Sealed Ampoules Research Articles

Properties of Cu2ZnSnS4 films obtained by sulfurization under different sulfur-vapor pressures in a sealed ambient

Thin-films of Cu2ZnSnS4 (CZTS), a promising photoabsorber for photovoltaics, were obtained by sulfurization of the precursor films at 550 °C in evacuated and sealed quartz ampoules under various partial pressures (22.3–232.5 kPa) of sulfur-vapor, and its effects on the morphological and optical properties were studied. The precursor films were obtained on the molybdenum (Mo) coated soda-lime glass substrate via solution-chemistry. The observed changes in the morphology have been explained based on the amount of CuS formed and its conversion to sulfur-poor Cu2S. A decrease in the grain size from 448 to 223 nm was observed with the increase in partial pressure of sulfur-vapor. The thickness of the molybdenum sulfide (MoS2) layer that forms at the CZTS – Mo interface during sulfurization, increased from 62 to 479 nm. The structural disorder, estimated using Raman spectroscopy, increased with the increase in the partial pressure of sulfur-vapor.

Curie temperature adjustment in the solid solution Gd1–x Y x PtMg

Abstract GdPtMg and YPtMg (both crystallize with the ZrNiAl-type structure) form a complete solid solution Gd1–x Y x PtMg. Samples in x = 0.1 steps were synthesized from the elements in sealed tantalum ampoules in an induction furnace and characterized by Guinier powder patterns. The structures of four members of the solid solution were refined from single-crystal X-ray diffractometer data, confirming the mixed occupation of the Gd/Y site; however, without any indication for Gd/Y ordering. Temperature dependent magnetic susceptibility measurements reveal Curie-Weiss behavior for all samples and ferromagnetic ordering in the low-temperature regime. The Curie temperature drops linearly from 97.6 K for GdPtMg to 3.7 K for Gd0.1Y0.9PtMg. All samples are soft ferromagnets. The Gd/Y substitution is a suitable tool for adjusting magnetic ordering temperatures of gadolinium intermetallics over a broad temperature range.

EuTMg2 (T = Pd, Ag, Ir, Pt, Au), EuTCd2 (T = Pd, Pt, Au) and CaRhMg2 – intermetallic compounds with orthorhombically distorted tetrahedral magnesium (cadmium) substructures

Abstract The magnesium- and cadmium-rich intermetallic phases EuTMg2 (T = Rh, Pd, Ag, Ir, Pt, Au), EuTCd2 (T = Pd, Pt, Au) and CaRhMg2 were synthesized from the elements in sealed niobium or tantalum ampoules and with heat treatments in muffle or induction furnaces. The samples were characterized by powder X-ray diffraction and the structures were refined from single crystal X-ray diffractometer data. EuTMg2 (T = Pd, Ag, Pt, Au) and EuTCd2 (T = Pd, Pt, Au) crystallize with the MgCuAl2 type, space group Cmcm, while EuRhMg2, EuIrMg2 and CaRhMg2 adopt the YSiPd2 type, space group Pnma. The striking crystal chemical motif of both series of compounds are networks of puckered Mg(Cd) hexagons in ABAB stacking sequence that derive from the aristotype AlB2; however, with different tiling. Temperature dependent magnetic susceptibility and 151Eu Mössbauer spectroscopic measurements indicate stable divalent europium. Antiferromagnetic ordering sets in at 20.2 (EuIrMg2), 22.3 (EuPdMg2), 21.3 (EuAgMg2), 10.9 (EuPdCd2) and 15.5 K (EuPtCd2), respectively. The stable antiferromagnetic ground states are substantiated by metamagnetic transitions. The 151Eu isomer shifts show a linear correlation with the valence electron count for the whole series of EuTMg2, EuTCd2, EuTIn2 and EuTSn2 phases.

