JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Shaokun Ling,Xiaoyan Qin,Chang chen,Kai Meng,Yifeng Yan,Junyun Ming,Sen Liao,Yingheng Huang,Lei Hou
Despite long-term development of LEDs, problems urgent to resolve is still existing. The most outstanding problem to tackle is luminescent stability at high temperature working situation. In this study, a novel type of β-NaYF 4 based phosphor incorporated with Eu 3+ and Tb 3+ is reported. A series of β-NaYF 4 :0.065Eu 3+ , x Tb 3+ ( x = 0.001, 0.002, 0.003, 0.004, 0.005) phosphors were synthesized by hydrothermal method . The sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ possesses optimal luminescent property at room temperature. The mechanism of energy transfer from Tb 3+ to Eu 3+ ion is quadrupole-quadrupole interactions. The sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ demonstrates zero thermal quenching (ZTQ) property at 303 K to 383 K. According to XRD and XPS characterizations, nonequivalent replacement between intrinsic ion Na + and Y 3+ were discovered, which finally leads to production of crystal defects. According to electron paramagnetic resonance (EPR) characterization and density functional theory (DFT) calculation, the type of crystal defect of β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ is confirmed to be V Y vacancies which are the predominant defect of crystal. The depths and densities of defects were calculated according to data of thermoluminescence spectra (TL spectra). Crystal defects play the role of electrons traps that could store electrons. Electrons stored in traps will be excited to excitation state of Eu 3+ under the thermal stimulation to offset undesirable impact of thermal quenching (TQ), which leads to ZTQ property of the sample β-NaYF 4 :0.065Eu 3+ ,0.002Tb 3+ . The CRI and CCT of fabricated WLED are 3830 K and 84.1, respectively.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Science China-Materials
·
2025
·
IF 7.4
Huang Fuxia,Liu Yifei,Wang Feng,Liu Ya,Guo Liejin
BiOI materials show significant potential for photocatalytic CO 2 reduction, but their limited CO 2 activation and poor charge carrier properties hinder conversion efficiency. In this study, we engineered BiOI-based photocatalysts with abundant crystal defects to enhance performance. X-ray diffraction (XRD), Raman spectroscopy, and high-resolution transmission electron microscopy (HRTEM) revealed lattice distortions and twin crystals in BiOI-LD and BiOI-TC. Ultraviolet-visible spectroscopy, micropore and chemisorption analyses, and photoluminescence spectroscopy demonstrated that crystal defects improved light absorption, CO 2 adsorption, charge transfer efficiency, and carrier lifetime. Electron paramagnetic resonance (EPR) spectroscopy showed increased superoxide radical generation in BiOI-TC, suggesting higher reactivity. Consequently, BiOI achieved a CH 3 CH 2 OH generation rate of 6.2 µmol g −1 h −1 with 100% selectivity. Key intermediates (*CO, *COCO, *CHO, *CH 2 ) for CH 3 CH 2 OH production were identified, and C 2 H 6 formation in BiOI-LD was linked to the generation of *CH 3 .
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Dongbo Wang,Xuan Zhou,Yanbo Liu,Mingyang Chen,Dandan Han,Junbo Gong
With the rise of research on functional sugar, we found that preparing crystalline powders into spherical crystals will significantly improve quality, stability, appearance, and texture. In this work, d-ribose (D-RIB) spherical crystal aggregates were prepared for the first time. And D-RIB spherical crystal aggregates with superior filterability, flowability, and tap density can be prepared in ethanol, 1-propanol, and isopropanol. Specifically, we used ethanol as an example to reveal the formation mechanism of D-RIB spherical crystal aggregates: solvent-induced crystal defects, which in turn trigger noncrystallographic branching and further spherulite growth. Finally, a comparison of the properties of the D-RIB spherical crystal aggregates with those of commercially available products is given, demonstrating the fabrication of D-RIB spherulites with better tap density and flowability by solvent-induced noncrystallographic branching. This will provide a new insight into the preparation of high-quality D-RIB crystals.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Gas Science and Engineering
·
2023
·
IF 0
Guanhua Zhang,Shaocong Mo,Hongtao Xu,Xiaoyu Yan,Binlin Dou,Guomin Cui,Qiguo Yang,Wei Lu
