Search Results (6,188)

Although fast-paced ongoing industrial growth, on the one hand, enhances the lifestyle of the population, on the other hand, it affects human health and the environment as a result of the discharge of pollutants. To address this, designing a novel and effective photocatalyst is necessary to mitigate increasing environmental pollutants. In the present work, we aim to synthesize a single-phase high-entropy zirconate pyrochlore oxide (Ce_0.2Pr_0.2Zn_0.2Nd_0.2Tb_0.2)₂Zr₂O₇ using a modified Pechini method. The physicochemical properties of the prepared nanoparticles were investigated using X-ray diffraction, UV-visible spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The photocatalytic properties were examined using cationic dye (methylene blue), anionic dye (Congo red), and Cr(VI). Photocatalytic degradation experiments demonstrate exceptional efficiency in the removal of persistent organic pollutants. The photocatalytic results indicate that the prepared high-entropy (Ce_0.2Pr_0.2Zn_0.2Nd_0.2Tb_0.2)₂Zr₂O₇ zirconate pyrochlore oxide could effectively degrade dyes and reduce Cr(VI). Radical trapping experiments indicate that the degradation of dyes was driven by the hydroxyl radicals, superoxide radicals, and holes. Furthermore, the position of the valence band and conduction band promoted efficient photocatalytic reaction kinetics. The prepared photocatalyst remains structurally stable and can be reused three times without losing activity. Full article

Anion exchange membrane fuel cells (AEMFCs) represent a promising class of clean energy devices, with their performance being critically dependent on the efficiency of the cathode oxygen reduction reaction (ORR) catalyst. Manganese-cobalt spinel (Mn_1.5Co_1.5O₄, MCS) has been demonstrated to be a highly active ORR catalyst. Herein, we report a strategy of incorporating Cu (MCCS) and Fe (MCFS) into MCS to form ternary spinel oxides for tuning ORR activity. Among them, MCS exhibits the best ORR performance, with a half-wave potential (E_1/2) of 0.736 V vs. RHE in 0.1 M KOH and a peak power density (PPD) of 248.3 mW·cm⁻² for the fuel cell test. In contrast, MCCS and MCFS show divergent behaviors in a rotating disk-ring electrode (RRDE) and fuel cell tests. X-ray diffraction (XRD) analyses and X-ray photoelectron spectroscopy (XPS) analyses reveal that the introduction of Cu²⁺ and Fe³⁺ induces a phase transformation in the spinel structure, leading to a reduction in oxygen vacancies and an increase in the valence state of Mn, thereby degrading catalytic activity. However, the incorporation of these elements also modulates the hydration capability of the catalysts, which is critical for the ion and charge transfer in the fuel cell environment and has been validated in the distribution of relaxation time (DRT) analysis of the fuel cell test. This study provides a valuable strategy for designing and synthesizing low-cost, highly efficient, and stable ternary spinel electrocatalysts for AEMFC applications, and bridges the gap between RRDE evaluation and fuel cell testing through DRT analysis. Full article

A major bottleneck in evaluating the environmental health implications of micro-nanoplastics (MNPs) is the inadequacy of analytical techniques for their precise quantification within complex environmental and biological matrices. Additionally, there is a conspicuous paucity of studies addressing environmentally relevant, photo-aged MNPs. In this study, the effects of UV aging on toxicity and bioavailability were investigated utilizing inductively coupled plasma mass spectrometry (ICP-MS)-traceable 25 nm gold-core polystyrene shell nanoplastics (AuPS25 NPs) and a triculture small intestinal epithelium (SIE) model coupled with simulated digestions to mimic physiological bio-transformations post-ingestion. Employing dynamic light scattering (DLS), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS), the physicochemical and morphological alterations of AuPS25 NPs as a function of UV exposure time were investigated, revealing significant photo-oxidation within 14 days. Toxicological evaluations demonstrated that, contrasting with un-aged AuPS25 NPs, the digesta from UV-aged AuPS25 NPs at oral concentrations of 4 and 40 µg/mL weakened barrier integrity by ~15% and ~18% and heightened cytotoxicity by ~4.3% and ~5.4%, respectively. Although the NP translocation rates were similar for both aged and un-aged PS NPs, the uptake by SIE of aged AuPS25 NPs was significantly higher, reaching 72.2% at 4 µg/mL and 59.2% at 40 µg/mL. In contrast, less than 0.5% of the un-aged PS NPs at both 4 µg/mL and 40 µg/mL were taken up by SIE. These findings highlight the imperative to integrate environmentally aged MNPs into toxicological assessments, as they facilitate “real-world” MNPs. Finally, the use of ICP-MS-traceable core–shell MNPs enables the identification and quantification of PS MNPs in cell lysates and biological media via ICP-MS, showcasing the use of such a tracer MNP approach in cellular uptake and in vivo biokinetic studies. Full article

