UV Visible Light Research Articles

Improving Blueberry Anthocyanins' Stability Using a Ferritin Nanocarrier.

Blueberries are fruits known for their high level of anthocyanins, which have high nutritional value and several biological properties. However, the chemical instability of anthocyanins is one of the major limitations of their application. The stability of blueberry anthocyanin extracts (BAEs) encapsulated in a ferritin nanocarrier was investigated in this study for several influencing parameters, including pH, temperature, UV-visible light, redox agents, and various metal ions. The outcomes supported the positive role of protein nanoparticles in enhancing the stability of blueberry anthocyanins by demonstrating that the stability of encapsulated BAE nanoparticles with ferritin carriers was significantly higher than that of free BAEs and a mixture of BAEs and ferritin carriers. This study provides an alternative approach for enhancing blueberry anthocyanin stability using ferritin nanocarrier encapsulation.

Synthesis and photocatalytic evaluation of 2D MoS2/TiO2 heterostructure photocatalyst for organic pollutants degradation

This study presents a successful method for synthesizing a 2D MoS2/TiO2 nanocomposite through hydrothermal synthesis. The amount of MoS2 in the composite was 5–10 wt% to optimize the heterojunction formation to enhance the photocatalytic degradation of the organic rhodamine under visible light. The prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDX), UV-diffuse reflectance spectroscopy (UV-DRS), and Fourier transforms infrared spectroscopy (FTIR) techniques. High-resolution TEM imaging confirmed the successful exfoliation of few-layer MoS2 nanosheets with lateral sizes ranging from 200 to 800 nm. Based on the results obtained, it was determined that the most effective loading of MoS2 was 5.0 wt% for achieving efficient rhodamine photodegradation under UV–visible light, outperforming both the ten wt. % MoS2 loading and pristine TiO2. The present study highlights the superior photocatalytic performance of the 5.0 wt% MoS2-TiO2 nanocomposite can be attributed to proper heterojunction formation and enhanced charge transfer leading to delayed recombination.

Supramolecular Chirogenesis in a Sterically Hindered Porphyrin: A Critical Theoretical Analysis.

Invited for the cover of this issue are the groups of Irina Osadchuk at Tallinn University of Technology and Mathias Senge at Trinity College Dublin. The image depicts how a porphyrin with two guest molecules (R)-camphor sulfonic acid is irradiated with UV-visible light to measure and simulate ECD and UV-Vis spectra. Read the full text of the article at 10.1002/chem.202301408.

Exploring the low cell adhesion of photoinduced superhydrophilic surfaces for improving the effect of antifouling protective coatings on porous building materials

The susceptibility of building materials to biological colonization is associated with accelerated decay processes, aesthetical alterations and health risks. Thus, preventive measurements involving the use of coatings with passive (bioreceptivity decrease) and active (biocides) antifouling mechanisms are common. Hydrophobic and superhydrophobic coatings that decrease water availability are the most common anti-fouling strategies, although they can promote cell adhesion under the right circumstances and lose effectiveness after the initial biofilm setting.In this work, we explore an innovative alternative strategy to improve the anti-fouling effect of a hydrophobic coating through surface modification to grant low cell-adhesion superhydrophilic properties (while preserving its low water absorption) and its combination with nano-biocides. This is achieved by the incorporation of Ag or CuO-modified TiO2 into an ormosil sol–gel matrix. Irradiation with UV–Vis light activates the superhydrophilic surface while maintaining a decrease in capillary water absorption of >90% and accelerated algal exposure tests showed a markedly lower colonization rate compared to the superhydrophobic surface, owing to the modifications in cell-water-surface interfacial tensions. The nano-biocides showed a dual effect, promoting the transition to superhydrophilic and further decreasing colonization. Furthermore, the superhydrophilic surfaces enhance the biocide effect by promoting the interaction of the nanoparticles with the surrounding media.

