IONICS
·
2022
·Vol. 28
·期 9
·4273-4282
·
IF 2.961
Gao Jiayi,Yang Yujie,Ren Yujie,Zhu Wenjie,Li Jin,Liu Yongguang,Dai Lei,Wang Ling,He Zhangxing
Vanadium redox flow batteries have the advantages of long life, flexible design, safety, and reliability, so they have broad development prospects in the field of energy storage. Borides are extensively used in electrochemistry due to their excellent electrical conductivity. In this program, HfB 2 was used as catalyst for the V 3+ /V 2+ pair. The catalytic effect was verified by electrochemical impedance spectroscopy and cyclic voltammetry. The result shows that the cell using HfB 2 as negative catalyst can exhibit excellent rate capability when the current density is 50 ~ 125 mA cm −2 . At 125 mA cm −2 , the discharge capacity of the modified cell is 68.7 mA h, which is much higher than pristine cell (22.8 mA h). And the energy efficiency of pristine cells is 11.2% lower than that of modified cells. These consequences suggest that HfB 2 is a catalyst with promising prospects to enhance electrochemical activity of V 3+ /V 2+ redox reaction in VRFB.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2024
·Vol. 48
·期 17
·7718-7725
·
IF 2.7
Yanping Luo,Chengjin Xu,Jianhui Su,Xiujing Peng,Xiangfeng Kong,Shuo Wang,Jiahui Sun,Yu Cui,Yong Nie,Xuchuan Jiang,Guoxin Sun
Nuclear-grade zirconium and hafnium play an essential role in the nuclear industry. It is difficult to separate and purify zirconium and hafnium because of the similar properties caused by lanthanide shrinkage and the preferential extraction of hafnium is challenging. In this work, a new extractant, di(p-tert-butylphenyl)phosphate (DTBPPA), was synthesized, and its separation performance of zirconium and hafnium in the sulfuric acid system was evaluated. Under identical extraction conditions, DTBPPA shows excellent preferential extraction properties for hafnium compared to current commercial extractants, such as D2EHPA and PC88A. The highest SFHf/Zr value is up to 16.3. A crystal of the hafnium extracted species was grown to study the extraction mechanism and the principle of preferential extraction of hafnium. It was found that the crystal growth of zirconium-extracted species was difficult under the same conditions. Hafnium extracted species crystals reveal a six-coordinated hafnium ion bound to six extractant molecules. The electron withdrawing effect of the aromatic substituents results in a low electron density of O atoms in the P–O group of the new extractant, and the extractant coordination group shows the characteristics of a soft base. This matches the soft acid properties of hafnium ions. DTBPPA shows a solid ability to identify hafnium ions, thus achieving preferential separation of hafnium from zirconium and hafnium mixtures.
研究领域:
核化学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Luyao Yang,Rong Liu,Meiying Xie,Fan Yang
Metal–organic framework materials (MOFs) have potential for practical applications in solid-phase separation technology. However, no studies of the separation of hafnium and zirconium using MOFs have been performed. This work synthesized MIL-101-DGA solid-phase adsorbent material, which was synthesized using amino-containing MIL-101-NH2 as a matrix material by introducing diglycolic acid (DGA) functional groups through a one-step ring-opening reaction. Betaine hydrochloride was selected as the complexing agent to establish the MIL-101-DGA coupling betaine hydrochloride push–pull system; this system could act as an alternative to the traditional MIBK-HSCN separation system. We are the first to report that this MIL-101-DGA coupling betaine hydrochloride system could obtain separation coefficients (βZr/Hf) of 19.7 at pH 0.50 and 8.2 at pH 1.46. Furthermore, the highest adsorption capacity of MIL-101-DGA for Zr was 63.7 mg/g. These results demonstrated that MIL-101-DGA had excellent separation performance for zirconium and hafnium in the betaine hydrochloride medium. This system also exhibited an outstanding cycling performance and immersion stability. After multiple adsorption/desorption cycles and 1 week of immersion in various solutions, the structure and adsorption capability essentially remained unchanged. The adsorption mechanism was thoroughly examined using a suite of analysis and detection methods, including the slope method, FT-IR, XPS, and DFT. In conclusion, we propose that the MIL-101-DGA coupling betaine hydrochloride system, which is an efficient and green separation system, could replace the traditional MIBK-HSCN separation system; our study provides a concept for the industrialization of zirconium and hafnium separation from key mineral resources.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MATERIALS CHARACTERIZATION
