RSC Advances
·
2021
·Vol. 11
·期 55
·34754-34765
·
IF 3.361
Wei Qin,Kaixuan Xu,Junwei Wang,Xiaofeng Cui,Jianli Zhang,Yaqing Weng
To overcome the urgency of zirconium and hafnium separation, a novel mesoporous silica sorbent (PS-G1.0-MSNs) modified with phosphorous-functionalized G1.0 PAMAM dendrimers was prepared. The adsorption and separation behaviors of PS-G1.0-MSNs adsorbent on Zr(IV) and Hf(IV) were perfromed as a function of acidity, contact time, temperature, and ion concentrations by batch sorption methods. The maximum adsorption capacities for Zr(IV) and Hf(IV) were 25.7 mg g−1 and 5.36 mg g−1 under optimal experimental conditions, respectively, and the separation factor βHf/Zr = 2.0 > 1 demonstrated that the prepared sorbent had preferential selectivity for Hf(IV) in rich Zr(IV) solution. Moreover, kinetic data indicated that the sorption process on Zr(IV) and Hf(IV) achieved equilibrium within 120 min, and followed the pseudo-first-order model with a rate-determining step. The adsorption amount increased as temperature raised from 283 K to 303 K and the isothermal data plotted with the Langmuir model was better than the Freundlich model with monolayer behavior. Thermodynamic data analysis indicated that the sorption process was spontaneous and endothermic. Furthermore, XPS analysis revealed that the metal ion adsorption was mainly induced by the chemical coordination of Zr(IV) and Hf(IV) ions with N, O, P atoms of amide and phosphate groups. The present work provides good guidelines on the design of high efficient sorbent for the separation of Hf(IV) from Zr(IV) solutions.
研究领域:
材料科学
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化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2021
·
IF 8.067
Fengnian Zhang,Fuhao Cheng,Chufei Cheng,Meng Guo,Yufeng Liu,Yang Miao,Feng Gao,Xiaomin Wang
Abatract A series of compositionally complex fluorite oxides (CCFOs) were prepared by ball milling the mixture of ZrO 2 , HfO 2 , Y 2 O 3 , La 2 O 3 , and Pr 6 O 11 followed by conventional solid-state sintering. Both XRD and TG-DSC results demonstrated that single-phase (Zr 0.2 Hf 0.2 Pr 0.2 Y 0.2 La 0.2 )O 2-δ was formed at 1400 °C. Elements in bulk ceramic were uniformly distributed without evident accumulation according to SEM-EDS pictures. TEM results revealed that polycrystalline ceramic powder was assignable to cubic Fm-3m fluorite structure. The electrical conductivity ( σ ) was measured via EIS technology and activation energy ( E a ) of CCFOs was calculated in Arrhenius plots. In the temperature range of 300-750 °C, CCFOs preserved the same conduction mechanism and (Zr 0.1667 Hf 0.1667 Pr 0.1667 Y 0.25 La 0.25 )O 2-δ possessed higher σ and lower E a than other high entropy fluorite oxides which is related to the incorporation of Pr element or the connection of cation-V o complex.
