Fast Degradation Research Articles

Seasonal Effects on Outdoor Stability of Perovskite Solar Cells

AbstractThe critical challenge for the commercialization of perovskite solar cells (PSCs) is their operational stability. PSCs’ outdoor operation exposes the cells to a combination of stress factors that are difficult to reproduce by indoor testing due to diurnal and seasonal variations. This highlights the need for outdoor testing under operational conditions. The effect of climate conditions on outdoor operational lifetime/ degradation of n‐i‐p PSCs is systematically studied herein. Their lifetime indicators are determined in different seasons, and correlated with the outdoor irradiance and temperatures measured simultaneously. Based on this outdoor measurement analysis and indoor light cycling stability tests, it is suggested that ambient temperatures induce a more significant effect than the irradiance on the PSC's lifetime/ degradation. The study also suggests different roles played by the temperatures during the diurnal light versus dark periods: the day/ light time maximum temperatures have a more significant effect on the long‐term degradation. In contrast, minimum temperatures during the night/ dark cycles significantly affected the diurnal reversible degradation and the initial fast degradation. The results show that the commonly used lifetime indicators T80 and T50 are climate‐dependent, and their use for comparative purposes is valid only if measured in similar climatic conditions.

Predicting Long-Term Stability from Short-Term Measurement: Insights from Modeling Degradation in Perovskite Solar Cells during Voltage Scans and Impedance Spectroscopy.

A drift-diffusion model is used to investigate the effect of device degradation on current-voltage and impedance measurements of perovskite solar cells (PSCs). Modifications are made to the open-source drift-diffusion software IonMonger to model degradation via an increasing recombination rate during the course of characterization experiments. Impedance spectroscopy is shown to be a significantly more sensitive measure of degradation than current-voltage curves, reliably detecting a power conversion efficiency drop of as little as 0.06% over a 4 h measurement. Furthermore, we find that fast degradation occurring during impedance spectroscopy can induce loops lying above the axis in the Nyquist plot, the first time this experimentally observed phenomenon has been replicated in a physics-based model.

Understanding the Impact of Soil Characteristics and Field Management Strategies on the Degradation of a Sprayable, Biodegradable Polymeric Mulch

The use of non-degradable plastic mulch has become an essential agricultural practice for increasing crop yields, but continued use has led to contamination problems and in some cropping areas decreases in agricultural productivity. The subsequent emergence of biodegradable plastic mulches is a technological solution to these issues, so it is important to understand how different soil characteristics and field management strategies will affect the rate at which these new materials degrade in nature. In this work, a series of lab-scale hydrolytic degradation experiments were conducted to determine how different soil characteristics (type, pH, microbial community composition, and particle size) affected the degradation rate of a sprayable polyester–urethane–urea (PEUU) developed as a biodegradable mulch. The laboratory experiments were coupled with long-term, outdoor, soil degradation studies, carried out in Clayton, Victoria, to build a picture of important factors that can control the rate of PEUU degradation. It was found that temperature and acidity were the most important factors, with increasing temperature and decreasing pH leading to faster degradation. Other important factors affecting the rate of degradation were the composition of the soil microbial community, the mass loading of PEUU on soil, and the degree to which the PEUU was in contact with the soil.

A Tale of Two Cities in Fluorescent Sensing of Carbon Monoxide: Probes That Detect CO and Those That Detect Only Chemically Reactive CO Donors (CORMs), but Not CO.

Carbon monoxide (CO) is endogenously produced with a range of pharmacological activities. Sensitive and selective detection of CO is critical to studying its biology. Since the first report of a CO fluorescent probe in 2012, more than 100 papers on this topic have appeared. Noteworthy in such work is the widespread use of two commercially available ruthenium-carbonyl complexes (CORM-2 and CORM-3) as CO surrogates. Unfortunately, these two CORMs are chemically very reactive and preferentially release CO2 but not CO, unless in the presence of a nucleophile. As a result, there are "two tales" of the reported CO probes: those that detect CO and those that detect only the CORM used but not CO. In addition, because of their lack of reliable CO production and fast degradation in an aqueous solution, there is the question of what "detecting CORM-2 or CORM-3" really means in the context of CO research. Additionally, for applying fluorescent CO probes in detecting low levels (often nanomolar) of CO in vivo, fast reaction kinetics is a prerequisite for meaningful results. In this Perspective, we discuss in detail these issues with the understanding of the evolutionary nature of scientific discoveries and the aim of preventing further confusion.

