UV Light Research Articles

Enhanced UV photodetector performance using sputtered Mg-doped ZnO thin film

In this article, we demonstrate UV photodetector synthesized using Mg-doped ZnO thin film (TF) (10 % Mg) grown on a p-Si substrate using the radio frequency (RF) magnetron sputtering system. The fabricated MgZnO TF was annealed at 500 °C in air resulting in notable changes in morphology, optical band gap and crystallinity that significantly improved the UV light sensitivity. The annealed device (MgZnO TF/p-Si) exhibited a remarkable 155-fold increase in photocurrent density compared to the as-deposited device at + 2 V bias. Also, at the same bias the annealed device (500 °C) exhibited high photosensitivity (up to 1262 times), responsivity (20.32 A/W), specific detectivity (1.82 × 1013 Jones) and external quantum efficiency (EQE) (7745 %) in comparison to the as-deposited device. Additionally, the 500 °C device achieved a low noise equivalent power (NEP) of 0.07 × 10−12 W which is about 262 times lower than that of the as-deposited device (18.4 × 10−12 W). Furthermore, on UV illumination (λ = 325 nm) the MgZnO TF/p-Si (500 °C) detector showed fast device response with rise time/fall time values of 0.26 s/0.25 s respectively at + 2 V applied bias.

Photoinduced Onand OffPolymeric Room Temperature Phosphorescence Based On Polycyclic Aromatic Hydrocarbon Isomers.

As family members of polycyclic aromatic hydrocarbons, compound anthracene (Ant) and phenanthrene (Phe) as isomers are widely used in organic optical materials and electronic materials. But their photochemical and physical properties are very different. In this work, the room temperature phosphorescence (RTP) properties of PVA-B-Ant and PVA-B-Phe are discussed carefully which are prepared by B-O click reaction through polyvinyl alcohol (PVA) with 9-anthraceneboronic acid (B-Ant) and 9-phenanthrenylboronic acid (B-Phe), respectively. PVA-B-Phe 1%film exhibits excellent fluorescence (FL) emission at 374 nm and RTP emission at 523 nm with green afterglow and around 1.9 s phosphorescence lifetime. However, PVA-B-Ant 1% film only shows strong blue FL emission at 414 nm, and the emission intensity decreases seriously with the extension of irradiation time. Experimental and theoretical calculations results suggest that the photodimer of Ant which is formed in PVA matrix under the UV light irradiation would be competitive with the process of RTP emission. This work demonstratesthat the RTP properties of organic molecules might be probably affected by the photostability of the organic phosphor under UV irradiation.

Highly enhanced photocatalytic hydrogen production via GO-modified Cu-TiO2 system for dehydrogenation of alcohols under UV & sunlight irradiation

The high efficiency of the production of hydrogen from alcohols is vital to the advancement of energy technology. This study thoroughly investigates the process of alcohol dehydrogenation utilising GO-modified Cu-TiO2 photocatalyst under UV light and sunlight exposure. GO-modified Cu-TiO2 photocatalyst was synthesised using the hydrothermal method. Various experimental techniques, including FESEM, HRTEM, XPS, and DRS, confirmed the formation of the ternary composite. The influence of different alcohols (methanol, ethanol, propanol) and their concentrations (same vol% and molarity) on the amount of hydrogen (H2) production was examined in this study. The study thoroughly investigated the impact of various parameters, such as the influence of GO and Cu loading on TiO2 and their combined effect, time course, nature of alcohol and the reaction conditions on the photocatalytic hydrogen production. The GO(0.5 wt%)/Cu(3 wt%)-TiO2 (G0.5C3T) composite demonstrated the highest quantity of hydrogen production during methanol dehydrogenation when subjected to both UV and sunlight irradiation. The composite exhibited remarkably about three-fold higher hydrogen evolution in sunlight(881 mmol) than in UV light(294 mmol). The exceptional performance of this composite can be attributed to the efficient transfer of charge carriers and the delayed recombination of electron-holes, which is a result of the cooperative effect of GO and Cu deposited over the TiO2 system. This approach offers a proactive strategy, signifying the synergetic effect of loading GO and Cu over TiO2 to enhance the photocatalytic hydrogen production, which is regarded as a green fuel solution, and turns these materials into useful energy sources by using inexpensively synthesised photocatalysts.

