Search Results (24,750)

Water pollution from industrial dyes is a critical challenge due to the resistance of these types of compounds to degradation and potentially harmful effects on living organisms and human health. In this study, the electrochemical degradation of methylene blue (MB) was investigated using ink-based copper foam electrodes with reduced graphene oxide (rGO), antimony trioxide (Sb₂O₃), and rGO/Sb₂O₃ composites. The materials used to synthesize the electrodes were characterized by X-ray diffraction (XRD), which showed the successful synthesis of GO, rGO, and the Sb₂O₃-rGO composite. Additionally, the synthesized electrodes were examined using SEM. The MB degradation was studied using kinetic behavior and removal efficiency at pH levels from 3 through 6, monitored using UV-Vis spectroscopy. The electrocatalytic degradation was studied using sodium sulfate as the electrolyte across a pH range of 3 to 8. All electrodes investigated were determined to follow first-order kinetics. The Sb₂O₃-rGO composite showed the highest rate constants of MB degradation at pH 7 and 8, with rate constants of 0.0160 and 0.0159 min⁻¹, respectively. At the same time, the rGO ink-based electrode worked fastest at pH 3 and pH 4 with rate constants of 0.0178 and 0.0158 min⁻¹, respectively. The Sb₂O₃ also works best at pH 3 and 4 with rate constants of 0.0151 and 0.0152 min⁻¹. SEM analysis shows the composite electrode was more resilient to degradation than other materials. Full article

We used synchrotron X-ray diffraction (XRD) and ac-impedance spectroscopy (AIS) to uncover the structural and chemical modifications undergone by RbH₂PO₄ (RDP) at intermediate temperatures (150 °C < T < 300 °C) and investigate their relationship with RDP’s proton conductivity, σ. Nyquist plots collected on RDP samples sealed in a small volume (~50 mL) of dry air show a gradual increase in σ upon heating from 180 to 260 °C, but not the three-order-of-magnitude superprotonic jump observed in the Cs-based compound CsH₂PO₄ (CDP) within the same temperature range. Correspondingly, XRD measurements using synchrotron radiation (λ = 0.922 Å) on RDP crystalline powders sealed in a quartz capillary exhibit no evidence of a monoclinic-to-cubic superprotonic phase transition like the one observed in CDP. Instead, these temperature-resolved powder XRD patterns demonstrate that the intermediate-temperature RDP monoclinic phase (P2₁/m, a = 7.733 Å, b = 6.189 Å, c = 4.793 Å, and β = 109.21 deg) persists up to the melting point of the title compound. Our most significant finding comes from heating RDP under high pressure (P = 1 GPa), which leads to markedly different structural behavior. Indeed, our full profile refinements against XRD data collected on RDP crystals compressed at ~1 GPa show evidence of a polymorphic phase transition (at T_c = 300 °C) to a high-temperature cubic phase (Pm-3m, a = 4.784 Å) that is isomorphic with its CDP counterpart. This is significant, as it indicates that the superprotonic conduction in phosphate solid acids is not cation-specific, and a general highly efficient proton conduction mechanism is present in the high-temperature phases of these materials. Full article

The construction of Z-scheme heterojunctions is regarded as one of the most effective modification strategies for photocatalysts. However, how to improve the interfacial charge transfer efficiency to further enhance the photocatalytic activity remains an urgent issue to be addressed. In this study, sulfur vacancy-enriched ZnIn₂S₄/MoS₂ Z-scheme heterojunctions (V-ZIS/MS) containing interfacial Mo-S bonds was successfully synthesized using a hydrothermal method. The V-ZIS/2%MS showed the highest hydrogen evolution rate, achieving 19.21 ± 0.78 mmol·g⁻¹·h⁻¹ under visible light and 112.89 ± 10.98 mmol·g⁻¹·h⁻¹ under full-spectrum illumination, which are 5.07 and 4.41 times higher than ZIS (3.79 ± 0.79 mmol·g⁻¹·h⁻¹) and V-ZIS (4.36 ± 0.98 mmol·g⁻¹·h⁻¹) under visible light, respectively, outperforming most reported ZIS-based photocatalysts. This is because the composite of V-ZIS and MS enhanced its light absorption performance. More importantly, the formation of Mo-S bonds at the V-ZIS/MoS₂ interface facilitated efficient charge transfer and reduced interfacial resistance, leading to significantly improved photocatalytic activity. Cycling experiments further demonstrate that V-ZIS/2%MS exhibits considerable photocatalytic stability. X-ray diffraction analysis before and after the reaction further confirmed the structural stability of the catalyst. This work provides a certain reference for the preparation of high-performance ZIS-based photocatalysts. Full article

