APPLIED SURFACE SCIENCE
·
2018
·
IF 4.439
Zhen-Kun He,Qiang Sun,Zhongning Shi,Kaiyu Xie,Ali Reza Kamali
Spiky polycrystalline SnO 2 balls assembled from pyramid-shaped SnO 2 nanocrystals with surface oxygen vacancies were synthesized by a simple and facile in-situ molten salt oxidation method using SnCl 2 as the tin source and graphite as the surface reductant. In this method, perfect SnO 2 nanocrystals are first formed on the surface of graphite particles at 500 °C. By increasing the processing temperature to 700 °C, the formation of surface oxygen vacancy defects was confirmed, supported by various characterisation methods including Raman and XPS spectroscopy. A sharp increase in the bulk electrical conductivity of the samples was detected by exceeding the onset temperature corresponding to the formation of oxygen deficient SnO 2 crystals, at which the conductivity of the sample significantly outperformed that of commercial SnO 2 nanoparticles. The formation of oxygen vacancies on SnO 2 crystals is thermodynamically studied, and suggested to occur by surface carbon reduction of the crystals at sufficiently high temperatures. The enhanced electrical conductivity of oxygen deficient SnO 2 crystals can lead to a wider application of tin oxides in advanced electrical applications.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
Journal of Advanced Ceramics
·
2022
·Vol. 11
·期 9
·1491-1497
·
IF 11.534
Liu Yi,Wang Chuangye,Luo Wei,Bai Liang,Xu Yang,Hao Xiaodong,Zhu Jianfeng,Guo Shouwu
The microstructure and morphology of Ti 3 AlC 2 powders not only affect the preparation of Ti 3 C 2 MXene but also have a great influence on their potential applications, such as microwave absorbers, alloy additives, or catalytic supports. However, the synthesis of Ti 3 AlC 2 powders with desired microstructure and morphology remains a challenge. Herein, hollow Ti 3 AlC 2 microrods were prepared for the first time in NaCl/KCl molten salts by using titanium, aluminum, and short carbon fibers as starting materials. It was found that the short carbon fibers not only performed as carbon source but also acted as sacrificial template. Furthermore, it was revealed that TiC and Ti 2 AlC were initially formed on the surface of carbon fibers. The subsequent reactions between the outer Ti, Al and the inner carbon were dominated by the Kirkendall effect which gave rise to the formation of a hollow structure. Based on this mechanism, hollow Ti 3 AlC 2 microspheres and a series of hollow TiC, Ti 2 AlC, and V 2 AlC powders were also successfully fabricated. This work provides a facile route to synthesize hollow MAX phases and may give enlightenment on preparing other hollow carbide powders via the Kirkendall effect in the molten salts.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2025
·
IF 6.3
Fang Zhang,Yuchen Cui,Jingxin Gao,Ziang Li,Yiping Yu,Yuxuan Xia,Wei Lei,Jie Zhang,Nuofu Chen,Jikun Chen
While perovskite cobaltites ( Re CoO 3 , Re : rare-earth) exhibit multiple spin states and complex electromagnetic phase diagram, their intrinsic metastability at heavy rare-earth composition ( Re H CoO 3 ) impedes their synthesis. Herein, we effectively synthesized Re H CoO 3 ( Re H = Ho, Er, and Tm), without the necessity to use the previous high pressures, by descending their reaction temperatures within molten-salts. Owing to the intermediate valence of Co 3 + , their metastable perovskites cannot be stabilized by simply elevating oxygen pressures, in contrast to the synthesis of high-transitional valence metastable perovskites such as Re NiO 3 . Alternatively, the positive formation free energy of the Re H CoO 3 was reduced by introducing KCl that dissolve the precursors at lower temperatures to prevent varying the valence of Co without scarifying the reaction kinetics. The effective synthesis of metastable Re CoO 3 towards heavy rare-earth composition further extends the range for regulating both the electronic and magnetic phases of Re H CoO 3 , paving the way to their potential electromagnetic applications.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2020
·Vol. 23
·期 3
·671-677
·
IF 3.117
Sanzhao Song,Jian Sun,Jing Zhou,Chengzhi Guan,Zhiwei Hu,Ting-Shan Chan,Xian-Long Du,Xiao Lin,Jun Hu,Linjuan Zhang,Jian-Qiang Wang
Molten salts have been reported to be excellent media for the preparation of multicationic oxides, which require harsh conditions to crystallize. Molten salt synthesis provides a wider operational temperature range (usually extends to 1000 °C) and faster mass transport and nucleation processes, thus allowing the preparation of crystalline solids, which require higher temperatures, such as perovskites. However, the mechanisms that control the solid-state formation and phase selection are poorly understood. Herein, several typical molten alkali metal halide (Cl−) and oxosalt (CO32− and SO42−) systems were employed as the reaction media for the synthesis of LaCoO3 (LCO) crystals, and the effects of ionic salt species on the morphological, geometric and electronic structures of LCO crystals were examined by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray absorption spectroscopy (XAS). The LCO perovskite was successfully synthesized in a molten NaCl–KCl eutectic mixture at 700 °C, which was lower than that used for the conventional mixed oxide synthesis. Our results show that in the molten salt synthesis, the type of reaction medium, calcination temperature, the ratio of salt, and reaction time govern the microscopic mechanisms in the preparation of multicationic oxides. Most importantly, we observed that LaOCl was formed as an intermediate, which plays a key role in the reaction pathway for the phase-selective synthesis of perovskite LCO.
