查找使用阿拉丁产品的科研文献

Plastic Mg3(Sb,Bi)2-based thermoelectric compounds with enhanced texture via cold-deformation

Ziming Zhang,Zhiqiang Gao,Tingting Deng,Qingfeng Song,Lidong Chen,Shengqiang Bai

Mg3(Sb,Bi)2-based Zintl compounds have attracted lots of attention due to their high thermoelectric performance and good mechanical properties. However, thermally activated mobility, which is ascribed to the grain boundary scattering, greatly limits their practical use. In this work, we reveal the plasticity of Mg3(Sb,Bi)2-based compounds in the compressive strength test. The ab initio analysis indicates that this plasticity should be ascribed to the low slip barrier energy (∼580 mJ m−2), which is only one third of the cleavage energy (∼1600 mJ m−2). Based on this finding, we propose a cold-deformation procedure to elongate particles and to enhance texture, which successfully suppresses the grain boundary scattering. As a result, a high carrier mobility of 86.6 cm2 V−1 s−1 and a high power factor of 16.2 μW cm−1 K−2 in Mg3.1Bi1.5Sb0.49Te0.01 are obtained at room temperature. The plastic deformation capacity of Mg3(Sb,Bi)2 compounds provides a near-net-forming method to fabricate special-shaped devices at room-temperature, which will extend the application fields of thermoelectric techniques.

Structure, dielectric and impedance properties of BaTiO3–Bi(Y0.5Yb0.5)O3 lead-free ceramics

Huang Xuechen,Liu Hanxing,Hao Hua,Wang Zhijian,Hu Wei,Xu Qi,Zhang Lin,Cao Minghe

(1 − x)BaTiO 3 –xBi(Y 0.5 Yb 0.5 )O 3 (BT–BYYb, x = 0.01–0.12) ceramics were prepared via solid-state processing techniques. The structure, dielectric and impedance properties of (1 − x)BT–xBYYb ceramics are studied. The studies show that the ceramics are in tetragonal phase when x ≤ 0.07, transform to pseudocubic phase at x ≥ 0.08. The grain growth is obviously suppressed for (1 − x)BT–xBYYb samples with x value. Dielectric properties are depressed and dielectric peaks are broadened with x. T m first increases and then decreases. BT–BYYb system exhibits diffused phase transition and good temperature stability, which is due to the increased cation disorder, forming the local difference of the polar region due to the size and charge difference and inducing many different regions with different Curie points. The samples can meet the temperature requirements of X8R characteristics at 1 kHz with: ε ~ 1330, tanδ ~ 0.0076, |△C/C| ≤ ±15 % (−55 to 150 °C) for x = 0.11 and ε ~ 1032, tanδ ~ 0.012, |△C/C| ≤ ±15 % (−55 to 170 °C) for x = 0.12, respectively. The activation energy of the bulk material obtained from conduction and relaxation first increases and then decreases with increasing BYYb concentration. The different activation energy indicates various mechanisms are involved in the conduction and relaxation process, which may be due to the mixed conduction or doubly ionized oxygen and thermal motions of titanium ions (Ti 4+ ) or doubly ionized oxygen, respectively.

Synergistic effects of Bi and N doped on ZnO nanorods for efficient photocatalysis

N.R. Khalid,Hamid Ishtiaq,Faisal Ali,M.B. Tahir,Sumaira Naeem,A. Ul-Hamid,M. Ikram,T. Iqbal,M. Rizwan Kamal,Hussein Alrobei,Meshal Alzaid,A. Dahshan

The fast pace of industrial growth during the current decade has seen a large family of dyes employed copiously in the production of various products such as paper and ink. These dyes pollute earth's ecosystems. Researchers look at various ways to degrade these dyes including the use of suitable nanomaterials . ZnO is an important semiconductor material that can be employed for this purpose. In this research work, we optimized the photocatalytic capability of ZnO by co-doping it with 1–7 wt% of Bi and N. The synthesized Bi and N co-doped ZnO nanorod samples showed excellent photocatalytic behavior towards Rhodamine-B (RhB). It was confirmed using XRD and SEM that (5, 2.5) wt.% Bi/N co-doped ZnO nanorods exhibited unique morphology and structure. EDX successfully assessed the elemental composition of the synthesized samples. To provide further insight into its microstructure, the HRTEM and SAED analysis were performed. Optical properties were determined using PL and UV–Visible spectroscopy. The prepared nanorod material degraded almost 89% of RhB in 180 min. The superior degradation ability of co-doped ZnO material when exposed to visible portion of sunlight spectrum is credited to the decrease in the recombination rate of charges and an increase in the depth penetration of photons. The degradation efficiency of Bi/N co-doped ZnO material is enhanced due to reduced recombination rate and increased production of number of defects and oxygen vacancies .