In-situ fabrication of TiO2-MWCNT composite for an efficient electron transfer photocatalytic rhodamine B dye degradation under UV–visible light

In this work, TiO2 nanoparticles with MWCNT composite have been prepared via an in-situ method. The structure, morphology, and optical properties of the catalysts were characterized by XRD, FT-IR, UV-DRS, SEM, and mapping analysis. The optimized TiO2-MWCNT composite shows better photocatalytic rhodamine B dye degradation under UV–Visible Light. This higher photocatalytic activity of TiO2-MWCNT composite is due to reduce the band gap and also MWCNT acts as an electron relay system to enhance the charge separation and reduce the recombination of electron and hole pairs. This result was further confirmed through photocurrent and impedance spectroscopy. In addition, the effect of some common inorganic anions was investigated and discussed. The degradation mechanism was investigated via radical scavengers' test and discussed. We Hope, this work can provide new ideas for the efficient photocatalytic degradation of organic dyes and beyond.

Ternary Heterostructures Based on BaTiO3/MoO3/Ag for Highly Efficient and Reusable Photocatalytic Applications

AbstractThis work shows the fabrication of an efficient ternary heterostructure photocatalyst by integrating ferroelectric BaTiO3 (BTO) as the bottom layer, semiconductor MoO3 as the middle layer and plasmonic silver nanoparticles (Ag NPs) as the top layer, respectively. The BaTiO3/MoO3/Ag (BMA) heterostructure exhibits a higher photodegradation and photocatalytic efficiency of 100% for rhodamine B (RhB) dye under a UV–Visible light illumination of 60 min when compared with its binary heterostructure counterparts BaTiO3/Ag (BA) and MoO3/Ag (MA). The increased photocatalytic activity in BMA heterostructure is attributed to its enhanced interfacial electric field due to the electric double layer formation at BTO‐MoO3 and MoO3‐Ag interfaces. The higher blueshift in the surface plasmon resonance (SPR) peak observed for the BMA heterostructure clearly indicates an increased electron transfer toward the top Ag NPs layer under optical illumination. The higher resistive switching (RS) ratio, the increased difference in voltage minima, and the improved photocurrent generation, as evident from the I–V characteristics, illustrate the enhanced charge carrier generation and separation in BMA heterostructure. A smaller arc radius observed for the Nyquist plot of BMA heterostructure clearly showcases its increased interfacial charge transfer (CT). The CT mechanism and reusability of the BMA heterostructure are also studied.

Withered magnolia-derived BCDs onto 3D flower-like Bi2WO6 for efficient photocatalytic TC degradation and CO2 reduction

The biomass-derived carbon quantum dots (BCDs, explored from the withered magnolia blossom) modified Bi2WO6 (Bi2WO6/BCDs) was prepared and used to remove the water contaminants. The biomass-derived carbon quantum dots-modified Bi2WO6 was synthesized by the unique hydrothermal technology and dialyzed method, showing excellent photocatalytic degradation activity of tetracycline and CO2 photoreduction performance. The Bi2WO6/BCDs showed a better tetracycline (TC) degradation efficiency than that of Bi2WO6 (49 %) under the visible light, when mass of BCDs was 15 μL. Additionally, photo-electrochemical measurements proved the separation efficiency of electron-holes of Bi2WO6 was enhanced, due to the great electron transmission ability and light absorption of BCDs. The mechanism experiment showed that ·O2- was the main activity specie in the TC photodegradation process. Meanwhile, the Bi2WO6/BCDs also showed higher CO2 photoreduction performance to CO (18.2 μmol/g) under UV–vis light than the pure Bi2WO6. The CO2 reduction mechanism also investigated by in-situ FTIR. The favorable photocatalytic performances make the waste biomass carbon act as a new resource of application to wastewater treatment and carbon recycling process.

