Search Results (6)

In this work, various types of organosilanes were introduced into Sn-Si oxide through a simple aerosol process to yield synthesis precursors. Then, a series of Sn-Beta zeolites were successfully synthesized using a hydrothermal method in the presence of fluoride. The influence of amine groups (A, 2A, and 3A), the length of branched chains present in the organosilanes, as well as the use of dipodal silanization agents (B2A) on the morphology, pore structure, acidic properties, coordination state, and content of Sn species in the obtained Sn-Beta zeolite samples was investigated. Compared to the organosilane-free Sn-Beta (crystal size: 1.3 μm; Si/Sn = 119; Lewis acid density: 77 μmol·g⁻¹), all monopodal organosilane-doped samples (Sn-Beta-A, -2A, and -3A) exhibited reduced crystal sizes (~0.9 μm) and increased specific surface areas (up to 502 m²·g⁻¹ for Sn-Beta-2A). UV–Vis spectroscopy showed that Sn-Beta-2A (containing two amine groups) achieved the highest optical bandgap (4.68 eV) and the strongest suppression of extra-framework SnO_x species (peak at ~269 nm), indicating the most isolated tetrahedral framework Sn⁴⁺ sites. This sample also delivered the highest Lewis acid density (225 μmol·g⁻¹) and the best catalytic performance in the Baeyer–Villiger oxidation of cyclohexanone (39% conversion, TON = 106) and 2-adamantanone (37% conversion, TON = 101). By contrast, the dipodal organosilane (B₂A) caused severe steric hindrance, yielding the lowest crystallinity (relative crystallinity 64%), Si/Sn ratio (158), Lewis acid density (38 μmol·g⁻¹), and catalytic activity, despite forming a nanoaggregate morphology with high mesoporosity (V meso = 0.20 cm³·g⁻¹). These quantitative results demonstrate that monopodal organosilanes with two amine groups optimally balance Sn incorporation and textural properties, whereas dipodal silanes hinder framework Sn entry. This study provides clear, numerically grounded guidelines for selecting organosilane functional groups to design high-performance Sn-Beta zeolites. Full article

Uncooled microbolometers play a pivotal role in infrared detection owing to their compactness, low power consumption, and cost-effectiveness. This review comprehensively summarizes recent progress in thermistor materials and focal plane arrays (FPAs), highlighting improvements in sensitivity and integration. Vanadium oxide (VO_x) remains predominant, with Al-doped films via atomic layer deposition (ALD) achieving a temperature coefficient of resistance (TCR) of −4.2%/K and significant 1/f noise reduction when combined with single-walled carbon nanotubes (SWCNTs). Silicon-based materials, such as phosphorus-doped hydrogenated amorphous silicon (α-Si:H), exhibit a TCR exceeding −5%/K, while titanium oxide (TiO_x) attains TCR values up to −7.2%/K through ALD and annealing. Emerging materials including GeSn alloys and semiconducting SWCNT networks show promise, with SWCNTs achieving a TCR of −6.5%/K and noise equivalent power (NEP) as low as 1.2 mW/√Hz. Advances in FPA technology feature pixel pitches reduced to 6 μm enabled by vertical nanotube thermal isolation, alongside the 3D heterogeneous integration of single-crystalline Si-based materials with readout circuits, yielding improved fill factors and responsivity. State-of-the-art VO_x-based FPAs demonstrate noise equivalent temperature differences (NETD) below 30 mK and specific detectivity (D*) near 2 × 10¹⁰ cm⋅Hz ^1/2/W. Future advancements will leverage materials-driven innovation (e.g., GeSn/SWCNT composites) and process optimization (e.g., plasma-enhanced ALD) to enable ultra-high-resolution imaging in both civil and military applications. This review underscores the central role of material innovation and system optimization in propelling microbolometer technology toward ultra-high resolution, high sensitivity, high reliability, and broad applicability. Full article

