International Journal of Applied Ceramic Technology
·
2019
·Vol. 17
·期 2
·778-789
·
IF 1.074
Weihua Chen,Jiancheng Tang,Xingwang Shi,Nan Ye,Zhihao Yue,Xinghao Lin
High-purity titanium aluminum carbide (Ti 3 AlC 2 ) powders were synthesized by a microwave sintering method using different titanium sources as raw materials. The prepared products were characterized by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicated that the synthesized Ti 3 AlC 2 powders have high purity (97.5%) and even distribution of the grain size when using a 3TiH 2 /1.2Al/2C mixture as raw materials when the microwave sintering temperature and time were 1300°C and 30 minutes, respectively. The formation mechanism of the Ti 3 AlC 2 is described as proceeding via four stages. The solid-phase reaction between titanium and aluminum occurs below the melting point of aluminum and the main product is a Ti 3 Al phase, which is an observed intermediate compound for the formation of Ti 2 AlC and Ti 3 AlC 2 . Thus, this study provides a beneficial approach to low-temperature synthesis of high-purity Ti 3 AlC 2 materials.
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Environmental Science-Nano
·
2019
·Vol. 6
·期 11
·3431-3441
·
IF 7.704
Bowen Xiao,Yinqing Zhang,Xiaolei Wang,Meng Chen,Binbin Sun,Tong Zhang,Lingyan Zhu
The wide production and utilization of nanoparticulate Ag and Ti inevitably result in their release into the environment. Thus far, limited information is available regarding to what extent the nanoparticulate Ag and Ti could accumulate in biota and magnify along the food chain in real natural aquatic environments. With the application of single particle inductively coupled plasma mass spectroscopy, we quantitatively demonstrated that both nanoparticulate Ag (18.8–41.0 nm) and Ti (46.6–116 nm) occurred in the water, sediment and aquatic organisms in Taihu Lake, China. Nanoparticulate Ag exhibited greater bioaccumulation potential compared to its other chemical counterparts, and also a greater bioaccumulation factor than nanoparticulate Ti. Sediment served as a main reservoir for nanoparticulate Ag and Ti, and acted as one important exposure source for invertebrates. According to the concentrations of nanoparticulate Ag and Ti in aquatic organisms at different trophic levels, including a variety of invertebrates and fish species, the total and nanoparticulate Ti appeared to be biodiluted in the food web with trophic magnification factors (TMFs) < 1. Conversely, biomagnification of nanoparticulate Ag was found in the fish food web with a TMF of 1.21, while the total Ag was biodiluted. These findings serve as the first line of evidence on the transfer behaviors of nanoparticulate Ag and Ti along the natural aquatic food chain and underline the distinctive bioaccumulation and biomagnification behaviors of nanoparticles as opposed to their other chemical counterparts.
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INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2023
·
IF 3.6
Mengxian Zhang,Xianrui Zhao,Junting Zhang,Zhigang Fang,Huan Xu,Hongtao Wang
TiB 2 reinforced Ti(C,N)-based cermet was produced by the reaction spark plasma sintering of Co, Ni, Ti, C, BN, Mo 2 C, WC, and TaC mixtures. To understand the mechanism of reaction sintering, systematic investigation on the microstructure evolution and displacement variation rule was carried out. In addition, the influence of C/BN molar ratio on the microstructures and performances of cermet was investigated. Except an initially increased pressure, three densification patterns were found. The first method was the Co Ti, Ti Ni, and Ti-BN diffusion reactions, resulting in a shrinkage of 22.06%. The second pattern was the viscous flow and dissolution-reprecipitation, which corresponded to the synthesis of Ti(C,N) and TiB 2 . In this process, the shrinkage ratio was increased by 35.62%. The final densification mainly originated from the viscous flow of metallic binder. It contributed to the transformation of macrovoids into microvoids, and an increased displacement of 30.10%. With the increasing of C/BN ratio, more C atoms diffused into Ti(C,N). Furthermore, core/rim structure-Ti(C,N) and coreless (W,Mo,Ta,Ti)(C,N) were fabricated. However, the microvoids in cermets enhanced. As a result, the hardness and fracture toughness first increased and then decreased. Results from this work are helpful to understand the reaction spark plasma sintering technique, and can enrich the preparation method of cermet.
