查找使用阿拉丁产品的科研文献

Lubrication performance of MXene/Brij30/H2O composite lamellar liquid crystal system

Chao Song,Tong Wang,Xiaohuan Sun,Yimin Hu,Lei Fan,Rong Guo

The lamellar liquid crystal (LLCS) system constructed by surfactant aggregation was demonstrated to exhibit superior tribological properties due to its unique lamellar structure and creep recovery properties. However, the lubrication performance of this kind of liquid crystal system was greatly hindered by its soft nature. Emerging as two-dimensional material, MXene has been promising candidate in tribology on account of its unique layer structure and versatile composition . Taking account of the above fact, herein, nonionic surfactant polyoxyethylene lauryl ether (Brij30), MXene (Ti 3 C 2 T x ), and H 2 O were employed to construct a triple-component composite LLCS system and the related tribological properties were systematically investigated. The results demonstrated that the lubrication performance of the liquid crystal system formed in the presence of Ti 3 C 2 T x was significantly improved compared with that of Brij30/H 2 O LLCS. The average friction coefficient of the composite LLCS system was in the range of 0.1155–0.1266, and the best lubrication performance was achieved when the Ti 3 C 2 T x content was kept as 6 mg/mL. MXene is also able to achieve good dispersion in liquid crystal systems. The enhanced lubrication performance of the composite LLCS system was mainly due to the synergistic effect of MXene nanosheets and LLCS. In addition, the iron oxides generated by the reaction during the friction process also promote lubrication. It is believed that the current work provides an alternative method for the development of MXene/LLCS-lubricating materials.

Preparation of TiO2 Supported Mxene Catalyst for High Efficiency Hydrogen Production

Hu Mei,Xin Jin,Liu Zhenyu,Zeng Hui,Wang Yanze

We studied a method to prepare a novel titanium dioxide (TiO 2 ) composite photocatalyst, starting from improving the separation efficiency of photogenerated electrons and holes. Regular TiO 2 microspheres were prepared by sol-gel method and loaded onto Ti 3 C 2 T x (Mxene). The high electrical conductivity of Mxene was utilized to transfer photogenerated electrons quickly and effectively prevent their recombination. By adjusting the addition amount of Mxene, the hydrogen production efficiency of the sample was greatly improved, and the maximum efficiency reached 135.2 µmol·g −1 ·h −1 , which was twice that of pure TiO 2 . The nanocomposites were characterized by XRD, PL, TEM and SEM analysis and electrochemical methods, and the test proved that the improvement of hydrogen production efficiency was caused by the improvement of the separation efficiency of photogenerated electrons and holes. This work demonstrates the application of Mxene as a catalyst to improve efficiency and broadens the application prospects of Mxene.

Aqueous MXene inks for inkjet-printing microsupercapacitors with ultrahigh energy densities

Guixin Wang,Rui Zhang,Hongqiong Zhang,Kui Cheng

Although inkjet-printing technology has achieved significant development in preparing scalable and adaptable energy storage devices for portable and micro devices, searching for additive-free and environmentally friendly aqueous inks is a significant challenge. Hence, an aqueous MXene/sodium alginate-Fe 2+ hybrid ink (denoted as MXene/SA-Fe) with solution processability and suitable viscosity is prepared for direct inkjet printing microsupercapacitors (MSCs). The SA molecules are adsorbed on the surface of MXene nanosheets to construct three-dimensional (3D) structures, thus effectively alleviating the two notorious problems of oxidation and self-restacking of MXene. Concurrently, Fe 2+ ions can compress the ineffective macropore volume and make the 3D structure more compact. Moreover, the hydrogen and covalent bonding formed between the MXene nanosheet, SA, and Fe 2+ effectively protects the oxidation of MXene and thus increases its stability. Thus, the MXene/SA-Fe ink endows the inkjet-printed MSC electrode with abundant active sites for ion storage and a highly conductive network for electron transfer . As a demonstration, the MXene/SA-Fe ink is used to direct inkjet-printed MSCs with an electrode spacing of 310 μm, which exhibit remarkable capacitances of 123.8 mF cm −2 (@5 mV s −1 ), good rate capability, an extraordinary energy density of 8.44 μWh cm −2 at a power density of 33.70 μW cm −2 , long-term cycling stability of 91.4 % capacitance retention after 10,000 cycles, and surprising mechanical durability with 90.0 % of its initial capacitance retained after 10,000 bending cycles. Therefore, MXene/SA-Fe inks are expected to create various opportunities for printable electronics.

