Search Results (1,326)

This study investigates the atmospheric corrosion behavior of high-lead bronze alloys within a simulated aggressive environment characterized by high humidity, acidity, chlorides, oxygen, and CO₂. The evolution of surface morphology and corrosion products was systematically monitored using colorimetric analysis and micro-Raman spectroscopy. Results indicate that the initial patina primarily comprised cuprite (Cu₂O) and cassiterite (SnO₂), which are predominantly benign phases. During the early corrosion stage, lead oxidation and carbonation prevailed, generating abundant bright-white cerussite. Subsequently, as copper-driven corrosion became dominant, these white deposits diminished and were progressively replaced by characteristic green “bronze disease”, identified as atacamite (Cu₂(OH)₃Cl). The findings reveal that preferential lead corrosion is likely to induce localized pitting, thereby accelerating degradation of the copper substrate. Consequently, higher lead content may reduce the overall corrosion resistance of bronze artifacts under these specific conditions. These results offer experimental insights into atmospheric corrosion mechanisms and inform the development of evidence-based conservation strategies for bronze cultural heritage. Full article

Ag-SnO₂ composites are widely adopted as electrical contact materials in low-voltage apparatuses. Ongoing upgrades of electrical devices impose higher standards for their mechanical strength, machinability, and electrical conductivity, among which the SnO₂ volume fraction is a dominant factor regulating material performance. In this work, Ag-SnO₂ electrical contact composites are reinforced with 15 μm SnO₂ particles at various volume fractions. Increasing SnO₂ volume fractions can improve the hardness. The ultimate tensile strength reaches a maximum value of 219.1 MPa at the SnO₂ volume fraction of 18.3 vol%. Excessively high SnO₂ content (26.5 vol%) leads to the brittle fracture of the composite and a sharp decline in tensile strength. Indirect strengthening dominates the overall mechanical performance, among which grain refinement serves as the primary strengthening mechanism, followed by dislocation multiplication strengthening, while the Orowan looping effect is negligible for coarse 15 μm SnO₂ particles. This work clarifies the microstructure–performance correlation and strengthening mechanism of particle-reinforced Ag-SnO₂ composites, providing a theoretical and experimental basis for the optimal design and performance optimization of high-performance electrical contact materials. Full article

Strict monitoring of methane (CH₄) during underground coal mining is necessary, as the lower explosive limit (LEL) is 5 vol% in air. A conventional tin oxide (SnO₂)-based metal–oxide semiconductor (MOS) sensor has an operating temperature of 200–400 °C, which requires a prohibitive power demand and entails the risk of ignition within an intrinsically safe environment. The decoration of SnO₂ nanoarchitectures with palladium has been demonstrated to achieve room temperature (RT) detection of CH₄ due to the chemical sensitisation spillover mechanism and electronic sensitisation by Schottky barrier modulation. Moreover, palladisation of SnO₂ nanowires (NWs) is likely to be an effective route for achieving a more efficient detection of CH₄ aerosol at RT or near RT. The purpose of this mini-review is to provide a critical synthesis of advances that have been reported between 2020 and 2026. Because no published study to date has directly demonstrated room-temperature CH₄ detection using pure Pd-decorated SnO₂ nanowires, performance data from mechanistically analogous systems—namely H₂-sensing Pd–SnO₂ nanowires and CH₄-sensing non-nanowire Pd–SnO₂ nanostructures—are included in this review and are explicitly labelled as such throughout. This absence of direct RT CH₄ NW data constitutes the primary research gap motivating this review. The performance of Pd-containing SnO₂ nanostructures reported in the literature spans response values of 17.6 (300 ppm CH₄, 2.5 mol% Pd–SnO₂ nanoporous, 340 °C) to 21.3 (3000 ppm CH₄, bimetallic Pt–Pd–SnO₂ mesoporous, 400 °C), representing a 3–10× improvement over bare SnO₂ (response: 2–10 in the same concentration range). These benchmarks were obtained at elevated temperatures (340–400 °C); no equivalent room-temperature CH₄ detection data for Pd–SnO₂ nanowires currently exists in the published literature. Reported response times range from 3 to 9 s at elevated temperature (340–400 °C) to 74–78 s for room-temperature visible-light-activated systems, where photocatalytic oxygen activation is the rate-limiting step. The 30 s MSHA alarm threshold is met by elevated-temperature systems but remains a challenge for RT configurations. The LODs were 175.9 ppb (bimetallic PdxPt/SnO₂ mesoporous system). Two hybrid composites containing rGO exhibited an extended capability for RT operation. Bimetallic PdPt decoration and ML-augmented sensor arrays are identified as the most promising near-term pathways to bridge the selectivity and stability gaps for certified mining deployment. Full article