Polyol Synthesis of Ag-Doped Copper Oxide Nanoparticles as a Methylene Blue-Degrading Agent

The use of metal oxide nanomaterials as photocatalysts for wastewater treatment has received significant attention in recent years due to their unique physicochemical properties. In this study, we use a polyol-mediated refluxing method to synthesize silver-incorporated copper oxide nanomaterials (Ag@CuO NMs). The use of tetra butyl ammonium bromide (TBAB) as a capping agent and ethylene glycol as a reducing agent for Ag+ to Ag is elaborated upon. The prepared Ag@CuO NMs were tested for their ability to degrade water pollutants, specifically methylene blue (MB) dye. Two different Ag contents, weights of 3% and 5%, were used to produce modified CuO-based nanomaterials. The crystalline structures of the NMs were characterized via XRD diffraction, and the morphology of the materials was investigated using FE-SEM. The optical properties were studied using UV-vis spectroscopy. The photocatalytic activity of the Ag@CuO NMs was evaluated by analyzing the degradation of MB dye when exposed to UV-visible light. Our results showed that the 5% weight Ag@CuO NM sample exhibited the most efficient degradation activity against MB dye. Therefore, these nanomaterials hold potential for photocatalytic applications, particularly for wastewater purification.

Preparation, Characterization, and Application of pH-Response Color-Changeable Films Based on Pullulan, Cooked Amaranth (Amaranthus tricolor L.) Juice, and Bergamot Essential Oil.

Pullulan-based smart packaging films were prepared by mixing cooked amaranth juice and bergamot essential oil. The impact of cooked amaranth juice and bergamot essential oil on the color-changeability, structural characterization, and barrier, antioxidant, mechanical and thermal properties of pullulan-based films was determined. Results showed the cooked amaranth juice contained pH-response color-changing betacyanins. The pullulan films containing cooked amaranth juice were color-changeable in pH 9-12 buffers and in ammonia vapor. The color-changeable property of betacyanins in cooked amaranth juice was unaffected by bergamot essential oils. The inner structure of pullulan films was greatly affected by cooked amaranth juice, forming big and ordered humps in film cross-sections. The crystallinity of pullulan films was improved by the combined addition of cooked amaranth juice and bergamot essential oil. Among the films, the pullulan film containing cooked amaranth juice and 6% bergamot essential oil showed the highest UV-vis light barrier property, antioxidant activity, and tensile strength; while the pullulan film containing cooked amaranth juice and 4% bergamot essential oil showed the highest oxygen barrier property and thermal stability. Moreover, the pullulan films containing cooked amaranth juice were able to monitor the freshness of shrimp by presenting color changes from reddish purple to dark red.

Construction of P-C3N4/C3N5 isotypic heterojunction for effective degradation of organic pollutants

BackgroundPhotocatalysis was an effective method for organic pollutant degradation, and graphitic carbon nitride g-C3N4 and g-C3N5 were famous two-dimensional semiconductors. Compared to the allotypic heterojunction, the band alignment and compatibility of isotypic heterojunction were superior. MethodsIn this work, an organic isotypic heterojunction was constructed via coupling phosphorus-doped C3N4 (P-C3N4) and g-C3N5. The characteristics were evaluated using transmission electron microscope, Fourier transform infrared, X-ray diffractometer, X-ray photoelectron spectrum, ultraviolet-visible (UV–vis) diffuse reflection spectrum, electronic spin resonance (ESR) analysis, photoluminescence spectrometer, electrochemical impedance spectroscopy, and photocurrent analysis. SignificantIsotypic heterojunction displayed high UV–vis light harvest, high separation efficiency of photo-induced charge carriers, and low surface resistance. Additionally, an internal-electric-field was established at the interface, which was beneficial for spatial separation of photo-induced charge carriers. As expected, the Rhodamine B (RhB) degradation efficiency was 7.3 and 12.3 times higher than that of the P-C3N4 and g-C3N5. Radical trapping experiment and ESR analysis indicated that •O2−, •OH, hole, 1O2, and electron played joint role in RhB degradation. In this work, a photocatalyst with excellent photocatalytic degradation properties was designed, and it provided a simple and novel strategy for environmental remediation.