Developing a MXene quantum dot-based separator for Li–S batteries

Ke Yang,Chan Li,Haoyuan Qi,Yunfei Dai,Yuhong Cui,Yibo He

The shuttle effect of polysulfides seriously hinders the practical application of lithium–sulfur (Li–S) batteries, and separator modification is supposed to be an effective way to solve this issue. Herein, MXene quantum dots (MQDs) were self-assembled on the surface of g-C3N4 sheets (g-C3N4@MQDs) by electrostatic adsorption principles to construct a functional layer on a Celgard separator. Making MXene into quantum dots was conducive to solving the agglomeration issue of its sheets, providing more active sites to capture the dissolved polysulfides. Moreover, the MQDs could also work as an electrocatalyst to further facilitate the Li2S catalytic conversion, obtaining a high deposition current and capacity (257.4 mA h g−1). Attributed to the regulation effect of MQDs toward the kinetic behavior of polysulfides, the shuttle effect was effectively mitigated. An as-fabricated Li–S battery with a heterostructured g-C3N4@MQD-based separator achieved a high specific capacity of 1433 mA h g−1 at 0.1 C, excellent rate performance (532 mA h g−1 at 4 C), and good cycling performance (0.024% capacity fading per cycle after 1000 cycles at 2 C). The rational design of the g-C3N4@MQD-based separator not only broadens the application of MQDs, but also presents new insights to develop high-performance Li–S batteries.

MXene-supported copper-molybdenum sulfide nanostructures as catalysts for hydrogen evolution

Wu Jiajin,Jiamin Zhou,Feng Zhu,Hongyong Wang,Gang Xu

The development of efficient and low-cost sustainable electrocatalytic hydrogen precipitation materials is an effective way to support the reduction of fossil fuel use. In recent years, in order to overcome the problem of the poor electrical conductivity of transition metal chalcogenides (TMCs), carbon-based materials and the MXene family have become popular TMC carriers. In this work, Cu2MoS4/Ti3C2Tx-30% materials with a special structure were synthesized for the first time via a simple and friendly solvothermal method. We successfully grew Cu2MoS4in situ on a MXene (Ti3C2Tx) via solvent heating, and Cu2MoS4/Ti3C2Tx-30% was bonded together by electrostatic adsorption to form a special structure. Its overpotential is 103 mV lower than that of pure Cu2MoS4 at a current density of 10 mA cm−2 in an acidic medium (0.5 M H2SO4). At the same time, under the same conditions, the Tafel slope is 37 mV dec−1 lower than that of pure Cu2MoS4. Critically, the heterostructure retains high catalytic activity within 20 h. All of this is attributed to the special structure of Cu2MoS4/Ti3C2Tx-30%, resulting in increased conductivity, electrochemically active surface area (ECSA), and stability. This provides new ideas for future discoveries relating to the synthesis of non-precious transition metal two-dimensional composites.

MXene hybrid polyvinyl alcohol flexible composite films for electromagnetic interference shielding

Yuanyuan Yao,Shaohua Jin,Manman Wang,Feng Gao,Bolin Xu,Xijuan Lv,Qinghai Shu

The light weight and high integration of modern electronic equipment put forward higher and higher requirements for electromagnetic interference (EMI) shielding films. Herein, a structure of ternary MXene/graphene@Fe 3 O 4 /PVA (polyvinyl alcohol) films with high flexibility and good EMI shielding performance were prepared by simple casting method, the resulting fillers showed good compatibility with the PVA matrix. Surprisingly, the EMI SE of the resulting film with a thickness of only 1 mm reached 36 dB in X band, especially since it exhibited a shielding dominated by the absorption of electromagnetic waves (SE A was 32 dB). The obtained PVA composite films displayed classic ductile fracture characteristics, and the elongation at break was greater than 160%. Conductive MXene and graphene promoted the dielectric loss of electromagnetic waves, while magnetic Fe 3 O 4 particles were beneficial to the magnetic loss of electromagnetic waves. Furthermore, the layered ternary MXene/graphene@Fe 3 O 4 structure enhanced the multiple reflection and attenuation of electromagnetic waves inside the composites, which reinforced PVA films very promising as thinner and lighter EMI shielding materials in the field of flexible electronics.