ZnO is widely used as an electron transport layer in quantum-dot light-emitting diodes (QLEDs) because of its high electron mobility and suitable energy levels. However, rapid electron transport may cause excessive electron injection, leading to charge accumulation and parasitic recombination. SnO₂ provides weaker electron transport, but using it alone limits device performance. Here, a SnO₂/ZnO bilayer electron transport layer was introduced to regulate electron injection. Unlike previously reported structures in which SnO₂ directly contacts the QDs, the present configuration places SnO₂ on ITO and ZnO adjacent to the QD layer. The low-concentration ZnO overlayer reduced the RMS roughness of the SnO₂ film from 1.79 to 1.07 nm and facilitated electron injection, while the underlying SnO₂ layer moderated the electron supply. The bilayer also suppressed leakage current and showed the lowest capacitance peak, consistent with improved charge balance. The bilayer QLED achieved a maximum current efficiency of 13.40 cd/A and a maximum luminance of 33,210 cd/m². Its current efficiency was 100% and 32.7% higher than those of the SnO₂ and ZnO devices, respectively. These results demonstrate that the bilayer improves charge balance through facilitated electron injection and controlled electron supply. Full article

To improve the corrosion resistance of Sn coatings on Cu substrates in chloride-containing environments, pure Sn and Sn–P coatings containing 0.02, 0.05, and 0.08 wt.% P were prepared by hot-dip coating. Their surface morphology, surface-film chemistry, and corrosion behavior were characterized using electrochemical measurements, atomic force microscopy (AFM), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDS), and X-ray photoelectron spectroscopy (XPS). The results demonstrate that trace phosphorus addition enhances the electrochemical stability of Sn coatings prepared via the hot-dip method. The corrosion current density decreased from 1.55 × 10⁻⁶ A·cm⁻² for pure Sn to 3.28 × 10⁻⁷ A·cm⁻² for SnP0.02, corresponding to a reduction of approximately 79%. Meanwhile, the total resistance increased from 10.46 to 19.03 kΩ·cm², confirming the enhanced barrier effect of the surface film. AFM results showed that the surface roughness Ra decreased from 13.41 nm for pure Sn to 8.72–12.69 nm for the Sn–P coatings. XPS identified Sn–O, P–O, and Sn–P species, suggesting the formation of a Sn–O/P–O-containing protective film. SnP0.02 exhibited the best overall corrosion resistance, whereas excessive P promoted local P-rich regions and non-uniform film formation, limiting further improvement. Full article

In the present work, graphene-modified zinc oxide (ZnO-rGO) and fluorine-doped tin oxide (FTO) thin films were successfully fabricated using a simple, low-cost pulsed spray pyrolysis technique. The structural, morphological, optical, electrical, and surface electronic properties of the deposited films were systematically characterized. X-ray diffraction (XRD) analysis confirmed the formation of polycrystalline ZnO- and SnO₂-based phases with crystallite sizes in the nanometer range. The crystallographic parameters, microstrain, and dislocation density of the deposited films were found to be influenced by the incorporation of reduced graphene oxide (rGO) and fluorine dopants. Scanning electron microscopy (SEM) revealed compact and homogeneous surface morphologies with good film coverage and well-defined nanocrystalline features. Optical characterization demonstrated the wide-bandgap semiconducting behavior of the deposited films, with optical bandgap energies ranging from 3.262 to 3.312 eV for the ZnO-rGO films and from 3.91 to 4.01 eV for the FTO films. Kelvin probe measurements yielded work-function values in the range of approximately 5.0–5.2 eV, indicating favorable surface electronic characteristics suitable for optoelectronic applications. Furthermore, fluorine incorporation enhanced the dielectric response of the SnO₂ films, particularly in the low-frequency region owing to increased interfacial polarization effects. The obtained results demonstrate that pulsed spray pyrolysis provides a simple, cost-effective, and efficient route for fabricating ZnO-rGO and FTO thin films with desirable structural, optical, electrical, and surface electronic properties. These findings highlight the considerable potential of the developed materials for transparent electrodes and a wide range of optoelectronic applications. Full article