Treatment of chronic osteomyelitis with gradient release of DGEA and vancomycin hydrogel-microsphere system and its mechanism.

In recent years, the treatment of chronic osteomyelitis mediated by biodegradable polymer platforms has received increasing attention. This paper reports an advanced drug delivery system, vancomycin (VA) and DGEA loaded microspheres embedded in injectable thermosensitive polypeptide hydrogels (i.e., hydrogel-microsphere (Gel-MP) construct), for continuous release of drugs with different mechanisms and more comprehensive treatment of chronic osteomyelitis. The Gel-MP construct exhibits continuous biodegradability and excellent biocompatibility. Microspheres (MP) are wrapped inside Gel. With the degradation of Gel, VA and MP are released from them, VA released with faster degradation speed, achieving a potent antibacterial effect and effectively controlling infection. Due to the slower degradation rate of MP compared to Gel, subsequently, DGEA is released from MP to induce bone formation and produce the effect of filling bone defects. Compared with other formulations, the in vivo combinational treatment of Gel/VA-MP/DGEA can simultaneously balance antibacterial and osteogenic effects. More importantly, local sustained-release drug delivery systems can significantly mitigate the systemic toxicity of drugs. Therefore, the injection local sequential drug delivery system has broad prospects in the clinical application of treating chronic osteomyelitis.

Surface modified cellulose nanospheres with simultaneous nucleation and degradation-accelerating effects on poly(lactic acid)

As a novel type of nanocellulose material, cellulose nanospheres (CNSs) have gained significant attention and rapid development in recent years. In this work, the surface hydrophobic modification of CNSs was achieved by employing maleic anhydride as an esterifying agent. The effects of modified cellulose nanospheres (CNS-MA) on the crystallization and hydrolysis behaviors of polylactic acid (PLA)-based composites were systematically investigated. The results demonstrate that surface modification improves the dispersion of CNSs in the PLA matrix. Well-dispersed particles act as nucleation sites, which increases the crystallization rate and crystallinity of PLA and endows the composites with remarkable heat distortion resistance. The storage modulus of the PLA/CNS-MA composites exceeds 300 MPa, even at an elevated temperature of 90 °C. Furthermore, the hydrolytic degradation of PLA is dramatically accelerated with the addition of CNS-MA. Combining the morphology observations and theoretical calculations, it is speculated that the fast hydrolytic degradation is related to a transition in the main hydrolytic degradation mechanism from surface erosion to bulk erosion, because the presence of CNS-MA provides particular pathways for water molecules to diffuse into the interior of the composites. This research highlights the potential of CNSs as a multifunctional filler with both reinforcing and degradation-promoting effects, offering valuable insights for the study of other biomass nanomaterials.

Synthesis of Chitosan-Agar immobilized NiO-MgO bionanocomposites and their photocatalytic application towards toxic azo dye