A Self-Powered photodetector based on bi₂o₂se/wse₂ heterostructure for enhanced optoelectronic applications

Ning Qiyun,Li Bingwei,Zhou Wang,Xu Xiaoting,Li Jun

In this study, Bi₂O₂Se nanosheets were synthesized via a hydrothermal method, and a Bi₂O₂Se/WSe₂ heterostructure was subsequently constructed using a mechanical compounding approach to develop a photoelectrochemical photodetector. By optimizing the mass ratio and KOH electrolyte concentration, the Bi₂O₂Se/WSe₂ heterostructure exhibited optimal performance at a 7:1 ratio in 0.1 M KOH. Benefiting from the interfacial heterojunction between the two materials, the Bi₂O₂Se/WSe₂ heterostructure achieved a photocurrent density of -2.74 µA/cm² under zero external bias, representing an order-of-magnitude enhancement compared to pristine Bi₂O₂Se nanosheets. Concurrently, the rise time was significantly reduced from 0.86 s to 0.28 s, And the decay time decreased from 4.85 s to 0.32 s, demonstrating superior self-powered characteristics. Furthermore, the Bi₂O₂Se/WSe₂ heterostructure exhibited a maximum photoresponsivity of 61 µA/W. The optimized Bi₂O₂Se/WSe₂ photodetector showed no notable performance degradation during a 10,000 s cyclic on/off illumination test. This work highlights the immense potential of the Bi₂O₂Se/WSe₂ heterostructure-based self-powered photodetector in delivering exceptional self-driven functionality, outstanding optoelectronic properties, and robust stability for practical applications.

Effect of Honokiol on culture time and survival of Alzheimer’s disease iPSC-derived neurons

Duong Thi Thuy Le,Cuong Manh Vu,Thuy Thi Bich Ly,Nam Trung Nguyen,Phuong Thi Mai Nguyen,Ha Hoang Chu

Construction of a g-C3N4/Bi(OH)3 Heterojunction for the Enhancement of Visible Light Photocatalytic Antibacterial Activity

Jian Feng,Li Wang,Bo Xiao,Xia Ran,Caiying Wang,Jinming Zhu,Zuoji Liu,Chaozhong Li,Xinai Cui,Rong Li,Guangwei Feng,Zeqin Dai

Photocatalytic technology has been recently conducted to remove microbial contamination due to its unique features of nontoxic by-products, low cost, negligible microbial resistance and broad-spectrum elimination capacity. Herein, a novel two dimensional (2D) g-C3N4/Bi(OH)3(CNB) heterojunction was fabricated byincorporating Bi(OH)3(BOH) nanoparticles with g-C3N4(CN) nanosheets. This CNB heterojunction exhibited high photocatalytic antibacterial efficiency (99.3%) againstEscherichia coli(E. coli) under visible light irradiation, which was 4.3 and 3.4 times that of BOH (23.0%) and CN (28.0%), respectively. The increase in specific surface area, ultra-thin layered structure, construction of a heterojunction and enhancement of visible light absorption were conducive to facilitating the separation and transfer of photoinduced charge carriers. Live/dead cell staining, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) assays and scanning electron microscopy (SEM) have been implemented to investigate the damage to the cell membrane and the leakage of the intracellular protein in the photocatalytic antibacterial process. The e−, h+and O2•−were the active species involved in this process. This study proposed an appropriate photocatalyst for efficient treatment of bacterial contamination.

Synergistic charge separation and magnetic recovery in a noble-metal-free Fe3O4/TiO2/Bi photocatalyst for bromate reduction

