tracked regions of interest, and corresponding diffuse reflectance measurements recorded with a spectrometer. Providing the first openly accessible in human spectral video dataset for perfusion monitoring, our work facilitates the development and validation of new functional imaging methods.

TiO2 multi-leg nanotubes for surface-enhanced Raman scattering

Abstract In the recent past, significant research efforts have been put forth to fabricate cost-effective substrates for surface-enhanced Raman scattering (SERS) applications. Here we propose semiconducting TiO2 multi-leg nanotubes and Au nanoparticle-coated TiO2 multi-leg nanotubes (TiO2 MLNTs and Au/TiO2 MLNTs) as SERS substrates. The unique multi-leg architecture of TiO2 nanotubes demonstrated enhanced light-harvesting properties facilitated by an induced photonic absorption edge. Remarkable high SERS sensitivity is observed towards the detection of Methylene blue (MB), up to nM concentration (E.F. ∼104) using TiO2 MLNTs. The same is attributed to the resonantly matched photonic absorption edge of TiO2 MLNTs with the wavelength of incident laser probe light. On the other hand, the Au nanoparticle coating further leveraged the light absorption ability of TiO2 MLNTs with the aid of localized surface plasmon resonance mode. As such, Au/TiO2 MLNTs showed excellent enhancement in SERS sensitivity (E.F. ∼105 , for nM of MB) facilitated by the synergy between the plasmonic modes of Au and the photonic absorption mode of TiO2 MLNTs. UV-Vis diffuse reflectance and Raman spectroscopy measurements are highlighted to elucidate the light absorption and SERS sensitivity of the TiO2 and Au/TiO2 MLNTs.

Fabrication and adapting the optical, and dielectric performance of PVC/ MnFe2O4/ZnMn2O4 nanocomposite films for optoelectronic applications

The current study focuses on the fabrication of hybrid flexible polymers composed of MnFe2O4/ZnMn2O4 nanocomposites doped polyvinyl chloride (PVC). The doped polymers show great potential for utilization in a wide range of optoelectronics applications. PVC/(1-x)MnFe2O4/xZnMn2O4 were made using the casting and sol gel processes. The effect of (1-x)MnFe2O4/xZnMn2O4 nanocomposite samples on the optical parameters of PVC polymer has been explored using ultraviolet–visible diffused reflectance measurements. Doped polymers might be useful as protective barriers against ultraviolet radiation of various wavelengths (UVA, UVB, UVC) and as excellent absorber materials for solar cells. The direct and indirect bandgaps (Eg) of PVC are 4.26 and 4.08 eV. The direct/indirect optical band gap lowered to their lowest 3.97/3.45 eV as the PVC doped with nanofillers contained 50 %/80 % ZnMn2O4, respectively. Different models were used to extracted the refractive index (n) of different polymers based on the obtained optical band gaps (direct/indirect). Doped polymers containing 50 and 80 % ZnMn2O4 had the highest n values using direct and indirect Eg values, respectively. The n value (obtained from the direct optical bandgap energy) of PVC increased from 2.209 to the maximum value (2.262) as x = 0.5. The n value (obtained from the indirect optical bandgap energy) of PVC increased from 2.349 to the maximum value (2.367) as x = 0.8. All linear and nonlinear optical parameters of PVC polymer were improved as it doped with the nanocomposite fillers. The fluorescence (FL) intensity of PVC was reduced as it was doped with (1-x)MnFe2O4/xZnMn2O4 and this intensity reduced as the content of ZnMn2O4. The standard (CIE) color space chromaticity diagram was used to analysis the FL spectra for different samples. The effect of nanocomposite samples on the AC conductivity, dielectric constants and electric modulus of the PVC was studied. At 1 kHz, the dielectric constant of PVC was increased from 11.745 to 12.906 and 12.096 for polymers with x = 0 and x = 0.2, respectively. The enhanced optical and dielectric properties of the PVC/(1-x)MnFe2O4/xZnMn2O4 polymers nanocomposites suggest that these materials are suitable for smart electronic devices.

