查找使用阿拉丁产品的科研文献

Achieving high electrostrain performance in BNT-based lead-free piezoelectric ceramics modified by Sr(Sn0.5Ta0.4)O3

Qian Qiu,Haoyu Wang,Yanghao Xu,Xinyu Chen,Xinyu Liu,Yuan Zhou,Zeyu Lv,Jinfeng Sun,Shaofei Zhang,Haibo Zhang,Abdul Manan,Gang Liu,Yan Yan

Piezoelectric ceramics, renowned for their ability to interconvert mechanical strain/stress and electrical signals, are widely utilized in diverse fields, such as electronic communications, aerospace, and national defense. Their appeal lies in their rapid response, precise motion control, and low power consumption, making them indispensable in advanced electromechanical systems. Bismuth sodium titanate (BNT)-based ceramic materials exhibit excellent strain performance and piezoelectric response, making them highly promising for applications in actuators and transducers. In this study, the piezoelectric ceramic system of (0.93− x )Bi 0.5 Na 0.5 TiO 3 −0.07BaTiO 3 − x Sr(Sn 0.5 Ta 0.4 )O 3 ( x = 0–0.02, BNBT− x SST) were synthesized using the conventional solid-state reaction method. Through a combination of composition design and phase boundary engineering, the microstructure of the ceramics is modified, and a systematic analysis of the relationship between the electrical properties and the microstructure is conducted. The results indicate that the addition of SST reduces the domain size and influences the phase evolution, gradually transitioning the ceramics from non-ergodic relaxor (NR) to ergodic relaxor (ER) state. Among all the compositions, BNBT−0.010SST exhibits outstanding performance. At a relatively low driving electric field ( E = 50 kV/cm), the maximum piezoelectric strain coefficient ( d 33 * ) reaches 632 pm/V, while under a relatively higher driving electric field ( E = 80 kV/cm), a strain response of 0.42% is achieved. This exceptional performance is believed to result from a reversible phase transition between the FE and ER states driven by the electric field. Additionally, the strain of this ceramic remains stable at over 90% within the temperature range of 30°C–100°C, demonstrating outstanding temperature-insensitive properties. At the same time, compared to other BNT-based ceramic systems, the hysteresis at room temperature has been effectively reduced, remaining below 47%. Therefore, this study provides valuable insights for improving the strain performance of NBT-based lead-free piezoelectric ceramics, offering greater possibilities for their application in piezoelectric devices.

Optimizing microwave dielectric properties of low-temperature sintered Sr/Zn-substituted BaMg2V2O8 by mixing with TiO2

Burhan Ullah,Millicent Appiah,Yuting Xiao,Yixing Yang,Daniel Q. Tan

Ba 1 − x Sr x Mg 2 − y Zn y V 2 O 8 compounds, abbreviated as BSMZVO@ xy ( x = 0.0–0.2 and y = 0.02), were synthesized with tetragonal structures. The microstructure, molecular structure, and polarization mechanism were investigated using X-ray diffraction, electronic microscopy, Raman spectroscopy, and vector network analyzer. The sintering temperatures (<900°C) and microwave dielectric properties of BSMZVO are significantly impacted by (Sr/Zn) 2+ substitution and TiO 2 mixing. The BSMZVO@ xy ( x = 0.15 and y = 0.02) exhibited encouraging ε r (12.4–12.7), Q × f (40 054–40 973 GHz), and temperature coefficient of resonance frequency ( τ f ∼ −5.2 to 0.0 ppm/°C) after sintering at 860°C/4 h and 800°C/4 h. For the first time, TiO 2 was added to enhance the density and Q × f value without degrading τ f . The 0.25 wt.% TiO 2 resulted in optimum ε r of 13.4, Q × f of 43 636 GHz, and τ f of +1.8 ppm/°C after sintering at 760°C/4 h. The improved quality factor ( Q × f ) is linked to the Raman A 1g mode and relative density.