Kinetic Study of the Water Quality Parameters during the Oxidation of Diclofenac by UV Photocatalytic Variants

Diclofenac (DCF, C14H11Cl2NO2) is a widely used non-steroidal anti-inflammatory drug, with a significant occurrence in waste effluents. DCF is especially persistent and difficult to degrade, with numerous toxic effects on aquatic fauna and humans. In 2015, DCF was identified as a priority pollutant (EU Directives on water policy). In this work, UV irradiation and its combination with hydrogen peroxide only or catalyzed by iron salts (photo-Fenton) are analyzed to find the most efficient alternative. DCF aqueous solutions were treated in a stirred 150 W UV photocatalytic reactor. Depending on the case, 1.0 mM H2O2 and 0–5.0 mg/L Fe2+ catalyst, such as FeSO4, was added. During the reaction, DCF, pH, turbidity, UVA at 254 and 455 nm, dissolved oxygen (DO), and TOC were assessed. The degradation of DCF yields a strong increase in aromaticity because of the rise in aromatic intermediates (mono-hydroxylated (4-hydroxy-diclofenac and 5-hydroxy-diclofenac) and di-hydroxylated products (4,5-dihydroxy-diclofenac), which subsequently generate compounds of a quinoid nature), which are very stable and non-degradable by UV light. Thus, only if H2O2 is added can UV completely degrade these aromatic colour intermediates. However, adding ferrous ion (photo-Fenton) the aromaticity remains constant due to iron com-plexes, that generates maximum colour and turbidity at an stoichiometric Fe2+ : DCF ratio of 3. As a result of the study, it is concluded that, with UV light only, a strong yellow colour is generated and maintained along the reaction, but by adding H2O2, a colourless appearance, low turbidity (<1 NTU), and [DO] = 8.1 mg/L are obtained. Surprisingly, photo-Fenton was found to be unsuitable for degrading DCF.

Salmonella Inactivation Model by UV-C Light Treatment in Chicken Breast.

This study aims to evaluate the effectiveness of inactivating Salmonella enteritidis in fresh chicken breast by irradiation using a combination of short-wave UV (0, 3, 6, 9, 12, and 15 J/cm2) and a natural antimicrobial such as caffeine (0, 5, 10, 15, and 20 nM/g) at 14 °C as alternative proposals to conventional techniques to reduce pathogens in food. The effect of temperature was studied in an initial phase (2 to 22 °C). The most suitable models were double Weibull in 60% of cases, with an adjustment of R2 0.9903-0.9553, and Weibull + tail in 46.67%, with an adjustment of R2 of 0.9998-0.9981. The most effective combination for the reduction in Salmonella was 12 J/cm2 of UV light and 15 nM/g of caffeine, with a reduction of 6 CFU/g and an inactivation rate of 0.72. The synergistic effect was observed by increasing caffeine and UV light. Furthermore, the physico-chemical characteristics of the food matrix were not affected by the combination of both technologies. Therefore, these results suggest that this combination can be used in the food industry to effectively inactivate Salmonella enteritidis without deteriorating product quality.