Auxiliary Degumming and Pressurized High Temperature Water Washing to Mitigate the Formation of Monochloropropanediols in Palm Oil

AbstractThis study reports the benefits of auxiliary degumming (Aux.D) and pressurized high temperature (165 °C) water washing (PHTW) to mitigate the formation of monochloropropanediols (MCPD) during labscale physical refining of palm oil. Water‐based degumming in combination with bleaching and deodorization are performed as the selected physical refining process. The mitigation concepts Aux.D and PHTW are integrated into the refining protocol and the ultimately observed MCPD levels in the fully refined oils are determined. Aux.D is performed by extracting the hydratable gum from pressed sunflower oil and using it as a degumming agent to further purify palm oil that has been previously subjected to centrifugation and water degumming. This approach enables the mitigation of 3‐MCPD from the water washed reference 2.4–0.9 mg kg−1 in ampoules. Even stronger mitigation is obtained when Aux.D is combined with bleaching and executed twice allowing a mitigation from the reference 1.9–0.6 mg kg−1, in ampoules. PHTW is shown to decrease the 3‐MCPD content of the refined oil from the reference 2.4–1 mg kg−1, in ampoules and when combined with bleaching and executed twice showing a decrease from the reference 1.9–0.9 mg kg−1.Practical applications: The benefits of these mitigation concepts are confirmed both in sealed ampoule tests and in deodorizer experiments at the lab scale. A combined application of Aux.D or PHTW with physical refining may represent new insights that can help to potentially further mitigate the formation of MCPD in physically refined palm oil beyond the limits achievable with current refining practices.

A europium kagome lattice in the solid solution Eu3−х Sr х Pt4Zn12 – first zinc representatives of the Gd3Ru4Al12 type

Abstract Eu3Pt4Zn12 and Sr3Pt4Zn12 form a complete solid solution Eu3−x Sr x Pt4Zn12. Samples with x = 0, 0.5, 1, 1.5, 2, 2.5 and 3 were synthesized from the elements in sealed tantalum ampoules in an induction furnace. All samples were characterized by powder X-ray diffraction and the structures of Sr3Pt3.93Zn12.07, Eu1.80Sr1.20Pt4Zn12 and Eu3Pt3.68Zn12.32 were refined from single crystal X-ray diffractometer data. The new compounds are isotypic with Gd3Ru4Al12, space group P63/mmc. The striking building units in these phases are the kagome networks occupied by the europium and strontium atoms and Pt1@Zn8 and Pt2@Zn8 distorted cubes. Besides the Eu/Sr mixing within the solid solution, the structure refinements indicated small homogeneity ranges induced by Pt/Zn mixing. The europium containing samples of the solid solution Eu3−x Sr x Pt4Zn12 are Curie–Weiss paramagnets and the experimental magnetic moments manifest stable divalent europium. The samples with x = 0, 0.5 and 2 order magnetically: T N = 15.4(1) K for x = 0, T C = 12.4(1) K for x = 0.5 and T N = 4.0(1) K for x = 2. The 3 K magnetization isotherms tend toward Brillouin type behavior with increasing europium dilution. The divalent ground state of Eu3Pt4Zn12 is further confirmed by 151Eu Mössbauer spectroscopy with an isomer shift of −9.66(2) mm s−1 at 78 K. In the magnetically ordered state Eu3Pt4Zn12 shows full magnetic hyperfine field splitting (23.0(1) T).

Carbon nitride materials: impact of synthetic method on photocatalysis and immobilization for photocatalytic pollutant degradation

Different synthesis routes for carbon nitride materials (CN) and the resulting products were compared to study the photocatalytic activity (pollutant degradation) in dependence on structure and properties. The CN materials were synthesized by thermal decomposition of dicyandiamide in air and under argon as well as in sealed ampoules with or without the use of a salt melt. The as-prepared materials were characterized by IR spectroscopy, nitrogen adsorption measurement, solid-state NMR spectroscopy, diffuse reflectance UV–Vis spectroscopy, elemental analysis and powder X-ray diffraction (PXRD). The surface polarity of the CN materials was estimated by adsorption of the dicyano-bis(1,10-phenanthroline)-iron(II) complex, which allows an evaluation of the degree of condensation. The CN materials were tested with regard to the photocatalytic degradation of rhodamine B (RhB). It is shown that the photocatalytic activity increases with higher surface polarity. Promising CN materials with high RhB degradation of 85% within 25 min and high surface polarity of 0.89 were selected for an immobilization approach to obtain coatings on a silicone substrate using a high-volume low-pressure (HVLP) spray coating technique. To study the photocatalytic activity of the catalyst coatings, the degradation rates of an aqueous RhB solution and solutions of organic pollutants such as triclosan and ethinyl estradiol were examined. Pollutants are decomposed with up to 63% of the initial concentration. Xenon lamps and different LEDs were used as light sources for comparison. Particularly high degradation efficiencies were obtained using LEDs, and the degradation rates are increased by adjusting the emission spectrum of the lamp to the pollutant and absorption edge of the catalyst, which results in a 40 times higher degradation efficiencies of LEDs compared to a Xe lamp.Graphical abstract