Metal-organic frameworks (MOFs) are popular crystalline materials owing to their high porosity, tunable pore structure, and large surface area. By introducing a carboxylic acid to compete with 2,5-dihydroxyterephthalic acid for magnesium ions in solution, a crystal defect method was used to prepare multi-level pore Mg-MOF-74 with an unregular framework structure of Mg-MOF-74 in this paper. In the prepared samples, the adsorption amounts varied in descending order with various carboxylic acid species: Mg-MOF-74-Propionic acid (37.95 cm 3 /g STP) > Mg-MOF-74 (15.46 cm 3 /g STP) > Mg-MOF-74-Acetic acid (9.19 cm 3 /g STP) > Mg-MOF-74-Formic acid (7.81 cm 3 /g STP). At 1.5 kPa, the CO 2 adsorption of 2,5-dihydroxyterephthalic acid and propionic acid with a ratio of 2:1 can reach 2.78 cm 3 /g STP (standard temperature and pressure) with the comparison to 0.47 cm 3 /g STP of pristine Mg-MOF-74. Under atmospheric pressure, the adsorption capacity of modified Mg-MOF-74 can reach 37.95 cm 3 /g STP, equivalent to 2.45 times of the original Mg-MOF-74.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
JOURNAL OF CATALYSIS
·
2024
·
IF 6.5
Wei Jia,Wengang Liu,Yuandong Cui,Hang Song,Chengfeng Zhou,Wei Jiang,Haoxi Ben,Xiaoli Yang,De Chen
Converting cellulose into C 2 alcohols presents a sustainable alternative to fossil fuels, contributing to the development of eco-friendly and economically viable biofuels and chemicals. Tungsten oxide (WO 3 ) is a key solid acid catalyst for this process, yet limited research explores its diverse morphologies and unique catalytic effects. This study investigates diverse WO 3 morphologies (nanosheets, nanoflowers, nanoblocks, and tetrahedral octahedra) in combination with Pd for converting cellulose to C 2 alcohols. Optimized conditions with Pd/o-WO 3 catalyst resulted in the highest C 2 alcohols (ethylene glycol and ethanol, 80.9 %), notably yielding 64.8 % ethylene glycol. Extensive characterizations and DFT calculations reveal the smaller element occupancy rates and a longer W-O bond length led to a large number of crystal defects over Pd/o-WO 3 . It facilitated the formation of W 5+ –OH sites and Pd-O(H)-W interactions, further synergistically enhancing hydrogenation ability and acidity. Designed experiments to elucidate cellulose conversion pathways, including hydrolysis, retro -aldol condensation, and hydrogenation. This study emphasizes the unique impact of WO 3 morphologies and underscores the importance of supporting crystal defects for catalytic performance in eco-friendly biofuel and chemical production.
研究领域:
催化化学
·
可再生资源与环境科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Xing-Zhe Guo,Shuai-Shuai Han,Ji-Min Yang,Xiao-Meng Wang,Shui-Sheng Chen,Shuai Quan
We herein report that the morphology, size, and surface charge status of MIL-100(Fe) micro/nanoparticles can be tailored by adding a coordination modulator (HF or tetramethylammonium hydroxide) to the reaction system. Interestingly, the adsorption capacities of low-crystallinity MIL-100(Fe) and MIL-100(Fe)-TMA toward Congo red (CR) and acid chrome blue K (AC) were found to be significantly larger than that of the high-crystallinity MIL-100(Fe)-HF adsorbent, whereas there was little difference in the adsorption capacities of the three MIL-100(Fe) toward methyl orange (MO) and methylene blue (MB). The adsorption uptake of MIL-100-(Fe)-TMA toward the anionic dyes (CR, AC, and MO) was found to be highest, whereas the adsorption uptake of MIL-100(Fe) toward the cationic dye (MB) was the highest owing to different adsorption mechanisms. This adsorption behavior could be rationalized based on the morphological characteristics and crystal structure defects, zeta potential, and pore volume of MIL-100(Fe) and the adsorption characteristics and molecular structure of the dye. It was revealed that the adsorption performance of MIL-100(Fe) micro/nanoparticles is governed by the synergistic interplay between electrostatic, hydrophobic, and π–π stacking interactions, pore volume, crystal structure defects, and steric hindrance of the adsorbent.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2025
·
IF 7.3
Jiacheng Zhang,Xi Sun,Junhao Xin,Li Wang,Yong Fan,Jifu Zheng,Shenghai Li,Jianing Xu,Nanwen Li,Suobo Zhang