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
·
2022
·
IF 5.532
Wenzhong Zou,Guoyun Zhou,Yan Hong,Wei He,Shouxu Wang,Yuanming Chen,Chong Wang,Yao Tang,Yukai Sun,Chaoying Ma
In this work, the high-yield synthesis of BaTi 2 O 5 (BT2) nanorods with a growth direction at [020] was achieved in the medium of KCl salt through the molten-salt synthesis (MSS) with Ba(NO 3 ) 2 and anatase TiO 2 as reactants. By optimizing the involved reaction factors including particle sizes, thermal holding durations and crystalline forms of TiO 2 , ultra-pure BT2 nanorods with uniform size were obtained after 45 min of heating at 950 °C. Meanwhile, anatase and rutile TiO 2 were respectively mixed and calcined in KCl to study the formation and transformation process of BT2 nanorods in detail. It was found that anatase TiO 2 tends to merge together and convert into rutile TiO 2 . In particular, the formed rutile TiO 2 reacts with BaO and BaTiO 3 to spontaneously form BT2 nanorods without any presence of rod-like templates. Besides, BT2 takes priority over K 2 Ti 6 O 13 to generate the corresponding nanorods in the molten salt with high content of K + . In addition, the O 2 in air also promotes the formation of nanorods. According to the experimental results, a probable mechanism for the initial formation, subsequent growth and transformation of BT2 nanorods was thus proposed, which helps to facilitate the preparation of BT2-based one-dimensional nanomaterials.
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 NANOSCIENCE AND NANOTECHNOLOGY
·
2012
·Vol. 12
·期 1
·151-158
·
IF 1.563
Liu Chenglu,Wang Fang,Jia Peiyun,Lin Jun,Zhou Zhiqiang
Eu3+ and Dy3+-doped YVO4 nanocrystallites were successfully prepared at 400 °C in equal moles of NaNO3 and KNO3 molten salts. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, transmission electronic
microscopy (TEM), photoluminescence (PL) spectrum and lifetime were used to characterize the nanocrystallites. XRD results demonstrate that NaOH concentration and annealing temperature play important roles in phase purity and crystallinity of the nanocrystallites, the optimum NaOH concentration
and annealing temperature being 6:40 and 400 °C respectively. TEM micrographs show the nanocrystallites are well crystallized with a cubic morphology in an average grain size of about 18 nm. Upon excitation of the vanadate group at 314 nm, YVO4:Eu3+ and YVO4:Dy3+
nanocrystallites exhibit the characteristic emission of Eu3+ and Dy3+, which indicates that there is an energy transfer from the vanadate group to the rare earth ions. Moreover, the structure and luminescent properties of the nanocrystallites were compared with their
bulk counter-parts with same composition in detail.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
PubMed
高影响因子
Materials Futures
·
2022
·Vol. 1
·期 4
·045102
·
IF 0
Ruijia Liu,Na Li,Enyue Zhao,Jinkui Zhao,Lingxu Yang,Wenjun Wang,Huijun Liu,Chaoliu Zeng
Transition metal nitrides (TMNs), including titanium nitride (TiN), exhibit remarkable application prospects as anodes for durable high-rate lithium-ion batteries (LIBs). Regrettably, the absence of simple synthesis methods restricts their further development. Herein, a facile and low-cost molten salt synthesis strategy was proposed to prepare carbon-anchored TiN nanoparticles as an advanced anode material for LIBs with high rate capabilities. This nanosized TiN obtained is ∼5 nm in size and well-distributed onto carbon plates, which could release a reversible capacity of ∼381.5 mAh g−1 at 0.1 A g−1 after 250 cycles and ∼141.5 mAh g−1 at 1.0 A g−1 after 1000 cycles. Furthermore, it was confirmed that the conversion reaction between TiN and Li-ions happened during the electrochemical reaction process, resulting in the formation of Li3N and Ti. This unique microstructure attributed from TiN nanoparticles anchored by carbon could support the structural volume during cycling. This work highlights the method superiority of TiN prepared via a molten salt synthesis strategy as an anode for LIBs with impressive rate performances.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
JOURNAL OF RARE EARTHS
·
2012
·
IF 0.901
Fang WANG,Chenglu LIU,Zhiqiang ZHOU,Peiyun JIA,Jun LIN
YVO 4 :Eu nanocrystalline phosphors were successfully prepared at 400 °C in equal moles of NaNO 3 and KNO 3 molten salts. NaOH concentration and annealing temperature played important roles in phase purity and crystallinity of the nanocrystallines, and the optimum NaOH concentration and annealing temperature were 6:40 and 400 °C, respectively. The nanocrystallines were well crystallized with a cubic morphology in an average grain size of 18 nm. Upon excitation of the vanadate groups at 314 nm, YVO 4 :Eu nanocrystallines exhibited the characteristic emission of Eu 3+ , which indicated that there was an energy transfer from vanadate groups to Eu 3+ . Moreover, the influence of superficial effect, especially the dangling bonds on the structure and luminescent properties of the nanocrystallines was discussed in detail.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Environmental Chemistry Letters