In this study, NiO-MgO nanoparticles (NiMg NPs) were synthesized and incorporated into a biopolymer blend of chitosan (CTS) and agar agar gum (AA), forming the novel CTAG@NiMg bionanocomposite (BNC). Structural analysis revealed a crystal size of 19 nm and a direct band gap of 2.75 eV, indicating strong potential as a UV-active photocatalyst. TEM images confirmed uniform nanoparticle distribution with an average size of 25 nm. The elemental composition, verified by EDX spectra, showed weight percentages of C (21.32 %), O (31.47 %), Ni (35.39 %), and Mg (11.82 %). The CTAG@NiMg BNC demonstrated outstanding photocatalytic degradation of methyl orange (MO) dye, achieving 99.52 % degradation at pH 4 with 20-ppm concentration after 60 min under UV irradiation. The degradation followed pseudo-first-order kinetics, with rate constants (k1) ranging from 0.011 to 0.030 min−1, and a minimum half-life of 25.8 min at 15 ppm. Hydroxyl radicals (•OH) were identified as the primary reactive species driving the photocatalytic process. The material exhibited excellent reusability, retaining high degradation efficiency over four cycles. Compared to similar photocatalysts, CTAG@NiMg BNC demonstrated superior performance, faster degradation rates, and greater stability. Its enhanced surface area and porosity, as confirmed by BET analysis, contributed to better dye adsorption and faster reaction times. These properties make the CTAG@NiMg BNC a highly efficient, sustainable, and recyclable photocatalyst for environmental remediation, particularly in treating organic pollutants like methyl orange from aqueous solutions.

Crack Development and Electrical Degradation in Chromium Thin Films Under Tensile Stress on PET Substrates

The mechanical and electrical deterioration of chromium (Cr) thin films sputtered onto polyethylene terephthalate (PET) substrates under tensile strain was studied. Understanding mechanical and electrical stability due to imposed strain is particularly important for device reliability, as the demand for flexible electronic devices increases. Cr thin films, widely spread across the field of electronic and sensor applications, face crack propagation with electrical degradation with tensile stress that can seriously compromise the performance. Accordingly, this study offers new findings on how Cr film thickness might influence crack formation and electrical resistance differently and also the general guidelines for flexible electronic component design with respect to long-term durability. Electrical resistances were measured while mechanically stretching 100- and 200 nm thin sheets. The study focused on crack development and propagation mechanisms in both film thicknesses and their effects on percentage change in electrical resistance (PCER). Scanning electronic microscopy (SEM) was used to characterize surface morphology and observe cracks as the strain rose. Early crack formation in 100 nm Cr films led to rapid PCER increases due to quick crack propagation and fast electrical degradation. Thicker 200 nm films, however, showed a more gradual PCER rise with fewer but deeper cracks, indicating a regulated strain response. Unlike the sharp PCER spike in 100 nm films, 200 nm samples were more variable, with three out of four showing a slight PCER decrease at the end, hinting at partial crack repair or conductive realignment before full failure. These results underscore the role of layer thickness in managing crack propagation and electrical stability, relevant for flexible electronics and strain sensors. This paper is aligned with the ninth goal of the United Nations Sustainable Development Goals, specifically Target 9.5: Enhance Research and Upgrade Industrial Technologies.

Utilizing the superoxide dismutase activity of ceria nanoparticles to endow poly-l-lactic acid bone implants with antitumor function

Currently, numerous bone tumor patients undergo tumor recurrence after surgical resection, which seriously affects their quality of life. In this study, the ceria (CeO2) nanoparticle was added to Poly-L-Lactic Acid (PLLA) bone implants endowing the bone implant with antitumor function. The results showed that the reactive oxygen species increased in U2OS cells while it dropped in HEK293 cells as the CeO2 content increased. Meanwhile, the PLLA-8CeO2 showed a high cell inhibition rate of 53.66 % for U2OS cells and possessed a high cell viability of 76.96 ± 2.20 % for HEK293 cells, meaning that the implant could kill bone tumor cells meanwhile show good cytocompatibility for normal cells. These were mainly due to the fact that the CeO2 nanoparticles acted as a superoxide dismutase in tumor cells reducing superoxide to hydrogen peroxide, inducing an increase in reactive oxygen species levels. The excess reactive oxygen species could result in tumor cell apoptosis by disrupting mitochondrial structure, oxidizing proteins, and promoting DNA denaturation. Moreover, the compressive strength of PLLA was improved by the CeO2 addition due to its particle dispersion strengthening. Besides, the PLLA-CeO2 had a faster degradation rate compared to PLLA. Overall, the PLLA-CeO2 is a promising implant material for bone tumor treatment.