To address increasing climate deterioration, it is of great value to prepare highly permselective separation membranes for CO2 enrichment and separation. In this study, zirconium-based metal-organic frameworks (Zr-MOFs) containing defective structures (defected-UiO-66-NH2, D-UN) with a high volume yield (12 g L–1 in a single batch) were prepared at room temperature for the first time using a simple green-synthesis strategy. After the modification with pentafluorobenzaldehyde, the fluorine-containing D-UN (named F-g-UN) nanoparticles showed the characteristics of local and dense distribution of fluorine elements. Due to the optimized CO2 affinity and improved dispersion of fluorination modification, the prepared mixed-matrix membrane (MMM) F-g-UN@AO-PIM-1 achieved synergistic improvement in CO2 permeability and selectivity, exceeding the 2008 Robeson upper bound (CO2 664.1 Barrer and CO2/CH4 34.2) and the 2018 binary CO2/CH4 mixed-gas upper bound (CO2/CH4 28.7). The substantial cause was the introduction of fluorine species, verified by relevant experiments and mechanism analyses such as CO2 adsorption. This work proves the feasibility of using crystal defect engineering and post-treatment strategies to enhance separation functions and offers new insights into designing efficient and low-cost MMMs for gas separation, promoting their application in separation membranes including but not limited to gas separation.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Quan-Ping Zhang,Yun-Chuan Xu,Jia-Le Li,Ao-Jie Liu,Dui-Gong Xu,Ming Wei,Yuan-Lin Zhou
Increasing exposure chances of humans to low-energy gamma-rays occur with the rapid application expansion of nuclear technology, which tend to induce carcinogenic and mutagenic effects on living bodies, and then need to be protected from. PbWO 4 has excellent gamma-rays attenuating ability while Pb displays a weak shielding property of low-energy gamma-rays from 40 keV to 88 keV. Here, crystal defect engineering with Ce doping is applied to fabricate the crystal structure of PbWO 4 for tailoring its low-energy gamma-rays shielding property. Characterization with XRD , Raman, XPS, XRF , SEM and TEM techniques indicates cerium ions have been introduced into the lattice of PbWO 4 crystals during the doping process. In addition, Ce doping amount plays key roles in tuning the crystal defects in PbWO 4 including ion substitution, charge compensation and structural deformation. Importantly, PbWO 4 doped with 10 mol% Ce displays an optimal mass attenuation coefficient (2.61 cm 2 /g) to 59.5 keV gamma-rays and shows a 39% increase ratio to the PbWO 4 without doping. In addition, typically anisotropic PbWO 4 crystals are found at 40 mol% Ce doping amount, which give its potential versatility. This work provides a solution to make up for PbWO 4 to shield low-energy gamma-rays that could further promote its application in personal protection, such as clothing.
研究领域:
材料科学
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辐射防护
·
核技术应用
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
·
2016
·
IF 9.307
Zan Dai,Fan Qin,Huiping Zhao,Jie Ding,Yunling Liu,Rong Chen
Crystal defects have been extensively proved to have great influence on semiconductor photocatalysis. To optimize the reactivity of crystalline photocatalysts and achieve ideal solar energy conversion, crystal defect engineering has initiated a considerable interest in real catalysts. Herein, we develop a general strategy to manufacture and mediate crystal defects in the host Bi2MoO6 lattice by varying the cerium dopant content, resulting in greatly improved visible-light-driven photocatalytic performance for the degradation of highly toxic nerve agent simulants (NAS) and organic dyes, as well as bacterial photoinactivation. After careful examination of crystal defect structure and charge carrier dynamics, it was proved that Ce-doping-mediated crystal defects are crucial for controlling the photocatalytic efficiency of aurivillius Bi2MoO6. More importantly, the well-engineered crystal defects not only exert a beneficial influence on the electron dynamics and band structure but also facilitate the one-electron and two-electron reactions by introducing the Ce3+/Ce4+ and Mo4+/Mo6+ redox couples, which results in a significant enhancement in reactive oxygen species (ROS) photogeneration.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Ruixiang DENG,Bingbing CHEN,Haogeng LI,Zhong LI,Tao ZHANG,Yun YU,Lixin SONG
Microwave shielding materials and absorbers serve important roles in improving the reliability of smart devices and military equipment. In this work, three-dimensional (3D) Ti 3 C 2 T x /Fe 3 O 4 composites with adjustable electromagnetic responses are studied. Taking advantage of the negatively charged surface of the Ti 3 C 2 T x , the cationic surfactant cetyltrimethylammonium bromide (CTAB) is used to precipitate the delaminated Ti 3 C 2 T x sheets. The volatilization of CTAB during the annealing process inflates the Ti 3 C 2 T x , and leads to the three-dimensional architecture of the composite. The results show that the free-standing 3D Ti 3 C 2 T x /Fe 3 O 4 composite film exhibits a high shielding efficiency of 60 dB in the X band. Owing to the traits of great flexibility, low apparent density, and thin thickness, the 3D