Search Results (508)

Elemental arsenic (As) is essential for diverse industrial applications. Most elemental As in China is produced by reducing gaseous arsenic trioxide (As₂O₃) with carbonaceous materials in steel reactors. This study aimed to extend the reactor lifespan through corrosion experiments and analysis. In this study, corroded regions of steel reactors were inspected after each production batch, and the corrosion process was examined. X-ray diffraction (XRD) was used to identify the major corrosion products, X-ray fluorescence (XRF) was used to measure the composition of corroded area, scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to inspect the features and elemental distributions of the corroded steel-plate cross-sections. The results revealed that the steel wall near the charcoal zone exhibited the highest corrosion rate. Tin (Sn), selenium (Se), and antimony (Sb) did not promote the corrosion process, whereas carbon (C) accelerated it by forming an Fe–As–C system at the grain boundaries of the steel matrix, characterized by a low melting temperature. The important source of C responsible for initiating corrosion was solid-state C particles originating from reused materials from previous batches. Additionally, owing to the high processing temperature, oxygen (O) was transferred to the inner side of the steel wall before the dramatical corrosion of the matrix by elemental As and C. Results of this study provide references to increase the lifespan of steel reactors for elemental As production. Full article

Two-dimensional carbide crystals (MXenes) are emerging as a promising platform for the development of novel gas sensors, offering advantages in energy efficiency and tunable analyte selectivity. One of the most effective strategies to enhance and tailor their functional performance involves forming hetero-structured composites with metal oxides. In this work, we explore a chemiresistive effect in double-metal MXene of Ti_0.2V_1.8C and its composites with 2 mol. % SnO₂ and Co₃O₄ nanocrystalline oxides toward feasibility tests with alcohol and ammonia vapor probes. The materials were characterized by simultaneous thermal analysis, X-ray diffraction analysis, Raman spectroscopy, and scanning/transmission electron microscopy. Gas-sensing experiments were carried out on composite layers deposited on multi-electrode substrates to be exposed to the test gases, 200–2000 ppm concentrations, at an operating temperature of 370 °C. The developed sensor array demonstrated clear analyte discrimination. The distinct sensor responses enabled a selective identification of vapors through linear discriminant analysis, demonstrating the further potential of MXene-based materials for integrated electronic nose applications. Full article

The effects of Ge⁴⁺ substitution on the microwave dielectric properties of inverse spinel Mg₂SnO₄ ceramics were systematically investigated. A series of Mg₂(Sn_1−xGe_x)O₄ (x = 0.00–0.05) ceramics were synthesized via solid-state reaction and sintered at 1450–1600 °C. X-ray diffraction confirmed single-phase inverse spinel structures (Fd-3 m) for compositions up to x = 0.03, while minor MgSnO₃ secondary phases appeared at x = 0.05. Rietveld refinement revealed a linear decrease in lattice parameter from 8.6579 Å (x = 0) to 8.6325 Å (x = 0.05), consistent with Vegard’s law for the substitution of smaller Ge⁴⁺ (0.53 Å, Shannon ionic radius, octahedral coordination) for Sn⁴⁺ (0.69 Å, Shannon ionic radius, octahedral coordination) in octahedral sites. Optimal dielectric properties were achieved at x = 0.03 sintered at 1550 °C; the dielectric constant (ε_r) increased from 7.6 to 8.0, while the quality factor (Qf) improved by 19% from 56,200 to 67,000 GHz, which is attributed to reduced phonon scattering from Ge-induced lattice contraction. The temperature coefficient of resonant frequency (τ_f) remained stable (−64 to −68 ppm/°C) across all compositions. Property degradation at x = 0.05 correlated with the onset of Ge⁴⁺ solubility limit and MgSnO₃ formation. These results demonstrate that controlled Ge⁴⁺ substitution effectively enhances the microwave dielectric performance of Mg₂SnO₄ ceramics for communication applications. Full article

Liquid organic hydrogen carriers (LOHCs) are promising materials for safe, reversible, and high-density hydrogen storage. Atomically dispersed bimetallic Pt–Sn nanocluster catalysts supported on TiO₂ (Pt–Sn/TiO₂) were developed to enhance the hydrogenation step in the toluene-methylcyclohexane cycle, a model LOHC system. Compared with monometallic Pt/TiO₂ and Sn/TiO₂, Pt–Sn/TiO₂ exhibited superior hydrogenation performance. Mechanistic studies, including X-ray photoelectron spectroscopy, kinetic analysis, and H₂-D₂ exchange experiments, revealed that Sn incorporation modulates the electronic structure of Pt, enhancing H₂ activation and spillover. These findings provide insights into the rational design of atomically dispersed bimetallic nanocluster catalysts for efficient and durable hydrogen storage in LOHC-based systems. Full article