In semiconductor photocatalysis, the strong redox ability of a wide band gap and the broad light absorption range of a narrow band gap are a pair of irreconcilable trade-offs. By combining semiconductors with different band gap widths and band edge positions, both of these advantages can be achieved simultaneously. A ternary Cu₂O-SnO₂/g-C₃N₄ (CuSnCN) composite photocatalyst was prepared through the hydrothermal and calcination method. Structural analyses confirm the successful integration of truncated octahedral Cu₂O, spherical SnO₂, and layered g-C₃N₄, which extends the visible-light response to 650 nm. The optimized system achieves a remarkable 96.58% degradation of methyl orange (80 min, 0.2 g/L catalyst, pH = 3) through dual heterojunction synergies: p–n junctions (Cu₂O/g-C₃N₄ and SnO₂/g-C₃N₄) and Z-scheme charge transfer (SnO₂/Cu₂O), with •O₂⁻/h⁺ identified as the dominant reactive species. This work establishes a tunable heterojunction platform for the elimination of multiple pollutants through engineered radical-generation pathways. Full article

Transparent conductive oxides (TCOs) are indispensable core materials for optoelectronic devices, yet the inherent conflict between electrical conductivity and optical transparency, along with the scarcity and brittleness of indium tin oxide (ITO), severely limits their sustainable development. This review systematically summarizes the research progress of next-generation TCOs, focusing on microstructural engineering, advanced doping strategies, and architectural innovation to decouple the conductivity–transparency trade-off. The fundamental mechanisms of carrier scattering (ionized impurity scattering, grain boundary scattering) and the mobility-centric design paradigm are elaborated. The research status of typical material systems (SnO₂-based, ZnO-based, In₂O₃-based) is analyzed, and the mechanisms of high-valent cation doping, interstitial doping, and critical nucleation in optimizing carrier mobility are clarified. The oxide/metal/oxide (OMO) multilayer architecture is highlighted as a breakthrough strategy for synergistic optoelectronic performance. Current challenges including thermal stability, large-area fabrication, and environmental reliability are discussed, and future directions such as resonant doping, machine learning-assisted optimization, and multifunctional integration are prospected. This work provides a systematic theoretical basis and technical reference for the development of high-performance, sustainable TCOs. Full article

The Feng Yun-3B (FY-3B) Infrared Atmospheric Sounder (IRAS) provides key infrared observations for numerical weather prediction (NWP) and climate applications, but long-term consistency is affected by three factors: spectral response function (SRF) central wavenumber shifts, changes in the nonlinear coefficient of the instrument in orbit, and fixed brightness-temperature (BT) uniformity screening. We propose a three-step refinement chain consisting of SRF central wavenumber shift correction (SSC), in-orbit nonlinearity-coefficient optimization (NCO), and channel-dependent adaptive quality control (AQC). First, SSC conducts fine adjustment of SRF central wavenumbers by jointly minimizing mean bias and standard deviation, reducing uncertainty by about 10–25% in sensitive absorption channels. Second, NCO refines the quadratic term under two-point anchoring constraints, recentering mean biases toward zero without changing linear gain. Third, AQC applies channel-dependent BT-uniformity thresholds to suppress scene-driven variance while preserving sample representativeness. Using FY-3B/IRAS and Meteorological Operational Satellite Programme-A/Infrared Atmospheric Sounding Interferometer (Metop-A/IASI) simultaneous nadir overpass (SNO) matchups from 2010–2019, the integrated SSC–NCO–AQC chain substantially improves cross-calibration consistency: most CO₂ channels show mean biases reduced from >1 K to <0.2 K, with narrower uncertainty envelopes, while window channels remain stable. The results support more reliable long-term radiometric consistency and cross-year comparability for FY-3B/IRAS. Full article