Electrocatalytic degradation of perfluorooctanoic acid by LaNixY1-xO3 (Y = Fe, Cu, Co, Sr) gas dispersion electrode

Yongyang Chen,Dan Guo,Xiaochun Dong,Yahui Li,Yixuan Huang,Hao Chen,Shanping Li

Perfluorooctanoic acid (PFOA), as a refractory organic pollutant, seriously harms the environment and damages human health. Here, the electrocatalytic method was selected to degrade PFOA. In this work, perovskite catalysts doped with different elements, and corresponding gas diffusion electrodes (GDE) were prepared by the gel-sol method and citric acid complexation method. The crystal structure, microscopic morphology, and electrochemical properties of the LaNi x Y 1-x O 3 (Y = Fe, Cu, Co, Sr) perovskite catalyst electrode were analyzed by XRD, TEM, and CV. Moreover, the electrocatalytic performances of the as-prepared electrodes were assessed by the degradation of PFOA, and the Sr-doped GDE exhibited the highest degradation rate of PFOA. The optimum degradation conditions, such as the current density, pH, and initial concentration were also investigated. It was observed that when the current density was 20 mA/cm 2 , pH was 5, and initial concentration was 0.25 mmol/L, the Sr-doped GDE had the best degradation and defluorination efficiency of PFOA reached 90.0 % and 75.1 %, respectively. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to analyze the intermediate products of PFOA degradation and obtain the degradation pathway. With the combined action of OH and O 2 , PFOA was degraded by stepwise removal of CF 2 groups, which were ultimately degraded into F − and CO 2 .

Energy transfer and luminescence properties of Sr[1−3(x+y)/2]Al2B2O7:xEu3+, yBi3+ phosphor

Renping Cao,Tao Liang,Wensheng Li,Chunyan Cao,Yufeng Wen,Qianglin Hu

Sr [1−3( x + y )/2] Al 2 B 2 O 7 : x Eu 3+ , y Bi 3+ ( x   =   0–5   mol% and y   =   0–5   mol%) phosphors are synthesized by a solid-state reaction method in air, and their crystal structure, fluorescence lifetime, and luminescence properties are investigated. The optimal composition is determined to be (Sr 0.94 Eu 0.03 Bi 0.01 )Al 2 B 2 O 7 . The PLE band peaks within the range 200–550   nm are due to O 2−   →   Eu 3+ charge transfer band, 7 F 0   →   5 H 3 , 5 D 4 , 5 L 7 , 5 L 6 , 5 D 3 , 5 D 2 , and 5 D 1 transitions, respectively. The strongest PL band peak under excitation 394   nm light is at ∼615   nm owing to 5 D 0   →   7 F 2 transition of Eu 3+ ion. The PL intensity of Eu 3+ , Bi 3+ co-doped SrAl 2 B 2 O 7 phosphor is 1.3   times that of Eu 3+ doped SrAl 2 B 2 O 7 phosphor due to the energy transfer between Eu 3+ and Bi 3+ ions, which is explained by the energy level diagrams of Bi 3+ and Eu 3+ ions. The CIE chromaticity coordinates of Sr 0.955 Al 2 B 2 O 7 :0.03Eu 3+ and Sr 0.94 Al 2 B 2 O 7 :0.03Eu 3+ , 0.01Bi 3+ phosphors under excitation 394   nm light are ( x   =   0.6292, y   =   0.3702) and ( x   =   0.6284, y   =   0.3711), respectively. These phosphors will be used as reddish orange emitting phosphor candidate for white LED with ∼394   nm near ultraviolet LED chip.