Conventional synchronous grouting materials often exhibit low early strength, delayed setting, and insufficient utilization of excavated soil, hindering the green and efficient advancement of metro shield tunneling technology. To overcome these challenges, this study developed a high-performance grouting material by utilizing shield muck—primarily composed of quartz (71.47%) and calcite (15.3%)—as the main raw material, with sodium trimethylsilanolate (TMS-Na) introduced as a performance enhancer. Through orthogonal experiments and range analysis, the influences of cement content, slag content, and TMS-Na dosage on the workability and mechanical properties of synchronous grouting materials were systematically evaluated. Microstructural evolution was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric (TG) analysis, and mercury intrusion porosimetry (MIP) to elucidate the mechanism by which TMS-Na modifies the grout microstructure. The results demonstrate that incorporating 8% slag and 0.2% TMS-Na increases the utilization rate of shield muck to 60.8%. Compared with conventional grouts, the novel material exhibits approximately 97.4% and 93.3% enhancements in 3-day and 28-day compressive strength, respectively, alongside an impermeability grade reaching P10. The addition of slag improves the apparent density and early strength of the grout, although its contribution diminishes at later ages. TMS-Na effectively activates the hydration reactivity of slag, accelerates early hydration, reduces the setting time, and participates in a secondary hydration reaction with argillaceous siltstone present in the excavated soil, promoting the formation of additional calcium silicate hydrate (C-S-H). This process densifies the hardened grout matrix, refines the pore structure, and significantly enhances both mechanical performance and impermeability. Field application in a trial tunnel section confirms that the proposed grouting material achieves complete cavity filling, eliminates water leakage, controls ground deformation effectively, and offers favorable economic viability, demonstrating strong potential for large-scale engineering application. Full article

The influence of Zn²⁺, Ca²⁺ and Co²⁺ doping on the thermal, structural, morphological, and magnetic characteristics of CdBi_0.1Fe_1.9O₄ nanoparticles synthetized via the sol–gel technique and calcined at 300, 600, 900 and 1200 °C was investigated. Thermal analysis revealed the initial formation of metallic glyoxylates up to 300 °C, followed by their decomposition into metal oxides and subsequent ferrite formation. X-ray diffraction revealed that the ferrites were poorly crystallized at lower temperatures, whereas at higher calcination temperatures all nanocomposites exhibited well-crystalized ferrites coexisting with the SiO₂ matrix, except for the Co_0.1Cd_0.9Bi_0.1Fe_1.9O₄@SiO₂ nanocomposite, which formed a single, well-defined crystalline phase. Atomic force microscopy images revealed spherical ferrite particles encapsulated within an amorphous layer, with particle size, surface area, and coating thickness influenced by both the type of dopant ion and the calcination temperature. The structural parameters estimated by X-ray diffraction, as well as the magnetic characteristics, were strongly influenced by the dopant type and thermal treatment. These results demonstrate that the structural and magnetic characteristics of CdBi₀.₁Fe₁.₉O₄ ferrites can be effectively tuned through controlled doping and calcination, providing insights for the design of tailored functional applications. Full article