Cadmium sulfide has been widely used as a conventional n-type window/buffer layer or heterojunction partner in several p-type thin-film solar cells, including CdTe/CdSeTe-, chalcopyrite-, kesterite-, antimony chalcogenide-, tin sulfide- and iron pyrite-based devices. Its success is related to its ability to form suitable heterojunctions, partially passivate absorber surfaces and provide favorable electronic selectivity. However, the parasitic absorption associated with the relatively narrow band gap of CdS, the toxicity and waste-management issues related to cadmium-containing auxiliary layers and the need for improved band alignment have motivated extensive research on CdS-free window and buffer layers. This review summarizes the main efforts devoted to replacing CdS in thin-film solar cells based on absorbers such as CdTe/CdSeTe, CIS, CIGS, CZTS, CZTSe, CZTSSe, Sb₂S₃, Sb₂Se₃, Sb₂(S,Se)₃, SnS and FeS₂. The most investigated alternative materials, including Zn(O,S), ZnS, In₂S₃, ZnMgO, ZnSnO, TiO₂, SnO₂ and SnS₂, are discussed with emphasis on their optical properties, band alignment, interface quality, deposition methods and impact on device performance. The analysis highlights that CdS replacement cannot be treated as a universal material substitution problem. Instead, each absorber and device architecture requires a specific front-interface design, where chemical compatibility, conduction band offset, defect passivation, optical transparency and process-induced interfacial modifications play a decisive role. CdS-free approaches are relatively mature for CdTe/CdSeTe- and CIGS-based solar cells, whereas kesterite absorbers, antimony chalcogenides and SnS still require further interface engineering. In FeS₂, by contrast, buffer-layer substitution remains secondary to the control of intrinsic surface and bulk electronic defects. This review provides a concise comparison of the most relevant CdS-free front/window materials and identifies key challenges for the future design of sustainable thin-film solar cells. Full article

The marketable viability of perovskite solar cells (PSCs) is currently hindered by challenges related to interfacial charge-carrier extraction and thermal degradation. This study presents a comprehensive finite element method (FEM) analysis using COMSOL Multiphysics to evaluate the efficacy of bi-layer electron transport layer (ETL) engineering in addressing these limitations. We developed a coupled optical–electrical model to investigate three planar architectures: a conventional TiO₂-based reference device, a ${\mathrm{TiO}}_2/{\mathrm{SnO}}_2$ bi-layer configuration, and a ${\mathrm{TiO}}_2/{\mathrm{SnO}}_2:\mathrm{Fe}$ (iron-doped) bi-layer device. Simulation results under AM1.5G illumination reveal that the bi-layer configurations significantly enhance optical absorption across the visible spectrum (350–700 nm) compared to the single-layer counterpart. The incorporation of Fe-doped SnO₂ resulted in optimized energy band alignment, creating a favourable conduction band offset that facilitates electron extraction. Consequently, the ${\mathrm{TiO}}_2/{\mathrm{SnO}}_2:\mathrm{Fe}$ device achieved a peak power conversion efficiency (PCE) of 18.3% at 300 K, outperforming the undoped bi-layer (18.0%) and the reference device (17.5%). Furthermore, thermal stress simulations indicated that the Fe-doped architecture exhibits superior stability, maintaining a PCE of 12.8% at 440 K compared to 12.3% for the reference. This enhanced performance is attributed to the passivation of interfacial defects and the formation of a stronger built-in electric field at the ETL/absorber junction, validating the strategic doping of metal oxides as a robust pathway for high-efficiency, thermally stable perovskite photovoltaics. Full article

Background and Objectives: Hypoxia is the most common adverse event in patients undergoing procedural sedation. Burn-related pain is severe and often requires high doses of opioids and anxiolytics, increasing the risk of respiratory depression. This study aimed to compare the effectiveness of high-flow nasal oxygen (HFNO) and standard nasal oxygen (SNO) in preventing hypoxia during deep sedation in patients with minor and moderate burns. Materials and Methods: This single-center prospective observational study enrolled 76 adult patients (ASA I–III) with minor to moderate burns undergoing supine-position procedures under sedation. Patients were allocated to HFNO (n = 38) or SNO (n = 38) groups according to a pre-specified, non-randomized allocation rule based on an alternating/sequential assignment by admission order. Peripheral oxygen saturation (SpO₂), Bispectral Index (BIS), and Near-Infrared Spectroscopy (NIRS) were monitored throughout. Desaturation was defined as SpO₂ ≤ 90%; severe hypoxia as SpO₂ < 75%. Sedation depth was standardized using BIS (target: 60–80). Propofol–ketamine-based induction was used in all patients. Results: Groups were comparable in demographics, comorbidities, burn characteristics, and procedural duration. SpO₂ ≤ 90% occurred in 79% of SNO patients vs. 11% in the HFNO group (p < 0.001). SpO₂ between 75 and 90% was observed in 68% of SNO vs. 0% of HFNO patients (p < 0.001), and SpO₂ < 75% in 26% vs. 0% (p < 0.001). Airway interventions—jaw thrust, flow increase, and FiO₂ increase—were significantly more frequent in the SNO group (84% vs. 2.6%, 84% vs. 11%, and 84% vs. 5.3%, respectively; all p < 0.001). No significant between-group differences were noted in procedure interruptions, laryngospasm, BIS, NIRS, or hemodynamic parameters. Conclusions: HFNO significantly reduced the incidence of hypoxia and the need for airway interventions compared with SNO during deep sedation in minor and moderate burn patients. These findings suggest that HFNO may represent a preferable oxygenation strategy in this population; given the observational design of this study, confirmation in randomized controlled trials is warranted before this can inform routine practice recommendations. Full article