Impact of laser interaction on morphological and mechanical properties of palladium thin film

This research work investigates surface morphology, plasma plume intensity and the hardness of palladium thin film deposited on silicon substrates under the action of laser light. For this purpose, a pulsed Nd:YAG laser (1064 nm, 10 mJ, 12 ns) was used to irradiate the specimen with repetitive laser pulses. The experiment was repeated under the illumination with UV light. The surface morphology of the specimens was examined through an Optical and Field-Emission Scanning Electron Microscopy showing thermal conduction, exfoliation, crater formation, re-deposition of the material, ripples formation, debris, heat-affected zone, holes formation and the formation of nanoparticles. The diameter and the depth of the crater formed on non-UV illuminated Pd thin film were greater than the crater formed on UV illuminated Pd thin film, because of its higher absorption. The photographs of the plasma plume were captured with a computer-controlled image capture system and examined by image processing software. The intensity of UV-illuminated Pd thin film was higher than non-UV illuminated Pd thin film because UV illumination induces defects in the specimen that have additional electronic states. These defects cause higher absorption and more ionization of the target material and emerge a more luminous plasma plume. A nanoindentation test was applied on the material surface to investigate the mechanical properties such as hardness and elastic modulus of the target specimen. The hardness and elastic modulus of the material were increased by cumulative laser shots.

Azobenzene-based liposomes with nanomechanical action for cytosolic chemotherapeutic drug delivery

The stimuli-responsive nano-carriers are at the forefront of research in nanotechnology and materials science. These advanced systems are designed to alter their physicochemical properties upon exposure to specific stimuli, enabling controllable and targeted delivery of therapeutic agents. Nevertheless, limited endosomal escape reduces the drug bioavailability in clinical use. We herein report azobenzene (Azo)-based liposomes, prepared by co-assembling the photoisomerizable cationic Azo lipids and helper lipids, which achieve controllable doxorubicin (Dox) release and enhanced cytosolic transport upon light irradiation. Azo lipids undergo reversible isomerization between cis-isomers and trans-isomer when received UV and visible (Vis) light irradiation, causing liposomal membrane permeability changes for controlled drug release. Moreover, the nanomechanical action created by the isomerization of Azo lipids promotes the endosomal escape of the liposomes. DSPC-Azo liposomes, with minimal Dox leakage, showed significant tumor cell killing upon irradiation. For in vivo study, we co-encapsulated the upconverting nanoparticles (UCNPs), which can convert the near-infrared (NIR) light into UV/Vis emissions, facilitating Azo units activation. UCNP/Dox-loaded DSPC-Azo liposomes inhibited tumor growth under NIR irradiation in a 4T1 tumor-bearing mouse model.

Investigation of the performance and stability of self-powered polythiophene-based photodiodes under UV and visible light illumination

In this study, we fabricated polythiophene (PTh) and silver-decorated polythiophene (Ag@PTh) films on n-type silicon substrates using the electrochemical deposition method to investigate their electrical and photoelectrical properties in metal/interlayer/n-Si heterostructures under various conditions. The physical properties of the films were comprehensively investigated through UV-Vis, Raman, XPS and SEM analysis. The results from these analyses confirmed the successful deposition and formation of the films on the n-Si substrates. Additionally, a comparison of the current-voltage (I-V) characteristics of the PTh/n-Si and Ag@PTh/n-Si devices was conducted under both dark conditions and illumination with visible and UV light. While both devices exhibited typical rectifying diode behavior, the Ag@PTh/n-Si device demonstrated greater rectification with a RR of 2.49 x 105 at ± 2 V under dark conditions. In addition, the Ag@PTh/n-Si device, with self-powered property, displayed notably enhanced performance metrics, including a significantly higher ON/OFF ratio, responsivity, and detectivity, particularly evident under UV light illumination when compared to white light. Furthermore, to assess the long-term reliability of these devices, stability tests were conducted by repeating the I-V measurements after 90 days under identical conditions. The Ag@PTh/n-Si device exhibited considerably better stability over time than the PTh/n-Si device, maintaining consistent performance without notable degradation. So, in light of the findings, it can be concluded that the Ag@PTh/n-Si device has substantial potential for advancing optoelectronic technology.

