Journal of Advanced Dielectrics
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2020
·
IF 0
Maomao Ju,Yawei Yang,Jianqiu Zhao,Xingtian Yin,Yutao Wu,Wenxiu Que
Interfacial water evaporation through solar heating with photothermal materials is a promising strategy for seawater desalination and wastewater purification. Tightly packed 2D membranes with high reflection losses and limited vapor escape channels result in a low evaporation rate. In this work, 3D MXene architecture was fabricated by dropping the delaminated Ti 3 C 2 ( d -Ti 3 C 2 ) nanosheets onto the carbonized melamine foam (CMF) framework. Owing to the macroporous 3D architecture, more effective broadband solar absorption and vapor escaping were achieved. As a result, the 3D CMF@ d -Ti 3 C 2 -based evaporator delivers a water evaporation rate of 1.60 kg/m 2 ⋅ h with a solar-to-vapor conversion efficiency of up to 84.6%.
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ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Minglong Yang,Ye Yuan,Ying Li,Xianxian Sun,Shasha Wang,Lei Liang,Yuanhao Ning,Jianjun Li,Weilong Yin,Yibin Li
Assembling Ti3C2Tx MXene nanosheets into three-dimensional (3D) architecture with controllable alignment is of great importance for electromagnetic wave absorption (EMA) application. However, it is a great challenge to realize it due to the weak van der Waals interconnection between MXene nanosheets. Herein, we propose to introduce gelatin molecules as a “chemical glue” to fabricate the 3D Mxene@gelatin (M@G) nanocomposite aerogel using a unidirectional freeze casting method. The Ti3C2Tx MXene nanosheets are well aligned in the M@G nanocomposite aerogel, yielding much enhanced yet anisotropic mechanical properties. Due to the unidirectional aligned microstructure, the M@G nanocomposite aerogel shows significantly anisotropic EMA properties. M@G-45 shows a −59.5 dB minimum reflection loss (RLmin) at 14.04 GHz together with a 6.24 GHz effective absorption bandwidth in the parallel direction (relative to the direction of unidirectional freeze casting). However, in the vertical direction of the same M@G aerogel, RLmin is shifted to a much lower frequency (4.08 GHz) and the effective absorption bandwidth decreases to 0.86 GHz. The anisotropic electromagnetic energy dissipation mechanism was deeply investigated, and the impendence match plays a critical role for electromagnetic wave penetration. Our lightweight M@G nanocomposite aerogel with controllable MXene alignment is very promising in EMA application.
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PubMed
高影响因子
Small
·
2020
·Vol. 16
·期 36
·2002433
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IF 11.459
Shuyi Shen,Tao Ke,Krishnamoorthy Rajavel,Kun Yang,Daohui Lin
The environmental stability of 2D MXene flakes must be systematically studied before their further application. Herein, the colloidal dispersibility and photochemical stability of delaminated Ti 3 C 2 T x MXene flakes modified with hydrazine (HMH) and KOH and with water as the control (HMH-Ti 3 C 2 , KOH-Ti 3 C 2 , and H 2 O-Ti 3 C 2 , respectively) are experimentally and theoretically studied. Modification greatly increases the dispersibility of Ti 3 C 2 T x flakes. Their critical coagulation concentrations are 28.7, 106, and 49.1 m m NaCl, and their Hamaker constants are 23.7 × 10 −21 , 19.1 × 10 −21 , and 37.7 × 10 −21 J, respectively; the colloidal interaction follows the classical Derjaguin–Landau–Verwey–Overbeek theory. HMH-Ti 3 C 2 and KOH-Ti 3 C 2 exhibit higher photochemical stability, as indicated by their stronger resistance to oxidation under UV and visible light irradiation. Changes in their physicochemical properties and the generation of reactive oxygen species (ROS) are assayed. Spin-polarized density functional theory calculations and molecular dynamics simulations are used to determine the mechanisms underlying the differences in the photochemical stability of Ti 3 C 2 T x flakes. K + ions protect the flakes from oxidation by acting as a middle layer to reduce the coupling between Ti 3+ and ROS, while HMH provides stronger protection by absorbing photoelectrons or reacting with ROS. These findings provide new insight into the environmental transformation and design of functional MXenes.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Krishnamoorthy Rajavel,Yougen Hu,Pengli Zhu,Rong Sun,Chingping Wong