To address rising global food demand, improving phosphorus (P) use efficiency in agriculture is crucial. Organic fertilizers and biochar are recognized for their potential to improve soil phosphorus availability and reduce environmental losses. However, the synergistic effects of their combined application on phosphorus retention and transformation have received insufficient attention. This study investigated the synergy between cow dung-derived biochar (produced at 400 °C and 700 °C) and organic fertilizer using P fractionation, leaching, and extraction tests. Results indicated that the H₂O-P content in organic fertilizer as high as 42.17 mg·g⁻¹, resulting in a cumulative leaching loss of up to 11.62 mg·g⁻¹. In contrast, biochar exhibited lower leaching due to more stable C–P compounds, as confirmed by X-ray photoelectron spectroscopy (XPS). When biochar and organic fertilizer were co-applied, complexation with Ca²⁺ on their surfaces reduced phosphorus leaching from the mixture by 83.69%. The formation of Ca₂P₂O₇ crystals, detected through X-ray diffraction (XRD), indicates a strong synergistic effect between biochar and organic fertilizer. Additionally, the porous structure of biochar adsorbed phosphorus from organic fertilizer, further inhibiting leaching losses. This synergy enhances P retention, offering an effective strategy to improve P use efficiency and support sustainable soil management. Full article

High-efficiency diesel and lean-burn engines produce lower exhaust temperatures, which can delay the activation of after-treatment catalysts such as Diesel Oxidation Catalysts (DOCs). This study explores ion beam sputtering as a post-synthesis strategy to enhance the low-temperature activity of commercial Pt/CeO₂–ZrO₂ catalysts. Low-energy ions (0.5–1.5 keV) were applied with controlled variations in treatment number, beam current, and exposure time to selectively generate oxygen vacancies and improve Pt dispersion. Structural and chemical effects were characterized using X-ray diffraction (XRD), BET surface area measurements, X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). Catalytic performance was evaluated through CO and C₃H₆ oxidation under conditions mimicking lean-burn engine exhaust. Increasing the number of ion treatments progressively lowered light-off temperatures, correlating with enhanced Pt–Ce³⁺ interactions and improved surface reducibility. Variations in beam current and exposure time further modulated these surface effects, confirming the tunable nature of the approach. The results demonstrate that ion beam sputtering selectively modifies the catalyst surface without altering the bulk structure, directly linking atomic-scale modifications to improved low-temperature activity. This strategy offers a promising route to overcome delayed light-off issues in modern high-efficiency engines, providing a precise, controllable method to optimize emission control catalysts. Full article

The aim of the presented work is to develop a more energy- and time-saving modification of a well-known hydrothermal synthesis method by reducing the time of the synthesis regime and drying step, as well as the possible removal of the calcination procedure. The structure and morphology of Gd-doped ceria (Ce_1−xGd_xO_2−x/2, where x = 0, 0.1, 0.2, 0.3, and 0.5), synthesized via the optimized hydrothermal method, were thoroughly investigated. Phase composition was analyzed using X-ray diffraction (XRD), while the structural units of the materials were identified by Fourier-transform infrared spectroscopy (FTIR). Chemical composition was studied using energy-dispersive X-ray spectroscopy (EDS) and further confirmed by energy-dispersive X-ray fluorescence (EDXRF). Transmission electron microscopy (TEM) was employed to analyze the size and shape of the nanoparticles. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the presence of Ce³⁺ ions in both doped and undoped CeO₂ samples. Full article