·
2024
·
IF 4.8
Shuai Ma,Di Dong,Mengyao Zhang,Ye Gao,Zhuangzhi Wu,Dezhi Wang
W-Re-HfC alloys have been extensively applied in the field of high-temperature structural parts. To ensure high temperature reliability, it is essential to enhance creep resistance ability. In this study, the microstructures of forged W-Re-HfC alloys were adjusted using different heat treatment processes . The corresponding tensile creep properties were also measured at 2000 °C with 40 MPa. Furthermore, a possible creep fracture mechanism was also explored. The forged W-Re-HfC sample annealed for 2 h exhibited the best creep performances with a steady-state creep rate of 3.28 × 10 −6 and a creep life of 5.6 h. Generally, a larger grain size indicates a lower steady-state creep rate; however, the precipitation of carbides at the grain boundaries (GBs) deteriorates the bonding strength of interfaces, thus reversing the former trend. The dominant creep mechanism is diffusion creep , in which the voids nucleate perpendicular to the GBs, grow and connect into cracks, ultimately leading to fractures.
研究领域:
材料科学
·
金属学与热处理
·
高温结构材料
·
固态物理
·
力学性能
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Bin Li,Jing Xue,Chao Han,Na Liu,Kaixuan Ma,Ruochen Zhang,Xianwen Wu,Lei Dai,Ling Wang,Zhangxing He
In aqueous zinc-ion batteries, metallic zinc is widely used as an anode because of its non-toxicity, environmental benignity, low cost, high abundance and theoretical capacity. However, growth of zinc dendrites, corrosion of zinc anode, passivation, and occurrence of side reactions during continuous charge-discharge cycling hinder development of zinc-ion batteries. In this study, a simple strategy involving application of a HfO 2 coating was used to guide uniform deposition of Zn 2+ to suppress formation of zinc dendrites. The HfO 2 -coated zinc anode improves electrochemical performance compared with bare Zn anode. Therefore, for zinc-zinc symmetric cells, zinc anode with HfO 2 coating (48 mV) shows lower voltage hysteresis than that of bare Zn anode (63 mV) at a current density of 0.4 mA cm −2 . Moreover, cell with HfO 2 coating also shows good cycling performance in Zn-MnO 2 full cells. At a constant current density of 1.0 A g −1 , discharge capacity of bare Zn-MnO 2 full cell is only 37.9 mAh g −1 after 500 cycles, while that of Zn@HfO 2 -MnO 2 full cell is up to 78.3 mAh g −1 . This good electrochemical performance may be the result of confinement effect and reduction of side reactions. Overall, a simple and beneficial strategy for future development of rechargeable aqueous zinc-ion batteries is provided.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
PubMed
高影响因子
IET Nanodielectrics
·
2020
·Vol. 3
·期 4
·131-137
·
IF 0
Zhi-Gang Liu,Peng-Zu Ge,Hui Tang,Xin-Gui Tang,Si-Ming Zeng,Yan-Ping Jiang,Zhen-Hua Tang,Qiu-Xiang Liu
PbHf 1− x Sn x O 3 (PSH) ceramics were synthesised by a conventional solid-state reaction method. Dielectric properties were investigated in the temperature range of 20–650°C. As the Sn 4+ content goes up, the phase transition temperatures of an antiferroelectric (AFE1) to another intermediate antiferroelectric (AFE2) phase and AFE2 to the paraelectric (PE) phase decrease gradually. When x ≥0.1 for PSH ceramics, the ferroelectric (FE) phase appears around 225°C, and phase transition temperature from FE phase to PE phase goes up with the increasing concentration of Sn 4+ . Moreover, high-temperature dielectric relaxation (HTDR) phenomenon can be seen from all samples. Mechanism of HTDR was discussed from impedance spectroscopy and conductivity for PSH ceramics. It was found that three dielectric responses were observed in complex impedance plots and HTDR was involved with the movement of oxygen vacancies. Activation energy calculated from dielectric data suggested that the HTDR was governed by the hopping conduction process.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Liang-ping Xiong,Kai Lv,Mei Gu,Chu-ting Yang,Feng-cheng Wu,Jun Han,Sheng Hu