Sustainable polylactide materials with the function of blocking a specific wavelength of light based on aloe-emodin

Polylactide, a biodegradable polymer, can alleviate white pollution, but the use of polylactide in food packaging is limited by high transmittance to light with a specific wavelength, UV (185–400 nm) and short-wavelength visible (400–500 nm) light. Herein, the polylactide end-capped with renewable light absorber aloe-emodin (PLA-En), is blended with commercial polylactide (PLA) to fabricate the polylactide film with the function of blocking light with a specific wavelength, PLA/PLA-En film. Only 40 % of light around 287 and 430 nm transmits through PLA/PLA-En film incorporating 3 mass% of PLA-En, while the film still maintains good mechanical properties and high transparency more than 90 % at 660 nm because of the good compatibility with PLA. The PLA/PLA-En film exhibits stable light-blocking properties under light irradiation and anti-solvent migration under the immersion of fat simulant. Almost no PLA-En migrated out of the film with the molecular weight of PLA-En only 2.89 × 104 g/mol. Compared with PLA film and commercial PE plastic wrap, the designed PLA/PLA-En film exhibits a better preservative effect on riboflavin and milk for inhibiting the production of 1O2. This study offers a green strategy for developing UV and short-wavelength light protective food package film based on renewable resource.

G-C3N4 stacked Co0.75Zn0.25Fe2O4 magnetically separable nano hybrids for intensified removal of methylene blue under UV–Visible light

Over the years, there has been a surge in interest in the use of photocatalysts for the removal of organic pollutants in wastewater. In this work, we report the successful fabrication of magnetic Co0.75Zn0.25Fe2O4/g-C3N4 nano hybrids for wastewater treatment. The produced photo catalysts were used to decompose methylene blue dye. SEM, elemental mapping, XPS, Raman, and UV-visible spectroscopy were used to validate the successful creation of the nanohybrid structure. The catalysts were synthesized in three different ferrite/graphitic carbon nitride ratios and employed for the optimization of maximum photo degradation efficiency against methylene blue dye. The optimal A1 (50%Co0.75Zn0.25Fe2O4/50%g-C3N4) photo catalyst exhibited excellent degradation efficiency of 99.34% for methylene blue removal in 60 minute experiment. The integration of both components in a nanohybrid favours charge separation with efficient Z-scheme charge transport via redox mediators. Scavenging investigations provide credence to superoxide and hydroxyl radicals as reactive species in MB breakdown. An appropriate mechanism with outstanding stability and confirmed reusability for the envisaged photo catalyst has been described.

The Enzymatic Role in Honey from Honey Bees and Stingless Bees

Abstract: A variety of biomolecules known as enzymes are found in honey and originated from bees and plant nectars. The plant yields nectar that aids bees in producing honey. Diastases, invertases, glucosidases, glucose oxidases and proteases are the common enzymes present in honey and highly sensitive toward UV-vis light, heat, and microwave energy. Among all enzymes, invertase and diastase have been used for assessing the freshness of honey. The enzyme's capacity to transform amylose into glucose enhances the sweetness and flavor of honey. The role of enzymatic reactions in two types of honey, based upon bee sting morphology, namely honey from honey bees (HB) and stingless bees (SB) are discussed in this review. Enzymes that act as the main ingredient in honey production are comprehensively discussed for their significance in producing good quality and therapeutic properties of honey.

Optimization of photocatalytic degradation of malachite green using nano-scaled V/CeO2-functionalized steel-slag-based catalyst by response surface design approach

The utilization of steel slag with high added value is an important means for sustainable development of the iron and steel industry and environment. A new nano-scaled V/CeO2-functionalized steel-slag-based catalyst (V/CeO2-SC) was prepared. The XPS results revealed that V was embedded in the CeO2 lattice with V4+ and V5+ forms. The regression equation analysis of variance told that the order of influencing factors on malachite green dye degradation rate is: catalyst dosage > V doping amount > malachite green dye concentration. The optimum values of the parameters were dye concentration 10 mg/L, catalyst dosage 0.1 g, and V doping amount 1wt%. Under the optimal condition, the predicted and actual response values of the degradation rate of malachite green dye were 100.00%. UV–Visible light absorption spectroscopy results demonstrated that after the photocatalytic degradation reaction, the absorption peak of the malachite green dye solution almost completely disappeared, indicating that the malachite green dye solution was almost completely degraded. The excellent degradation activity of the 1V/CeO2-SC specimen was attributed to the co-action of the high SBET, large mesoporous volume, and the coupled semiconductors formed by V-doped CeO2 and FeO in the catalyst carrier. A possible photocatalytic degradation mechanism of the V/CeO2-SC specimen was proposed.