Niosomes: A promising approach for targeted drug delivery

Niosomes, also known as nonionic surfactant vesicles, are small lamellar structures that are created by combining nonionic surfactants from the alkyl or dialkyl polyglycerol ether category with cholesterol, and then hydrating them in water-based solutions. These are vesicle systems resembling liposomes that can be utilized as carriers for drugs that are both amphiphilic and lipophilic. The production process of niosomes is derived from liposome technology. The fundamental manufacturing method remains unchanged, wherein the lipid phase is hydrated by the aqueous phase. The lipid phase can consist of either a pure surfactant or a combination of surfactant and cholesterol. Niosomes effectively tackle the challenges associated with medication insolubility, instability, inadequate bioavailability, and fast degradation. The amphiphilic character of niosomes, which combines both hydrophilic and lipophilic properties, enhances their capacity to encapsulate medicines that are either hydrophilic or lipophilic. Cholesterol is frequently utilized as one of the ingredients. Preserving the stiffness of the niosome structure. The present article discusses the essential elements of niosomes, including their structural constituents, methods of manufacturing, and their uses in different disorders.

Co‐Generation of Electricity and Chemicals From Methane Using Direct Internal Reforming Solid Oxide Fuel Cells

AbstractThe co‐generation of electricity and chemicals via direct internal reforming solid oxide fuel cells (DIR‐SOFCs) offers a promising route to carbon‐neutral energy solutions. However, challenges such as inadequate performance and fast degradation, particularly when using hydrocarbon fuels like CH4, hinder the deployment of DIR‐SOFC technology. This study addresses three critical issues: the effect of fuel composition on electrochemical properties, the mechanisms and microstructural impacts of carbon deposition, and the practical feasibility of DIR‐SOFCs at an industrial scale. First, comprehensive polarization and impedance analyses are conducted to assess the impact of varying fuel compositions—specifically p(CH4) and p(H2O)—on DIR‐SOFC performance. Second, advanced morphological characterization, machine learning‐assisted 3D reconstructions, and numerical simulations are utilized to reveal carbon deposition behavior and its effects on anode microstructures. Quantitative analysis of carbon's impact on pores, Ni, and YSZ phases provides novel insights into carbon‐induced microstructural changes. Finally, the industrial‐scale co‐generation of electricity and chemicals is validated, emphasizing both energy efficiency and operational stability. This study enhances the understanding of electrochemical and microstructural mechanisms, offering crucial insights for optimizing DIR‐SOFC design and operation, and laying the groundwork for their broader adoption in a carbon‐neutral future.

Subgrade performance assessment for rigid runway using long-term pavement performance database

Maintaining desired subgrade performance is an effective way to reduce runway pavement deterioration. Due to lack of extensive field test data, life-cycle performance of runway subgrade has not been fully understood. In order to quantitatively estimate subgrade condition, a novel method of evaluating subgrade performance was developed and validated using the 726 sets of Heavy Weight Deflectometer (HWD) test data of ten runway sections. Statistical analysis demonstrates that the structural behaviour of rigid runway subgrade follows normal distribution in different service stages and can be efficiently evaluated by the subgrade performance index (ψ). The results of factor analysis show that Accumulated Air Traffic Volume (ATV) during service life is the major cause of spatial variations in subgrade condition. In the designed service period of runway, it validates that sea-reclaimed subgrade results in faster degradation in the initial stage of service life while thicker pavement exhibits better capability in protecting the subgrade soil in long-term view. Besides, the differences in applied loads and pavement thickness give rise to the subgrade performance variation in longitudinal direction. Meanwhile, the comparison between the main and the less trafficked test lines in transversal direction reveals that the aircraft impacts play a positive role in resisting the natural fatigue process. By the suggested method, subgrade performance of HWD test points can be categorized into 4 levels from “Excellent”, “Good”, “Fair” to “Poor” based on ψ value. It is helpful for airport agency to make scientific decisions on Maintenance and Rehabilitation (M&R) treatment by calculating the effective area of envelope (β) using the ratio of subgrade performance (η).