The dynamic development of laser therapy in dentistry is associated, among other factors, with the bactericidal effect of the energy emitted by laser devices. Therefore, they are also helpful for decontamination. They are increasingly used in the treatment of peri-implantitis, a bacterial inflammation of peri-implant tissues that is the most severe late complication of implantation and a potential cause of implant loss. Therefore, this study aimed to assess the safety of laser decontamination of the implant surface with respect to its effect on the integrity of the implant structure. In the present study, blocks of the titanium alloys Ti-6Al4V and Ti6Al7Nb were fabricated using electron-beam powder bed fusion and laser powder bed fusion, respectively. These alloys, commonly used in implantology, here in the form of Ti block scaffolds, have been exposed to an Er³⁺:YAG laser under various parameters (energy range of 50–320 mJ, exposure times of 20 or 30 s), and their effects have been further observed. To determine the changes induced by the laser, the following techniques were used: X-ray diffraction (XRD), Rietveld refinement method, scanning electron microscopy (SEM) with EDS (Energy-dispersive X-ray Spectroscopy), and thermography. The results show that the proposed Ti6Al4V and Ti6Al7Nb scaffolds can be exposed to an Er³⁺:YAG laser without damage when the power is limited to 0.5 W. Full article

ZnO and ZnO:5%B nanoparticles produced by sol–gel synthesis exhibit a single-phase wurtzite structure. X-ray diffraction (XRD) investigation reveals crystallite sizes in the range of $32.37–39.63$ nm and microstrain values on the order of $(1.98–8.03)\times {10}^{-4}$, despite the Uniform Stress Deformation Model (USDM) indicating the presence of considerable tensile stress. Significant band-tail states are introduced via boron doping, resulting in Urbach energies ranging from $110$ to $193$ meV and a narrowed optical band gap of $3.216$ eV. With a refractive index range of $2.05–2.71$, the material exhibits tunable optical characteristics. Violet and blue emissions originating predominantly from zinc interstitials (Znᵢ) and zinc vacancies (V_Zn) dominate the photoluminescence spectra, while oxygen interstitial-related contributions remain relatively weak. A high spin density is confirmed by electron spin resonance measurements, which reveal a strong defect-related signal at $g\approx 2.294$. The formation of Znᵢ/V_Zn defect centers due to charge compensation and ionic size mismatch induced by B³⁺ substitution for Zn²⁺ significantly modifies the band-edge states and optical constants. These defect-engineered properties render the material promising for applications in ultraviolet (UV) photodetectors, transparent conducting oxides, and electron transport layers in organic photovoltaic devices. Full article

Microencapsulated phase change materials (MPCMs) offer a promising way to enhance the thermal performance of cement-based materials; however, their incorporation often compromises mechanical properties and durability, limiting practical application. A mechanistic understanding of how MPCM particle size governs the coupled thermal, mechanical, and transport behavior of cementitious systems remains incomplete. In this paper, two organic MPCMs with identical core–shell chemistry but distinct particle sizes (mean diameters of 10.78 μm and 34.21 μm) were incorporated into mortar at dosages of 10 wt.% and 20 wt.% under w/b ratios of 0.35 and 0.45. The effects of MPCM particle size and content on hydration kinetics, rheology, strength development, pore transport behavior, and thermal conductivity were systematically investigated using isothermal calorimetry, flow spread testing, compressive strength measurements, capillary water absorption, thermal conductivity analysis, X-ray diffraction, and SEM–EDS characterization. Results show that MPCM incorporation delays early-age hydration and reduces peak hydration rates, with finer particles exerting a stronger inhibitory effect due to increased specific surface area and water adsorption. While all MPCM-modified mortars exhibit reduced compressive strength and increased capillary absorption, larger MPCM particles mitigate strength loss by limiting the total interfacial transition zone (ITZ) area and reducing ITZ connectivity. In contrast, smaller MPCM particles more effectively decrease thermal conductivity, achieving up to a 33% reduction, owing to enhanced interfacial thermal resistance. Microstructural observations confirm that MPCMs do not alter cement hydration products but influence performance through interfacial defects, porosity evolution, and particle-scale interactions. These findings demonstrate that MPCM particle size critically controls the trade-off between thermal regulation and structural integrity, providing quantitative guidance for designing PCM-modified concrete through optimizing particle-size. Full article