The stannides Ca1.692Pt2Sn3.308, SrPtSn2 and EuAuSn2

Abstract Polycrystalline samples of the stannides Ca1.692Pt2Sn3.308, SrPtSn2 and EuAuSn2 were synthesized directly from the elements, using sealed tantalum ampoules as crucible material. The reactions were performed in muffle or induction furnaces. The phase purity of the samples was studied by X-ray powder diffraction (Guinier technique). The structures of Ca1.692Pt2Sn3.308 and SrPtSn2 were refined from single-crystal X-ray diffractometer data: NdRh2Sn4 type, Pnma, a = 1887.22(13), b = 441.22(3), c = 742.89(4) pm, wR = 0.0626, 1325 F 2 values, 45 variables for Ca1.692(8) Pt2Sn3.308(8) and CeNiSi2 type, Cmcm, a = 462.59(5), b = 1932.8(2), c = 458.00(5) pm, wR = 0.0549, 481 F 2 values, 18 variables for SrPtSn2. The calcium compound shows a homogeneity range Ca1+x Pt2Sn4−x with substantial Sn4/Ca2 mixing on one of the 4c Wyckoff positions. The [PtSn2] network is characterized by Pt–Sn (269–281 pm) and Sn–Sn (306–336 pm) bonding interactions. SrPtSn2 contains two different tin substructures: (i) Sn1–Sn1 zig-zag chains (282 pm) and (ii) orthorhombically distorted Sn2 squares (326 pm) with stronger and weaker Sn–Sn bonding. Together, the platinum and tin atoms build up a three-dimensional [PtSn2] network in which the platinum atoms have a distorted square-pyramidal tin coordination with Pt–Sn distances ranging from 261–270 pm. EuAuSn2 also crystallizes with the CeNiSi2-type structure with the lattice parameters a = 453.9(1), b = 2018.9(5) and c = 456.8(1) pm. Temperature dependent magnetic susceptibility studies indicate europium(II) with an experimental magnetic moment of 8.28(2) µB per Eu atom. EuAuSn2 is ordered antiferromagnetically at T N = 14.8(2) K. 151Eu Mössbauer spectra confirm the oxidation state +2 for europium (isomer shift δ = −11.17(2) mm s−1) and the magnetic ordering at low temperature (21.8 T magnetic hyperfine field at 6 K).

An improved analyzer for measuring in-situ gas pressure in sealed quartz tube, and absolute and differential temperatures in heat treatments up to high temperatures

The measurement of in-situ pressure in synthesis and decomposition experiments, carried out in sealed quartz tubes or ampoules, provides important information about the reactions that occur during the heat treatment processes. In this work, a thermobarometric differential-thermal analyzer (TBDTA) is detailed to perform measurements of in-situ pressure in sealed quartz ampoules, and absolute and differential temperatures in heat treatments up to 800°C. The system can also operate, with certain precautions, above 800°C to approximately 1100°C, but in this temperature range the pressure sensor is not so perfectly linear elastic. The uncertainties in the in-situ pressure measurements of the developed analyzer are ± 0.01 bar, and the data acquisition was performed with a sampling rate of 2 readings per second. The analyzer can be used in synthesis and decomposition processes, and in isochoric thermodynamic studies of pure substances. The developed TBDTA was applied to study the vaporization of pure water, and the measurements of pressure and temperature between 200 and 300°C allowed to determine precise experimental values of the enthalpy of vaporization of the water at 220°C (the temperature of 220°C was chosen just as an example). In another application, it was possible to follow, during the heating and vaporization up to about 1000°C, the in-situ pressure of the element selenium, indicating the formation of different gas species (selenium allotropes in the gaseous phase) as a function of temperature. The results obtained can be considered compatible with mass spectroscopy technique results.