Cr3+doped α-Fe2O3 nanoparticles for photodegradation of organic pollutants with their disinfection efficacy

Pristine and Cr-doped α-Fe2O3 nanoparticles were synthesized using a low-cost and simple one-step hydrothermal method without any precipitating agent. Cr-doped α-Fe2O3 was found to be a promising candidate for recyclable photocatalytic application for Tetracycline (TC) and Congo-red (CR) degradation under normal sunlight irradiation along with excellent antibacterial properties. Addition of Cr shows a significantly improved degradation efficiency from 20% to 91% in just 25 min for CR, while the degradation rate reached to 81% for TC, which was also monitored in real-time using internet of things (IoT). Also, a high degree of mineralization was achieved (∼87.9%), which was confirmed using total organic carbon (TOC) content. In parallel, the biochemical oxygen demand/chemical oxygen demand (BOD5/COD) ratio confirmed the fast degradation efficiency using a small amount of catalytic dosage (∼ 0.40 g/L). Also, degradation of multiple dyes provides a promising avenue for addressing complex waste water treatment challenges. Moreover, Cr-doped α-Fe2O3 displays excellent antibacterial activity towards E.coli and E.Faecium. Major factors involved in sunlight driven photocatalytic activity for example absorbance range, porosity, separation between e--h+, and charge transfer property were surprisingly improved by Cr doping and henceforth increased photocatalytic activity and antibacterial properties. This work highlights the potential utilization of Cr-doped α-Fe2O3 for the purification and disinfection of industrial waste water.

Transfer of pesticides and metabolites in corn: Production, processing, and livestock dietary burden

Corn stover is widely used in livestock feed but has received limited attention regarding its potential risks. In this study, pesticide residues were monitored across 12 provinces in China, and terminal residues of four pesticides, chlorantraniliprole, thiamethoxam, epoxiconazole, and pyraclostrobin, were tested. In addition, the silage processing experiment was conducted. All processing factors (PF) were <1, indicating pesticide degradation. The physicochemical properties of pesticides, especially log P, were related to degradation efficiency. Pesticides with higher log P values showed higher PFs (0.43 to 0.85), indicating lower degradation efficiency. The dietary burden of livestock before and after silage processing was calculated using OECD livestock dietary burden calculator. Results showed that after silage fermentation, the dietary burden was reduced by 28.8 % to 79.2 %. Throughout the entire production and processing process, the fastest degradation of all pesticides in whole corn was primarily observed from the pesticide application time to the harvest time, with some pesticides also showing accelerated degradation during subsequent processing stages. Therefore, in actual production, especially for pesticides which are difficult to degrade, appropriate extension of the safety interval or selection of suitable processing methods can be taken to further reduce pesticide residues in agricultural products.

Symmetry-Engineered BINOL-Based Porous Aromatic Frameworks for H2O2 Production via Artificial Photosynthesis and In Situ Degradation of Pharmaceutical Pollutants.

Accomplishing visible light-driven H2O2 production at millimolar concentrations is practically challenging, particularly for organic semiconductors. In this context, achieving a maximum H2O2 production rate of 31.60 mmol·g-1·h-1 by using porous aromatic frameworks (PAFs) represents a significant accomplishment. We report the unusual photoactivity of tetraphenylmethane-BINOL-linked PAFs in triplet oxygen activation to facilitate the generation of reactive oxygen species (ROS), as confirmed by their optical and electrochemical responses, despite the absence of a conventional chromophoric moiety. Moreover, an in situ BINOL formation strategy was used to synthesize these PAFs during polymerization in contrast to the reported protocols involving chiral BINOLs as precursors. The as-synthesized polymers had a capsule-like morphology (for TPM-BINOL-6), high thermal stability up to 348 °C, and a high Brunauer-Emmett-Teller (BET) surface area of up to 1382 m2/g (for TPM-BINOL-4). Interestingly, they showed sunlight-driven production of H2O2 via an oxygen reduction reaction of up to 17.05 mmol·g-1·h-1 in 1:10 isopropanol in water for TPM-BINOL-6, which was quantified by titration with ceric sulfate. It also exhibited exemplary photocatalytic efficiency with an H2O2 production rate of 6.65 mmol·g-1·h-1 in seawater. Interestingly, the H2O2 production rate reached a maximum of 18.03 mmol·g-1·h-1 with an SCC efficiency of 4.5% under an AM 1.5G solar simulator and apparent quantum yield (AQY) of 15.8% (at λ = 456 nm) for TPM-BINOL-6 in ethanol:water = 1:10. Moreover, the exceptionally high H2O2 production rate of 31.60 mmol·g-1·h-1 was achieved in 1:1 ethanol in water under 50 W blue LED light. Furthermore, these PAFs generated adequate ROS, which were utilized in the photocatalytic degradation of tetracycline via the superoxide intermediate. Additionally, the as-formed H2O2 was further channelized in the pollution abatement catalytic system for the fast degradation of ciprofloxacin (within 4 h) and the reduction of toxic oxometallate Cr(VI) within 10 min, which is one of the earliest reports of utilizing photosynthesized H2O2 for environmental detoxification.