Nanochitin/MXene Composite Coated on Quartz Crystal Microbalance for Humidity Sensing

Yanqi Li,Xianhe Huang,Qiao Chen,Yao Yao,Wei Pan

MXenes, as a typical graphene-like material, excels in the realm of humidity sensing owing to its two-dimensional layer structure, high electrical conductivity, tunable chemical properties, hydrophilicity, and large specific surface area. This study proposed a quartz crystal microbalance (QCM) humidity sensor using a nanochitin/Ti3C2TxMXene composite as a humidity-sensing material. The morphology, nanostructure, and elemental composition of nanochitin, Ti3C2TxMXene, and nanochitin/Ti3C2TxMXene composite materials were characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. Compared to the pure Ti3C2TxMXene-coated QCM humidity sensor, the nanochitin/Ti3C2TxMXene-coated QCM humidity sensor exhibited a higher sensitivity (20.54 Hz/%RH) in the humidity range of 11.3% to 97.3%. The nanochitin/Ti3C2TxMxene-coated QCM humidity sensor also demonstrated low humidity hysteresis (2.12%RH), very fast response/recovery times (4.4/4.1 s), a high quality factor (37 k), and excellent repeatability and sustained stability over time. Eventually, a bimodal exponential kinetics adsorption model was utilized for the analysis of the response mechanism of the nanochitin/Ti3C2TxMXene composite material-based QCM humidity sensor. This study provides new ideas for optimizing the moisture-sensitive performance of MXene-based QCM humidity sensors.Keywords:humidity sensor;quartz crystal microbalance (QCM);nanochitin;Ti3C2TxMXene;high quality factor

Functionalization of expanded MXene to recover palladium ions by capacitive deionization

Jiming Lu,Shuangzhe Zhang,Chuan Zhou,Xinyang Wang,Binda Lu,Yi Liu,Yingzhi Li,Timothy N. Hunter,Zhouguang Lu,Lei Li,David Harbottle,Zhenghe Xu

This work prepared a sulfur/nitrogen co-doped MXene (S/N-MXene) electrode material via a facile hydrothermal method. The electrode material has been specifically designed to recover palladium(II) from wastewater. Numerous S/N-containing functional groups were introduced into the MXene by S and N co-doping, with the contents optimized for the preferential recovery of Pd(II). These functional groups acted as pillars to expand the interlayer spacing of MXene, facilitating Pd 2+ diffusion between MXene layers and enhancing accessibility to the anchor sites (–OH groups and heteroatom functional groups). The S/N-MXene electrode exhibited a high recovery capacity of 2.92 mmol g −1 , high recovery efficiency of 96.4 % in 15 min and good long-term cycling performance with greater than 80 % capacity retained after 260 cycles. The S/N-MXene electrode showed preferential adsorption of Pd 2+ from wastewater. The adsorption mechanism was elucidated through density functional theory (DFT) calculations showing that the downward shift of the p -band center of the MXene-OH groups induced by pyrrolic-N and -C=S in S/N-MXene (compared to single doping with S or N) favours enhancement of the soft ion-soft ion interactions. Furthermore, the adsorbed Pd 2+ on the S/N-MXene electrode could be enriched by simple reversing of the applied voltage to strip the ions from the sorbent, thus avoiding the need to use harsh chemicals for regeneration and minimizing the amount of secondary waste.