Understanding the microscopic occurrence states of shale oil—particularly the distribution between adsorbed and free phases—is essential for optimizing the development of unconventional reservoirs. In this study, we propose an integrated methodology that combines experimental techniques with molecular dynamics simulations to investigate shale oil behavior within kerogen nanopores. Specifically, pyrolysis–gas chromatography–mass spectrometry (PY-GC-MS), solid-state ¹³C nuclear magnetic resonance (¹³C NMR), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were performed to construct a representative kerogen molecular model based on shale samples from the Lianggaoshan Formation in the Sichuan Basin. Grand Canonical Monte Carlo (GCMC) simulations and a theoretical occurrence model were applied to quantify the adsorption characteristics of n-dodecane under varying pore sizes, temperatures, and pressure. The results show that temperature exerts a stronger influence than pore diameter on adsorption capacity, with adsorption decreasing by over 50% at higher temperatures, and pressure has a limited effect on the adsorption amount of dodecane molecules. This study offers a robust workflow for evaluating shale oil occurrence states in complex pore systems and provides guidance for thermal stimulation strategies in tight oil reservoirs. Full article

Gold nanoparticles (AuNPs) are of significant interest due to their unique properties and applications in biomedicine. While hyaluronic acid (HA) has been used to modify pre-formed AuNPs, its thiolated derivative (HA−SH) has been less explored for the direct synthesis and stabilization of AuNPs. This study investigates the use of thiolated hyaluronic acid as a key component in the synthesis of AuNPs. A series of HA-AuNPs (HA-AuNP1-4) were synthesized by reacting HA-SH with HAuCl₄ at different mass ratios. The resulting nanoparticles were characterized using UV-Vis spectroscopy, scanning/transmission electron microscopy (SEM/STEM), X-ray photoelectron spectroscopy (XPS), photon cross-correlation spectroscopy (PCCS), and zeta potential measurements. The chemical transformations of the thiol ligand were studied using NMR spectroscopy. The morphologies and sizes of AuNPs depended on the HA-SH-to-HAuCl₄ ratio, ranging from icosahedral and triangular particles (≥146 nm) to quasi-spherical particles with a bimodal distribution (6–7 nm and 45–60 nm). XPS confirmed the presence of metallic gold (Au⁰) and a Au−S bond, while NMR and XPS revealed the partial oxidation of thiol groups to sulfonic acid. Zeta potential measurements showed that lower HAuCl₄ concentrations resulted in higher negative charge (up to −41.5 mV), enhancing colloidal stability. This work demonstrates a versatile approach to the synthesis of hyaluronic acid-based gold nanomaterials with tunable properties for potential biomedical applications. Full article

Elucidating the characteristics of methane adsorption in coal is essential for accurately assessing coalbed methane (CBM) potential. Methane adsorption is primarily governed by the compositional complexity of coal and its pore structure. Molecular simulation enables characterization of coal’s molecular composition at the microscopic level and facilitates the construction of nanoscale pore models. In this study, Nuclear Magnetic Resonance (NMR), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the molecular structure of coal. Pore models of various sizes were constructed in Materials Studio (MS) to simulate methane adsorption under different temperatures and pressures. To further clarify the influence of molecular structure, a reconstructed macromolecular model (RMM) was compared with a graphite model, revealing differences in methane adsorption behavior across varying pore sizes, temperatures, and pressures. The results show that absolute methane adsorption increases with pore size, while excess adsorption behavior is strongly associated with the adsorption layer. In the pore size range of 0.4 nm to 1.2 nm, excess adsorption increases due to spatial confinement, but decreases as pore size exceeds 1.2 nm. Structural differences between the RMM and graphite models also resulted in distinct temperature responses, with the graphite model underestimating methane adsorption capacity, highlighting the importance of realistic macromolecular representations in adsorption studies. Full article