Ti 3 C 2 T x /Fe 3 O 4 composite film achieves a high specific shielding efficiency of 3.5 × 10 5 dB/(g·cm −2 ). Furthermore, through the control of crystal defects in one-step annealing treatment, the shielding material can be transformed into a wideband microwave absorber. A high reflection loss up to −57 dB can be realized. And a 2-mm-thick absorber whose reflection loss is better than −10 dB in 11.2 ~ 18 GHz is also achieved. The experimental and first-principal studies on the evolution mechanism reveal that the destruction of the Ti-C bond mainly leads to the degradation of electrical conductivity and the improvement of impedance matching. Introduced crystal defects can help enhance the dielectric loss as well. The synergistic effects of ohmic loss, dielectric loss, and magnetic loss give birth to a broadband absorption of the composite.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF APPLIED PHYSICS
·
2017
·Vol. 122
·期 17
·
IF 2.068
Tong Liping,Saito Katsuhiko,Guo Qixin,Zhou Han,Fan Tongxiang,Zhang Di
Visible-light-activated near-infrared luminescent materials are promising photoluminescent materials due to their convenience and low cost. Crystal defects can seriously affect the performance of luminescent materials, and better understanding of the complexity of the structural disorder and electronic structures of such materials opens up new possibilities in luminescent material development. In this work, we successfully design a novel, effective, visible-light-activated near-infrared luminescent Gd 3 Ga 5 O 12 : 4.2%Yb 3+ , 8.4%Er 3+ , and 4.2%Bi 3+ system based on first principles. This exhibits strong emission intensity and high luminous efficiency (0.993) and also has a lifetime (7.002 ms) that is at least twice as long as the longest lifetime reported in published papers. We utilize density functional theory with an effective LSDA + U method to study the structural properties of Gd 3− x − y − z Ga 5 O 12 : x Yb 3+ , y Bi 3+ , z Er 3+ (GGG: Yb 3+ , Bi 3+ , Er 3+ ). The d and f electron orbits of rare-earth ions are considered for an effective Hund exchange. Detailed analysis reveals that GGG: 4.2%Yb 3+ , 8.4%Er 3+ , 4.2%Bi 3+ has the smallest cell volume because of the strong covalent bonds of Bi–O, Er–O, and Yb–O. Bi 3d is a hybridized state that acts as sensitizing ions during the process of luminescence in GGG: Yb 3+ , Bi 3+ , Er 3+ . Together with experimental and theoretical results, we analyze the influence of defects on emission intensity. The locations of Yb 3+ , Er 3+ , and Bi 3+ are determined by X-ray absorption fine structure measurements, which are in agreement with the model constructed using first principles. This work may provide innovative guidance for the design of high-performance visible-light-activated near-infrared luminophores based on calculations and a new methodology for application of coherent laser radar and optical communication.
研究领域:
材料科学
·
光学
·
物理学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2025
·Vol. 27
·期 5
·678-686
·
IF 2.6
Dongling Xie,Jianan Wang,Bo Huang,Yiyi Yang,Dunmin Lin,Chenggang Xu,Fengyu Xie
Rational design of viable routes to develop affordable and efficient oxygen evolution reaction (OER) catalysts is essential for advancing electrochemical water splitting, yet significant challenges remain, particularly in seawater. Here, we propose a ligand defect engineering strategy to modify the electronic structure of NH2-MIL-88B(Fe) using a monodentate ligand (acetic acid, AcOH), inducing ligand vacancies in NH2-MIL-88B(Fe) for oxygen evolution in an alkaline seawater electrolyte, thereby improving the performance of the electrocatalysts. The resulting defective MOFs (denoted as NH2-MIL-88B(Fe)-x) exhibited exceptionally high catalytic activity for OER, requiring low overpotentials of 313 and 329 mV at a current density of 100 mA cm−2 in 1 M KOH and simulated seawater (1 M KOH + 0.5 M NaCl) solutions, respectively. Experimental analyses revealed that the introduction of AcOH can modulate the d-band center of active sites in NH2-MIL-88B(Fe)-x and play a critical role in alleviating chloride ion (Cl−) corrosion, thereby enhancing catalytic stability in seawater. When directly used as an OER catalyst in an alkaline electrolyte, wind and solar power were harnessed to operate the NH2-MIL-88B(Fe)-x || Pt/C configuration to drive the electrolytic water reaction. Thus, the ligand defect strategy can be employed to design and prepare high-performance OER electrocatalysts, particularly for generating H2 through water electrolysis powered by renewable energy sources.
研究领域:
材料科学
·
电化学
·
能源工程
✓ 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）