研究领域:
材料科学
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无机非金属材料
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固体离子学
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功能陶瓷
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能源材料
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 7
·4382-4389
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IF 3.9
Yongqiang Tan,Wei Liao,Zhen Teng,Haibin Zhang
Two high-entropy carbides, including stoichiometric (Zr,Ti,Nb,Ta,Hf)C and nonstoichiometric (Zr,Ti,Nb,Ta,Hf)C 0.8 , were prepared from monocarbides and ZrH 2 . Their sinterability, microstructures, mechanical properties, thermophysical properties, and oxidation behaviors were systematically compared. With the introduction of carbon vacancy, the sintering temperature was lowered up to 300°C, Vickers hardness was almost unaffected, whereas the strength decreased significantly generally due to the decrease of covalent bonds. The thermal conductivity shows a 50% decrease for nonstoichiometry high-entropy carbide, which is a major consequence of the lower electrical conductivity. The oxidation resistance in high temperature water vapor was not sensitive to carbon stoichiometry.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Shuaijun Yang,Mei Wang,Yetong Lv,Huilin Sheng,Yexia Qin
Oxidation resistance is crucial to the potential applications of high-entropy carbides (HECs) at elevated temperatures. Here, we realize the exploration of (Hf, Ta, Zr, Cr)C high-entropy carbides (HEC-TM, TM = Hf, Zr, Ta, and Cr) with good oxidation resistance by optimizing their compositions. To be specific, 21 kinds of HEC- x TM ( x = 0–25 mol%) samples are fabricated by a high-throughput ultrafast high-temperature sintering technique, followed by oxidation testing at 1673 K for 30 min. Among all the HEC samples, the as-fabricated HEC-0Zr samples are proved to possess the best oxidation resistance with an oxidation depth of only 53 µm. Further study on isothermal oxidation kinetics demonstrates that the as-fabricated HEC-0Zr samples follow a linear oxidation law. The good oxidation resistance of the as-fabricated HEC-0Zr samples is believed to result from the (Ta, Me) 2 O 5 phase with a low melting point, which can promote the densification of the oxide layer. This research opens up a new way for efficiently discovering new HECs for extreme applications.
研究领域:
材料科学
·
高温材料
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2024
·
IF 13
Diancheng Duan,Junlang Huo,Jiaxiang Chen,Bin Chi,Zhangsen Chen,Shuhui Sun,Yang Zhao,He Zhao,Zhiming Cui,Shijun Liao
Single-atom metal-doped M–N–C (M═Fe, Co, Mn, or Ni) catalysts exhibit excellent catalytic activity toward oxygen reduction reactions (ORR). However, their performance still has a large gap considering the demand for their practical applications. This study reports a high-performance dual single-atom doped carbon catalyst (HfCo–N–C), which is prepared by pyrolyzing Co and Hf co-doped ZIF-8 . Co and Hf are atomically dispersed in the carbon framework and coordinated with N to form Co–N 4 and Hf–N 4 active moieties. The synergetic effect between Co–N 4 and Hf–N 4 significantly enhance the catalytic activity and durability of the catalyst. In an acidic medium, the ORR half-wave potential ( E 1/2 ) of the catalyst is up to 0.82 V , which is much higher than that of the Co–N–C catalyst without Hf co-doping (0.80 V). The kinetic current density of the catalyst is up to 2.49 A cm −2 at 0.85 V , which is 1.74 times that of the Co–N–C catalyst without Hf co-doping. Moreover, the catalyst exhibits excellent cathodic performance in single proton exchange membrane fuel cells and Zn–air batteries. Furthermore, Hf co-doping can effectively suppress the formation of H 2 O 2 , resulting in significantly improved stability and durability.
研究领域:
材料科学
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催化化学
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Ankita Sinha,Kaixin Ma,Huimin Zhao
Present work reports preparation of colloidal single/few layer Ti 3 C 2 T x MXene flakes using minimally intensive layer delamination (MILD) method for rapid electroanalytical screening of carbamate pesticides . Lithium fluoride salt and hydrochloric acid (7.5 M LiF/9M HCl) was used to produce in-situ generated HF as etchant to remove Al successfully from Ti 3 AlC 2 MAX phase. Unlike the clay method (5 M LiF/6M HCl), this methodology simplified Ti 3 C 2 T x synthesis protocol resulting in Li + ions intercalated Ti 3 C 2 T x which was delaminated without further sonication . The delaminated Ti 3 C 2 T x flakes were found to be single/few layered sheets with mostly –OH and –O terminated surface groups. The characteristic 002 peak observed in X-ray diffraction (XRD) at 2θ = 6.4° with interplaner distance of 1.1137 nm suggested broadening of the peak attributed to the presence of Li + ions between Ti 3 C 2 T x flakes. Delaminated Ti 3 C 2 T x flakes were utilized as working electrode which demonstrated simultaneous and selective detection of carbamate pesticides methiocarb and diethofencarb by voltammetry . The oxidation peaks of the two pesticides were well separated by a potential difference of 0.35 V in 0.5 M H 2 SO 4 and DPV detection limits were calculated as 0.19 μg mL −1 and 0.46 μg mL −1 for methiocarb and diethofencarb respectively. Ti 3 C 2 T x flakes as electrochemical sensor exhibited long term stability and acceptable recoveries in real sample for environmental applications.
