INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2024
·
IF 8.1
Jing Wang,Min Wang,Zhenjiang Lu,Jing Xie,Jianguo Huang,Jindou Hu,Yali Cao
The inefficient Ni/Fe ion utilization and poor electrical conductivity of nickel-iron layered double hydroxide (NiFe-LDH) restricts to its development in electrocatalytic oxygen evolution reaction/urea oxidation reaction (OER/UOR). Herein, self-supported Hf-doped NiFe-LDH nanosheet arrays were successfully prepared on nickel foam (Hf-NiFe-LDH/NF) via a one-step solvothermal approach for the first time, in which the introduced high-valent Hf 4+ altered the structure of electrons and chemical environment of the atoms and promoted the production of more active sites, thus realizing the fast kinetics of electron transfer on the layer. Meanwhile, the doped metal Hf ions increased the electric conduction and recycling stability of the catalyst. Astoundingly, the overpotential of Hf-NiFe-LDH/NF is barely 258 mV at a current density of 100 mA cm −2 , which is 61 mV lower than that of NiFe-LDH/NF, as well as outstanding stability for over 90 h during the OER. Similarly, the potential is only 1.37 V at 100 mA cm −2 during the UOR, 118 mV less was than at OER. Notably, Hf-NiFe-LDH/NF electrocatalyst exceeds the most previously reported electrocatalysts in terms of performance. This study highlights the benefits of Hf doping strategy in electrocatalytic OER/UOR and presents a promising new type of catalyst for future research.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
MICROELECTRONIC ENGINEERING
·
2024
·
IF 2.6
Wenwu Li,Caifang Gao,Xifeng Li,Jiayan Yang,Jianhua Zhang,Junhao Chu
Device stability is one of the key parameters for transistor applications. To improve the stability of Indium oxide (In 2 O 3 ) after a long-time gate bias, a synthetic solution of hafnium chloride (HfCl 4 ) and indium nitrate (In(NO 3 ) 3 ∙xH 2 O) reagents were used to obtain 0% to 5-at.% Hf doped In 2 O 3 thin-film transistors. With the increase of Hf doping concentration, oxygen vacancies and residual hydroxyl groups continue to decrease, suppressing the carrier concentration and influencing the trap state density of In 2 O 3 . The sub-threshold slope (SS) 0.78 V·dec −1 for the undoped In 2 O 3 transistor in this work is a typical value. When the dopant dose is up to 5-at.%, SS decreases to 0.32 V·dec −1 . According to the proportional relationship between SS and the density of trap states, it shows that the density of trap states in the dielectric layer and the semiconductor/dielectric interface SS is greatly reduced after 5-at.% Hf doping. The probability of the charge being trapped is dropped as well. At the same time, under the doping of Hf, the transistor exhibits a very small threshold voltage shift. Especially at the dopant dose of 5-at.%, the transfer characteristic curve hardly shifts. This work demonstrates an In 2 O 3 transistor with high bias stability by doping method.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
高影响因子
BIOMATERIALS
·
2020
·
IF 10.317
Ya Su,Shi Liu,Yuyao Guan,Zhigang Xie,Min Zheng,Xiabin Jing
Carbon dots (CDs) are emerging as powerful nanoprobes for multiple-model bioimaging. Nowadays, orthotopic xenograft models attract increasing attention because of their superiorities of duplicating the tumor microenvironment . However, compared with the extensive study of subcutaneous xenograft tumors , less attention has been paid to CDs for in vivo orthotopic tumor imaging . Furthermore, it is very desirable for a nanoprobe to achieve preferential accumulation at the tumor site and efficient renal clearance . In this work, a novel kind of Hafnium-doped CDs (HfCDs) were successfully prepared via a simple one-pot pyrolysis method. The significant advantages including robust stability, good biocompatibility , excellent water solubility, remarkable computed tomography (CT) contrast performance and preferential tumor accumulation capability endow HfCDs with particular functions of CT/fluorescence imaging of orthotopic liver cancer initially. More importantly, HfCDs could locate at the tumor site and achieve the rapid imaging within 1 min. The findings of the current study represent a facile and universal approach to fabricate outstanding renal clearable multimodal imaging nanoprobes with great potential for clinical diagnosis.
研究领域:
医学影像学
·
纳米医学
·
肿瘤学
✓ 已验证
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
Nanomaterials
·
2019
·Vol. 9
·期 8
·1128
·
IF 4.034
Yao-Bing Huang,Yu-Jia Luo,Fei Wang
The development of an efficient solid catalyst for Friedel–Crafts (FC) reactions is of great importance to organic synthetic chemistry. Herein, we reported the hafnium-doped mesoporous silica catalyst Hf/SBA-15 and its first use for Friedel–Crafts alkylation reactions. Catalysts with different Si/Hf ratios were prepared and characterized, among which Hf/SBA-15(20) (Si/Hf = 20:1) was the most active catalyst, offering up to 99.1% benzylated product under mild reaction conditions. The influences of reaction conditions on the product were systematically investigated and compared. Pyridine-IR characterization of the catalyst showed that Lewis acid formed the primary active sites for the Friedel–Crafts alkylation reaction. X-ray photoelectron spectroscopy (XPS) characterization revealed that the electron shift from the Hf center to the silica framework resulted in a more active Lewis metal center for FC reactions. Moreover, the catalyst was successfully applied to the alkylation reaction with different alcohols and aromatic compounds. Finally, the Hf/SBA-15(20) catalyst also showed good recyclability in the recycling runs, demonstrating its high potential of being used for large scale FC reactions in the industry.Keywords:Friedel–Crafts alkylation;hafnium-doped mesoporous silica;benzyl alcohol;aromatics;Lewis acid
研究领域:
有机化学
·
催化材料科学
✓ 已验证
DOI
PubMed
高影响因子
Small
·
2025
·Vol. 21
·期 21
·2500943
·
IF 12.1
Weizong Wang,Kexuan Jing,He Ma,Kang Liang,Peng Wei,Jiangchuan Liu,Yurong Ren,Qian Zhao,Zhengping Ding
Halide solid-state electrolytes (SSEs) with high ionic conductivity and oxidation stability show significant potentials for the commercialization of all-solid-state batteries (ASSBs). However, their practical applications are limited by poor humidity tolerance and decreased ionic conductivity. Herein, the Li 3/3- x In 1- x M x Cl 5.6 F 0.4 ( M = Hf, Zr, Fe, and Y; x = 0.015, 0.02, 0.025, 0.075, 0.1, 0.125, and 0.15) are synthesized by co-doping Li 3 InCl 6 with M and F ions for high-performance ASSBs. Li 2.98 In 0.98 Hf 0.02 Cl 5.6 F 0.4 achieves the highest ionic conductivity of 1.04 mS cm −1 at room temperature and good humidity tolerance of 87.96% conductivity retention after 24 h exposure. The analysis of experiments combining BVSE and AIMD simulations indicates that it benefits from the enhanced rigid structure that is thermodynamically stable to water caused by Cl − doping with F − and higher Li + vacancies concentration that facilitates Li + conduction generated by In 3+ doping with Hf 4+ . Moreover, an all-solid-state battery ensembled with Li 2.98 In 0.98 Hf 0.02 Cl 5.6 F 0.4 , LiCoO 2 and Li–In alloy, exhibits a high discharge capacity of 83.6 mAh g −1 and 78.6% capacity retention after 100 cycles under 0.5 C at 25 °C. This work provides a reliable strategy for designing advanced halide SSEs for commercial applications in ASSBs by cation–anion co-doping.
研究领域:
材料科学
·
电化学
·
储能技术
·
固态离子学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）