A kind of unconventional metal–organic framework (UMOF), hafnium phosphonates (HfP) with different molar fractions P/(P + Hf), were synthesized via a template-free, one-pot method by the reaction between hafnium chloride octahydrate (HfOCl 2 ·8H 2 O) and amino tris(methylenephosphonic acid) (ATMP); the structure, sorption behaviors for actinides, acid resistance and radiolytic stability of the synthesized materials were then investigated. The results reveal that the materials were amorphous and porous, and HfP with a higher molar fraction P/(P + Hf) exhibited a higher sorption capacity for Th(IV) and U(VI). In 3 mol/L HNO 3 , K d values of HfP for Th(IV) and U(VI) were 5.84 × 10 4 and 5.09 × 10 3 mL/g, respectively, indicating superiority to other MOF materials in strong acidic solution. The K d values for tracer amounts of radioactive 239 Pu and 237 Np were 1.19 × 10 4 and 6.68 × 10 3 mL/g in 4 mol/L HNO 3 , respectively. This is the first case of applying MOF materials to capture transuranic elements from a strong acidic medium. Moreover, the materials were quite stable when dipped into strong acidic solutions, while their sorption performances were unexpectedly enhanced after irradiated by high dosage γ-rays in air. All the results support its anticipated application as actinide sorbents in many practical nuclear processes.
研究领域:
核化学与放射化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Molecular Catalysis
·
2023
·
IF 4.6
Congcong Zhao,Niuniu Zhu,Guo Qiu,Manyu Zhang,Hongyu Tian
5-Hydroxymethylfurfural (5-HMF) is considered as a bridge connecting biomass and petrochemical products with excellent application potential and market prospects. In this work, a series of hafnium-aluminum bimetallic oxide (Al-HfO x ) catalysts were synthesized with the coprecipitation method, possessing outstanding catalytic effect in the conversion of glucose or fructose to 5-HMF. 5-HMF yield of 49.31% was acquired from glucose in a methyl isobutyl ketone (MIBK)/saturated salt water (SSW) biphasic solvent at 170 ℃ after 2 h. When fructose was the substrate, 5-HMF yield was 74.85% in DMSO at 150 ℃ after 75 min. In addition, the reaction mechanism was speculated that the isomerization process could be promoted by the synergistic effects of aluminum and hafnium species, in which Hf-OH and Al-OH groups, and Hf active sites served as Brønsted and Lewis acidic sites, respectively. After at least four cycles, there was no remarkable wastage in the catalytic activity of Al-HfO x . This paper offers a prospective catalytic strategy for heterogeneous bimetallic oxide catalysts used in the effective conversion of carbohydrates to 5-HMF.
研究领域:
催化化学
·
生物质转化
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2024
·
IF 4.7
Shuai LI,Sheng-hai YANG,Yong-ming CHEN,Chao-bo TANG,Yan-qing LAI,Chao-yong DENG,Chang-hong WANG
Electrodissolution-coupled hafnium alkoxide synthesis (EHS) is a promising pathway for efficient electro- synthesis. It employs simultaneous heterogeneous reactions of Hf dissolution and ethanol dehydrogenation, and spontaneous solution-based combination reaction between Hf 4+ cations and alkoxy anions. To elucidate the mechanism and kinetics of EHS process, the electrochemical behaviors of anodic Hf dissolution and cathodic ethanol dehydrogenation were explored through electrochemical measurements, SEM observations, gas chromatography, and micro-kinetics modeling. The results indicated the supporting electrolytes of tetraethylammonium chloride (Et 4 NCl) to be preferable, which facilitated a passive-film-punctured pitting mechanism for Hf dissolution and a two-stage dehydrogenation mechanism. Three indicators related to passive rate, sensitivity towards puncture of the passive film, and pitting rate were extracted to quantify the kinetics of passive puncture and Hf corrosion. Micro-kinetics models were developed to evaluate the Et 4 NCl-based EHS process, which achieved electric energy requirements of 1.53–1.83 kW·h/kg Hf(OC 2 H 5 ) 4 .
