SENSORS AND ACTUATORS B-CHEMICAL
·
2021
·
IF 7.46
Yuehua Li,Shaoxian Li,Weiwei Meng,Lei Dai,Ling Wang
A series of impedancemetric sensors for ammonia detection were fabricated using yttrium stabilized zirconia (YSZ) electrolyte and La n+1 Ni n O 3n+1 (n = 1, 2, and 3) sensing electrodes. The sensing materials with layered perovskite structure were prepared using in-situ impregnation method and well-dispersed in YSZ porous skeleton after calcination at 900 °C. The sensing performances of the sensors with La n+1 Ni n O 3n+1 sensing electrodes were investigated using the impedancemetric modulus |Z| and phase angle Θ as response signals, respectively. The results show that the sensor with La 2 NiO 4+ δ sensing electrode exhibits the higher response values and sensitivity compared to the sensor using La 3 Ni 2 O 7- δ or La 4 Ni 3 O 10- δ sensing electrodes, which is attributed to the largest NH 3 adsorption capacity of La 2 NiO 4+ δ . The response signals |Z| or Θ of the La 2 NiO 4+ δ based sensor linearly depend on NH 3 concentrations. The sensor hardly is insensitive to co-existing gases such as CO 2 , CH 4 , H 2 and relative humidity, but NO or NO 2 causes a positive error.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2020
·
IF 12.35
Xiaoxiang Xu,Ran Wang,Xiaoqin Sun,Meilin Lv,Shuang Ni
Sr2TiO4 and NaLaTiO4 are structural congeners with K2NiF4-type layered perovskite structure. However, nitrogen doping results in distinct modifications to their visible light absorption. Na/La ordering in the structure of NaLaTiO4 brings interesting structural features that are critical to a wealth of important factors such as nitrogen uptake, defect concentration, microstructures, and so forth. In sharp contrast to nitrogen-doped Sr2TiO4 (i.e., Sr2TiO4–xNy) whose photocatalytic activity is negligible under visible light illumination, nitrogen-doped NaLaTiO4 (i.e. NaLaTiO4–xNy) demonstrates very high activities for both photocatalytic water reduction and oxidation reactions. High apparent quantum efficiency ∼3.2% at 420 ± 20 nm has been recorded for NaLaTiO4–xNy, outperforming many other active metal oxynitride photocatalysts investigated under similar conditions. Theoretical calculations reveal that Na/La ordering incurs a strong electric field across Ti(O, N)6 octahedron layers and breaks the coplanar settlement of highest occupied molecular orbitals and lowest unoccupied molecular orbitals which are helpful to inhibit intralayer charge recombination.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2021
·
IF 8.067
Yang Zhao,Yameng Zhu,Jinpeng Zhu,Hailong Wang,Zhuang Ma,Lihong Gao,Yanbo Liu,Kaijun Yang,Yongchun Shu,Jilin He
Perovskite functional ceramics have been widely applied for thermal protection owing to their unique physical properties. However, formation of oxygen vacancies under external stimuli usually limits their performance in practical applications. Therefore, the mechanism of the effect of oxygen vacancy on the layer structure of perovskite La 0.9 Sr 0.1 TiO 3+ δ was investigated by experiments and first-principles simulations. The experimental results showed that the lattice distortion occurred in oxygen-deficient environment to give a longer c -axis, along with a significant adjustment in the modes of A/B–O bond vibration, resulting in lower reflectivity. Advanced transmission electron microscopy studies revealed that oxygen vacancies induced localized atomic rearrangements via [TiO 6 ] layer movements to adapt to the lattice distortion. This eventually restructured a part of the layer interfaces by expanding the overlapping projection of atoms in the c -axial direction. The specific transformation process was described as a compendious process, while geometric phase analysis effectively clarified how oxygen vacancies can inhibit reflectivity on the layer structure. Thus, this study provides effective approaches for researching the effects of oxygen vacancy on the physical properties of orthorhombic layer perovskite structures, which may facilitate the development of perovskite-based functional devices.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Feng Li Lin,Bing Liu,Qing Wei Zhou,Yu Hua Cheng,Kai Xin Song