Flexible electrochemical glucose sensor based on PtNPs modified MXene/SF membrane

Yasi Wang,Yi Wang,Jingyuan Deng,Hongjia Liu,Yan Ma,Zhi Li,Tonghua Zhang

3D flower-like hollow MXene@MoS2 heterostructure for fast sodium storage

Kaihang She,Ying Huang,Wanqing Fan,Meng Yu,Jiaxin Zhang,Chen Chen

Constructing an anode with fast electron transport and high cycling stability is important but challenging for large-scale applications of sodium-ion batteries (SIB). In this study, hierarchical flower-like MXene structures were synthesized using poly (methyl methacrylate) (PMMA) microsphere as templates. Subsequently, a straightforward hydrothermal reaction was utilized to anchor small-sized MoS 2 nanosheets . The resulting MXene@MoS 2 heterostructure exhibits a distinctive three-dimensional (3D) porous hollow architecture. This structure effectively addresses challenges related to self-aggregation of MoS 2 nanosheets and volume expansion of the electrode material during Na + insertion/extraction processes. Furthermore, the robust hetero-interface supports fast and stable electron transfer, thereby enhancing electrochemical reaction kinetics. The prepared MXene@MoS 2 electrode demonstrates the specific capacity of 682.1 mA h g −1 at 0.2 A/g and the reversible capacity of 494.4 mA h g −1 after 1000 cycles at 5 A/g. It is noteworthy that the full battery assembled with the composite material as the anode can still maintain the capacity of 456.2 mA h g −1 after 80 cycles at 0.5 A/g. This outstanding reversible capacity and sustained stability over numerous cycles highlights its potential for a wide range of applications.

Flexible TiVCTx MXene film for high-performance magnesium-ion storage device

Yuming Zhang,Dongdong Li,Junzhi Li,Yilin Li,Lili Wang,Hao Xu,Wei Han

Magnesium-based battery system has emerged as the potential candidate to beyond Li-ion battery system due to the numerous advantageous of magnesium anode, such as natural abundance, high capacity and dendrites free. However, the selection of cathode materials and the intercalation of magnesium-ions in the cathode host material remains a challenge due to the strong interaction of highly polar divalent magnesium ions with the cathode material, making the diffusion of magnesium ions relatively difficult. Herein, the flexible TiVCT x MXene film was developed via a facile and economical approach. As the cathode host material for magnesium-ion storage, the freestanding TiVCT x MXene film displays a high specific capacity of 111 and 135 mAh g −1 at a current density of 0.05 A g −1 for magnesium-ion batteries (MIB) and Mg/Li hybrid batteries (MLHB). Furthermore, a long-term cycling stability over 1000 cycles was demonstrated and a detailed investigation of the unique long activation phenomenon of MXene films during cycling. More importantly, the reaction mechanism of magnesium-ion storage was validated, i.e., the MXene interlayer spacing variation with the reversible Mg 2+ diffusion behavior. This work reveals the magnesium storage mechanism of MXene materials and provides a new pathway for high-performance storage of magnesium-ion cathode materials.

Polycation-Intercalated MXene Membrane with Enhanced Permselective and Anti-Microbial Properties

Jie Yang,Shilin Zhu,Hongli Zhang

Two-dimensional (2D) nanomaterial-based membranes feature attractive properties for molecular separation and transport, which exhibit huge potential in various chemical processes. However, the low permeability and bio-fouling of the MXene membrane in water treatment become huge obstacles to its practical application. Herein, a highly permselective and anti-bacterial 2D nanofiltration membrane is fabricated by intercalating a polycation of polydiallyldimethylammonium chloride (PDDA) into the Ti3C2TxMXene laminar architecture through a facile and patternable electrostatic assembly strategy. As a result, the as-fabricated Ti3C2Tx/PDDA composite membrane exhibits higher water permeance up to 73.4 L m−2h−1with a rejection above 94.6% for MgCl2. The resultant membrane simultaneously possesses good resistance to swelling and long-term stability in water environments, even after 8 h. Additionally, the Ti3C2Tx/PDDA membrane also demonstrates a high flux recovery ratio of nearly 96.1% to bovine serum albumin proteins after being cleaned. More importantly, the current membrane shows excellent anti-adhesive and anti-microbial activity against Gram-negativeEscherichia coli(E. coli) and Gram-positiveStaphylococcus aureus(S. aureus), with inhibition rates of 90% and 95% againstE. coliandS. aureus, respectively. This holds great potential for the application of the polyelectrolyte-intercalated MXene membrane in serving as a promising platform to separate molecules and/or ions in an aquatic environment.Keywords:Ti3C2Tx;MXene membrane;nanofiltration;two-dimensional membrane;anti-biofouling;PDDA