Modeling of nonlinear processes of nucleation and growth of GaSxSe1–x(0 ≤ х≤ 1) solid solutions

The results on the study of modeling and physico-chemical study of the kinetics ofnucleation and growth of GaSxSe1–x(0 ≤ х≤ 1) solid solution. The nucleation heterogeneous process and growth of GaSxSe1–xcrystals have been studied and simulated taking into account nonlinear equations considering the kinetic behavior of crystallizing phases.GaSxSe1–xsingle and nanocrystals were grown from solution, melt, and by chemical transport reaction through steam. GaSxSe1–xcrystals were grownbychemical transport reaction in a two-tem-perature gradient furnace in a sealed quartz ampoule. Iodine was used as a transporting additive. Using the Fokker–Planck equation, the evolution of the distribution function of crystals of solid solutions of the GaS–GaSe system by size at the nucleation time is studied by a numerical method. For the convenience of comparing theory with experimental data, we used the GaS1–xSex(x= 0.7 molar fraction of GaSe) composition of the solid solution. The Monte Carlo method is used to approximate the time evolution of the nucleation of two types of particles for the GaS0.3Se0.7 solid solution, simulated by a constant nucleus size. The results of modeling non-linear crystallization processes are consistent with experimental data.

Intermetallic phases in the Sc–Ir–In system – synthesis and structure of Sc1.024Ir2In0.976 and Sc3Ir1.467In4

Abstract The intermetallic scandium compounds Sc1.024Ir2In0.976 and Sc3Ir1.467In4 were synthesized by reactions of the elements in sealed tantalum ampoules at high temperature followed by annealing for crystal growth. Both structures were refined from single-crystal X-ray diffractometer data: MnCu2Al type, F m 3 ‾ m $Fm‾{3}m$ , a = 639.97(19) pm, wR2 = 0.0376, 41 F 2 values, seven variables for Sc1.024Ir2In0.976 and P 6 ‾ $P‾{6}$ , a = 769.99(5), c = 684.71(4) pm, wR2 = 0.0371, 967 F 2 values, 33 variables for Sc3Ir1.467In4. Sc1.024Ir2In0.976 is a new Heusler phase with a small homogeneity range due to Sc/In and In/Sc mixing. The structure of Sc3Ir1.467In4 is closely related to that of Sc3Rh1.594In4 and belongs to the large family of ZrNiAl superstructures. The striking structural motif is the ordered stacking of empty In6 and filled Ir@In6 prisms with Ir–In distances of 269 pm.

The germanides APtGe2 (A = Ca, Sr, Eu)

Abstract The germanides APtGe2 (A = Ca, Sr, Eu) were synthesized from the elements in sealed tantalum ampoules in an induction furnace followed by annealing. The polycrystalline samples were characterized by powder X-ray diffraction (Guinier patterns). The structures of CaPtGe2 (CeRhSn2 type, Cmcm, a = 443.45(3), b = 1593.03(12), c = 886.15(6) pm, wR = 0.0464, 673 F 2 values, 30 variables) and EuPt1.043(5)Ge1.957(5) (CeNiSi2 type, Cmcm, a = 445.23(4), b = 1752.5(2), c = 429.63(4) pm, wR = 0.0415, 389 F 2 values, 19 variables) were refined from single crystal X-ray diffractometer data. One of the germanium site in EuPt1.043(5)Ge1.957(5) showed a small Ge/Pt mixed occupancy. SrPtGe2 (a = 451.13(6), b = 1764.8(2), c = 429.60(5) pm) is isotypic with EuPtGe2. The platinum atoms in both germanides have trigonal prismatic coordination: Pt@Ca4Ge2 and Pt@Eu4Ge2. The germanium substructures differ significantly: Ge2 dumb-bells with 246 and 262 pm Ge–Ge distances in CaPtGe2 versus germanium zig-zag chains (253 pm Ge–Ge distances) and a distorted square net (309 pm Ge–Ge distances) in EuPtGe2. CaPtGe2 and SrPtGe2 are diamagnetic. EuPtGe2 is a Curie–Weiss paramagnet with an experimental magnetic moment of 7.88(1) µB Eu atom−1. The purely divalent character of europium is manifested by a single signal at δ = −11.38(1) mm s−1 in the 151Eu Mössbauer spectrum at 78 K. EuPtGe2 orders antiferromagnetically at T N = 5.4(1) K.