Ying Xu,Shuili Yu,Zhiqiang Fan,Xingli Ji,Cong Huang,Zheng Xu,Rui Liu,Chao Jiang

Bromate (BrO 3 − ), a carcinogenic and regulated disinfection by-product, poses a persistent challenge to drinking water safety due to its high solubility and chemical stability. In this work, a noble-metal-free Fe 3 O 4 /TiO 2 /Bi photocatalyst was successfully prepared and subsequently applied for BrO 3 − reduction under ultraviolet light. The ternary composite design enables cooperative functionality among the components, where Fe 3 O 4 facilitates charge transfer and magnetic separability, Bi 0 acts as a hole scavenger, and TiO 2 serves as the primary photoactive material. Characterization results confirmed the successful formation of the heterostructure with enhanced charge separation properties. The composite containing 5 wt% Bi exhibited the highest activity, achieving 99 % BrO 3 − removal within 25 min at pH 7.0, with a pseudo-first-order rate constant of 0.185 min −1 , which is 11.8 times that of pure TiO 2 . The enhanced photocatalytic performance is ascribed to the synergistic effect between Bi, Fe 3 O 4 and TiO 2 . Bi 0 nanoparticles functioned as hole acceptors to suppress recombination, while Fe 3 O 4 facilitated electron transport and provided magnetic separability. The photocatalyst retained high activity over five consecutive cycles with negligible metal leaching and performance loss. In addition, its effectiveness was verified in tap water containing typical inorganic ions and dissolved organic matter, demonstrating moderate inhibition but maintaining BrO 3 − reduction capability. This study provides a cost-effective, magnetically recoverable, and noble-metal-free photocatalyst with improved charge separation efficiency and recovery feasibility, offering practical potential for BrO 3 − mitigation in drinking water treatment.

One-step synthesis of Z-scheme BiOBr/Bi/BiOI efficient heterojunction photocatalysts and the effect of ascorbic acid

Yongyu Li,Yaping Wang,Zhengkang Zhu,Shenshen Shi,Xinyi Ma,Jianjun Chen,Haijie Sun,Lingxia Chen

Ternary-component BiOBr/Bi/BiOI composites were successfully prepared by a one-step hydrothermal method under the reducing effect of ascorbic acid. Ascorbic acid not only converts Bi 3+ to Bi 0 as a reducing agent, but also inhibits the growth of grains and controls the morphology, resulting in a multilayered hierarchical floral structure of the BiOBr/Bi/BiOI composites formed by the assembly of nanosheets dotted with nanoparticles on the surface. The composite has highest photocurrent density, lowest photogenerated electron-hole recombination rate and high specific surface area, and exhibits excellent degradation performance for both single and mixed pollutant systems of tetracycline, rhodamine B and methylene blue. h + is the most dominant reactive oxygen species in the photodegradation process, while ·OH and ·O 2 − provide weak auxiliary degradation. A Z-scheme photocatalytic degradation mechanism of BiOBr/Bi/BiOI with excellent photocatalytic performance was proposed.

Lightweight Bi-GdF3/Ti3C2Tx packaging aerogel with high electron radiation protection efficiency for MOSFET radiation hardening

Tianyu Zhang,Yang Hong,Xiaolei Shi,Hongchao Zheng,Jingyang Li,Wenjing Wei,Kai Cui,Yang Li,Wei Qin,Xiaohong Wu

Developing lightweight packaging materials with high radiation protection efficiency for MOSFET radiation hardening is highly significant for enhancing the radiation resistance of MOSFETs in space radiation environments. This work presented lightweight Bi-GdF 3 /Ti 3 C 2 T x aerogel (BGTA) with high electron radiation protection efficiency (RPE) through self-assembly and directional freezing. Subsequently, a radiation hardened MOSFET was obtained by packaging with BGTA. The resulting BGTA packaging material demonstrates excellent electron protection efficiency (92.23 %) compared to conventional Al packaging materials (23.80 %) at the same areal density. Meanwhile, the BGTA-packed MOSFET shows outstanding radiation resistance, exhibiting a much smaller negative threshold voltage drift value of 0.10 V compared to the Al-packed MOSFET (1.17 V). The electron shielding mechanism of BGTA was analyzed and elucidated by FASTRAD simulation on a micro scale. Due to the synergistic effect of the honeycomb aerogel structure and Bi/GdF 3 functional filler in BGTA aerogel, the incident electrons are effectively attenuated, thereby reducing radiation damage to the SiO 2 layer of the MOSFET and improving the radiation resistance of the MOSFET. Theoretical calculation results substantiate that the BGTA-packed MOSFET exhibits lower threshold voltage shifts and trapped charges. This work presents a lightweight and highly efficient MXene aerogel packaging material for MOSFET radiation hardening.

Competitive coordination initiated one-pot synthesis of core–shell Bi-MOF@BiOX (X = I, Br and Cl) heterostructures for photocatalytic elimination of mixed pollutants

