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Recent achievements in semiconductor surface‐enhanced Raman scattering (SERS) substrates have greatly expanded the application of SERS technique in various fields. However, exploring novel ultra‐sensitive semiconductor SERS materials is a high‐priority task. Here, a new semiconductor SERS‐active substrate, Ta2O5, is developed and an important strategy, the “coupled resonance” effect, is presented, to optimize the SERS performance of semiconductor materials by energy band engineering. The optimized Mo‐doped Ta2O5 substrate exhibits a remarkable SERS sensitivity with an enhancement factor of 2.2 × 107 and a very low detection limit of 9 × 10−9 m for methyl violet (MV) molecules, demonstrating one of the highest sensitivities among those reported for semiconductor SERS substrates. This remarkable enhancement can be attributed to the synergistic resonance enhancement of three components under 532 nm laser excitation: i) MV molecular resonance, ii) photoinduced charge transfer resonance between MV molecules and Ta2O5 nanorods, and iii) electromagnetic enhancement around the “gap” and “tip” of anisotropic Ta2O5 nanorods. Furthermore, it is discovered that the concomitant photoinduced degradation of the probed molecules in the time‐scale of SERS detection is a non‐negligible factor that limits the SERS performance of semiconductors with photocatalytic activity. A semiconductor surface‐enhanced Raman scattering (SERS)‐active substrate Ta2O5 is developed, and an important strategy, the “coupled resonance” effect, is presented to optimize its SERS performance by energy band engineering. Furthermore, the unique photocatalytic degradation of probed molecules in the time‐scale of SERS detection by semiconductors is revealed as another non‐negligible factor that limits the SERS performance of some semiconductors with photocatalytic activity.

In this work, a capacitive pH sensor consisting of Ta2O5 functional film is designed and fabricated by employing MEMS-based procedures. The Ta2O5 thin film has an amorphous microstructure, and its surface roughness is less than 3.17 nm. A signal processing circuit and a software filtering algorithm are also designed to measure the pH value, thus improving the detection accuracy and anti-interference ability. Good linearity (R2 = 0.99904) and sensitivity (63.12 mV/pH) are recorded for the proposed sensing element in the range of pH 2~12. In addition, the sensor’s drift and hysteresis are equal to 5.1 mV and 5.8 mV, respectively. The enhanced sensing performance in combination with the facile miniaturization process, low fabrication cost, and suitability for mass production render the fabricated sensor attractive for applications where pH change measurements in a water environment are required.

In this study, for the first time, diamagnetic 5d0 Ta5+ ions and Ta2O5 nanocrystals were utilized to enhance the structural, mechanical, magnetic, and radiation shielding of heavy metal oxide glasses. Transparent Ta2O5 nanocrystal-doped heavy metal oxide glasses were obtained, and the embedded Ta2O5 nanocrystals had sizes ranging from 20 to 30 nm. The structural analysis of the Ta2O5 nanocrystal displays the transformation from hexagonal to orthorhombic Ta2O5. Structures of doped glasses were studied through X-ray diffraction and infrared and Raman spectra, which reveal that Ta2O5 exists in highly doped glass as TaO6 octahedral units, acting as a network modifier. Ta5+ ions strengthened the network connectivity of 1–5% Ta2O5-doped glasses, but Ta5+ acted as a network modifier in a 10% doped sample and changed the frame coordination units of the glass. All Ta2O5-doped glasses exhibited improved Vicker’s hardness, magnetization (9.53 × 10−6 emu/mol), and radiation shielding behaviors (RPE% = 96–98.8%, MAC = 32.012 cm2/g, MFP = 5.02 cm, HVL = 0.0035–3.322 cm, and Zeff = 30.5) due to the increase in density and polarizability of the Ta2O5 nanocrystals.