Gadolinium spin dilution in the solid solution Gd1–xYxAuMg – gradual decrease of the Néel temperature

AbstractThe intermetallic compounds GdAuMg and YAuMg form a continuous solid solution Gd1–xYxAuMg. Samples in x=0.1 steps were synthesized from the elements in sealed tantalum ampoules in an induction furnace. Phase purity of the samples was checked by powder X‐ray diffraction. The structures of two members of the solid solution were refined from single crystal X‐ray diffractometer data: ZrNiAl type, P 2m, a=756.16(6), c=413.06(4) pm, wR2=0.0402, 328 F2 values, 16 variables for Gd0.80(2)Y0.20(2)AuMg and a=754.82(7), c=411.24(4) pm, wR2=0.0292, 325 F2 values, 16 variables for Gd0.37(1)Y0.63(1)AuMg. Temperature dependent magnetic susceptibility studies show a continuous decrease of the Néel temperature from TN=81.1(1) K (GdAuMg) to 3.5(1) K (Gd0.1Y0.9AuMg). With increasing x in Gd1–xYxAuMg the saturation magnetization increases, with a maximal value of 6.44(1) μB Gd atom−1 for Gd0.1Y0.9AuMg at 3 K. The dilution of the gadolinium substructure with yttrium pushes the magnetization isotherms close to Brillouin type behavior (free Gd3+).

Si-doped graphene nanosheets as a metal-free catalyst for electrochemical detection of nitroaromatic explosives

Si-doped graphene nanosheets (SiGNS) have been successfully constructed via high temperature annealing of graphene oxide and tetraethoxysilane mixture in a sealed glass ampoule. The Si atoms doped into graphene’s carbon network mainly existed as C3-Si-O and C2-Si-O2 configurations. The as-prepared SiGNS exhibited excellent electrochemical detection ability to nitroaromatic compounds in 0.1 M phosphoric acid buffer solution (PBS, pH = 8.0) via an electrochemical catalytic process. Five nitroaromatic compounds, including nitrobenzene, 2-nitrotoluene, 4-nitrotoluene, 2, 4-dinitrotoluene and 2, 4, 6-trinitrotoluene, were taken as the analyte to demonstrate the electrochemical catalytic ability of SiGNS. Density functional theory (DFT) calculation was carried out to explore the electrochemical catalytic mechanism of SiGNS. A hydrogen bond mediated electrochemical catalytic mechanism was proposed. Both the excellent electrical conductivity and the rich surface hydroxyl groups enhanced the electrochemical detection ability of SiGNS to nitroaromatic compounds. Si atoms in SiGNS played a key role for the excellent electrochemical detection ability of SiGNS due to most of the surface hydroxyl groups anchored on the Si atoms.

The impact of boron atoms on clathrate-I silicides: composition range of the borosilicide K8-xBySi46-y.

The clathrate-I borosilicide K8-xBySi46-y (0.8 ≤x≤ 1.2 and 6.4 ≤y≤ 7.2; space group Pm3[combining macron]n) was prepared in sealed tantalum ampoules between 900 °C and 1000 °C. By high-pressure preparation at 8 GPa and 1000 °C, a higher boron content is achieved (x = 0.2, y = 7.8). Crystal structure and composition were established from X-ray diffraction data, chemical analysis, WDX spectroscopy, and confirmed by 11B and 29Si NMR, and magnetic susceptibility measurements. The compositions are electron-balanced according to the Zintl rule within one estimated standard deviation. The lattice parameter varies with composition from a = 9.905 Å for K7.85(2)B7.8(1)Si38.2(1) to a = 9.968(1) Å for K6.80(2)B6.4(5)Si39.6(5).

STUDY OF PESO - PHO Y OF PESO - PHOTORESISTIVE CH ORESISTIVE CHARACTERISTICS OF TERISTICS OF TlInSe2 SINGLE CRYSTALS

Objective. The aim of the study is to establish the patterns and mechanisms of the effect of various impurities on the tensoresistive characteristics of TlInSe2 single crystals, as well as in solid solutions based on it. When studying the piezophotoresistive characteristics of TlInSe2 single crystals, it will determine the nature of the effect of uniaxial elastic deformation on the electrical, photoelectric and tensoresistive properties of TlInSe2 crystals. Methods. Crystals synthesized by fusing the components in accordance with stoichiometry in evacuated (~ 10-4 mm Hg) and sealed quartz ampoules were used for the study. Highly pure elements thallium (Tl - 000), indium (In - 000) and selenium (Se - high purity grade - 17 - 4) were used as initial components for the synthesis. Single crystals were grown by the improved Bridgman method, the crystallization front velocity varied from 0.5 to 0.9 mm / h. The samples required for the study were prepared by cleaving the grown single crystals from an ingot by the simplest indentation with a sharp knife, the blade thickness of which is ≤ 0.01 mm, along two mutually perpendicular planes of natural cleavage.