A novel Lithium triflate-incorporated Solid Polymer Electrolyte (SPE) has been developed by using the optimized blend of Ghatti Gum (GG) and Xanthan Gum (XG) with a biodegradable synthetic polymer, Polyvinyl alcohol (PVA), ethylene glycol as a plasticizer, and formaldehyde as a cross-linker for energy storage applications. They are examined by X-ray diffraction, Fourier transform infrared spectroscopy, and electrochemical impedance analysis. The frequency-dependent conductivity adheres to Joshner’s universal power law, with the TF10 composition achieving the higher ionic conductivity of 2.73 × 10⁻⁵ S cm⁻¹. Temperature-dependent conductivity confirms Arrhenius-type behavior and shows a low activation energy of 0.15 eV that supports facile ion transport. The conduction process in TF10 follows the Correlated Barrier Hopping (CBH) model. Dielectric and modulus investigations indicate relaxation dynamics with the shorter relaxation time (6.45 × 10⁻⁶ s) from tangent loss spectra. From the SEM analysis, the uniform distribution and the porous nature of the electrode activated carbon are confirmed. A supercapacitor is assembled with TF10 displays electric double-layer capacitive features, delivering a specific capacitance of 7.1 Fg⁻¹ at 15 mVs⁻¹. Charge–discharge analysis reveals energy and power densities of 2.52 Wh kg⁻¹ and 2500 W kg⁻¹, respectively, for the supercapacitor. Full article

The corrosion behavior and passive-film stability of a β-TiZrNbTa (β-TZNT) alloy were investigated in artificial seawater (ASW), focusing on the effects of pH, temperature, immersion time, fluoride ion concentration, and potential scan rate. In addition to electrochemical methods such as open-circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were employed for surface characterization. The establishment of a stable and efficient passive layer enriched in Zr-, Nb-, and Ta-oxides was responsible for the β-TZNT alloy’s superior corrosion resistance in fluoride-free ASW when compared to commercially pure titanium. Reduced passive-film resistance resulted from corrosion kinetics being greatly accelerated by decreasing the pH and increasing the temperature. The presence of fluoride ions strongly affected the passivity of the alloy due to the chemical dissolution of TiO₂ through the formation of soluble fluoride complexes, resulting in an increase in the corrosion current densities by more than one order of magnitude. A bilayer passive structure with a compact inner barrier layer and a porous outer layer was identified by EIS analysis. The stability of this structure gradually decreased with increasing fluoride concentration and acidity. Over time, passive-film degradation was dominant in fluoride-free seawater, whereas prolonged exposure in fluoride-containing media promoted partial re-passivation. Overall, these results highlight the potential and limitations of the β-TZNT alloy for marine and offshore applications by offering new mechanistic insights into the synergistic effects of fluoride ions and environmental factors on corrosion performance. Full article

A defect-rich nucleation layer near the substrate is widely regarded as a key thermal bottleneck in thick polycrystalline diamond films. Here, we quantitatively evaluate this effect by progressively removing the nucleation layer via depth-controlled inductively coupled plasma (ICP) etching and measuring the thermal conductivity. The thermal conductivity increases from 1549.9097 W·m⁻¹·K⁻¹ (as-grown) to 1656.1743 W·m⁻¹·K⁻¹ (1 h), 1783.3763 W·m⁻¹·K⁻¹ (3 h), and 1792.0250 W·m⁻¹·K⁻¹ after 5 h of etching, consistent with the reduction of defects and non-diamond carbon revealed by X-ray diffraction (XRD) and Raman analyses. These results provide a quantitative, depth-resolved validation of the nucleation-layer thermal resistance and establish an effective post-growth route to enhance thermal transport in thick polycrystalline diamond films. Full article

This research focuses on the passive behavior changes of 3 Ah pouch LiFePO₄ (LFP) batteries during low-temperature storage, a point often neglected in previous studies. This experiment examines the low-temperature non-operational endurance of fully charged batteries (FCB) at 25 °C, −10 °C, and −35 °C. Battery performance reliability under these conditions is evaluated through capacity retention and internal resistance (IR) analysis. Microstructural changes on the surfaces of thawed battery electrodes are acquired using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. After seven freeze–thaw cycles, the maximum usable capacity is marginally affected. Notably, a pronounced increase in polarization resistance (R_p) has been observed, particularly at −10 °C conditions, with an increase of about 40.57 mΩ. Microstructural analyses reveal that low-temperature storage significantly led to cracking of the electrolyte layer and of the particles in the anode material. Subsequently, at room temperature (RT, 25 °C), external short circuit (ESC) tests were performed on thawed batteries. At 50C, the peak temperatures recorded at the center of the FCB₋₁₀, FCB₂₅, and FCB₋₃₅ batteries are 104.35 °C, 94.67 °C, and 90.56 °C, respectively. The batteries exhibit rupture at approximately 47 s, 60 s, and 70 s during the ESC process. The results show that battery FCB₋₃₅ exhibits a slower temperature rise and delayed physical damage during ESC. Full article