The development of smart, structured hybrid materials with superior electrical conductivity are vastly desired for the depletion of unwanted electromagnetic interference (EMI). Herein, novel multilayered two-dimensional MXene/Metal Oxides-Ag ternary hybrid nanostructures with various heterogeneous assemblies were constructed by self-reduction and oxidation of MXene (Nb 2 CT x and Ti 3 C 2 T x ) in the presence of metallic salt (AgNO 3 ), and its EMI shielding performance in X- and K u -band are demonstrated. The effect of different silver nitrate addition into MXene on their structural evaluation reveals that the successful formation of MXene/Metal Oxides-Ag (Nb 2 CT x /Nb 2 O 5 -Ag; Ti 3 C 2 T x /TiO 2 -Ag) ternary hybrid nanostructures derived from MXene (Nb 2 CT x ; Ti 3 C 2 T x ). Remarkably, the Nb 2 CT x /Nb 2 O 5 -Ag hybrid assembly attains reflection dominated shielding performance with a maximum total shielding effectiveness of 68.76 dB and 72.04 dB in the X- and K u -band region respectively at a thickness of 1 mm compared to other nanostructures. The large enhancement in electromagnetic shielding capability of ternary nanostructure attributed to the strong electrical conductivity and increased interface polarization and multiple reflection loss between the ternary interfaces. The synergistic effect of metallic silver nanoparticles, semiconducting metal oxides and conducting stacked multilayer causes to conduction loss, polarization effect (dipole, and interfacial polarization), and multiple reflections of incoming radiation favor the complete dissipation of EM waves. Consequently, the demonstrated simple, cost-effective, and large scale production of highly conductive composites could pave for the potential prospect materials in advanced EM wave shielding applications.
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高影响因子
TRIBOLOGY INTERNATIONAL
·
2021
·
IF 4.872
Dongmei He,Meng Cai,Han Yan,Qilan Lin,Xiaoqiang Fan,Lin Zhang,Minhao Zhu
Multiple advantages of Ti 3 C 2 T x MXene are of significance to enhance the mechanical properties of organic coating . Herein, few-layer amino-functionalized Ti 3 C 2 T x nanosheets (k-Ti 3 C 2 ) were introduced into interpenetrating polymers network (IPN) for constructing k-Ti 3 C 2 /IPN composite coatings , and their tribological properties were investigated in depth. The composite coating with 0.75 wt% k-Ti 3 C 2 nanosheets displays excellent tribological behaviors under extremely operating conditions, like the lowest COF (0.18) and the highest OCP value (−0.28 V) under tribocorrosion condition. Such excellent tribological properties mainly depend on good dispersion and interfacial compatibility of k-Ti 3 C 2 nanosheets in IPN matrix, as well as amino functionalized Ti 3 C 2 T x nanosheets as barrier to external damage. This work highlights a pathway to solve the wear/corrosion problem of organic coatings under extreme conditions.
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高影响因子
ACS Omega
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2021
·
IF 3.512
Wanxin Peng,Ran Hu,Weijiao Jiang,Jian Kang,Jingping Li,Ya Cao,Ming Xiang
MXenes, a family of two-dimensional transition-metal carbides/nitrides, have attracted great attention and shown promising application in polymer composites. In this study, a typical MXene Ti3C2Tx was prepared by selective etching. The structure and morphology of Ti3C2Tx were studied by X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy, and the results proved that Ti3C2Tx was successively fabricated. Then, Ti3C2Tx/isotactic polypropylene composites with different Ti3C2Tx dosages were fabricated, and the nonisothermal crystallization kinetics and melting behavior of the composites were investigated. The results indicated that when a small amount of Ti3C2Tx was added, the crystallization parameters including the crystallization peak temperature and the crystallization rate increased, suggesting that crystallization was promoted. When the weight percentage of Ti3C2Tx exceeded 1%, the crystallization parameters showed a reverse trend, suggesting that crystallization was hindered. The activation energy of composites with 0, 0.25, 0.5, and 1 wt % Ti3C2Tx were calculated to be −164.5, −196.5, −193.8, and −147.95 kJ/mol, respectively, revealing that the crystallization of composites is concentration-dependent. The impact of Ti3C2Tx dosage on the crystalline structure of the composites was studied using XRD. The related mechanism was proposed.