研究领域:
材料科学
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环境科学
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分析化学
✓ 已验证
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Hu Li,Tingting Yang,Zhen Fang
The use of organic chemicals derived from renewable sources to synthesize functional solid materials for heterogeneous catalysis is of great significance. Herein, a new porous and acid-base bifunctional hybrid (FDCA-Hf) was designed and prepared by simple assembly of biomass-derived 2,5-furandicarboxylic acid (FDCA) with hafnium (Hf) under template-free conditions. The resulting FDCA-Hf hybrid with mesopores centered at 6.9 nm, moderate surface area (365.8 m 2 /g) and acid-base couple sites (density: 0.51 vs 0.97 mmol/g, acid/base molar ratio: 0.53), could selectively catalyze the Meerwein-Ponndorf-Verley reduction of carbonyl compounds under mild reaction conditions (as low as 90 °C in a short time of 1 h), especially of ethyl levulinate to γ -valerolactone, in quantitative yields (95–100%) and relatively higher reaction rate (e.g., turnover frequency: 2.28 h −1 ) compared to other catalysts. Moreover, the efficient simultaneous (trans)esterification of Jatropha oils with high acidic values to biodiesel (up to 98% yield) could also be achieved over FDCA-Hf with robust acid-base catalytic sites. The FDCA-Hf hybrid was highly stable due to the presence of robust metal-organic framework and could be resued with no decline in activity. Further studies demonstrated that the synergistic role of Lewis acid-base couple species (Hf 4+ –O 2− ) and Brønsted acidic species ( OH) of FDCA-Hf contributed greatly to its pronounced catalytic activity.
研究领域:
催化化学
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材料科学
·
可再生资源利用
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2021
·Vol. 8
·期 24
·5186-5194
·
IF 6.569
Yan Zhang,Yanjie Liang,Shihai Miao,Dongxun Chen,Shao Yan,Jingwei Liu
A series of Cr3+-doped BaMSi3O9 (M = Zr, Sn, Hf) near-infrared emitting phosphors with tunable luminescence properties have been successfully synthesized by using a simple solid-state reaction method. The developed BaMSi3O9:Cr3+ phosphors show a broad near-infrared emission band ranging from 650 nm to 1200 nm with a peak wavelength longer than 800 nm and a full width at half maximum (FWHM) of more than 155 nm upon blue light excitation. The optimized phosphor also demonstrates good thermal stability, whose emission intensity at 150 °C can retain about 59% of its initial intensity at room temperature. The near-infrared LED prototypes constructed by combining the BaMSi3O9:Cr3+ phosphor with a blue LED chip give a maximum output power of 12.19 mW at a drive current of 320 mA. By using the fabricated near-infrared LED device as a lighting source, night-vision lighting and blood vessel imaging of human fingers and arms are successfully realized, demonstrating the great potential of BaMSi3O9:Cr3+ phosphors for near-infrared LED applications.
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
DRUG DELIVERY
·
2022
·
IF 6.819
Luxi Peng,Jiajun Qiu,Lidan Liu,Xiaoyu Li,Xuanyong Liu,Yongjun Zhang
Melanoma is one of the highly malignant tumors whose incidence and fatality rates have been increased year by year. However, in addition to early surgical resection, there still lacks specific targeted drugs and treatment strategies. In this study, it was discovered that hinokiflavone (HF) encapsulated in zeolitic imidazolate framework-8 (ZIF-8) exhibited a superior anti-melanoma effect in vitro and in vivo. HF was encapsulated in ZIF-8 through a one-step synthesis method, and polyethylene glycol (PEG-2000) was used to optimize the size and dispersion of the drug-loaded complex (PEG/ZIF-8@HF). The results show that the prepared PEG/ZIF-8@HF has a high encapsulation efficiency (92.12%) and can achieve selective drug release in an acidic microenvironment. The results of in vitro anti-melanoma experiments indicate that PEG/ZIF-8@HF shows up-regulation of reactive oxygen species (ROS) levels and can restrain the migration and invasion of B16F10 cells. Moreover, in vivo animal experiments further confirm that PEG/ZIF-8@HF shows anti-tumor effect by up-regulating the pro-apoptotic proteins caspase-3 and caspase-8, and down-regulating the migration-promoting invasion protein MMP-9. This study developed a safe and effective oral administration of HF based on the high-efficiency delivery ZIF-8 system, which provides an effective treatment strategy for melanoma.