This work reports the elaboration and testing of polydimethylsiloxane/titanium dioxide (PDMS/TiO₂) polymer nanocomposites, focusing on producing and combining TiO₂ nanoparticles with a polymer matrix through an ex situ route. By mixing the inherent flexibility of PDMS with the unique properties of nanoparticles, the nanocomposites aim to enhance mechanical stability, optical response, and photocatalytic activity. X-ray diffraction (XRD) confirmed the successful incorporation of TiO₂ into the PDMS matrix. UV–visible spectroscopy monitored photocatalytic performance using metronidazole as a model pollutant under 365 nm irradiation. Kinetic analysis revealed degradation and showed that the reaction rate constant (k) increased with TiO₂ loading, reaching a maximum of 0.0019 min⁻¹ for the 6 wt.% composite. These findings indicate that while the reaction kinetics are slower than those of free powders, the PDMS/TiO₂ nanocomposites provide a viable, recoverable, and flexible solution for environmental remediation applications. Future efforts will target improved durability, broadened visible light absorption, and process optimization for scalable fabrication. Full article

This study investigates the presence of Technology-Critical Elements in the Trepça mine (Stan Tërg, Mitrovicë), representing the first assessment of their distribution within this mining district. Samples were collected in all ore bodies (three samples per ore body) in horizons VIII-XI. Mineralogical, geochemical and microstructural characterization was performed using X-ray diffraction (XRD), Inductively Coupled Plasma Mass-Spectrometry (ICP-MS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The analyses confirmed the presence of several Technology-Critical Elements, especially Bi, Co, Ge, W, Ga, In, Te and Sb, whose distribution, correlation with mineral phases and structure were also identified. XRD enabled the identification of mineral phases while SEM-EDX provided structural and morphological characteristics of these mineral phases. The ICP-MS results indicate significant variability in the distribution of these elements. Bi reached extremely high concentrations (up to 2570.68 ppm in ore body 136), well above the method detection limit (MDL = 0.01 ppm), whereas Co exhibited elevated yet moderate concentrations that increased with depth, indicating a depth-dependent rise in concentration. V, W, Sb and Sn also exhibited elevated concentrations. Peak enrichment levels were observed for Bi (up to 2750 ppm) in Horizon IX, Sb (up to 504 ppm) in Horizon XI, W (up to 308 ppm) in Horizon VIII, and In (up to 34,730 ppm) within selected ore bodies, indicating pronounced vertical geochemical zonation. The results demonstrate that selected ore bodies represent significant potential sources of Technology-Critical Elements, supporting future resources and strategic raw material assessment within the Trepça mining district. Full article

Enhanced catalytic activity for composite solid propellants (CSPs) can be achieved through high-efficiency dispersion of active sites on the surface of two-dimensional (2D) materials. In this study, we report the in situ formation of MnCo₂O_4.5 nanoneedles on the surface of covalent triazine frameworks (CTFs), resulting in 2D CTF/MnCo₂O_4.5 composites with outstanding catalytic properties for the thermal decomposition of ammonium perchlorate (AP). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the successful preparation of the CTF/MnCo₂O_4.5 composites and revealed the interaction between CTFs and MnCo₂O_4.5. Scanning electron microscopy (SEM) and elemental mapping further demonstrated the uniform anchoring and dispersion of MnCo₂O_4.5 nanoneedles on the layered CTF surfaces. Additionally, the obtained CTF/MnCo₂O_4.5 composites exhibited promising catalytic capacity for AP decomposition. When added at a loading of 2 wt%, the CTF/MnCo₂O_4.5 composites significantly reduced the thermal decomposition temperature of AP by 81.3 °C, while simultaneously decreasing the content to 30 wt% compared to pure MnCo₂O_4.5 catalysts. Full article