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BIOSENSORS & BIOELECTRONICS
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2023
·
IF 12.6
Caixia Sun,Xue Zhang,Hao Huang,Ya Liu,Xianwei Mo,Yufei Feng,Jiahong Wang,Wenhua Zhou,Paul K. Chu,Xue-Feng Yu,Wenxin Liu
Nanozymes with enzyme-like characteristics have drawn wide interest but the catalytic activity and substrate selectivity of nanozymes still need improvement. Herein, Se-vacancy-rich TiSe 2-x @Au nanocomposites are designed and demonstrated as nanozymes. The TiSe 2-x @Au nanocomposites show excellent peroxidase-like activity and the chromogenic substrate p-phenylenediamine (PPD) can be selectively oxidized to compounds that exhibit an absorption peak at 413 nm that differs from that of self-oxidation or generally oxidized species, suggesting high catalytic activity and strong substrate selectivity. Theoretical calculations reveal that the PPD adsorption geometry at Se vacancies with an adsorption energy of −3.00 eV shows a unique spatial configuration and charge distribution , thereby inhibiting the free reaction and promoting both the activity and selectivity in PPD oxidation . The TiSe 2-x @Au colorimetric system exhibits a wide linear range of 0.015 mM–0.6 mM and a low detection limit of 0.0037 mM in the detection of glucose. The blood glucose detection performance for human serum samples is comparable to that of a commercial glucose meter in the hospital (relative standard deviation < 6%). Our findings demonstrate a new strategy for rapid and accurate detection of blood glucose and our results provide insights into the future design of nanozymes.
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PubMed
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Materials Today Communications
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2023
·
IF 3.8
Xinwei Geng,Yongfeng Xia,Hanqin Liang,Dongxu Yao,Yu-Ping Zeng
Magnéli phase ceramics have gained extensive attention in a variety of fields, including batteries, electrocatalysis , and wastewater treatment, due to their distinctive properties. In this study, high-performance Magnéli phase Ti 4 O 7 ceramics were synthesized by in-situ hot-pressed sintering of titanium (Ti) and titanium dioxide (TiO 2 ) in a single step. The effects of the sintering temperature and Ti content on the phase transformation and morphology of ceramics were investigated. Moreover, the mechanical properties and electrical conductivity of the samples were systematically characterized. Results show that the sample with the Ti/TiO 2 weight ratio of 0.09 sintered at 1000 °C has impressive comprehensive properties, including a high bulk density of 4.281 g·cm −1 , a mean value of flexural strength of 125.58 MPa, and an excellent conductivity of 1129 S·cm −1 . Furthermore, an evolution mechanism of the in-situ sintering for Ti/TiO 2 was discussed based on the experimental data, and the pattern of variation observed by samples can be reasonably explained.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Sheng Pang,Liangwei Cong,Youpeng Xu,Yiwei Sun,Dong Wang,Guoyu Qian,Zhi Wang
Typically, the X-ray diffraction spectrum of a highly oriented structure (HOS) MAX phase displays a prominent (002) characteristic peak. Surprisingly, this principle does not hold true for Ti 2 SC. Instead, the synthesized Ti 2 SC consistently exhibits a polyhedral structure (PS). Furthermore, even with hot-pressing sintering, the purity of Ti 2 SC remains relatively low. The primary factors contributing to anomalous crystal structures and low purity are insufficient crystal growth and limited reactant contact. In this study, we successfully achieved dual regulation of the crystal structure and purity of Ti 2 SC within the Ti/TiC/FeS 2 system, which was accomplished by enhancing reactant contact and controlling the growth rates of crystal planes. Notably, the intermediate products FeS and Fe, existing in a liquid phase at varying temperatures, played a crucial role in both the formation of Ti 2 SC and the growth of Ti 2 SC crystals. As a result, PS-Ti 2 SC and HOS–Ti 2 SC with purity greater than 99 wt% were successfully prepared. The formation of PS-Ti 2 SC can be attributed to the inadequate growth of each crystal plane at relatively lower temperatures (1500 °C). While the synthesis of HOS–Ti 2 SC necessitates the utilization of both a liquid phase and high temperature, as the epitaxial growth mechanism followed by vertical growth has been demonstrated to facilitate the generation of highly oriented crystals. The liquid phase facilitates the swift growth of Ti 2 SC crystals along the (001) crystal plane, while the (002) crystal plane necessitates a higher temperature (1760 °C) for relatively rapid growth. This work will open a new pathway for the development of the MAX phase from the perspective of crystal structure regulation and high purification preparation.