Dimensionally stable anodes of titanium (Ti) metal coated with mixed metal oxides (MMO) are widely used in several electrochemical applications, especially chloro-alkali electrolysis. Herein, we deposited MMO coatings on Ti substrates in different compositions, namely, (60%RuO 2 -40%TiO 2 ), (60%RuO 2 -30%TiO 2 -10%IrO 2 ), and (60%RuO 2 -20%TiO 2 -15%IrO 2 -5%Ta 2 O 5 ), where RuO 2 has the same percentage ratio in all coatings. The aim was to use these electrodes for chlorine evolution reaction (CER) and oxygen evolution reaction (OER) applications. Electrochemical characterization of the coated samples was performed to identify the best Ti/MMO electrodes with the highest efficiencies among the various prepared combinations. The role of IrO 2 and Ta 2 O 5 in enhancing corrosion resistance and electrochemical efficacy was up for debate. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses were exploited to determine the surface morphology, chemical composition, crystallinity, surface composition, and chemical states of the acquired coatings. The differential scanning calorimetry (DSC) method was used to evaluate the apparent activation energy ( E a ) of the deposited MMO. Additionally, the electrochemical performance of our designed coatings was scrutinized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), a current on–off test, a CV stability test (ST), and an accelerated stability test (AST). Furthermore, linear sweep voltammetry (LSV) was incorporated to assess the catalytic efficacy of the prepared anodes toward the CER in a brine solution of pH 2 and the OER in 1 M H 2 SO 4 . It became clear that the CER and OER incurred almost the same potential value (1.1 V) on both Ti/RuO 2 -TiO 2 and Ti/RuO 2 -TiO 2 -IrO 2 electrodes. However, on the Ti/RuO 2 -TiO 2 -IrO 2 -Ta 2 O 5 anode, there was a 0.2 V potential difference between the CER occurring at 1.1 V and the OER happening at 1.3 V.

Ultralow-absorption laser films have critical applications in high-power continuous-laser and gravitational-wave-detection systems. During film deposition, the ionic oxygen concentration significantly affects the absorption loss of the film. In this study, Ta 2 O 5 monolayers were deposited using an ion-assisted electron beam evaporation technique, and the weak absorption at 1064 nm, temperature rise, optical band gap, element content, and binding energy were tested and analyzed. The band structure and microdefects of the Ta 2 O 5 films were characterized, and their correlation with the absorption properties was established. The analyses revealed that the primary mechanism responsible for reducing the absorption loss in Ta 2 O 5 films was an appropriate ionic oxygen concentration, which improved the optical band gap and stoichiometric ratio and reduced oxygen vacancy defects. For Ta 2 O 5 monolayers deposited with the optimal ionic oxygen concentration, the weak absorption was approximately 7.2 ppm and the temperature rise was approximately 0.6 °C, 1/4 and 1/3 of the values of those deposited with an excessive concentration, respectively—an important finding in the preparation of ultralow-absorption laser films.

Background Maxillofacial prosthetic materials exhibit a range of qualities that vary considerably, including the hardness and stiffness of alloys and polymers, as well as the flexibility of elastomers and soft polymers. Silicone elastomers are the primary materials employed for maxillofacial prostheses due to their physical properties, which allow for adaptation to the movement of soft tissue. They also exhibit exceptional tensile and tear strength across a broad temperature range. Silicone elastomers can be classified according to the vulcanization process: High-temperature vulcanization (HTV) silicones, and Room temperature vulcanization (RTV) silicones. The addition of nanoparticle enhances thermal and tear strength of maxillofacial silicon. This study estimates the influence of addition tantalum oxide nanoparticle on thermal conductivity and tear strength after addition on maxillofacial silicone. Method Tantalum oxide nanoparticles were added into VST-50F platinum silicone elastomer at two weight percentages: 1wt% and 1.5wt%. 60 specimens were prepared and classified into two groups: one control group for each property and two experimental groups. All collected data underwent statistical analysis by one-way ANOVA and Bonferroni's multiple comparison test, with significance set at p < 0.05. The Shapiro-Wilk test and Bartlett's test were employed to assess the normality and homogeneity of the data, respectively. Result The one-way ANOVA test found a very significant difference between all groups, while Bonferroni's test revealed a highly significant difference between the control and experimental groups. Thermal conductivity test found no significant difference between the 1wt% and 1.5wt% groups, however the tear strength test was highly significant. Conclusions The addition tantalum oxide nano particles improve tear strength and thermal conductivity.