·
2022
·Vol. 20
·期 4
·2253-2259
·
IF 13.615
Shi En,Wang Xinyu,Zhang Miao,Wang Xin,Gao Jianchun,Zheng Yunbin
Wastewater treatment generates increasing amounts of unwanted sewage sludges, calling for advanced recycling methods. Here, we transformed sewage sludge into activated carbon by molten salt synthesis with ZnCl 2 . We analyzed the structure and specific surface area of sludge-derived activated carbon by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analysis. Results show that the mass ratio of ZnCl 2 to sludge had a significant effect on the textural properties and adsorption performance of sludge-derived activated carbon. The maximum specific surface area was 549.72 m 2 /g, and the carbon utilization potential was 178.56 mg (C atom) /g (sludge) , for a mass ratio of ZnCl 2 to sludge of the total carbon mass in sludge-derived activated carbon adsorbed CO 2 and methylene blue can be achieved to 186.68 and 203.18 mg (C atom) /g (sludge) , respectively.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2023
·Vol. 12
·期 1
·354-363
·
IF 11.9
Yunxiang Zhang,Chenliang Zhou,Shishi Xu,Hazem Abdelsalam,Zhichao Mu,Wei Chen,Zhili Chen,Xiangyu Cheng,Diab Khalafallah,Qinfang Zhang
Numerous studies disclosed that molten salts provide a special liquid reaction environment, accelerate the diffusion rate of active elements, and promote the formation of high-purity materials in the molten-salt synthesis method. Herein, the interlayer halogen-competing reactions between molten salts and halogen layers during the formation of BaBi4TiNbO11X (X = Cl, Br) oxyhalides were discovered for the first time. The liquid environment provided by molten salts can facilitate the full migration of halogen atoms between molten salts and halogen layers and form an even distribution of halogen atoms, which is ascribed to the weak van der Waals forces of the halogen layers between [BaBiO2]+ and [Bi2O2]2+ blocks. By employing this mechanism, BaBi4TiNbO11(Cl1−xBrx) with different x contents could be easily obtained. DFT calculations showed that the mixed halogen oxyhalides, such as BaBi4TiNbO11(Cl0.5Br0.5), introduce new chemical bonds between the O and Bi atoms, which increase their contribution to lowest occupied/unoccupied orbitals, thus regulating the energy band and accelerating the separation and transfer of photogenerated charge carriers. Consequently, the optimized BaBi4TiNbO11(Cl0.5Br0.5) sample showed a superior degradation rate of RhB compared to the traditional P25 photocatalyst, and its O2 evolution performance was also enhanced compared with other blank samples.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 3
·2244-2251
·
IF 3.094
Shanshan Ning,Tongqi Wen,Beilin Ye,Yanhui Chu
Synthesis of the powders is critical for achieving the extensive applications of high-entropy carbides (HECs). Previously reported studies focus mainly on the high-temperature (>2000 K) synthesis of HEC micro/submicropowder, while the low-temperature synthesis of HEC nanopowders is rarely studied. Herein we reported the low-temperature synthesis of HEC nanopowders, namely (Ta 0.25 Nb 0.25 Ti 0.25 V 0.25 )C (HEC-1), via molten salt synthesis for the first time. The synthesis possibility of HEC-1 nanopowders was first theoretically demonstrated by analyzing lattice size difference and chemical reaction thermodynamics based on the first-principle calculations, and then the angular HEC-1 nanopowders were successfully synthesized via molten salt synthesis at 1573 K. The as-synthesized nanopowders possessed the single-crystal rock-salt structure of metal carbides and high compositional uniformity from nanoscale to microscale. In addition, their formation mechanism was well interpreted by a classical molten salt-assisted growth.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Pengtao Qiu,Jinglei Bi,Xiaojing Zhang,Shengchun Yang
We present a novel synthetic strategy for the shape-controlled synthesis of Pt-based alloy nanoparticles (NPs) in inorganic molten salt without using any organic surfactants or capping agents. Graphene oxide (GO) was chosen as the stabilizer in the inorganic molten salt synthetic strategy, due to the existence of various oxygen-containing functional groups on its surface, which adsorb, anchor, and stabilize the metal ions or NPs. After GO was added in molten salt, the PtPd nanosheets were formed on its surface in H2 atmosphere. In addition, when KI was chosen as the shape-inducing agent to selectively adsorb on and fully protect the (100) facets of alloys, PtPd nanocubes with core–shell structure, PtCu nanohemicubes, and PtPdCu nanocubes were prepared successfully on the surface of GO in molten salt. Introduction of GO as the stabilizer in molten salt proves a new approach in synthesis of Pt-based nanocrystals with controlled morphologies.
研究领域:
材料科学
·
纳米技术
·
化学工程
✓ 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）