研究领域:
材料科学
·
电化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2025
·
IF 8.3
Qinqin Tan,Dehong Huang,Zhantao Wu,Zezhi Zeng,Yangjun Zhang,Dengjie Chen
Alkaline-earth-based perovskite cathodes like Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3−δ (BSCF) often suffer from CO 2 -induced degradation due to carbonates formation (e.g., SrCO 3 ), severely impairing oxygen reduction reaction (ORR) activity and long-term stability for solid oxide fuel cells. This study demonstrates that treating CO 2 -poisoned BSCF with the HfCl 4 solution not only restores ORR activity by chemically dissolving carbonates, but also enhances stability by introducing high-valence, reduction-inactive Hf 4+ cations. The modified BSCF exhibits superior electrochemical performance, with area-specific polarization resistance (ASR P ) decreasing from 0.077 to 0.038 Ω cm 2 and maximum power density increasing from 1.185 to 1.510 W cm −2 at 650 °C. Furthermore, under CO 2 exposure, the degradation rates of ASR P and cell voltage for the HfCl 4 solution-treated BSCF are significantly lower (0.007 Ω cm 2 min −1 and 4.08 × 10 −4 V h −1 ) compared to pristine BSCF (0.027 Ω cm 2 min −1 and 8.14 × 10 −4 V h −1 ). This facile acidic HfCl 4 solution treatment effectively regenerates degraded cathodes while simultaneously improving their CO 2 tolerance and operational stability.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 47
·期 5
·6842-6847
·
IF 3.83
Shunjin Xiong,Rongxia Huang,Congfei Peng,Yejing Dai,Jiajiu Li,Wen Bai,Hua-Tay Lin
A series of HfO 2 -modified (Bi 0 .475 Na 0 . 405 K 0 . 055 Li 0.015 ) 0.95 Ba 0 . 05 Ti (1- x ) Hf x O 3 ( x = 0–0.015) lead-free ceramics were prepared. Results of detailed characterizations showed that the addition of HfO 2 had little influence on the grain size, and all of the samples showed the pure perovskite structure. As the Hf 4+ content increases, the samples changed from the normal ferroelectric phase to the ergodic relaxor state at room temperature, and the ceramics with x = 0.01 showed a high electro-strain of 0.295% at 6 kV/mm. Therefore, this study provides a new insight into of how the HfO 2 addition influences the ferroelectric property of the BNT-based ceramics by B-site substitution.
研究领域:
材料科学
·
无机非金属材料
·
功能陶瓷
·
铁电材料
·
压电材料
✓ 已验证
DOI
高影响因子
Coatings
·
2022
·Vol. 12
·期 4
·439
·
IF 3.236
Xiangduo Cui,Kamale Tuokedaerhan,Haotian Cai,Zhenchuan Lu
Lanthanum-doped HfO2films were deposited on Si by sol–gel technology. The effects of annealing temperature on the optical properties, interface chemistry, and energy band structure of Lanthanum-doped HfO2films have been investigated. The crystallinity and surface morphologies of the films are strongly dependent on the annealing temperature. X-ray diffraction (XRD) analysis showed a monoclinic phase, and there was a tendency to preferentially grow with increasing temperature. The calculated grain sizes ranged from 17.1 to 22.4 nm on average. It was also confirmed from Raman spectroscopy that increasing the annealing temperature can improve the crystallinity of the films. The surface of the film was smooth, and the film had good interfacial contact with the silicon substrate. The band gap increased from 5.53 to 5.91 eV with increasing annealing temperature. The calculated conduction band offset and valence band offset both exceeded 1 eV. In conclusion, smaller grain size, good crystallinity and interfacial contact can be obtained by adjusting the annealing temperature. Higher conduction band and valence band offsets can meet the minimum barrier height requirements of complementary metal oxide semiconductors (CMOS) and have potential applications.Keywords:high-k gate;sol–gel;thin films;annealing temperature
研究领域:
材料科学
·
半导体物理
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）