This study presents the synthesis and comprehensive characterization of tin dioxide nanoparticles (SnO₂NPs). SnO₂NPs were obtained using a conventional wet-chemistry route and an environmentally friendly green-chemistry approach employing plant extracts from rooibos leaves (Aspalathus linearis), pomegranate seeds (Punica granatum), and kiwifruit peels (family Actinidiaceae). The thermal stability and decomposition profiles were analyzed by thermogravimetric analysis (TGA), while their structural and physicochemical properties were investigated using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS), Raman spectroscopy, and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy. Transmission electron microscopy (TEM) confirmed the nanoscale morphology and uniformity of the obtained particles. The photocatalytic activity of SnO₂NPs was evaluated via the degradation of methyl orange (MeO) under UV irradiation, revealing that nanoparticles synthesized using rooibos extract exhibited the highest efficiency (68% degradation within 180 min). Furthermore, surface-enhanced Raman scattering (SERS) spectroscopy was employed to study the adsorption behavior of L-phenylalanine (L-Phe) on the SnO₂NP surface. To the best of our knowledge, this is the first report demonstrating the use of pure SnO₂ nanoparticles as SERS substrates for biologically active, low-symmetry molecules. The calculated enhancement factor (EF) reached up to two orders of magnitude (10²), comparable to other transition metal-based nanostructures. These findings highlight the potential of SnO₂NPs as multifunctional materials for biomedical and sensing applications, bridging nanotechnology and regenerative medicine. Full article

The surface of chalcopyrite was studied by XPS characterization for an unleached chalcopyrite, and, after being leached in an alkaline oxidant medium at room temperature, pH 12.5, and [ClO⁻] 0.34 M, the reaction of enargite presented high selectivity with respect to chalcopyrite, allowing the removal of arsenic from copper concentrates with high arsenic content prior to smelting. Based on the XPS analysis, the original chalcopyrite is composed of a combination of its constituents in different oxidation states, and chalcopyrite has the following stoichiometric formula: Cu(I)_0.85Cu(II)_0.15Fe(II)_0.65Fe(III)_0.35S²⁻_1.5S₂²⁻_0.17S_n0.08²⁻. The unleached chalcopyrite on its surface presents an iron deficiency, which raises the ratio Cu/Fe up to 2, reaching the chalcopyrite Cu/Fe rate in the fifth cycle. The Cu/S ratio of chalcopyrite, 0.5, remains constant at the surface as after the peeling. Surface sulfur shows a decrease in monosulfides, increasing the S_n²⁻/S²⁻ y S₂²⁻/S²⁻ ratio. Chalcopyrite leached with ClO⁻/OH⁻ media generates surface layers with the following intermediate products: Chalcopyrite → CuFe_1-xS₂/CuS_n/Fe³⁺ -OH → Fe³⁺-OH/CuO/SO₄²⁻. Neither sulfur intermediates nor oxidized final products are passivating, allowing the chalcopyrite transformation to progress in depth with increasing reaction time. Full article

We have fabricated amorphous tin oxide (a-SnO_x) thin-film transistors (TFTs) with Al₂O₃ gate insulator from deep eutectic solvents (DESs). DESs were formed using the chloride derivates of each precursor (SnCl₂, or AlCl₃) mixed with urea. The DESs were then used as precursors for the semiconductor and dielectric. Our target was to form extremely thin semiconductor film, and a sufficient high capacitance insulator. We characterized the physical and chemical properties of the DES-derived thin films by X-ray diffraction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). We could evaluate that the highest content of metal–oxygen bonds was from the DES condition SnCl₂–urea = 1:3. At a low 300 °C budget temperature, we could fabricate a 3.2 nm thick a-SnO_x layer and 30 nm thick Al₂O₃, from which the TFT demonstrated a mobility of 80 ± 17 cm²/Vs, threshold voltage of −0.29 ± 0.06 V, and subthreshold swing of 88 ± 11 mV/dec. The proposed process is adequate with the back-end of the line (BEOL) process, but it is also eco-friendly because of the use of DESs. Full article