Niobium (Nb), a transition element, has been applied mainly as steel additive, among other cutting-edge applications. Nb is mainly produced from pyrochlore-containing ores, dominated by mines at Araxá, Catalão (both from Brazil), and Niobec (Saguenay Region, QC, Canada). At these plants, flotation is employed as the main beneficiation method that all plants apply direct pyrochlore flotation; Catalão and Niobec apply additional reverse flotation prior to pyrochlore flotation. During flotation, depressants are added to improve selectivity, which highlights their importance to Nb mineral flotation. However, most of the available studies related to Nb mineral flotation focus on collectors; the knowledge on depressants is limited. In the present work, various depressants, including sodium silicate, oxalic acid, F100, starch, carboxymethyl cellulose (CMC), and chitosan, are compared for pyrochlore flotation at pH 7 in the presence of sodium oleate and dodecylamine (DDA) collectors. The results are compared with common gangue minerals, including dolomite, calcite, and hematite. It was observed that the performance of depressants is related to the collector applied, which was justified by the mineral surface charge after depressant adsorption and the charge of the collector. Among the tested combinations, 5 kg/t F100 + 2 kg/t DDA and 5 kg/t CMC + 2 kg/t DDA showed potential selectivity toward pyrochlore and hematite, whereas both carbonate minerals could be successfully depressed. Zeta potential measurement and X-ray photoelectron spectroscopy were applied to understand the interaction between depressants and the model minerals. Full article

Industrial air pollution, particularly acidic gases such as hydrogen chloride (HCl), poses serious environmental and health hazards. Here, hopcalite catalysts were introduced into activated carbon fibers via the impregnation process to enhance HCl capture. The Cu/Mn molar ratio was fixed at 1:1 while the Cu precursor loading was varied with the weight of Cu (Cu 0.04–0.1). Structural and surface modifications were examined using scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma mass spectrometer, and Brunauer–Emmett–Teller analyses. Progressive CuMnOx deposition increased Cu and Mn contents up to 4 at.% and 3.7 at.%, respectively, but decreased the specific surface area from 1565.1 to 1342.7 m²/g owing to pore blocking. Fixed-bed breakthrough tests (50 ppm HCl, 1000 mL/min) showed that moderate catalyst addition (Cu 0.04) yielded the highest total removal (83.6%) and adsorption capacity (12,354.6 mg/g), benefiting from combined physical and catalytic chemisorption. Higher loadings (Cu 0.06–0.1) further reduced microporosity and led to lower removal efficiencies. These results demonstrate that an optimal CuMnOx level effectively promotes chemical adsorption without compromising the intrinsic microporous network of ACFs. Full article

The rational design of transition metal oxides with tailored electronic structures and defect chemistries is critical for advancing high-performance supercapacitors. Herein, we report the engineering of cobalt oxide (Co₃O₄) gels through controlled sol–gel synthesis and rare earth (RE) incorporation using neodymium (Nd), gadolinium (Gd), and dual neodymium/gadolinium (Nd/Gd) doping. X-ray diffraction (XRD) confirmed the preservation of the cubic spinel structure with systematic peak shifts and broadening, evidencing lattice strain, oxygen vacancy generation, and defect enrichment. Field-emission scanning electron microscopy (FE-SEM) analyses revealed distinct morphological evolution from compact nanoparticle assemblies in pristine Co₃O₄ to highly porous, interconnected frameworks in Nd/Gd–Co₃O₄ (Nd/Gd-Co). X-ray photoelectron spectroscopy (XPS) verified the stable incorporation of RE ions, accompanied by electronic interaction with the Co–O matrix and enhanced oxygen defect states. Electrochemical measurements demonstrated that the Nd/Gd–Co electrode achieved a remarkable areal capacitance of 25 F/cm² at 8 mA/cm², superior ionic diffusion coefficients, and the lowest equivalent series resistance (0.26 Ω) among all samples. Long-term cycling confirmed 84.35% capacitance retention with 94.46% coulombic efficiency after 12,000 cycles. Furthermore, the asymmetric pouch-type supercapacitor (APSD) constructed with Nd/Gd–Co as the positive electrode and activated carbon as the negative electrode delivered a wide operational window of 1.5 V, an areal capacitance of 140 mF/cm², an energy density of 0.044 mWh/cm², and 89.44% retention after 7000 cycles. These findings establish Nd/Gd-Co gels as robust and scalable electrode materials and demonstrate that RE co-doping is an effective strategy for bridging high energy density with long-term electrochemical stability in asymmetric supercapacitors. Full article