Tumor Microenvironment Cascade Activated Biodegradable Nano-Enzymes for Glutathione-Depletion and Ultrasound-Enhanced Chemodynamic Therapy.

Chemodynamic therapy (CDT) is emerged as a novel and promising tumor therapy by using the powerful reactive oxygen species (ROS) to kill cancer cells. However, the current CDT is remarkably inhibited due to insufficient H2O2 supply and over-expression of glutathione (GSH) in the tumor microenvironment (TME). Herein, a biodegradable self-supplying H2O2 nano-enzyme of CuO2@CaP with a GSH-consumption effect is designed for cascade enhanced CDT to overcome the problem of H2O2 deficiency and GSH overexpression. In this design, CuO2@CaP is gradually degraded to Ca2+, Cu2+, and H2O2 in acidic TME, resulting in synergistically enhanced CDT owing to the efficient self-supplied H2O2 and GSH-depletion and Ca2+ overload therapy. Interestingly, the faster degradation of CuO2@CaP and promoted production rate of •OH are further achieved after triggering with ultrasound (US). And, the US-enhanced CDT and Ca2+ overload synergistic antitumor therapy is successfully achieved in vivo. These findings provide a promising strategy for designing biodegradable nano-enzymes with self-supplying H2O2 and GSH consumption for US-mediated CDT.

Boosting Reactive Oxygen Species Generation via Contact‐Electro‐Catalysis with FeIII‐Initiated Self‐cycled Fenton System

AbstractContact Electro‐Catalysis (CEC) using commercial dielectric materials in contact‐separation cycles with water can trigger interfacial electron transfer and induce the generation of reactive oxygen species (ROS). However, the inherent hydrophobicity of commercial dielectric materials limits the effective reaction sites, and the generated ROS inevitably undergo self‐combination to form hydrogen peroxide (H2O2). In typical CEC systems, H2O2 does not further decompose into ROS, leading to suboptimal reaction rates. Addressing the generation and activation of H2O2 is therefore crucial for advancing CEC. Here, we synthesized a catalyst by loading the dielectric material polytetrafluoroethylene (PTFE) onto ZSM‐5 (PTFE/ZSM‐5, PZ for short), achieving uniform dispersion of the catalyst in water for the first time. The introduction of an FeIII‐initiated self‐cycling Fenton system (SF‐CEC), with the synergistic effects of O2 activation and FeIII‐activated H2O2, further enhanced ROS generation. In the FeIII‐initiated SF‐CEC system, the synergistic effects of ROS and protonated azo dyes enabled nearly 99 % degradation of azo dyes within 10 minutes, a sixfold improvement compared to the CEC system. This represents the fastest degradation rate of methyl orange dye induced by ultrasound to date. Without extra oxidants, this system enabled stable dissolution of precious metals in weakly acidic solutions at room temperature, achieving 80 % gold dissolution within 2 hours, 2.5 times faster than similar CEC systems. This study also corrects the unfavorable perception of CEC applications under acidic conditions, providing new insights for the fields of dye degradation and precious metal recovery.