Dye-sensitized solar cells (DSSCs), belonging to the third generation, are highlighted for their low production cost compared to other photovoltaic technologies. These cells are composed of a cathode, an electrolyte, and an anode, commonly using TiO₂. This work aims to produce and characterize CeO₂, SnO₂, and ZrO₂ oxides as substitutes for TiO₂ in DSSCs. The semiconductor oxides were synthesized using the Pechini methodology and applied as the anode of the system. The device was assembled in a sandwich configuration, with an anode and cathode (graphene), an active area of 0.2 cm², and an electrolyte containing the I₃⁻/3I⁻ redox pair. The techniques employed included scanning electron microscopy (SEM), dynamic light scattering (DLS), X-ray diffraction (XRD), UV-Vis spectroscopy, open-circuit potential curves and electrochemical impedance spectroscopy (EIS). The oxides exhibited good crystallization with non-defined morphology. The obtained band gap values were 2.8 eV, 3.0 eV, 3.1 eV, and 4.8 eV for CeO₂, TiO₂, SnO₂, and ZrO₂, respectively. In DSSCs, these oxides showed photosensitivity, generating potential when exposed to light with TiO₂-based cell exhibited the lowest charge transfer resistance (R_ct = 57.8 kΩ). This comparative framework establishes a preliminary screening of the intrinsic interfacial charge transfer and recombination kinetics of alternative standalone photoanodes, serving as a baseline for future device optimization. Full article

Beer quality assessment increasingly requires rapid and scalable analytical tools for product discrimination and authenticity control. In this study, a data-driven metal oxide semiconductor (MOX) chemosensing approach was investigated for the discrimination of commercial lager beers with different alcohol contents and brands. Alcoholic and alcohol-free beer samples from four commercial brands were analyzed using a six-element SnO₂-based MOX sensor array, and the resulting response patterns were classified using supervised machine-learning algorithms. Headspace solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME-GC–MS) was employed as a reference technique to characterize volatile organic compound profiles and support the interpretation of sensor-based fingerprints. GC–MS analysis highlighted a shared volatile backbone dominated by fermentation-related compounds, while also revealing brand- and category-dependent differences in VOC distribution. The MOX sensor array captured these differences as multidimensional volatile fingerprints. Machine-learning models achieved high classification performance in brand-matched alcoholic versus alcohol-free comparisons, with balanced accuracy ranging from 0.937 to 1.000, while brand discrimination within the same category reached balanced accuracy values of 0.875 (alcoholic) and 0.933 (alcohol-free). These results highlight MOX-based chemosensing combined with data-driven analysis as a rapid, portable platform for beer discrimination, with applications in food quality screening, authenticity assessment, and at-line monitoring. Full article

Hydrogen is a clean energy carrier essential for carbon neutrality, but its invisible and odorless nature poses significant safety risks, particularly during low-concentration leaks. Although metal oxide semiconductor (MOS) sensors offer fast response and high sensitivity, their ability to detect ppb-level hydrogen remains limited. In this work, we present a high-performance hydrogen gas sensor based on nickel-doped tin dioxide (Ni-SnO₂) nanorods, directly grown on planar electrodes via aerosol-assisted chemical vapor deposition (AACVD). By optimizing the Ni doping ratio and nanorod morphology, the 3 wt% Ni-SnO₂ sensor achieves a low detection limit of 100 ppb for H₂, demonstrating promising potential for low-concentration hydrogen detection. Moreover, the sensor exhibits outstanding selectivity, with a response to 100 ppm H₂ nearly six times higher than that to the next most responsive interfering gas (NH₃). Comprehensive XPS and Raman analyses reveal that Ni doping introduces abundant oxygen vacancies and lattice defects, which are the key origins of the enhanced sensing performance. Notably, the 3 wt% Ni-SnO₂ sensor strikes an optimal balance between lattice defects and structural stability, delivering both high sensitivity and good moisture resistance with minimal baseline drift over weeks of operation. This work establishes a facile and scalable AACVD strategy for engineering defect-rich SnO₂ nanostructures, enabling sub-ppm hydrogen detection with high selectivity and long-term stability—addressing a critical gap in practical hydrogen safety monitoring. Full article