With the rapid development of communication technologies such as 5G, yttrium iron garnet (YIG) has been widely applied in microwave devices and other systems owing to its low ferromagnetic resonance linewidth. Loss reduction and effects of doping on performance have been important research areas for garnet ferrite. This study prepared Ca²⁺, In³⁺, and Sn⁴⁺ codoped YIG ferrite samples with the chemical formula Y_3−xCa_xFe_5−x−yIn_ySn_xO₁₂ (x = 0.05–0.3) (y = 0.2, 0.45) via solid-state reaction. The analyses of the crystal structure, micromorphology, and magnetic properties enabled the identification of the causes of variations in parameters, such as saturation magnetization and coercivity. Theoretical calculations of the anisotropy constants clarified the patterns upon substituting Fe³⁺ with In³⁺ and Sn⁴⁺, revealing a shift in the positions of Fe³⁺ substitution. Finally, the primary factors influencing loss were identified, and the key process parameters influencing performance were determined. The resulting polycrystalline garnet ferrite exhibited an extremely low ferromagnetic resonance linewidth parameter (ΔH = 29 Oe) and a high density (>5.2 g/cm³). This study provides specific guidance on process parameters and element selection for high-performance, low-loss YIG materials, as well as a detailed theoretical explanation of the performance changes resulting from co-doping YIG with In³⁺ and Sn⁴⁺. Full article

DJ-1/PARK7 is a multifunctional protein that plays a vital role in sensing oxidative stress and maintaining redox homeostasis. As an oncogene, DJ-1 influences p53-mediated stress responses and contributes to cancer progression. This study investigates the impact of X-ray-induced DNA breaks on cellular responses under varying DJ-1 expression levels. Using siRNA knockdown and overexpression approaches, transcriptional changes were analyzed by RNA-seq. Naïve cells exhibited only a moderate response to X-ray exposure, including suppression of the cell cycle and activation of stress pathways. In contrast, DJ-1 overexpression caused pronounced gene-expression suppression, particularly affecting ribosomal genes and mitochondria, with 21- and 3.5-fold enrichment, respectively. DJ-1 knockdown led to extensive, non-specific transcriptional changes affecting ~18% of all transcripts (~3400), indicating disrupted cellular homeostasis. Under DJ-1 knockdown, X-ray irradiation resulted in a 3.7-fold enrichment of suppressed DNA-damage response genes. Notably, approximately 25% of non-coding RNAs (ncRNAs) were differentially expressed following DJ-1 manipulation. X-ray-irradiated cells with DJ-1 overexpression also showed reduced expression of SNHG lncRNAs that host snoRNAs, potentially altering miRNA-sponging capacity and ribosomal regulation. These findings underscore DJ-1’s critical role in modulating cellular responses to genotoxic stress, reshaping transcriptional landscapes, and regulating ncRNA profiles. The dual impact of DJ-1 on redox and transcriptional networks positions it as a potential therapeutic target in diseases involving oxidative stress and impaired DNA repair. Full article

This study explores how post-deposition thermal annealing alters the structural, morphological, and electronic properties of Sn–Te–O thin films grown by radio-frequency magnetron co-sputtering. Thin films were annealed at temperatures ranging from 298 K to 873 K and analyzed using a suite of techniques, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Annealing at 473 K resulted in increased surface roughness (R_q) in Te-rich films, while higher annealing temperatures promoted a chemical shift in tin oxidation states from Sn²⁺ to Sn⁴⁺. XRD patterns of films annealed at 473 K revealed the emergence of cubic-phase SnTe reflections not prominent in unannealed samples. Contact angle measurements indicated enhanced wettability in high-Te films after annealing, and work function analysis via Kelvin probe showed a trend of decreasing surface potential with lower Te content. These results provide insight into the thermal oxidation behavior and surface evolution of SnTe films, relevant for thermoelectric and topological applications. Full article

Comprehensive studies of Famille rose porcelains, particularly ruby-back pieces, are rare and have generally not addressed the vibrational signatures arising from gold nanoparticles. Due to the high cultural and material value of these artifacts, a strictly non-invasive approach combining X-ray fluorescence (XRF) and Raman (micro-)spectrometry must be employed. If the conservation of porcelain does not pose any difficulties, fakes exist and they must be identified. Preliminary studies show that the presence of metal nanoparticles generates plasmon-related fluorescence. Our results confirm that plasmon fluorescence is more effective than pXRF for detecting colloidal gold, whereas pXRF efficiently identifies associated elements such as arsenic, tin, and, newly observed, antimony; the presence of iron is difficult to demonstrate due to its ubiquitous occurrence. Yellow and green hues, distinct from those produced by Cu²⁺ ions alone, are mainly due to simple tin yellow (PbSnO₃), while the cobalt used originates from a mixture of European smalt (rich in arsenic and potassium) and Asian ores (rich in manganese). Minimal variability was observed among egg-shell porcelains with similar decorations and dimensions, suggesting a common workshop or standardized raw materials and procedures. Two other egg-shell plates employ a different gold preparation technique (addition of Sn and Sb rather than As), which is visually evident in the ruby color. Full article