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Surfaces and Interfaces
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2023
·
IF 6.2
Hongyuan Cui,Lin Yang,Xueqi Fu,Guodong Li,Shu Xing,Xiao-Feng Wang
The simultaneous detection of multiple diabetes markers is important for the diagnosis and typing of diabetes because of the complex causes of diabetes. Two-dimensional titanium carbide (MXene), an emerging material, has great potential for biomedical sensing, in addition to its electrical applications. In this study, a fluorescence resonance energy transfer (FRET) aptasensor with high sensitivity and specificity was constructed using monolayer Ti 3 C 2 MXene for the simultaneous detection of insulin and visceral adipose tissue-derived serotonin (vaspin). Fluorescein-labeled insulin binding aptamers (IBAs) and Cy7-labeled vaspin-binding aptamers (VBAs) were attached to Ti 3 C 2 , and their fluorescence was effectively quenched by FRET between the fluorescein and Ti 3 C 2 . Insulin and vaspin were preferentially bound to IBA and VBA for a higher affinity. This process led to the subsequent shedding of fluorescein from Ti 3 C 2 , resulting in fluorescence recovery. The high fluorescence quenching efficiency and broad wavelength absorption of Ti 3 C 2 MXene enabled the quenching of two different, wide spectrum fluorescence at two different wavelengths, thus enabling the simultaneous detection of both insulin and vaspin. The aptasensor was highly sensitive, with a low detection limit of 36 pM for insulin and 45 pM for vaspin. Importantly, this Ti 3 C 2 -based aptasensor can precisely detect insulin and vaspin in human serum and diagnose a specific type of diabetes and identify its cause to facilitate subsequent treatment. The above results indicate that the Ti 3 C 2 -based aptasensor has promising applications in the clinical diagnosis and typing of diabetes mellitus.
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Crystals
·
2023
·Vol. 14
·期 1
·14
·
IF 2.7
Yufei Zu,Zi Wang,Hongliang Tian,Fan Wu,Lianshen Fu,Jixiang Dai,Jianjun Sha
High-entropy diboride-based (MeB2-based) ceramics are promising high-temperature structural materials because of their excellent mechanical properties, high-temperature stability, and oxidation resistance. In order to achieve low-temperature sintering of the high-entropy ceramics, a novel preparation method of high-entropy (Ti,Zr,Nb,Mo,W)B2-SiC ceramics based on reactive sintering of pre-alloyed solid-solution metals and nonmetals of Si, C, B4C was conducted in the current work. Mechanical alloying behavior of the mixed metal powders, as well as the phase composition, microstructure, mechanical properties, and oxidation behavior of the as-sintered MeB2-SiC ceramic were investigated. The XRD, SEM, and EPMA results indicated that the primary MeB2solid-solution and SiC phases could be successfully formed during reactive sintering at a relatively low temperature of 1650 °C. The as-sintered MeB2-SiC ceramics had a high relative density of 97.8% and high mechanical properties (hardness of 19.74 ± 0.8 GPa, flexure strength of 533 ± 38 MPa, and fracture toughness of 6.01 ± 0.77 MPa·m1/2). Combining the oxidation behavior and microstructure evolution of the oxidation layer, a continuous and relatively dense MeOx-SiO2oxidation layer was gradually formed and covered on the external surface, leading to decelerating oxidation behavior after an oxidation exposure time of 10 min.
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CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xinwei Geng,Yongfeng Xia,Hanqin Liang,Dongxu Yao,Yu-Ping Zeng
Magnéli phases are an important class of transition metal oxides widely utilized in fields such as batteries, electrocatalysis , and photocatalysis . However, there are no reports on the use of Magnéli phases as additives in ceramic sintering. In order to explore the impact of the Magnéli phase as an additive on the sintering process, self-made Magnéli phase Ti 4 O 7 powder was added to the graded mixture of titanium dioxide (TiO 2 ) coarse powder and nanopowder , and sintered under atmospheric conditions in this study. The sintering characteristics, microstructure, and mechanical properties of TiO 2 ceramics with different content of Ti 4 O 7 were characterized. The results revealed that the addition of Ti 4 O 7 contributed to the reduction of the densification temperature of TiO 2 ceramics. Compared to the undoped sample, the addition of 1 wt% Ti 4 O 7 powder significantly improved the flexural strength and Vickers hardness of TiO 2 ceramics by 13.5% and 24.8%. According to the results of thermal analysis, UV–Vis–NIR, and XPS, the mechanism of Ti 4 O 7 in the sintering process of TiO 2 ceramics under atmospheric conditions was systematically discussed. This work not only obtained TiO 2 ceramics with improved performance but also showed the tremendous potential of Magnéli phases in the field of ceramic sintering.