Enabling efficient visible light photocatalytic water splitting over SrTaO2N by incorporating Sr in its B site

Xiaoqin Sun,Fangfang Wu,Gang Liu,Xiaoxiang Xu

The perovskite oxynitride SrTaO2N is a promising compound for solar energy conversion because it has strong visible light absorption at wavelengths as long as 650 nm. However, its photocatalytic activity is generally very poor, primarily because of the high defect concentration induced during its synthetic procedures as well as photocatalytic self-decomposition events. In this work, we introduce Sr into the B site of SrTaO2N to form a complex perovskite oxynitride, Sr3(Sr1/3Ta2/3)3O9−xNy (i.e. Sr4Ta2O9−xNy). The new compound has a much lower defect concentration compared to SrTaO2N and much higher stability against photocatalytic self-decomposition. More importantly, Sr4Ta2O9−xNy demonstrates significantly improved photocatalytic activity for water oxidation and reduction reactions under visible light irradiation (λ ≥ 400 nm) than SrTaO2N, approaching an apparent quantum efficiency as high as 3.4% at 420 ± 20 nm.

Solution-processed Sr-doped NiOx as hole transport layer for efficient and stable perovskite solar cells

Jiankai Zhang,Wujian Mao,Xian Hou,Jiaji Duan,Jianping Zhou,Sumei Huang,Wei Ou-Yang,Xuehua Zhang,Zhuo Sun,Xiaohong Chen

Nickel oxide (NiO x ) hole transport layer (HTL)-based planar perovskite solar cells (PSCs) have attracted much attention due to high power conversion efficiency (PCE) and simple processing. In this work, smooth and compact Sr-doped NiO x films with different Sr doping concentration were successfully prepared through a simple low temperature sol-gel method. The 1 at.% Sr-doped NiO x HTL-based PSCs exhibited the best performance with PCE of 20.07%, which is greatly higher than PCE of reference NiO x based PSCs (15.73%). Furthermore, the unencapsulated PSCs based on Sr:NiO x HTL still retains over 60% of the original PCE value aging for 100 days under ambient air, showing better stability. The superior performance of Sr-doped NiO x based PSCs is attributed to better electrical conductivity, crystallinity of perovskite film and energy level matching with perovskite layer, which can greatly improve hole transport and extraction abilities and reduce carrier recombination, resulting in high PCE and better stability.

Facile Synthesis of MOF-Derived Hierarchical Flower-Like Sr-Doped Co3O4 Structure for Effective TEA Sensing

Heming Sun,Xiaonian Tang

AIn3Si4P9 (A = Ca, Sr): quaternary phosphides with double-helix structures exhibiting high laser-induced damage thresholds

Ming-Shu Zhang,Bin-Wen Liu,Xiao-Ming Jiang,Guo-Cong Guo

Two quaternary phosphides AIn3Si4P9 (A = Ca, 1; Sr, 2) belonging to the non-centrosymmetric space group P41212 are discovered and synthesized through the solid-state method for the first time. They present extraordinary double-helix frameworks composed of corner-shared tetrahedral [InP4] and [SiP4] units. Although compounds 1 and 2 have undesirable band gaps (1.25 and 1.15 eV), their extremely low thermal expansion coefficients (∼10−6) result in high laser-induced damage thresholds approximately seven times that of benchmark AgGaS2 under a 2050 nm laser. Moreover, both compounds show weak second-harmonic generation intensities primarily caused by Kleinman forbidden nonlinear optical coefficients. Theoretical calculations further reveal that the electron transitions mainly originated from the tetrahedral [InP4] and [SiP4] units.

Novel high-entropy microwave dielectric ceramics Sr(La0.2Nd0.2Sm0.2Eu0.2Gd0.2)AlO4 with excellent temperature stability and mechanical properties

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.

Tunable luminescence of Bi3+/Eu3+-doped SiO2–Al2O3-MCO3 (M = Ca, Sr, Ba) glasses for WLED

