Catalysts
·
2022
·Vol. 12
·期 10
·1140
·
IF 4.501
Wei Zhang,Caiping Ma,Xingwu Liu,Yong Yang,Yongwang Li,Xiaodong Wen
Elucidation of the intrinsic catalytic principle of iron carbides remains a substantial challenge in iron-catalyzed Fischer-Tropsch synthesis (FTS), due to possible interference from other Fe-containing species. Here, we propose a facile approach to synthesize single-phase θ-Fe3C via the pyrolysis of a molecularly defined Fe-C complex (Fe4[Fe(CN)6]3), thus affording close examination of its catalytic behavior during FTS. The crystal structure of prepared θ-Fe3C is unambiguously verified by combined XRD and MES measurement, demonstrating its single-phase nature. Strikingly, single-phase θ-Fe3C exhibited excellent selectivity to light olefins (77.8%) in the C2-C4hydrocarbons with less than 10% CO2formation in typical FTS conditions. This strategy further succeeds with promotion of Mn, evident for its wide-ranging compatibility for the promising industrial development of catalysts. This work offers a facile approach for oriented preparation of single-phase θ-Fe3C and provides an in-depth understanding of its intrinsic catalytic performance in FTS.Keywords:θ-Fe3C;single phase;Fischer-Tropsch synthesis;Prussian blue analogue
研究领域:
催化
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Materials
·
2015
·Vol. 8
·期 8
·5363-5375
·
IF 2.651
Liangjie Pan,Benxue Jiang,Jintai Fan,Qiuhong Yang,Chunlin Zhou,Pande Zhang,Xiaojian Mao,Long Zhang
The synthesis of pure and well dispersed lutetium aluminum garnet (LuAG) powder is crucial and important for the preparation of LuAG transparent ceramics. In this paper, high purity and well dispersed LuAG powders have been synthesized via co-precipitation method with lutetium nitrate and aluminum nitrate as raw materials. Ammonium hydrogen carbonate (AHC) was used as the precipitant. The influence of aging time, pH value, and dripping speed on the prepared LuAG powders were investigated. It showed that long aging duration (>15 h) with high terminal pH value (>7.80) resulted in segregation of rhombus Lu precipitate and Al precipitate. By decreasing the initial pH value or accelerating the dripping speed, rhombus Lu precipitate was eliminated and pure LuAG nano powders were synthesized. High quality LuAG transparent ceramics with transmission >75% at 1064 nm were fabricated using these well dispersed nano LuAG powders.Keywords:co-precipitation method;single phase;pH values;LuAG powder;transparent ceramics
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Biosensors-Basel
·
2022
·Vol. 12
·期 5
·294
·
IF 5.743
Jia Man,Luming Man,Chenchen Zhou,Jianyong Li,Shuaishuai Liang,Song Zhang,Jianfeng Li
Microfluidics devices have widely been employed to prepare monodispersed microbubbles/droplets, which have promising applications in biomedical engineering, biosensor detection, drug delivery, etc. However, the current reported microfluidic devices need to control at least two-phase fluids to make microbubbles/droplets. Additionally, it seems to be difficult to make monodispersed microbubbles from the ambient air using currently reported microfluidic structures. Here, we present a facile approach to making monodispersed microbubbles directly from the ambient air by driving single-phase fluid. The reported single-phase-fluid microfluidic (SPFM) device has a typical co-flow structure, while the adjacent space between the injection tube and the collection tube is open to the air. The flow condition inside the SPFM device was systematically studied. By adjusting the flow rate of the single-phase fluid, bubbles were generated, the sizes of which could be tuned precisely. This facile bubble generator may have significant potential as a detection sensor in detecting viruses in spread droplets or haze particles in ambient air.Keywords:microfluidic device;single-phase fluid;bubbles;air detection
研究领域:
生物医学工程
·
传感器技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Yidong Hu,Fan Yang,Guoliang Ren,Jianguo Li,Qiaodan Hu
Preparation of dense Bi 2 Ti 2 O 7 ceramics with single-phase pyrochlore structure is challenging using the conventional sintering method due to its thermal instability at ≥ 650 °C. Here we synthesized dense and phase-pure Bi 2 Ti 2 O 7 ceramics from a mixture of Bi 2 O 3 and TiO 2 by a novel deep undercooling rapid solidification method using the aerodynamic levitation technique. We reported a surprising discovery that the pyrochlore phase can exist with Bi/Ti ratio varying between 0.9 and 1.1. By a comprehensive investigation on the phase purity, crystal structure, oxidation states and electrical properties, we revealed that the pyrochlore structure is primarily stabilized by the solidification process rather than presence of a large amount of Ti 3+ . With the advantages of being containerless, one-step and fast processing, deep undercooling rapid solidification is an effective and efficient approach to prepare dense Bi 2 Ti 2 O 7 pyrochlores, and can be expanded to other thermally unstable compounds to obtain bulk materials.