Gelatin Improves the Performance of Oregano Essential Oil Nanoparticle Composite Films-Application to the Preservation of Mullet.

In this study, the addition of oregano oil chitosan nanoparticles (OEO-CSNPs) was conducted to enhance the comprehensive properties of gelatin films (GA), and the optimal addition ratio of nanoparticles was determined for its application in the preservation of mullet. Oregano oil chitosan nanoparticles were organically combined with gelatin at different concentrations (0%, 2%, 4%, 6% and 8%) to obtain oregano oil-chitosan nanoparticle-GA-based composite films (G/OEO-CSNPs), and thereafter G/OEO-CSNPs were characterized and investigated for their preservative effects on mullet. Subsequent analysis revealed that OEO-CSNPs were uniformly dispersed in the GA matrix, and that G/OEO-CSNPs had significantly improved mechanical ability, UV-visible light blocking performance and thermal stability. Furthermore, the nanoparticles exhibited excellent antioxidant and antibacterial properties, and they improved the films' suitability as edible packaging. The attributes of the G/OEO-CSNPs were optimized, the films had the strongest radical scavenging and lowest water solubility, and electron microscopy also showed nanoparticle penetration into the polymer when the concentration of OEO-CSNPs was 6% (thickness = 0.092 ± 0.001, TS = 47.62 ± 0.37, E = 4.06 ± 0.17, water solubility = 48.00 ± 1.11). Furthermore, the GA-based composite film containing 6% OEO-CSNPs was able to inhibit microbial growth, slow fat decomposition and protein oxidation, reduce endogenous enzyme activity, and delay the spoilage of mullet during the refrigeration process, all of which indicate its excellent potential for meat preservation application.

Stability and thermophysical properties enhancement of Al2O3-water nanofluid using cationic CTAB surfactant

Excellent thermal characteristics of homogeneous dispersion of nano-sized particles in a carrier fluid (nanofluid) make it appealing for use in a variety of thermal applications. The study aims to prepare stable aqua-Al2O3 nanofluid utilizing a two-step method. To increase nanofluid stability, a cationic surfactant called cetyltrimethylammonium bromide (CTAB) is used. The carrier fluid is heated while magnetic stirring is used to increase nanoparticle distribution. Bath sonication with concurrent heating and probe sonication is used to improve long-term stability. The chemical composition of γ-Al2O3 was confirmed by X-ray diffraction (XRD) results, and Scanning Electron Microscopy (SEM) images revealed the shape and mean size of the particles. The stability of the synthesized sample is evaluated utilizing a variety of stability evaluation techniques, including visual examination, UV-vis spectrometry, and Dynamic Light Scattering (DLS), at various time intervals, including 1, 8, 15, and 30 days. After 15 days of manufacture, the stability of the nanofluid without surfactant was low. Due to improved particle suspension, nanofluid with surfactant has demonstrated greater UV-vis light absorption. After a month of synthesis, it was discovered that the mean particle sizes of suspended nanoparticles in carrier fluid were 80 nm and 536 nm for nanofluid with and without surfactant respectively. KD2Pro thermal analyzer and viscometer were used to measure the thermal conductivity and viscosity of nanofluid. As per the experimental results, a nanofluid's thermophysical characteristics were found to be improved with volume concentration of nanofluid. Maximum augmentation in thermal conductivity and dynamic viscosity is 8.5% and 76.2% respectively at 1% nanofluid volume concentration.

Facile synthesis of visible-responsive photocatalytic Eu-doped layered double hydroxide for selective removal of NOx pollutant