A universal method for rapid and large‐scale growth of layered crystals

AbstractLayered van der Waals (vdW) materials, consisting of atomically thin layers, are of paramount importance in physics, chemistry, and materials science owing to their unique properties and various promising applications. However, their fast and large‐scale growth via a general approach is still a big challenge, severely limiting their practical implementations. Here, we report a universal method for rapid (~60 min) and large‐scale (gram scale) growth of phase‐pure, high‐crystalline layered vdW materials from their elementary powders via microwave plasma heating in sealed ampoules. This method can be used for growth of 30 compounds with different components (binary, ternary, and quaternary) and properties. The ferroelectric and transport properties of mechanically exfoliated flakes validate the high crystal quality of the grown materials. Our study provides a general strategy for the fast and large‐scale growth of layered vdW materials with appealing physiochemical properties, which could be used for various promising applications.

YIrIn with ZrNiAl-type structure

Abstract The indide YIrIn was synthesized from the elements in a sealed tantalum ampoule in a high-frequency furnace. YIrIn adopts the ZrNiAl type. The crystal structure was refined from single-crystal X-ray diffractometer data: P6–2m, a = 750.63(6), c = 392.04(3) pm, wR = 0.0346, 308 F 2 values and 16 variables. Refinement of the occupancy parameters revealed a small degree of Ir/In mixing (0.912(9) Ir2/0.088(9) In1) on the 2d site. The YIrIn structure contains two crystallographically independent iridium sites, both with tri-capped trigonal prismatic coordination: Ir1@In6Y3 and Ir2@In3Y6.

Structure, Magnetic Properties, and 151 Eu Mössbauer Spectra of the Indium‐rich Phase Eu 3 Rh 2 In 15

Structure, Magnetic Properties, and ¹⁵¹ Eu Mössbauer Spectra of the Indium‐rich Phase Eu ₃ Rh ₂ In ₁₅

Efficient photoelectrocatalytic degradation of tylosin on TiO2 nanotube arrays with tunable phosphorus dopants

Photoelectrocatalytic (PEC) degradation of antibiotics residues is one of the most effective strategies for wastewater treatment. TiO2 has been widely used as an efficient photoelectrode material for pollutant removal. However, the degradation efficiency of UV light-driven TiO2-based photoelectrodes is still low. In this study, phosphorus-doped TiO2 nanotube arrays (TNTAs/P) were fabricated by calcination TNTAs with amorphous red phosphorus in sealed ampoules. By tuning the amount of P dopants, the optimized TNTAs/P(0.75) photoelectrode exhibits excellent PEC degradation performance under the Xenon lamp (100 mW/cm2, λ > 300 nm) light irradiation, with 79 % tylosin removal within 250 min.. The TNTAs/P(0.75) photoelectrode also displays about 4-fold photocurrent enhancement than bare TNTAs. It is suggested that the P-doping treatment could improve the light-harvesting ability and accelerate the separation efficiency of photo-induced electron-hole pairs in TNTAs, which benefits the production of •OH radicals and thus leads to the enhancement in tylosin degradation activity. This present work demonstrates a facile approach for improving the PEC degradation efficiency by doping heteroatoms in the photoelectrode.Capsule: P-doped TiO2 nanotube arrays were fabricated for boosting photoelectrocatalytic tylosin degradation activity due to the enhanced light absorption and charge transfer efficiency.

Si-doped graphene nanosheets for NOx gas sensing

Si-doped graphene nanosheets (SiGNSs) were constructed via high temperature annealing of the precursor mixture (the graphene oxide and tetraethoxysilane) in a sealed glass ampoule. Si-doped graphene nanosheets annealed at 400 °C (SiGNS-400) exhibited excellent NOx sensing ability with a high response value (21.5%–50 ppm of NO2), a fast response (126s), a fast recovery (378s), a broad detectable concentration range (300 ppm∼18 ppb) and outstanding selectivity. The doped Si atoms play a key role in NOx sensing. The sensor prepared by SiGNS-400 detected NOx not only in environments with a single harmful gas but also in complex environments containing several harmful gases. The detectable concentration range of the SiGNS-400 sensor decreased with increasing operating temperature.