研究领域:
材料科学
·
无机化学
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2021
·Vol. 54
·期 37
·375101
·
IF 3.207
Min Yang,Yujia Yan,Enzhou Liu,Jun Fan,Xiaoyun Hu
As a typical sulfide bimetallic semiconductor material, AgInS2 has been widely studied for its excellent photoelectrochemical properties. However, due to the large lattice mismatch, it is difficult to obtain AgInS2 single phase nanocrystals by conventional reaction. Therefore, the ligand and pH were selected and adjusted for the preparation of AgInS2 single phase nanocrystals. Adding organic molecules containing sulfhydryl groups as ligands could combine with metal ions to form covalent bonds, while OH− could react with transition metal ions to form soluble metal hydroxides, which could protect metal ions from direct reaction with S2−. With the help of x-ray powder diffraction, AgInS2 single phase nanocrystals were successfully prepared by hydrothermal reaction at 180 °C with L-cysteine (L-Cys) or glutathione as the ligand in an alkaline environment. Finally, it was determined that the AgInS2 single phase nanocrystals obtained when the ligand was L-Cys and the reaction time was locked to 24 h had high catalytic activity as determined by a rhodamine B (RhB) removal experiment. In addition, AgInS2/TiO2 (AIS-TO) heterojunction photocatalysts were prepared by an in-situ hydrothermal method to improve the photocatalytic activity of TiO2. Among them, the 5% AIS-TO sample showed the highest catalytic activity, and the degradation rate of RhB was 2.4 times that of TiO2. It was also proved that electrons were transported by a Z-type mechanism in the AIS-TO heterojunction photocatalytic system. This work would provide a feasible scheme for the preparation of more sulfide bimetallic semiconductor single phase nanocrystals.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2021
·
IF 5.062
Wei Su,Qingyun Li,Youyan Liu,Yimin Qin,Haibo Liu,Aixing Tang
Taking advantage of the intersolubility of alcohol and water, we developed an efficient single-phase system for chemoenzymatic epoxidation of (-)-α-pinene. Different from traditional methods, it included all substrates, such as (-)-α-pinene, acyl donors and oxidants, into one phase. Isopropanol was eventually selected as the epoxidation medium to optimize three controllable parameters. Under the optimal conditions of 3.35 mol/L ethyl acetate and 1.1 mol/L H 2 O 2 , the conversion and selectivity reached 92.3% and 86.6% in 90 min, respectively, and the initial reaction rate was 13.58×10 −4 mmol·min −1 ·mg −1 with Novozym435 as a catalyst. Trisodium citrate was screened as an acid-trapping reagent to eliminate the negative impact of acetic acid on (-)-α-pinene oxide. The enzyme reusability was at least 6 cycles with a relative activity of 57.5% at the sixth cycle.
研究领域:
生物化学
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Bo Ma,Zhiqin Wen,Jiedong Qin,Zhenyu Wu,Junxiao Liu,Yunming Lv,Junjie Yu,Yuhong Zhao
In this work, single-phase (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2-δ high-entropy fluorite oxides (HEFOs) were successfully prepared by conventional solid-phase reaction method and crystal structure and microstructure were studied in-depth. Single-phase (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2-δ is formed at 1600 °C for 12 h, and five cationic elements are uniformly distributed without any segregation at the micrometer and nanometer scales. And the XRD patterns with Rietveld refinement reveal the formation of single-phase fluorite structure of (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2-δ . The SAED patterns on the [0 1 ‾ 1] band axes are similar to the diffraction patterns of face-centered cubic fluorite structure, and the standard deviation of the cation radius (coordination VIII) distribution of the specimens is 0.1277, which is again identified as forming a single-phase fluorite structure. The bulk specimens are solid compacts free of obvious cracks with randomly distribution porosity at a rare level, and the powder specimens are irregular fragmented shapes with an average particles size of 5.41 μm. The average cation radius and interplanar spacings becomes larger compared with standard fluorite structure of CeO 2 due to the cation radius of La 3+ , Sm 3+ and Nd 3+ are larger than that of Ce 4+ , leading to an increase in lattice parameters of the HEFOs. In addition, the concentration of Ce 3+ in the Ce cation is only 8.1 %, and the δ -value is calculated to be 0.3081 based on the content of all cations per mole of the substance, which indicates that the composition of the prepared specimen is (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 1.6919 .