A multi-strip detector made of synthetic single crystal diamond (SCD), based on a p-type/intrinsic diamond/Schottky metal transverse configuration and operating at zero bias voltage, was developed for imaging from extreme UV (EUV) to soft X-rays. The photodetector was patterned with 32 strips made of boron-doped diamond directly deposited, by means of the CVD technique and the standard lithographic technique, on top of the HPHT diamond growth substrate. The width of each strip and the gap between two adjacent strips were 100 μm and 20 μm, respectively. The strips were embedded in intrinsic SCD of an active area of 3.2 × 2.5 mm², also deposited using the CVD technique in a separate growing machine. In the present structure, the prototype photodetector is suitable for 1D imaging. However, all the dimensions above can be varied depending on the applications. The use of p-type diamond strips represents an attempt to mitigate the photoelectron emission from metal contacts, a non-negligible problem under EUV irradiation. The detector was tested with UV radiation and soft X-rays. To test the photodetector as an imaging device, a headboard (XDAS-DH) and a signal processing board (XDAS-SP) were used as front-end electronics. A standard XDAS software was used to acquire the experimental data. The results of the tests and the detector’s construction process are presented and discussed in the paper. Full article

Conventional polishing of glass substrates often results in surface scratches caused by passivated abrasive particles, leading to defects and reduced yield. To overcome this limitation, an iron-bonded wheel with free abrasive grains was proposed in ELID (Electrolytic In-process Dressing) grinding. The polishing mechanisms were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and micro-indentation. Polishing efficiency was assessed via mass loss measurements, surface quality was characterized by atomic force microscopy (AFM), and optical transmittance was evaluated using a transmittance meter. Results indicate that the proposed wheel does not contain fixed abrasive particles but generates α-Fe₂O₃ particles during polishing, effectively preventing surface scratches and achieving superior surface quality. The polishing efficiency ranged from 0.02 to 1.6 μm/min, with a resulting surface roughness of 2.1 nm. Furthermore, the glass substrates exhibited higher transmittance compared to those polished using conventional methods, contributing to improved display performance and brightness. This polishing technology demonstrates significant potential for applications in the display industry. Full article

Perfluorooctanesulfonate (PFOS) is a typical persistent organic pollutant, which presents a significant risk to the ecosystem and human health. Therefore, the development of a highly sensitive and effective detection technique for PFOS has aroused wide concern. In this study, for the mesoporous metal–organic frameworks (MOFs), Cr-MIL-101 were used as the precursor. And the poly(3,4-ethylenedioxythiophene) (PEDOT) using as molecularly imprinted polymers (MIPs) was loaded on Cr-MIL-101 to form a core–shell structure. The obtained Cr-MIL-101@PEDOT/MIP composites integrate the high specific surface area of Cr-MIL-101 and the specific recognition capability of PEDOT/MIP. The glassy carbon electrode (GCE) interface modified by them can specifically adsorb PFOS through electrostatic interactions, coordination by Cr metal nodes, hydrophobic interaction, and hydrogen bonding, etc. The adsorbed PFOS molecules could block the active sites at the electrode interface, causing the current decay of the redox probe. Following the quantitative analysis of peak current decay values using the Langmuir model and the Freundlich–Langmuir model, a wide detection range (0.1–200 nM) and a low detection limit (0.025 nM) were obtained. Characterization techniques including scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), and electrochemical methods were employed to validate the fabrication of the composites. Moreover, Cr-MIL-101@PEDOT/MIP/GCE showed satisfactory stability, repeatability, and selectivity, providing an effective method for the detection of PFOS in practical samples, showing a wide prospective application. Full article