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高影响因子
Surfaces and Interfaces
·
2021
·
IF 4.837
Chenya Ruan,Dongdong Zhu,Jiqiu Qi,Qingkun Meng,Fuxiang Wei,Yaojian Ren,Yanwei Sui,Hao Zhang
Bimetallic transition metal sulfides (TMSs) and MXene are the two kinds of promising candidates as electrode materials for supercapacitors based on different storage mechanisms. However, little work has been performed on their composites. In this paper, Ti 3 C 2 MXene-wrapped CoNi 2 S 4 nanotrees were synthesized controllably using flake ZIF-67 as precursor grown on nickel foam, which was transformed into dendrite CoNi 2 S 4 dendrite in MXene suspension (weak acidic environment). The formation mechanism of CoNi 2 S 4 dendrite was discussed. Ti 3 C 2 MXene-wrapped CoNi 2 S 4 nanotrees delivered very high specific capacity of 933 C g −1 at 1 A g −1 and good rate performance. This is due to that the unique dendrite morphology can provide many exposed electro-active sites and wrapped conductive MXene can facilitate the charge transfer. An asymmetric supercapacitor was assembled using CoNi 2 S 4 /MXene/NF and RGO as positive and negative electrodes, which delivered a high energy density of 30.5 Wh kg −1 without deteriorating its high power density (1587 W kg −1 ). This device can power the clock for 55 minutes, demonstrating its broad practical application potential.
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高影响因子
JOURNAL OF MATERIALS SCIENCE
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2019
·Vol. 55
·期 3
·1148-1156
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IF 3.442
Chen He,Yu Lanyong,Lin Zifeng,Zhu Qizhen,Zhang Peng,Qiao Ning,Xu Bin
MXenes are 2D transition metal carbides or nitrides with high electrical conductivity that have attracted great attention as promising electrode materials that supersede carbon-based material designed for supercapacitors. However, the aggregation and self-restacking of MXene 2D nanosheets limit their high-rate performance. In this work, flexible and conductive Ti 3 C 2 T x MXene/carbon nanotubes (CNTs) composite film was prepared through a simple vacuum filtration of the Ti 3 C 2 T x MXene and CNTs suspension mixture. The CNTs integrated MXene nanosheets can effectively prevent the restacking while creating fast ion transport channels for enhanced capacitance. The designed films exhibit excellent performance as supercapacitor electrodes with high capacitance of 300 F g −1 at 1 A g −1 with superior rate performance of 199 F g −1 even at 500 A g −1 , together with excellent cyclic stability of 92% capacitance retention after 10000 cycles at 20 A g −1 . The excellent workability demonstrates potential application of the system for flexible, portable and highly integrated supercapacitors.
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高影响因子
Journal of Materials Chemistry A
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2019
·Vol. 7
·期 10
·5635-5642
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IF 10.733
Lin Yang,Yohan Dall'Agnese,Kanit Hantanasirisakul,Christopher E. Shuck,Kathleen Maleski,Mohamed Alhabeb,Gang Chen,Yu Gao,Yoshitaka Sanehira,Ajay Kumar Jena,Liang Shen,Chunxiang Dall'Agnese,Xiao-Feng Wang,Yury Gogotsi,Tsutomu Miyasaka
MXenes, a class of two-dimensional (2D) transition metal carbides and nitrides, have a wide range of potential applications due to their unique electronic, optical, plasmonic, and other properties. Herein, we explore the use of the Ti3C2 MXene in organic–inorganic lead halide perovskite solar cells (PSCs). SnO2–Ti3C2 MXene nanocomposites with different contents of Ti3C2 (0, 0.5, 1.0, 2.0, and 2.5 wt‰) were used as electron transport layers (ETLs) in low-temperature processed planar-structured PSCs. Mixing SnO2 with 1.0 wt‰ Ti3C2 effectively increases the power conversion efficiency (PCE) from 17.23% to 18.34%, whereas the device prepared with pristine Ti3C2 as the ETL achieves a PCE of 5.28%. Photoluminescence and electrochemical impedance spectroscopy results reveal that metallic Ti3C2 MXene nanosheets provide superior charge transfer paths, enhancing electron extraction, electron mobility, and decreasing the electron transfer resistance at the ETL/perovskite interface, and thus leading to higher photocurrents. This work proposes a new field of application for MXenes and a promising method to increase the efficiency of solar cells.