Nanostructured Schottky barrier gas sensors have emerged as novel semiconductor devices with large surface areas and unique electronic characteristics. Although it is widely known that operating these gas sensors requires heating to an optimal temperature for the highest sensitivity, the fundamental mechanism that governs the temperature-dependent sensitivity has yet been well understood. In this work, we present new evidence to support that thermionic field emission (TFE) is the dominant transport mechanism for Schottky contacted nanostructured heterojunction gas sensors at their optimal sensing temperature. Through the fabrication and characterization of Pt/MoO3 Schottky contacts, and Pt/Ta2O5/MoO3 heterojunctions, we found a previously unreported connection between TFE transport and optimal gas sensing temperature. This connection enables the description of Schottky barrier gas sensing performance using transport theory, which is a major step towards systematic engineering of gas sensors with nanostructured high-k oxide layers.

Ta2O5 coatings were created using micro-arc discharges (MDs) during anodization on a tantalum substrate in a sodium phosphate electrolyte (10 g/L Na3PO4·10H2O). During the process, the size of MDs increases while the number of MDs decreases. The elements and their ionization states present in MDs were identified using optical emission spectroscopy. The hydrogen Balmer line Hβ shape analysis revealed the presence of two types of MDs, with estimated electron number densities of around 1.1 × 1021 m−3 and 7.3 × 1021 m−3. The effect of MDs duration on surface morphology, phase and chemical composition, optical absorption, and photoluminescent, properties of Ta2O5 coatings, as well as their applications in photocatalytic degradation of methyl orange, were investigated. The created coatings were crystalline and were primarily composed of Ta2O5 orthorhombic phase. Since Ta2O5 coatings feature strong absorption in the ultraviolet light region below 320 nm, their photocatalytic activity is very high and increases with the time of the MDs process. This was associated with an increase of oxygen vacancy defects in coatings formed during the MDs, which was confirmed by photoluminescent measurements. The photocatalytic activity after 8 h of irradiation was around 69%, 74%, 80%, and 88% for Ta2O5 coatings created after 3 min, 5 min, 10 min, and 15 min, respectively.

Plant virus-like particles, and in particular, tobacco mosaic virus (TMV) particles, are increasingly being used in nano- and biotechnology as well as for biochemical sensing purposes as nanoscaffolds for the high-density immobilization of receptor molecules. The sensitive parameters of TMV-assisted biosensors depend, among others, on the density of adsorbed TMV particles on the sensor surface, which is affected by both the adsorption conditions and surface properties of the sensor. In this work, Ta2O5-gate field-effect capacitive sensors have been applied for the label-free electrical detection of TMV adsorption. The impact of the TMV concentration on both the sensor signal and the density of TMV particles adsorbed onto the Ta2O5-gate surface has been studied systematically by means of field-effect and scanning electron microscopy methods. In addition, the surface density of TMV particles loaded under different incubation times has been investigated. Finally, the field-effect sensor also demonstrates the label-free detection of penicillinase immobilization as model bioreceptor on TMV particles.

In this study, magnetically-recoverable core–shell catalysts with different amount of H 3 PW 12 O 40 loading [Fe 3 O 4 @C@mTa 2 O 5 -NH 2 -PW 12 (w%)] were prepared by the application of phosphotungstic acid supported on amino group functionalized magnetic core–shell mesoporous tantalum pentoxide microspheres. The prepared samples were characterized by FT-IR, N 2 -adsorption–desorption isotherms, TEM, SEM, Pyridine-IR analysis, XRD and magnetism. Fe 3 O 4 @C@mTa 2 O 5 -NH 2 -PW 12 samples present both Brönsted and Lewis acidity, large BET surface area and high magnetization. The catalytic activity was evaluated by the acetalization of different aldehydes with diols, and the results show that Fe 3 O 4 @C@mTa 2 O 5 -NH 2 -PW 12 (14.47%) catalyst exhibits the highest catalytic activity for acetalization of aldehydes with glycols with 94.5% conversion of benzaldehyde and 99% selectivity to benzaldehyde glycol acetal at 80 °C. The catalytic activity of the catalyst for acetalization is related to its total acidity and Brönsted–Lewis acid synergy. The catalyst Fe 3 O 4 @C@mTa 2 O 5 -NH 2 -PW 12 can be easily recovered and reused for at least 5 times without obvious decrease of catalytic activity. Graphic Abstract