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Science China-Materials
·
2023
·Vol. 67
·期 1
·272-278
·
IF 8.1
Zhang Yajun,Han Meikang,Hu Rongxiang,Zhang Peigen,Pan Long,Sun ZhengMing
Constructing three-dimensional (3D) porous structures is an effective method to improve microwave absorbing performance due to the multiple reflections. However, in traditional 3D porous structures, multiple reflections only occur within the pores. Promoting multiple reflections beyond the pores should further improve the absorbing performance. Herein, a 3D porous composite foam with sandwiched cell walls was developed to boost multiple reflections in both the submillimeter-scale pores and the submicron-scale cell walls, achieving multiscale microwave absorption. Polydopamine (PDA)-modified polyimide foam (PIF) was used as the 3D porous skeleton. The cell walls of the PDA@PIF were sandwiched by Ti 3 C 2 T x MXene. The resulting Ti 3 C 2 T x @PDA@PIF can absorb over 90% of the incident microwave over the whole X band, which is contributed by multiscale multiple reflections, conduction loss, and interfacial polarization. Meanwhile, the composite foam exhibits excellent flexibility and a low density of ∼30 mg cm −3 . This work offers a realistic approach for lightweight, flexible, and broadband microwave absorbers, enriching the structures for effective electromagnetic protection.
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ELECTROCHIMICA ACTA
·
2023
·
IF 6.6
Ubaid Khan,Bowen Gao,Ling Bing Kong,Zhong Chen,Wenxiu Que
The electrochemical properties of carbides and nitrides dominated two dimensional MXenes can be effectively engineered for a wide variety of applications. Herein, we report a hydrothermal Alkali etching process to prepare Ti 3 C 2 T x @Al-NaOH (T x = -OH, -O) MXene without fluorine from Sodium hydroxide (NaOH) and MAX solution. The T i3 C 2 T x @Al-NaOH sample etched for 15 h in NaOH solution exhibits optimal electrochemical properties. Also, the T i3 C 2 T x @Al-NaOH samples, which have NaOH concentrations of 22.5, 25, 30, 35 and 40 M, respectively, show higher rates of charge-discharge and pseudocapacitive effect in 1 M sulfuric acid electrolyte solution, while the corresponding specific capacity values are 378, 445, 565, 365 and 176 Cg −1 , respectively. Meanwhile, their retention rates are still retained at 94 %, 119 %, 150 %, 113 % and 29 %, after continuous cycling of about 8000 times. It is demonstrated that the Ti 3 C 2 T X @Al-NaOH (30 M) for 15 h shows great potential as a candidate electrode for supercapacitors and other energy storage devices, since its capacitance value surpasses (by ∼465 %) to that of the multilayer Ti 3 C 2 T x MXene prepared via normal hydrofluoric acid etching. As a consequence, our Alkali-assisted hydrothermal reaction treatment is a highly advantageous process to realize fine-tune of surface chemistry.
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Energy Technology
·
2023
·Vol. 12
·期 3
·2300736
·
IF 3.8
Peilong Zhou,Xinwei Geng,Dongxu Yao,Yongfeng Xia,Yu-Ping Zeng
Traditional carbon materials suffer from weak adsorption of lithium polysulfides and excessive consumption of electrolyte. A simple and feasible molten salt method is applied for constructing an active nanocrystalline TiC shell on the surface of porous carbon. The highly active TiC nanoshells endow the core–shell composite with efficient chemical–physical synergistic adsorption, which can effectively confine and convert polysulfides, thereby improving the electrochemical performance of lithium–sulfur batteries. The lithium–sulfur batteries assembled with modified separator deliver a high initial discharge specific capacity of 1396 mAh g −1 at a discharge rate of 0.5 C and a high capacity retention of 747.1 mAh g −1 after 500 cycles, with a high coulombic efficiency of 98% during cycling. Besides, this molten salt method can be applied to modify the porous carbon materials of various composite sulfur cathodes such as graphene, carbon nanotubes, and 3D nonwoven carbon fabrics.
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