Effects of mixing ratio on physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein and pea protein

Physicochemical, structural properties and application in lycopene-loaded emulsions of blends of whey protein isolate (WPI) and pea protein isolate (PPI) at varying mass ratios (100/0, 75/25, 50/50, 25/75, 0/100) were investigated. Data indicated that the mass ratios affected the physical, chemical and storage stability of the emulsion by influencing the particle size, zeta-potential, surface hydrophobicity, free sulfhydryl content, and secondary structure of the blends. Particularly, emulsion with a mixing ratio of 75/25 exhibited superior physical stability against salt concentrations (200 and 500 mM), better chemical stability against UV light and heat, and maintained stability over a 30-day storage period. Emulsions stabilized by blends of different ratios exhibited similar digestion behavior, with no significant differences observed in lycopene's transformation stability and bio-accessibility. Data indicated that substitution of whey protein by pea protein is effective in term of emulsifier application and replacement ratio is an important factor need to be considered.

Improving the power performance of microbial fuel cells using UV light

Improving the power performance of microbial fuel cells using UV light

Systematic literature review of acne vulgaris, its sophisticated treatment approaches, types, treatment and their side effects.

Background: Acne formation can be controlled effectively but it heals slowly and has numerous interactions with neuropeptides. Once gone another one pops up. Sometimes it can be filled with pus. Its size varies and can cause anxiety, depression, stress and social withdrawal. The mechanism is hyper secretion of sebaceous glands. Introduction: Acne vulgaris is a condition when hair follicles are accumulated with oil, dead cells and bacteria from skin. It can lead to formation of blackhead, whitehead, oily skin, pimples and scarring eventually. Patients have raised sebum level and thus skin is more prone to acne formation; triggered by propionibacterium, genetics, environment and food. Most commonly occurring on the face, upper limb and trunk between teen to middle age. Sebum contains wax esters, cholesterol, and triglyceride. Objectives: · To extensively explain the etiology of acne vulgaris, hormonal, bacterial causes and UV light. · To write comprehensive review on treatment of AV conventional, topical, retinoid and antibiotics based treatment. · Write a comprehensive review on its complications and its management. Methodology: In this research article we have explained systematic review, as well as we have described the systematic literature review of Acne Vulgaris, We did a literature search using electronic bibliographic databases and Journals : such as ELSEVIER ,British Medical Journals ,MEDLINE (Ovid SP and PubMed), EMBASE, The Cochrane Library (Cochrane Database of Systematic Reviews (CDSR), and Cochrane Central Register of Controlled Trials (CENTRAL), as well as annual meetings abstracts from inception till Oct 2024. The literature search has focused mainly on randomized clinical trials, Meta-analysis, phase II/III, and retrospective studies. Results and Conclusion: The review included 45 studies with a total of 12000 participants. Acne vulgaris affects 9% of the population worldwide, 85% are between 12-24 years. Characters such as age and sex may vary among different studies. Many papers demonstrate the effect of demographic factors. Reaching late teenage can decrease its prevalence, and eruption is higher in females compared to male. Topical retinoid and benzoyl per oxide were effective in reducing inflammatory and non-inflammatory lesions. For mild to moderate acne pharmacological treatment, chemical, antibiotic and photodynamic therapy are among most effective. Oral antibiotics while effective, have raised concerned about resistance. For moderate to severe, the most effective one is oral Isotretinoin and photodynamic treatment. Most of us already know too much about this topic. Its 8th commonest disease known globally. It has many treatments. It’s the cause of social withdrawal and depression. In this case it is important to know about the causes that shift non inflammatory to inflammatory ones. Dermatologists are trying their best in combination of multiple therapies to treat it successfully. Personalized treatment plans considering patient-specific factors, such as acne severity, patient preference and risk of adverse effects, are essential for optimal management.