Realization of new n = 3 and n = 4 Dion-Jacobson layered perovskite series with interlayer K+ ions and perovskite blocks stabilized by Pr3+ ions

The structural flexibility of the perovskite blocks in the Dion-Jacobson family of layered perovskite oxides has successfully resulted in the generation of KPrNan-2NbnO3n+1 and KPrCan-2Nb2Tin-2O3n+1 (n = 3, 4). The stabilization of K+ ions preferring a six coordination in the interlayer region is significant compared to the facile formation of layered perovskite oxides possessing bigger Rb+ or Cs+ ions with an eight coordination in the interlayer. The structure of the n = 3 members, KPrNaNb3O10 (S. G. Cmcm; a = 3.8858(1) Å, b = 29.6553(9) Å, c = 7.7635(3) Å) and KPrCaNb2TiO10 (S. G. Cmcm; a = 3.8634(2) Å, b = 29.4808(2) Å, c = 7.6945(5) Å) were confirmed respectively using the Rietveld and Le Bail methods utilizing the powder X-ray diffraction data. The n = 4 members, KPrNa2Nb4O13 and KPrCa2Nb2Ti2O13 are synthesized through high-temperature ceramic methods. The compounds are phase pure as confirmed from the X-ray diffraction data and were characterized by UV–visible diffuse reflectance measurements. These two-dimensional oxides also undergo facile topochemical ion-exchange and intercalation reactions and opens up several interesting possibilities. We have replaced the K+ ions in the interlayer by H+, Li+, Na+ ions and [CuCl]+ groups through low temperature reactions. The usefulness of various Dion-Jacobson layered perovskite oxides for potential photocatalytic applications has been explored by determining the optical band gaps, the valence band, and the conduction band energy levels based on the UV–visible diffuse reflectance measurements.

Fabrication and evaluation of a spatially resolved fiber-optic probe for diffuse reflectance measurement for noninvasive diabetic foot ulcer diagnosis perspective

Fabrication and evaluation of a spatially resolved fiber-optic probe for diffuse reflectance measurement for noninvasive diabetic foot ulcer diagnosis perspective

In-Line Chemical Composition Monitoring for the Injection Molding Process of Biodegradable Polymer Blends Using Simultaneous Measurement of Near-Infrared Diffuse Reflectance and Transmission Spectra.

In the processing of polymer blends and composites, in-line near-infrared (NIR) spectroscopy enables monitoring of the composition and its composite uniformity and contributes to rapid process development and quality control. However, in the injection molding process, the study of the composition of polymer materials has been delayed due to high-pressure conditions. Our research group developed NIR probes for transmission and diffuse reflectance measurements that can withstand high-pressure and temperature conditions up to 130 MPa and 200 °C. In this research, transmission and diffuse reflectance spectra were measured inline during the injection molding process of polymer blends of poly(lactic acid) and polybutylene succinate adipate. The intensity of each polymer band in the second-derivative spectra exhibited a monotonic increase or decrease in response to changes in the blend ratio. Using transmission and diffuse reflectance spectra as explanatory variables of the partial least squares regression model simultaneously, the model showed high estimation accuracy for the entire region of the blend ratio. Finally, this model was applied to monitor the polymer changeover operation, and the change in the blend ratio in the molded product was successfully estimated in line.

Intensification of organic pollutant degradation under visible light irradiation using ZnO nanostructured photocatalysts doped with praseodymium

Zinc oxide nanostructures doped with praseodymium (ZnO:Pr) at varying Pr content (0.05 % to 1.0 % w/w) were synthesized using the electrospinning-calcination technique. Comprehensive morphological and structural characterizations were conducted through SEM, XRD, and XPS analyses. In addition, diffuse reflectance and photoluminescence spectroscopy measurements were performed to assess the optical properties of materials. The produced photocatalysts (ZnO:Pr) were then employed for the degradation of methylene blue dye and oxytetracycline under visible-light irradiation. ZnO:Pr(0.1 %) demonstrated the best photocatalytic performance against methylene blue showing a pseudo-first-order rate constant of k = 3.630 × 10-2 min−1. Investigation of oxytetracycline photodegradation with ZnO:Pr(0.1 %) revealed a pseudo-second-order rate constant of ks = 1.165 × 10-1 L mg−1 min−1, resulting in a reaction half-life (τ½) of approximately 1 min under optimal conditions. Total organic carbon and mass spectrometry analyses highlighted mineralization and identified the main reaction intermediates, respectively, for the oxytetracycline photodegradation. The photodegradation mechanism of oxytetracycline was proposed by the photocatalytic degradation measurements in the presence of scavengers such as hydroquinone and isopropanol. These nanostructures exhibited robust photocatalytic activity over multiple cycles, demonstrating excellent stability. This study underlines the promising potential of ZnO:Pr(0.1 %) as an efficient photocatalyst able to intensify the photodegradation of organic pollutants.