A novel highly sensitive voltammetric sensor based on a glassy carbon electrode (GCE) modified with a mixture of cerium and tin dioxide nanoparticles (NPs) as a sensing layer was developed. Surfactants of various nature (anionic sodium dodecyl sulfate, cationic N-cetylpyridinium bromide, and non-ionic Triton X-100, Brij^® 35, and Tween-80) were used as dispersive agents for NPs. Complete suppression and a significant decrease in the dye oxidation peak occurred in the case of Tween-80 and sodium dodecyl sulfate, respectively. CeO₂–SnO₂ NPs in Brij^® 35 gave the best response to Acid Yellow 3 caused by its adsorption at the electrode surface. Linear dynamic ranges of 0.50–7.5 and 7.5–25 mg L⁻¹ with a detection limit of 0.13 mg L⁻¹ of Acid Yellow 3 were achieved using differential pulse mode in Britton–Robinson buffer pH 5.0. Full article

This work prepared SnO₂ coatings on 304 stainless steel via the sol–gel and dip-coating techniques, using tin (II) chloride (SnCl₂) and tin (II) oxalate (SnC₂O₄) as precursors. The crystal structure analyzed by X-ray Diffraction (XRD) confirmed the cassiterite-type SnO₂ in both cases. The corrosion resistance in a 3 wt.% NaCl solution was evaluated by polarization resistance (Rp) and anodic potentiodynamic polarization. Coatings derived from the SnC₂O₄ precursor demonstrated exceptional performance, reducing the corrosion rate by up to three orders of magnitude (from 0.0973 mpy for uncoated steel to 0.00015 mpy), corresponding to a protection efficiency of 99.8%. In contrast, coatings from the SnCl₂ precursor increased the corrosion rate. X-ray Photoelectron Spectroscopy (XPS) analysis confirmed that this detrimental effect was due to the presence of chlorine (5.54 wt.%), which acted as an initiation site for pitting corrosion. Atomic force microscopy (AFM) and XRD of the effective SnC₂O₄-derived coatings revealed a homogeneous surface with low roughness and a textured cassiterite structure. The primary limitation of this work is that the sol–gel synthesis route using SnCl₂ is unsuitable for corrosion protection in chloride environments due to the incorporation of aggressive chlorine ions, whereas the chlorine-free SnC₂O₄ precursor yields highly protective SnO₂ coatings. Full article

In this article, we present density functional theory (DFT) calculations for $Z{n}_{(1-x)}{M}_{x}O$, where M represents one of the following substitutional metallic impurities: Ga, Cd, Cu, Pd, Ag, In, or Sn. Our study is based on the wurtzite structure of pristine ZnO. We employ the Quantum Espresso package, using a fully unconstrained implementation of the generalized gradient approximation (GGA) with an additional U correction for exchange and correlation effects. We analyze the density of states, energy gaps, and absorption spectra for these doped systems, considering the limitations of a finite-size cell approximation. Rather than focusing on precise numerical values, we highlight the following two key aspects: the location of impurity-induced electronic states and the overall trends in optical properties across the eight systems, including pristine ZnO. Our results indicate that certain dopants introduce electronic levels within the band gap, which enhance optical absorption in the visible, near-infrared, and near-ultraviolet regions. For instance, Sn-doped ZnO shows a pronounced absorption peak at ∼2.5 eV, which is in the middle of the visible spectrum. In the case of Ag and Pd impurities, they lead to increased electromagnetic radiation absorption at the near ultra-violet spectrum. This represents a promising performance for efficient solar radiation absorption, both at the Earth’s surface and in outer space. Furthermore, Ga- and In-doped ZnO present bandgaps of ∼0.9 eV, promising an interesting performance in the near infrared region. These findings suggest potential applications in solar energy harvesting and selective sensors. Full article

Hierarchical NiO-SnO₂ nanoflowers were prepared via a one-step hydrothermal method. The morphology, structure and components of the hierarchical NiO-SnO₂ nanoflowers were examined via scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. The ethanol gas-sensing performance was systematically analyzed between pure hierarchical SnO₂ nanoflowers and the hierarchical NiO-SnO₂ nanoflowers. The results indicated that the hierarchical NiO-SnO₂ nanoflowers showed better gas-sensing properties than the pure hierarchical SnO₂ nanoflowers at 164 °C. The enhanced gas-sensing performance was ascribed to the formation of p-n heterojunctions between p-type NiO and n-type SnO₂. Additionally, NiO has a catalytic role. Therefore, hierarchical NiO-SnO₂ nanoflowers could be a potential gas-sensing material for the fabrication of high-quality ethanol gas sensors. Full article