Dingliang Dai,Jianhao Qiu,Guanglu Xia,Yong Tang,Zhonghao Wu,Jianfeng Yao

Core-shell Bi-MOF@BiOX (X = I, Br and Cl) hybrids were fabricated by a one-pot solvothermal strategy via regulating the concentration and type of halogen ions in the Bi-based CAU-17 synthesis. By virtue of the competitive coordination effect to Bi 3+ between CAU-17 and BiOX, CAU-17 was converted into another Bi-MOF with similar structures and compositions. Moreover, Bi 3+ plays the role of “bridge” and endows an intimate interface contact between BiOX and the Bi-MOF, which immensely expedites the charge and mass transportation. The obtained Bi-MOF@BiOX hierarchical heterostructures were applied to photocatalytic elimination of solo and mixed pollutants (Cr(VI)/tetracycline and Cr(VI)/o-nitrophenol), and exhibited favorable performances. Choosing Bi-MOF@BiOI as a typical example, the corresponding performances for Cr(VI) reduction, tetracycline and o-nitrophenol degradation in their solo systems are 14, 10, 8 times higher than those of CAU-17, and 13, 7, 5 times higher than those of BiOI under visible light, respectively. Of note, the above photocatalytic performances could be further improved in the coexisting environment of Cr(VI) and tetracycline or o-nitrophenol, which is attributed to the elevated charge separation efficiency caused by the timely consumption of photo-excited electrons and holes. This work gives some insights into the delicate design of MOF photocatalysts and their applications in environmental restoration.

Fabrication of Bi/BiOCOOH/PVDF with improved photocatalytic activity for the degradation of ciprofloxacin

Yue Shen,Haoyang Xu,Yage Zheng,Yao Wang,Liang Zhang,Zhiqiang Zhang,Lvling Zhong,Zhixian He

The development of a low-cost and recyclable method for wastewater treatment has been a major challenge. Polyvinylidene fluoride (PVDF) membranes have received considerable attention owing to their excellent mechanical strength , unique antioxidant properties, and low cost. In this study, Bi/BiOCOOH/PVDF composite membrane materials were prepared using a simple two-step solvent thermal method and phase conversion method. The results showed that under the synergistic action of adsorption and photocatalysis , the photocatalytic degradation efficiency of Bi/BiOCOOH composite material and Bi/BiOCOOH/PVDF composite membrane material for ciprofloxacin (CIP) was much higher than that of BiOCOOH. The introduction of PVDF acted as a carrier, improved the adsorption of the catalytic material to CIP, and facilitated the effective collision of the photocatalytic active site and CIP. The experimental results and theoretical calculations confirmed that the combination of Bi and BiOCOOH effectively improved the light absorption capacity and photocatalytic performance. The reproducibility test revealed that the small amount of new composite catalyst for Bi/BiOCOOH/PVDF as a carrier was lost and that the Bi/BiOCOOH/PVDF catalyst still had high catalytic activity. In addition, the influence of water matrix factors, such as pH and anion, on the photocatalytic degradation experiment was investigated, which would provide some reference for the actual wastewater treatment of the composite catalyst. This study demonstrates a photocatalytic activation mechanism between metals and semiconductors and provides some basis for constructing catalysts for the synergistic and effective treatment of water pollution through a combined adsorption and photocatalysis process.

Thermo-Electro-Magnetic Interactions and ≈1 nm Fe Interfacial Layer Realize High Average ZT in Fe/Mg3(Sb,Bi)2 Below 300 °C

Kangpeng Jin,Haonan Nie,Fengxian Gao,Jiang-Jiang Ma,Mingfang Shu,Xi Yan,Zhen-Hua Ge,Xiao Gao,Weiyun Zhao,Ming Liu,Yuan Yu,Jie Ma,Biao Xu,Liangwei Fu

Mg 3 (Sb,Bi) 2 alloys offer exceptional near-room temperature thermoelectric (TE) performance comparable to Bi 2 Te 3 . However, the low carrier mobility due to Mg vacancies and relatively high lattice thermal conductivity adversely affect overall TE performance. Herein, carrier mobility and thermal conductivity of Mg 3 (Sb,Bi) 2 are decoupled by modulating both the phase interface and grain boundaries through incorporating different sizes of iron (Fe). Ferromagnetic micrometer-sized Fe particles enhance the figure of merit ( ZT ) more than superparamagnetic nano-sized counterparts. Magnetic moments of Fe induce the charge density overlap near phase boundaries and ≈1 nm Fe interfacial layer lowers grain-boundary barriers, leading to sharply increased carrier mobility. Moreover, the additional magnon-phonon scattering reduces lattice thermal conductivity by over 40%. Consequently, Fe/Mg 3 (Sb,Bi) 2 composite achieves a high average ZT of 1.4 over room temperature to 573 K. The fabricated Mg 3 (Sb,Bi) 2 -CdSb module demonstrates a high conversion efficiency of 8.4% under a 275 K temperature gradient, among the best for Mg 3 (Sb,Bi) 2 -based modules. This work uncovers the role of thermo-electro-magnetic interactions in bolstering TE performance and inspires the development of low-cost, high-efficiency TE modules for low-grade heat recovery.