Falin Zhang,Xiaoying Liang,Rongfei Wei,Hai Guo,Fangfang Hu

In this work, a group of Bi 3+ /Eu 3+ -doped SiO 2 –Al 2 O 3 -MCO 3 (M = Ca, Sr, Ba) glasses were fabricated through melt-quenching method. Their structure and photoluminescence characters were studied via X-ray diffraction (XRD), UV–Vis transmission spectra (TRS), excitation spectra, emission spectra and decay lifetimes. The XRD results show that no nano-crystal phase forms in glass matrix with different doping concentrations of Bi 3+ and Eu 3+ ions. Through regulating optical alkalinity value, the intensity of Bi 3+ ions increases and the peak position shifts to red wavelength. The Bi 3+ /Eu 3+ co-doped glasses show a blue-white-yellow-red luminescence by changing concentration of Eu 3+ ions. Energy transfer efficiency from Bi 3+ to Eu 3+ can reach as high as 10.54%. At 423 K, the emission intensity of 55SiO 2 –10Al 2 O 3 –35BaO-0.25Bi 2 O 3 (GBE0.5) is 31.1% of that at 308 K. Meanwhile, the activation energy of the glass matrix is 0.251 eV. All results suggest that these Bi 3+ /Eu 3+ co-doped glass samples possess potential application in LED field.

The immobilization of Sr(ll) and Co(ll) via magnetic easy-separation organophosphonate-hydroxyapatite hybrid nanoparticles

Keren Lu,Zhiren Zhao,Jin Cui,Cuiyun Bai,Hongling Zhang,Xuetao Zhao,Fengyun Wang,Mingzhu Xia,Yanru Zhang

The magnetic Hexamethylene diamine tetramethylene phosphonic acid (HDTMP)-hydroxyapatite nanoparticles (HD-MHAP) were firstly prepared and applied for the immobilization of radioactive Sr 2+ (Strontium ion) and Co 2+ (Cobalt ion). The molar ratio of organic phosphine in HDTMP to total phosphorus was 10% (10HD-MHAP) and can also be easily separated from aqueous solution. At the equilibrium concentration of Sr 2+ and Co 2+ (200 mg/L), the adsorption capacity of MHAP and 10HD-MHAP on Co 2+ was 28.4 mg/g and 172.3 mg/g, respectively and for Sr 2+ , the adsorption capacity was 54.9 mg/g and 320.7 mg/g. Additionally, the desorption percentage of Sr 2+ (%) and Co 2+ (%) was very low, which was 0.66 and 1.61, respectively. This is significant because the irreversible adsorption of HDTMP/Fe 3 O 4 /HAP composite for Sr 2+ and Co 2+ ensures the captured radionuclides will not be released back into the aquatic systems. Moreover, the affinity between HDTMP and HAP and the coordination of HDTMP and Sr 2+ or Co 2+ was probed by Multiwfn wavefunction analysis. The results indicated that the formation of a ternary surface complex of MHAP-HDTMP-M (Sr 2+ or Co 2+ ) was the key to the excellent immobilization performance of HD-MHAP composite for Sr 2+ or Co 2+ .

“Network-trapped engineering” of graphene oxide membrane with stable structure

Yi Huang,Yu Qiang,Ruobing Yi,Shuai Wang,Shanshan Liang,Liang Chen

Graphene oxide (GO) membranes are considered ideal candidates for efficient water treatment due to their unique two-dimensional structure and excellent sieving properties. However, the swelling of graphene oxide in aqueous solutions makes it still challenging for practical application. Inspired by the spider web, in this work, we developed a “network-trapped engineering” strategy to stabilize the interlayer spacings of GO membranes, which are defined as GS-Sr membranes. The sodium alginate (SA) and Sr 2+ were successfully fixed as the “network” and “rivets” in-between the GO nanosheets, respectively. Benefiting from the design of the network structure, the GS-Sr membranes exhibited excellent interlayer spacing stability. Meanwhile, this evenly distributed network structure in the GO laminates can further optimize the stacking of nanosheets, forming more orderly 2D confined nanochannels. As a result, the membranes exhibited superior salt/dye sieving performance, with a separation factor up to 179.13 for Na 2 SO 4 /CR, while still maintaining an outstanding water permeance of 70.14 L m −2  h −1 bar −1 . Furthermore, the GS-Sr membrane demonstrated stable separation performance in the long-term test, and the mechanical stability has also been enhanced in the mechanical test. Overall, compared with traditional simple cross-linking strategies, this strategy offers a new insight into fine-construction of two-dimensional nanochannels.