Sericin-TiO2 nanocomposite treated cotton fabrics for enhanced antibacterial and self-cleaning properties

The valorization of industrial byproducts is rising as a new dawn and has become a creative area of research for the scientists. Sericin is being a good resource of starting materials since it can be recovered and recycled. The research aimed to modify cotton fabric by sericin-TiO2 nanocomposite (STNc) for enhancement its antibacterial and self-cleaning properties. STNc were prepared using tetraisopropylorthotitanate (TIOT) and sericin with proportions 2:1, 2:2 and 1:2. The obtained STNc possesses anatase phase of TiO2 nanoparticles having an average 22.9 nm particle sizes. The STNc coated cotton samples were prepared with three different weight fractions of STNc and citric acid (2:1:2, 2:2:1 and 1:2:2). The incorporation of STNc onto cotton fabric was examined by FTIR spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analyses. The antibacterial activity of STNc coated cotton fabrics was investigated against drug resistant bacterium viz. Staphylococcus aureus, Pseudomonas 4A and Escherichia coli. The STNc coated cotton fabric exhibited effective resistance against Escherichia coli and Staphylococcus aureus. The antibacterial properties of STNc coated cotton fabrics were depended with the fraction of STNc. The uncoated and STNc coated cotton fabrics were stained with coffee and then irradiated on sunlight for 0, 30, 60, 90 h and UV light for 2, 4, 6, 8, 10 h. A noticeable decrease in the coffee stain's appearance was observed after 90 h sunlight and 10 h UV light exposure for STNc coated cotton fabric. The reusability of photo exposed samples was evaluated by FTIR spectroscopy.

Fabrication of fluorinated superhydrophobic oil-absorption cabins with controllable movement, elasticity, and wear resistance

Superhydrophobic materials that can withstand harsh environments are critical in oil spills. Here, fluorinated superhydrophobic monoliths were prepared in one step based on a high internal phase emulsion (HIPE) templating method. γ-methacryloyloxypropyltrimethoxysilane (KH570)-modified Fe3O4 nanoparticles were added into the emulsion as co-stabilizers and participated in the composition of micro-nano hierarchical structures. The fluorinated alkyl backbone and rough structure enabled the foam to exhibit excellent superhydrophobicity with a water contact angle (WCA) of 153.5° and a sliding angle (SA) of 5.92°. The unique structure and composition of the foam allowed it to maintain stable superhydrophobicity (153.97°) even after severe sandpaper abrasion tests (Drawn 10 m at 7.1 kPa on P400 grit sandpaper). It also demonstrated exceptional hydrophobicity to strong acids, bases, and UV light. The oil-saturated material can be regenerated through a simple extrusion process, showing outstanding reusability. After ten cycles of oil adsorption, the adsorption capacity remains above 90 % of the initial value. The additional magnetic properties of the material enable it to remove oil in confined or hazardous conditions. More importantly, with the assistance of a vacuum pump, the material permits continuous separation of organic solvents from the water. These excellent properties of the foam make it a potential material for treating wastewater.

Enhancement of Pickering effect of ovalbumin with bacterial cellulose nanofibers prepared by electron beam irradiation and encapsulation of curcumin

In this study, the enhancement of Pickering effect of ovalbumin (OVA) with bacterial cellulose nanofibers (BCNFs) prepared by electron beam irradiation was investigated and the environmental stability of oil-in-water Pickering emulsions stabilized by OVA/BCNFs complexes was explored by varying ratios of OVA/BCNFS (1:0.2, 1:0.4, 1:0.6, 1:0.8, 1:1) and oil phase concentrations (10 %, 20 %, 30 %, 40 %, 50 %, 60 %). Droplet sizes of Pickering emulsions were decreased with the increase of the proportion of BCNFs, while the viscosity and storage modulus (G') of Pickering emulsions were increased. The gel strength of Pickering emulsions was positively correlated with the oil phase content. Pickering emulsions stabilized by OVA/BCNFs complexes were endowed excellent environmental stability under varying pH, ionic strength, and thermal conditions. Moreover, after encapsulating curcumin in Pickering emulsions, the retention rates of curcumin were improved significantly during room temperature, UV light, and thermal treatment. The present study would contribute to the advancement of novel protein/polysaccharide stabilizers and offer novel insight for investigating the stability of Pickering emulsions and delivering lipophilic bioactive compounds.