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Xianke Zhang,Suqiong Xu,Zhiqian Yao,Xiaoqing Liu,Jujun Yuan,Fangguang Kuang,Shuying Kang,Huajun Yu
Single-phase materials with exchange bias (EB) effect at room temperature (RT) are very important for future applications in spintronic devices, magnetic storage, and sensors. To explore materials showing the EB effect at RT is an interesting and important issue. In this paper, LaFeO 3 micro-polyhedrons composed of an average particle size of 66 nm nanoparticles have been synthesized by annealing LaFe(CN) 6 precursors in air at 630 °C for 8 h. Magnetic hysteresis loops show that LaFeO 3 micro-polyhedrons present a large spontaneous EB (SEB) effect ( ∼ 1.5 kOe) at RT after zero-field cooling (ZFC) and a gigant conventional EB (CEB) effect ( ∼ 5.6 kOe) after field cooling (FC) of 70 kOe. To the best of our knowledge, the current compound shows the largest negative EB field after ZFC at RT among SEB materials discovered so far. The successful fitting of training effect (TE) data with Binek’s model shows that the origin of SEB lies in the interface exchange coupling between different magnetic phases. The interface with the “pinning” effect of antiferromagnetic (AFM) matrix relative to ferromagnetic (FM) clusters exhibits unidirectional anisotropy, which is formed during the initial magnetization process. This interesting finding of the SEB effect at RT in single-phase perovskite LaFeO 3 system may open a new direction for possible technological applications.
研究领域:
材料科学
·
磁学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Liujia Tian,Fan Peng,Xuemei Song,Wei Zheng,Ziwei Liu,Yiling Huang,Yi Zeng
High-entropy rare-earth niobates have garnered significant attention in the field of thermal barrier coatings (TBCs) due to their ultra-low thermal conductivity. However, the exceptional thermal properties of fluorite-phase high-entropy rare-earth niobates and the outstanding mechanical properties of monoclinic-phase high-entropy rare-earth niobates cannot be simultaneously harnessed. To address this limitation, this paper investigates and synthesizes five single-phase high-entropy rare-earth niobates: (RE 1/5 Ho 1/5 Er 1/5 Y 1/5 Yb 1/5 ) 3 NbO 7 (RE = Ce, Sm, Eu, Dy, Lu), and five composite-phase high-entropy rare-earth niobates with a molar ratio of (RE 1/5 Ho 1/5 Er 1/5 Y 1/5 Yb 1/5 )NbO 7 : (RE 1/5 Ho 1/5 Er 1/5 Y 1/5 Yb 1/5 )NbO 4 = 1:2 (RE = Ce, Sm, Eu, Dy, Lu). The objective is to fabricate niobate coatings that exhibit both outstanding thermal and mechanical properties. The test results reveal that the intrinsic thermal conductivity of the composite-phase samples stands at a mere 1.46 W m −1 ·K −1 at 1000 °C. Comparatively, the experimental thermal conductivity of the single-phase samples slightly surpasses that of the composite-phase at 1000 °C, registering a minimum of 1.57 W m −1 ·K −1 . Importantly, both values adhere to the TBC standard. The mechanisms behind the low thermal conductivity of the composite-phase and single-phase samples are elucidated by the phonon scattering mechanism and the Cahill model, respectively. Furthermore, the thermal expansion coefficient of the composite-phase samples exceeds that of the single-phase samples overall, and they demonstrate exceptional mechanical properties, offering nearly twice the fracture toughness of the single-phase samples while maintaining high hardness. Experimental evidence shows that composite-phase niobates exhibit enhanced thermodynamic properties compared to single-phase niobates. This work serves as a valuable reference for the utilization of high-entropy rare-earth niobates in the realm of thermal barrier coatings.