Novel non-equimolar high-entropy SrLa(Al 0.25 Zn 0.125 Mg 0.125 Ti 0.25 Ga 0.25 )O 4 (SLAZMTG) ceramics with a layered perovskite structure have been prepared via the standard solid-state reaction method. The high-entropy composition belongs to the tetrahedral structure with a space group of I 4/ mmm , which is confirmed by the XRD and TEM analyses. Excellent microwave dielectric properties with a suitable dielectric constant ( ε r = 22.5), high quality factor ( Qf = 83,003 GHz), and near-zero τ f value of −1.7 ppm/°C are obtained in SLAZMTG ceramics sintered at 1400 °C. Meanwhile, a significant enhancement in compressive strength was achieved due to the improvement of configuration entropy, 912 MPa for SLAZMTG compared to 578 MPa in the pure SrLaAlO 4 composition. Additionally, the high-entropy engineering in the present work suggests great potential in achieving low thermal conductivities . SLAZMTG ceramics exhibit low thermal conductivities ranging from 2.86 W/m•K at 323 K to 1.99 W/m•K at 673 K, much lower than those of SrLaAlO 4 and other perovskite ceramics.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
INTEGRATED FERROELECTRICS
·
2023
·
IF 0.7
Zengcai Zhao,Qiaolan Fan,Chunfeng Yin,Yaping Lu,Yuzhu Jin,Yangxin Zhou
In this work, 80-nm Bi3.15Nd0.85Ti3O12 thin films with different annealing temperature have been successfully fabricated on p-type silicon substrates by sol-gel method. The effect of annealing temperature on the microstructure, dielectric properties, and energy-storage performances of the thin films were investigated in detail. The prepared films at 750 °C had a layered perovskite structure with an excellent crystalline morphology, featuring a high dielectric constant of 43.8 and a low dielectric loss < 2% at 1 kHz, which lead the significantly improvement of breakdown strength to increase the energy storage properties. The maximum recoverable energy density of 4.3 J/cm3 with an efficiency of 70.7% under the electric field of 1.90 MV/cm has been obtained for the Bi3.15Nd0.85Ti3O12 film capacitors at 750 °C. These properties indicate that Bi3.15Nd0.85Ti3O12 system is a promising environmentally friendly lead-free ferroelectric.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Feng Li Lin,Bing Liu,Cheng Chao Hu,Kai Xin Song
Novel high-entropy Sr(La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )AlO 4 ceramics with a layered perovskite structure have been prepared via the standard solid-state reaction method. The design of high-entropy improves the bond valence and subsequently optimizes the large negative temperature coefficient of resonant frequency ( τ f = −32 ppm/°C) of the simple SrLaAlO 4 ceramics. Excellent temperature stability ( τ f = −6 ppm/°C) together with a relative permittivity ( ε r ) of 18.6 and a quality factor ( Qf = 14,509 GHz) are obtained in Sr(La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )AlO 4 ceramics sintered at 1475 °C. It indicates that the present ceramics have great application prospects in passive microwave components such as resonators and filters. Meanwhile, significant improvements in compressive strength and strain are achieved, which are 1040 MPa and 15.7% for Sr(La 0.2 Nd 0.2 Sm 0.2 Eu 0.2 Gd 0.2 )AlO 4 compared to 583 MPa and 12% in SrLaAlO 4 . The enhanced mechanical properties originate from the dislocation strengthening mechanism as the intertwining of interlayer lattices is revealed from the high-resolution transmission electronic micrographs.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2017
·Vol. 100
·期 6
·2582-2589
·
IF 2.841
Guang Rong Ren,Jun Yao Zhu,Lei Li,Bing Liu,Xiang Ming Chen
Dense SrLa( R 0.5 Ti 0.5 )O 4 ( R= Mg, Zn) ceramics were prepared by a standard solid-state reaction method. The single phase with complex K 2 NiF 4 -type layered perovskite structure and I 4/ mmm space group was revealed by XRD, and the refined structure was analyzed by Rietveld analysis. Significantly improved dielectric constant was obtained in SrLa( R 0.5 Ti 0.5 )O 4 ceramics compared to the analogues SrLaAlO 4 and SrLaGaO 4 , which is attributed to the increasing normalized bond lengths of Sr/La-O(1) and Sr/La-O(2a) bonds and the higher polarizability of ( R 0.5 Ti 0.5 ) 3+ than Al 3+ and Ga 3+ . In addition, τ f converts to a positive value with the increase in dielectric constant. The following microwave dielectric properties were obtained in the dense ceramics: ε r =25.5, Qf= 72 000 GHz, τ f = 29 ppm/°C for SrLa(Mg 0.5 Ti 0.5 )O 4 , and ε r =29.4, Qf= 34 000 GHz, τ f = 38 ppm/°C for SrLa(Zn 0.5 Ti 0.5 )O 4. Furthermore, the stability of K 2 NiF 4 -type structure in MLnB O 4 [ M =Ca, Sr, Ba; Ln =Y, Sm, Nd, La; B= Al, Ga, (Mg 0.5 Ti 0.5 ), (Zn 0.5 Ti 0.5 )] compounds was discussed in relation to the tolerance factor of perovskite layer and the radius ratio of M 2+ and Ln 3+ , based on which near-zero τ f values are expected to be obtained in SrLa( R 0.5 Ti 0.5 )O 4 -SrLaAlO 4 and SrLa( R 0.5 Ti 0.5 )O 4 –SrLaGaO 4 unlimited solid solutions.
研究领域:
材料科学
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）