Physical radiation induced the yield of triterpenoids in hypha of Inonotus obliquus to increase

HSD-IO01, a new pure strain of I. obliquus, was isolated and purified from the sclerotium of I. obliquus of Daxing'an Mountains. Physical radiation-assisted liquid fermentation technology was explored to increase the triterpenoids yield of HSD-IO01. In the 100 mL optimized liquid fermentation system, the hypha dry weight of HSD-IO01 was 1.7734 g, and the triterpenoids yield was 43.43 mg. Yields of triterpenoids increased after induction with ultrasound, microwave, or UV light, respectively. Among them, ultrasonic treatment had the most remarkable induction effect. The yield of triterpenoids would be increased to 68.35 mg (57.38 %) when the HSD-IO01 was treated by 100 W ultrasonic for 45 min. Establishing ultrasonic-assisted liquid fermentation technology could further promote the detailed development and comprehensive utilization of I. obliquus resources.

Revolutionizing Tetracycline Hydrochloride Remediation: 3D Motile Light-Driven MOFs Based Micromotors in Harsh Saline Environments.

Traditional light-driven metal-organic-frameworks (MOFs)-based micromotors (MOFtors) are typically constrained to two-dimensional (2D) motion under ultraviolet or near-infrared light and often demonstrate instability and susceptibility to ions in high-saline environments. This limitation is particularly relevant to employing micromotors in water purification, as real wastewater is frequently coupled with high salinity. In response to these challenges, ultrastable MOFtors capable of three-dimensional (3D) motion under a broad spectrum of light through thermophoresis and electrophoresis are successfully synthesized. The MOFtors integrated photocatalytic porphyrin MOFs (PCN-224) with a photothermal component made of polypyrrole (PPy) by three distinct methodologies, resulting in micromotors with different motion behavior and catalytic performance. Impressively, the optimized MOFtors display exceptional maximum velocity of 1305±327µms-1 under blue light and 2357±453µms-1 under UV light. In harsh saline environments, these MOFtors are not only maintain high motility but also exhibit superior tetracycline hydrochloride (TCH) removal efficiency of 3578±510mgg-1, coupling with sulfate radical-based advanced oxidation processes and peroxymonosulfate. This research underscores the significant potential of highly efficient MOFtors with robust photocatalytic activity in effectively removing TCH in challenging saline conditions, representing a substantial advancement in applying MOFtors within real-world water treatment technologies.

Photodynamic therapy with NIR-II probes: review on state-of-the-art tools and strategies.

In 2022 10% of the world's population was aged 65+, and by 2100 this segment is expected to hit 25%. These demographic changes place considerable pressure over healthcare systems worldwide, which results in an urgent need for accurate, inexpensive and non-invasive ways to treat cancers, a family of diseases correlated with age. Among the therapeutic tools that gained important attention in this context, photodynamic therapies (PDT), which use photosensitizers to produce cytotoxic substances for selectively destroying tumor cells and tissues under light irradiation, profile as important players for next-generation nanomedicine. However, the development of clinical applications is progressing at slow pace, due to still pending bottlenecks, such as the limited tissue penetration of the excitation light, and insufficient targeting performance of the therapeutic probes to fully avoid damage to normal cells and tissues. The penetration depth of long-wavelength near infrared (NIR) light is significantly higher than that of short-wavelength UV and visible light, and thus NIR light in the second window (NIR-II) is acknowledged as the preferred phototherapeutic means for eliminating deep-seated tumors, given the higher maximum permissible exposure, reduced phototoxicity and low autofluorescence, among others. Upon collective multidisciplinary efforts of experts in materials science, medicine and biology, multifunctional NIR-II inorganic or organic photosensitizers have been widely developed. This review overviews the current state-of-the art on NIR-II-activated photosensitizers and their applications for the treatment of deep tumors. We also place focus on recent efforts that combine NIR-II activated PDT with other complementary therapeutic routes such as photothermal therapy, chemotherapy, immunotherapy, starvation, and gas therapies. Finally, we discuss still pending challenges and problems of PDT and provide a series of perspectives that we find useful for further extending the state-of-the art on NIR-II-triggered PDT.