Mixed oxide Ir-Sn-Sb-O electrocatalyst was synthesized using thermal decomposition from chloride precursors in ethanol. Our previous results showed that Ir-Sn-Sb-O possesses electrocatalytic activity for an oxygen evolution reaction (OER) in acidic media. In the present work, the physicochemical characterization and performance of Ir-Sn-Sb-O in an electrolysis cell are reported. IrO₂ supported on antimony doped tin oxide (ATO) was also considered in this study as a reference catalyst. Scanning electron microscopy (SEM) images indicated that Ir-Sn-Sb-O has a mixed morphology with nanometric size. Energy dispersive X-ray spectroscopy (EDS) showed a heterogeneous atomic distribution. Transmission electron microscopy (TEM) analysis resulted in particle sizes of IrO₂ and ATO between 3 to >10 nm, while the Ir-Sn-Sb-O catalyst presented non-uniform particle sizes from 3 to 50 nm. X-ray diffraction (XRD) measurements indicated that synthesized mixed oxide consists of IrO₂, IrO_x, doped SnO₂ phases and metallic Ir. The Ir-Sn-Sb-O mixed composition was corroborated by temperature programmed reduction (TPR) measurements. The performance of Ir-Sn-Sb-O in a single cell electrolyser showed better results for hydrogen production than IrO₂/ATO using a mechanical mixture. Ir-Sn-Sb-O demonstrated an onset potential for water electrolysis close to 1.45 V on Ir-Sn-Sb-O and a current density near to 260 mA mg⁻¹ at 1.8 V. The results suggest that the mixed oxide Ir-Sn-Sb-O has favorable properties for further applications in water electrolysers. Full article

NO oxidation was conducted over MnO_x-CeO₂ catalysts, which were synthesized by the co-precipitation method. The calcination temperature and third metal doping were the main considerations. MnCe catalysts calcined at 350 °C and 450 °C attained the highest NO conversion efficiency, compared to 550 °C. XRD results suggested that the higher the calcination temperature, the higher the crystallization degree, which led to a negative effect on catalytic activity. Subsequently, Sn, Fe, Co, Cr, and Cu were separately doped into MnCe composites, but no improvement was observed for these trimetallic catalysts in NO conversion. Nevertheless, MnCeSn, MnCeFe, and MnCeCo still exhibited a desirable NO conversion efficiency, so they were tested under SO₂ addition together with MnCe catalyst. Among them, MnCeFe exhibited the highest NO conversion after whole poisoning testing. XPS results indicated that Fe could protect Mn and Ce metal oxides from being reduced during SO₂ poisoning process. Furthermore, in in-situ DRIFTS measurement, part of nitrate species maintained undestroyed on the MnCeFe catalyst surface after SO₂ poisoning. These characteristics reinforced that Fe dropping would achieve better performance under SO₂ atmosphere. Full article

The properties of Al-doped SnO_x films deposited via reactive co-sputtering were examined in terms of their potential applications for the fabrication of transparent and flexible electronic devices. Al 2.2-atom %-doped SnO_x thin-film transistors (TFTs) exhibit improved semiconductor characteristics compared to non-doped films, with a lower sub-threshold swing of ~0.68 Vdec⁻¹, increased on/off current ratio of ~8 × 10⁷, threshold voltage (V_th) near 0 V, and markedly reduced (by 81%) V_th instability in air, attributable to the decrease in oxygen vacancy defects induced by the strong oxidizing potential of Al. Al-doped SnO_x films maintain amorphous crystallinity, an optical transmittance of ~97%, and an adhesive strength (to a plastic substrate) of over 0.7 kgf/mm; such films are thus promising semiconductor candidates for fabrication of transparent flexible TFTs. Full article

We characterize the time evolution (≤120 s) of atmospheric-pressure plasma jet (APPJ)-synthesized Pt-SnO_x catalysts. A mixture precursor solution consisting of chloroplatinic acid and tin(II) chloride is spin-coated on fluorine-doped tin oxide (FTO) glass substrates, following which APPJ is used for converting the spin-coated precursors. X-ray photoelectron spectroscopy (XPS) indicates the conversion of a large portion of metallic Pt and a small portion of metallic Sn (most Sn is in oxidation states) from the precursors with 120 s APPJ processing. The dye-sensitized solar cell (DSSC) efficiency with APPJ-synthesized Pt-SnO_x CEs is improved greatly with only 5 s of APPJ processing. Electrochemical impedance spectroscopy (EIS) and Tafel experiments confirm the catalytic activities of Pt-SnO_x catalysts. The DSSC performance can be improved with a short APPJ processing time, suggesting that a DC-pulse nitrogen APPJ can be an efficient tool for rapidly synthesizing catalytic Pt-SnO_x counter electrodes (CEs) for DSSCs. Full article