Efficient nitrogen oxides (NOx) removal from the urban atmosphere is still a target for the researchers. Herein, a Zn2Al-CO3 based layered double hydroxide (LDH) was doped with increasing amounts of Eu3+ (0.01–0.04) and the photocatalytic oxidation of NOx gases was investigated. The LDHs were synthesized by a facile coprecipitation method at room temperature and ambient pressure. The successful Eu3+ substitution in the LDH layers induces a shift in the M−O bonds that modifies the electronic band structure of the doped photocatalysts. Compared to the undoped LDH, the NOx removal efficiency was enhanced by ∼ 17–25 % under UV–Vis light irradiation. Remarkably, a NOx removal efficiency of ∼ 47 % was attained by the optimally doped LDH under Visible irradiation (420 nm), surpassing raw LDH (∼ 9 %). Moreover, the Eu3+ doped LDHs retained its photocatalytic efficiency during long periods of irradiation during consecutive tests with high selectivity (>90 %). Photoluminescence studies indicated that Eu3+ was located in a non-centrosymmetric position, thereby producing structural disorder within the lattice. Eu doping promoted charge separation and a higher production of ⋅OH radicals as verified by time-resolved photoluminescence and electron paramagnetic resonance, respectively. We believe this work reports unprecedent results obtained by Eu-doping of Zn2Al-based LDHs under visible light for NOx photooxidation and serves as a new strategy to prepare functional LDHs for other photocatalytic applications.

Construction of photocatalyst by modification of argentum noble metal and hydrogen doping into WO3 nanoparticles: Enhancing the solar energy utilization

Solar energy is considered sustainable green energy to prevent environmental pollution. Tungsten trioxide (WO3) is one of the attractive solar energy-driven photocatalysts and photocatalytic supports. Besides, Hydrogen (H) has a small size and can move into many inorganic compounds, and occupy the sites in microstructure as well, with little space structure expansion. H doping in semiconductors attracts more and more attention due to its effect of providing free carriers, resulting in localized surface plasmon resonances which can improve the utilization efficiency of solar energy. In our research, we developed a new method to prepare the H-doped WO3 whose color turned green, and to prepare Ag/HxWO3, which could extend the solar light response range to near-infrared. Furthermore, the photocatalytic activity to degrade RhB solution under UV light and visible light was both improved. The density of free electrons is based on the Drude model to discuss the mechanism of photocatalysis upon the visible. The contact of noble metal Ag and HxWO3 can play a vital effect in the separation of photogenerated electron-hole pairs. The localized surface plasmon resonances and green coloration bring the tungsten trioxide more remarkable performance together. Results showed that constructed photocatalysis of this work greatly enhanced the utilization rate of solar energy. Photocatalytic for the Degradation of liquid organic pollutants with HxWO3 is believed to have a bright feature.

Nickel phosphide nanoparticles as a noble-metal-free co-catalyst for the selective photocatalytic aerobic oxidation of CH4 into CO and H2

In this study, we report the use of NiP2/TiO2 as a photocatalyst for the transformation of methane (CH4) to carbon monoxide (CO) and hydrogen (H2) under UV–visible light irradiation. As a co-catalyst, NiP2 can promote the charge separation of TiO2 on the one hand, and can effectively promote the activation of O2 to generate superoxide ions (O2–) on the other hand. O2–, as the main active species, cleaves CH4 molecules to form methoxyl radical (•CH3O). Under the influence of photogenerated holes, •CH3O gradually undergoes oxidation to form an intermediate *COOH, which is subsequently converted to CO. Meantime, H+ is reduced to form H2. Therefore, the production of CO and H2 attained 267.5 and 72.4 μmol g–1h−1 for the NiP2/TiO2-2 photocatalyst with the optimal ratio, respectively. In fact, this research showcases the capability of NiP2/TiO2 as a remarkably effective and specific photocatalyst for transforming CH4 into high-value commodities.

A Mars-analog sulfate mineral, mirabilite, preserves biosignatures

Abstract Various sulfate minerals exist on Mars; except for gypsum, they are understudied on Earth. Extremophiles have been documented in modern gypsum and halite and ancient halite, but other chemical sediments have not been evaluated for biosignatures. Here, we present the first observations and analysis of microorganisms and organic compounds in primary fluid inclusions in the Mars-analog mineral mirabilite, Na2SO4·10H2O, from Great Salt Lake, Utah, USA. Microscopy by transmitted light and ultraviolet-visible (UV-vis) light, and Raman spectroscopy, show abundant bacteria and/or Archaea, algae, fungi, diatoms, protozoa, and organic compounds such as beta-carotene. This discovery expands our current knowledge of biological materials trapped in salt and aids the search for life on Mars, both for sample selection by rover and for analyses of return samples on Earth.