Stability, release, and tyrosinase inhibition behaviors of kojic acid encapsulated in the interlayer space of layered yttrium hydroxide

Kojic acid (KA) is widely utilized in cosmetic formulations for skin brightening and as a food preservative to prevent oxidative browning in fruits and vegetables. However, its effectiveness is compromised by susceptibility to pH and temperature fluctuations, as well as oxidation after exposure to UV light. These limitations highlight the need for improvements to facilitate sustainable applications. In this study, KA was encapsulated within the interlayer space of layered yttrium hydroxide (LYH) through a two-step host-guest reaction involving dodecylsulfate and basic ethoxide anions. Examination of the X-ray diffraction (XRD) pattern of the resulting product (KA-LYH) revealed an expanded interlayer space from approximately 8.4 to 16.7 Å, conducive to a partially interdigitated bilayer arrangement of KA anions within the LYH interlayer. KA-LYH demonstrated significantly improved stability against light, heat, and oxygen compared to free KA, indicating effective confinement and protection of KA from photoreaction and oxidation in the interlayer space of LYH host. Minimal release of KA was observed in saline solution and simulated seawater, while sustained release occurred in a phosphate buffer solution even after 24 h. Notably, the KA released from the LYH interlayer space retained potent tyrosinase inhibition activity, showcasing the sustainable efficacy of KA-LYH under physiological conditions.

Controllable preparation of YPrO3 photocatalystvia sol-gel method with enhanced photocatalytic performance under ultraviolet light

In this work, an ultraviolet light-driven YPrO3 photocatalyst was successfully synthesized via the sol-gel method, utilizing yttrium nitrate hexahydrate (Y(NO3)3·6H2O) and praseodymium nitrate hexahydrate (Pr(NO3)3·6H2O) as the yttrium and praseodymium sources, respectively, with oxalic acid dihydrate (H2C2O4·2H2O) serving as an auxiliary solvent. In addition, the prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy(XPS), thermogravimetric and differential scanning calorimetry (TG-DSC), ultraviolet visible diffuse reflectance spectroscopy (UV VisDRS), and an electrochemical workstation. Also, the photocatalytic activity of YPrO3 samples was explored by using methyl orange (MO) solutionas a model pollutant to simulate wastewater under varying synthesis temperatures and illumination durations. The material with the highest degradation efficiency was subjected to cycling and recovery experiments to assess its stability. Furthermore, the photocatalytic mechanism of YPrO3 was investigated. Experimental results revealed that pure YPrO3 samples could be effectively synthesized at calcination temperatures ranging from 850 °C to 1000 °C, with the sample prepared at 900 °C exhibiting the optimal photocatalytic activity. This sample possessed an average grain size of 4–5 μm. Under UV light irradiation for 90min, the YPrO3 sampleprepared at 900°Cachieved approximately 80 % degradation of methyl orange at an initial concentration of 5 mg/L. After five consecutive cycles, the degradation rate remained as high as 70.39 %, with no change in the crystal structure, indicating excellent stability. The photocatalytic mechanism of YPrO3 was found to involve the synergetic effect of superoxide radicals and photogenerated holes in degrading pollutants. In conclusion, YPrO3could be a promising photocatalyst with excellent performance, holding broad application prospects.

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.