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高影响因子
ChemSusChem
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2019
·Vol. 12
·期 7
·1368-1373
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IF 7.804
Yanan Jiang,Tao Sun,Xi Xie,Wei Jiang,Jia Li,Bingbing Tian,Chenliang Su
Graphical S‘O’ much win with MXene : A facile method is reported to produce ultrathin Ti 3 C 2 MXene functionalized with oxygen as an electrocatalyst for the hydrogen evolution reaction. The terminal O on the basal plane increases the number of active sites for electrocatalysis. This combined with the high surface area and conductivity enables the O-functionalized MXene to show enhanced electrocatalytic performance for hydrogen evolution. Two-dimensional (2D) transition-metal carbides (MXenes) are widely adopted as potential electrocatalysts for the hydrogen evolution reaction (HER) owing to their metallic conductivity, rich tunable surface chemistry, and atomic thickness with highly exposed active sites. Previously published theoretical results indicate that MXenes functionalized entirely with oxygen have lower Δ G H* for HER. However, MXenes contain many terminal F groups on the basal plane, which is detrimental to the HER. Herein, the development of an ultrathin Ti 3 C 2 MXene nanosheet fully functionalized with oxygen is reported for the HER. The obtained oxygen-functionalized Ti 3 C 2 (Ti 3 C 2 O x ) exhibits a much higher HER activity (190 mV at 10 mA cm −2 ) than that of Ti 3 C 2 T x (T=F, OH, and O). The improved HER performance is attributed to the highly active O sites on the basal plane of Ti 3 C 2 T x MXenes. This study paves way for electrocatalytic applications of MXene materials by tuning their surface functional groups.
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高影响因子
InfoMat
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2019
·Vol. 1
·期 3
·407-416
·
IF 0
Lianjia Zhao,Kang Wang,Wei Wei,Lili Wang,Wei Han
Highly active two-dimensional (2D) nanocomposites, integrating the unique merits of individual components and synergistic effects of composites, are greatly desired for flexible sensing device applications. Although 2D transition metal carbides and nitrides (MXenes) combined with their high metallic conductivity and versatile surface chemistry have shown its huge potential for sensing reactions, it still remains a major challenge to construct functional materials with intriguing sensing performance at room temperature (RT). Herein, we used an integration of density functional theory (DFT) simulations and bulk electrosensitive measurements to show high electrocatalytic sensitivity of polyaniline/MXene (PANI/Ti 3 C 2 T x ) nanocomposites. Thanks to the synergistic properties of nanocomposites and high catalytic/absorption capacity of Ti 3 C 2 T x MXene, PANI nanoparticles are rationally decorated on Ti 3 C 2 T x nanosheet surface via in situ polymerization by low temperature approach to induce remarkable detection sensitivity, rapid response/recovery rate, and mechanical stability at RT. This study offers a versatile platform to use MXenes to fabricate 2D nanocomposites materials for high-performance flexible gas sensors.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
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2019
·
IF 6.019
Pengcheng Lin,Jiajin Xie,Yingdong He,Xiang Lu,Weijie Li,Jun Fang,Shouhuan Yan,Li Zhang,Xinxin Sheng,Ying Chen
Two-dimensional transition-metal carbides/carbonitrides (MXenes) have demonstrated wide application prospect in energy conversion and storage , mostly in the form of electrochemical energy storage . Compared with the conversion between chemical energy and electrical energy, an energy conversion process initiated by solar energy and driven by the physical change of energy materials will be a sustainable and environmentally friendly strategy. Therefore, a high-performance MXene aerogel-based phase change material for solar energy conversion and thermal energy storage is constructed. MXene nanosheets with an extinction coefficient of 25.67 L/(g.cm) at 808 nm demonstrate excellent light absorption performance , which can spontaneously convert the solar energy into thermal energy . The polyethylene glycol (PEG) possessing high affinity with MXene acts the medium for thermal energy storage and release in the process of fusion and solidification. The MXene@PEG aerogels are lightweight, with a density about 30 mg/cm 3 . The MXene skeleton is introduced as supporting materials to keep the shape of MXene@PEG aerogel stable during the phase change process . The MXene nanosheets improve the thermal stability of PEG, the thermal decomposition temperatures can be increased by 40 °C. The actual fusion and solidification enthalpies of MXene@PEG aerogels can reach 167.72 and 141.51 J/g, respectively. The photothermal storage efficiency of MXene@PEG aerogels reaches a relatively high value of 92.5%. This work provides a new type of scaffold for lightweight and shape-stable photothermal carrier and paves the way for the application of non-graphene 2D materials toward solar energy utilization.
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高影响因子
危险品化学品经营许可证（带存储）