Rapid α-Al2O3 Growth on an Iron Aluminide Coating at 600 °C in the Presence of O2, H2O, and KCl.

In this work, a slurry iron aluminide-coated ferritic steel SVM12 was subjected to a laboratory experiment mimicking superheater corrosion in a biomass-fired power boiler. The samples were exposed under model Cl-rich biomass conditions, in a KCl + O2 + H2O environment at 600 °C for 168, 2000, and 8000 h. The morphology of corrosion and the composition of the oxide scale and the coating were investigated by a combination of advanced analytical techniques such as FESEM/EDS, SEM/EBSD, and XRD. Even after short-term exposure, the coating developed a very fast-growing and up to 50 μm thick α-Al2O3 scale in contrast to the spontaneous formation of a protective, thin, dense, slow-growing, and very adhesive α-Al2O3 layer usually formed on metallic materials after high-temperature oxidation. In view of the literature on the formation of oxide scales on alloys and coatings, the formation of an α-Al2O3 scale at this relatively low temperature is very surprising in itself. The thick alumina scale was not protective as its formation resulted in fast degradation of the coating and rapid Fe2Al5 → FeAl phase transformation, which in turn generated porosity inside the coating. In all cases, the resulting thick Al2O3 scale was porous and consisted of both equiaxed α-Al2O3 grains and randomly oriented aggregated alumina whiskers. Potassium is concentrated in the outer part of the Al2O3 scale, while chlorine is concentrated close to the scale/aluminide interface. The unexpected formation of rapidly growing α-Al2O3 at relatively low temperature is attributed to the hydrolysis of aluminum chloride generated in the corrosion process.

Photoinitiated Degradation Kinetics of the Organic UV Filter Oxybenzone in Solutions and Aerosols: Impacts of Salt, Photosensitizers, and the Medium.

Organic UV filters like oxybenzone (BP3) in sunscreens are seawater pollutants suspected to transfer to the atmosphere via sea spray aerosol (SSA). This study examines the photoinitiated degradation of BP3 in artificial and real seawater compared to SSA mimics containing NaCl and 4-benzoylbenzoic acid (4-BBA). We investigated pure, binary, and ternary mixtures of BP3, NaCl, and 4-BBA using solar-simulated light to isolate the effects of salt and photosensitization on BP3 degradation. Results showed significantly faster degradation in the aerosol phase (J eff,env ≈ 10-3-10-2 s-1 or t 1/2 < 10 min) compared to bulk solutions (J eff,env ≈ 10-6 s-1 or t 1/2 > 1 day). The photosensitizer enhanced BP3 photodegradation in both phases more than when mixed with salt or all three components in solutions. BP3 photodegradation was most enhanced by salt in the aerosol phase. High-resolution molecular analysis via Orbitrap LC-MS/MS revealed more acutely toxic compounds (benzophenone, benzoic acid, and benzaldehyde) in irradiated aerosols than in solution, supported by electronic structure and toxicity modeling. These findings highlight that seawater may serve as a reservoir for BP3 and other organic UV filters and that upon transfer into SSA, BP3 rapidly transforms, increasing aerosol toxicity.

Rare earth-doped ZrB2-MoSi2 ceramics: Densification and oxidation behavior

The effect of rare earth oxides (REO), Nd2O3 and Eu2O3, on the densification and oxidation behavior of pressureless sintered ZrB2-MoSi2 ceramic composites was investigated. Addition of REO results in the formation of REO-silicates which are liquid at the sintering temperature and contribute to matter transfer mechanisms. Oxidation studies at 1500 °C for 0.5–4 h evidenced that Eu2O3 can improve oxidation resistance in the ZrB2-MoSi2 system, especially after prolonged exposition, whilst Nd2O3 induces faster degradation of the ceramic. It was found that the Eu dispersed both in silica and in zirconia modifies the rheological properties of the glassy phase thus playing an important role in hindering oxygen inward from the atmosphere to the subsurface, resulting in a noticeable improvement of the oxidation resistance.