研究领域:
肿瘤学
·
药剂学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·
IF 3.9
Zhe Zhao,Cheng Han,Xiaozhou Wang,Yingde Wang
Metallopolymers containing refractory metal in the main chain are highly desired but rarely reported as oxygen-free single-source precursors for preparing ultrahigh-temperature ceramics. Herein, a novel single-source precursor of poly-hafnium-borocarbosilane (PHBCNS) with an Hf–N–B backbone molecular structure was synthesized through the dehalogenation reaction between HfCl 4 and B(NHCH 3 ) 3 . The polymeric Hf–N–B chain with large bond angle and conjugated molecular structure endowed the PHBCNS precursor to be relatively stable, dissolvable, and meltable. Subsequent precursor pyrolysis up to 1800°C resulted in an HfC/HfB 2 nanocomposite comprising an Hf content of 87.54 wt%, with the average grain size of HfC and HfB2 to be 34.9 and 74.1 nm, respectively. The ceramization mechanism and phase evolution from the PHBCNS precursor to HfC/HfB 2 composite ceramics were thoroughly investigated. This work not only highlights a novel Hf–N–B backbone polymer with high metal content and good shaping properties but also provides fresh insights of designing single-source precursors for ultrahigh-temperature composite ceramics.
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 THE AMERICAN CERAMIC SOCIETY
·
2025
·Vol. 109
·期 1
·e70407
·
IF 3.8
Yuwei Zhang,Cuiwei Li,Guangjin Chen,Chenran Zhao,Zhikun Song,Kepi Chen,Haoran Sun,Linghao Wu,Junhui Xiang
A series of (Y, Yb, Zr, Hf, Sn, W)O 2−δ high-entropy ceramics with varying mole fraction of main elements were synthesized for the first time through the solid-state reaction synthesis method. The microstructure, phase composition, and properties of the prepared materials were thoroughly analyzed and tested. The results indicate that the phase composition transformed from a single-phase fluorite structure to a single-phase C-type rare earth sesquioxide structure as the mole fraction of +3 cations increases. The thermal conductivity of the prepared high-entropy ceramics with porosity of 49.8%–50.1% is very low ranging from 0.33 to 0.37 W·m −1 ·K −1 . Among them, the single-phase C-type rare earth sesquioxide with a higher oxygen vacancy concentration was employed as a catalyst in the CO 2 hydrogenation reaction, attaining a high CO 2 conversion rate of 82.0%. The obtained results have deepened understanding of the role of oxygen vacancies and have important guiding significance for the study of high-entropy oxides with fluorite derived structures.
研究领域:
材料科学
·
陶瓷
·
催化
·
能源材料
·
固态化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Hu Li,Yan Li,Zhen Fang,Richard L. Smith
An acid-base bifunctional nanohybrid phenylphosphonic acid (PhP) - hafnium (1:1.5) was synthesized through assembly of PhP with HfCl 4 for catalytic transfer hydrogenation of furfural (FUR) to furfuryl alcohol (FFA) using 2-propanol as both reaction solvent and hydrogen donor source. An FFA yield of 97.6 % with formation rate of 9760 μmol g −1 h −1 at 99.2 % FUR conversion was obtained with the reaction system at 120 °C for 2 h reaction time. Activation energy (Ea) was estimated to be 60.8 kJ/mol with respect to FUR concentration, which is comparable with or even lower than Ea values attained over metal catalysts. The pronounced catalytic activity of PhP-Hf (1:1.5) is attributed to its moderate acidity and relatively strong basicity. The PhP-Hf (1:1.5) catalyst was demonstrated to maintain its activity for five consecutive reuse cycles.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）