研究领域:
材料科学
·
热力学工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2021
·
IF 4.641
Yanzhen Yin,Zhen Wang,Maochen Zhu,Yue Zhang,Jianhong Li,Chao Dou,Shijia Sun,Bing Teng,Yang Che,Degao Zhong
A single-phased warm white phosphor of α-Sr 2 V 1.98 P 0.02 O 7 : 0.5 % Eu 3+ with low correlated color temperature (CCT) and high color rendering index (CRI) was synthesized by high temperature solid phase method. By changing the ratio of PO 4 3− /VO 4 3− , the emission intensity of VO 4 3− and the energy transfer efficiency of VO 4 3− →Eu 3+ can be effectively tuned, and the full-spectrum warm white light emission of phosphors in the range of 400−700 nm can be realized. Moreover, the temperature-dependent emission spectra and thermal quenching properties were investigated in detail. On this basis, the WLED prototype devices were packaged with the synthesized phosphors α-Sr 2 V 1.98 P 0.02 O 7 : 0.5 % Eu 3+ and 365 nm near-ultraviolet (NUV) chips and high-quality warm white light emission with CCT = 3188 K and CRI Ra = 93.5 were achieved. These findings provide new insights into exploring single-phased white phosphors for NUV-pumped warm w-LEDs with high CRI property and low CCT value.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Jinxu Ma,Kepi Chen,Cuiwei Li,Xiaowen Zhang,Linan An
The valence-combination strategy was applied to design B-site substitution non-equimolar stoichiometric high-entropy perovskite oxides (HEPOs). 29, 56 and 29 valence combinations with the maximum configurational entropy higher than 1.5R for five-component HEPOs were identified when the average valence of B-site is 3, 4 and 5, respectively. Synthesis experiment was performed on 8 valence combinations with the average valence of B-site equal to 4. Single-phase HEPOs were obtained from 6 of them. It was also found that most of HEPOs have ordered structures. The formation of single-phase HEPO and ordered structure was discussed in terms of structural tolerance factor and valence-difference factor.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Qinghai Sun,Zhibo Zheng,Xiaolu Yang,Yanxia Zhao,Zhou Luo,Chao Wang,Yanhua Song,Haifeng Zou,Shihou Sheng
Herein, a variety of single-phase full-spectrum emission phosphors doped with Eu 2+ were synthesized. Under the 350 nm excitation, as K + and Y 3+ were introduced into Ca 10 Na(PO 4 ) 7 (CNP):1.5%Eu 2+ , respectively, the emission color of Ca 9.85 K y Na (1- y ) ( PO 4 ) 7 :1.5%Eu 2+ (0 ≤ y ≤ 1.0) was tuned from yellow to cyan, while that of Ca (9.85- z ) NaY 0.667 z (PO 4 ) 7 :1.5%Eu 2+ (0 ≤ z ≤ 1.0) was tuned from yellow to green. The internal quantum yield (QY) of Ca 9·85 K 0·4 Na 0·6 (PO 4 ) 7 (CKNP):1.5%Eu 2+ and Ca 9·45 NaY 0·267 (PO 4 ) 7 (CNYP):1.5%Eu 2+ reached 47.47 % and 27.11 %, respectively. The introduction of K + or Y 3+ made Eu 2+ selectively occupy the Ca sites and led to changes in the local environment of Eu 2+ , allowing for spectral tuning emission. In addition, the luminescence intensity of the samples retained 54.59 % and 31.34 % of their room temperature values. Eventually, two white light emitting diode (WLED) devices were fabricated, combining the synthesized white emitting phosphors with 365 nm ultraviolet (UV) chips. They exhibited high color rendering indices of 84.7 and 77.0, along with low correlated color temperatures of 5435 K and 5023 K. The Commission Internationale de L'Eclairage (CIE) color coordinates were (0.3349, 0.3975) and (0.3517, 0.4366), respectively. The results pointed to the phosphors' potential suitability for use in the WLED sector.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）