查找使用阿拉丁产品的科研文献

Intrinsic voltage plateau of a Nb2CTx MXene cathode in an aqueous electrolyte induced by high-voltage scanning

Xinliang Li,Xinyao Ma,Yue Hou,Zhenhua Zhang,Yue Lu,Zhaodong Huang,Guojin Liang,Mian Li,Qi Yang,Jiale Ma,Na Li,Binbin Dong,Qing Huang,Furong Chen,Jun Fan,Chunyi Zhi

Although MXene has been widely used in many energy storage systems, the absence of a high intrinsic voltage plateau results in its poor discharging feature. Herein, we report a Nb 2 CTx MXene cathode with an apparent discharge voltage plateau for high-performance aqueous zinc ion batteries. Triggered by a repeated high-voltage scanning up to 2.4 V, the Nb 2 CTx cathode gradually displays a stable Zn 2+ storage dominated by a battery behavior. A high discharge voltage plateau of 1.55 V is presented, which is distinct from all reported MXene electrodes. Consequently, a record-level energy density among all aqueous MXenes electrodes of 146.7 Wh kg −1 with a 63% contribution from the plateau region is obtained, which is 292% that of the capacitive Nb 2 CTx electrode. The developed high-voltage scanning strategy is also effective for Ti 3 C 2 T x MXene to achieve a remarkable voltage plateau.

Additive-Free Anode with High Stability: Nb2CTx MXene Prepared by HCl-LiF Hydrothermal Etching for Lithium-Ion Batteries

Xiaoxue Zhu,Kai Yang,Zhen Zhang,Siyuan He,Zihao Shen,Wei Jiang,Yiling Huang,Yan Xu,Qiutong Jiang,Limei Pan,Qian Li,Jian Yang

MXenes, represented by Ti3C2Tx, have been widely studied in the electrochemical energy storage fields, including lithium-ion batteries, for their unique two-dimensional structure, tunable surface chemistry, and excellent electrical conductivity. Recently, Nb2CTx, as a new type of MXene, has attracted more and more attention due to its high theoretical specific capacity of 542 mAh g–1. However, the preparation of few-layer Nb2CTx nanosheets with high-quality remains a challenge, which limits their research and application. In this work, high-quality few-layer Nb2CTx nanosheets with a large lateral size and a high conductivity of up to 500 S cm–1 were prepared by a simple HCl-LiF hydrothermal etching method, which is 2 orders of magnitude higher than that of previously reported Nb2CTx. Furthermore, from its aqueous ink, the viscosity-tunable organic few-layer Nb2CTx ink was prepared by HCl-induced flocculation and N-methyl-2-pyrrolidone treatment. When using the organic few-layer Nb2CTx ink as an additive-free anode of lithium-ion batteries, it showed excellent cycling performance with a reversible specific capacity of 524.0 mAh g–1 after 500 cycles at 0.5 A g–1 and 444.0 mAh g–1 after 5000 cycles at 1 A g–1. For rate performance, a specific capacity of 159.8 mAh g–1 was obtained at a high current density of 5 A g–1, and an excellent capacity retention rate of about 95.65% was achieved when the current density returned to 0.5 A g–1. This work presents a simple and scalable process for the preparation of high-quality Nb2CTx and its aqueous/organic ink, which demonstrates important application potential as electrodes for electrochemical energy storage devices.

Submicromolar electrochemical sensing platform for fast Fluoxetine quantification based on Nb2CTx MXene and nitrogen-doped graphene oxide nanocomposites

Aiting Chen,Yanping Wei,Du Tuo,Chuanqin Zhou,Shuting Shi,Nana Tang,Quanguo He,Jun Liu

A facile and novel electrochemical determination of Fluoxetine (FLX) at submicromolar concentration Niobium carbide (Nb 2 CT x ) and Nitrogen-doped Reduced Graphene Oxide (NRGO) hybridized electrodes as sensing platform is demonstrated. Herein, Niobium carbide (Nb 2 CT x ) was successfully prepared by etching Nb 2 AlC and then ultrasonically compounded with Nitrogen-doped Reduced Graphene Oxide (NRGO), to form a well-dispersed Nb 2 CT x /NRGO composite, which was modified onto a glassy carbon electrode (GCE). The morphology, structure and electrochemical property of the Nb 2 CT x /NRGO/GCE was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The electrocatalytic activity of the Nb 2 CT x /NRGO/GCE for FLX oxidation was studied in detail. The peak currents showed two good linear relationships (R 2 = 0.9962 and 0.9949) with FLX concentrations (1.0–10 µM and 10–100 µM) and a detection limit of 0.34 µM (S/N = 3). The sensor has good selectivity, repeatability, reproducibility and stability, and is capable of sensitively determining FLX in human serum and urine samples of clinical biological fluids. This work is believed to be of great significance and of broad interest for research on innovative MXene materials development and biomedical sensing applications.

Nb2CTx MXene Integrated Tapered Microfiber Based on Light-Controlled Light for Ultra-Sensitive and Wide-Range Hemoglobin Detection

Wenjie Li,Yinping Miao,Yibo Zheng,Kailiang Zhang,Jianquan Yao

Investigation on the structural quality dependent electromagnetic interference shielding performance of few-layer and lamellar Nb2CTx MXene nanostructures

Krishnamoorthy Rajavel,Xuecheng Yu,Pengli Zhu,Yougen Hu,Rong Sun,Chingping Wong

Tunable Electromagnetic Interference (EMI) shielding behaviors of 2D MXene (Nb 2 CT x ) were explored via different exfoliation conditions. Stacked, lamellar few-layer, oxygen-related surface functional groups, and structural defects along with oxidative products of Nb 2 CT x were identified by tuning chemical etching conditions during one-step exfoliation process. Exfoliation of Nb 2 CT x with a tightly packed stacked structure remarked at lower etching times. The unpacking of Nb 2 CT x into lamellar morphology followed by separated few-layer Nb 2 CT x remarked at moderate etching time, whereas structural misalignment, defects, and oxidation of Nb 2 CT x occurred during prolonged chemical etching times. Synergistic effect of one-step extracted few-layers and lamellar structured Nb 2 CT x favorably enrich the assembly of multiple electrical conductive pathways responsible for absorption dominated EMI shielding performance in X- and Ku-band region. The assembled wax nanocomposites with 80% of Nb 2 CT x loading exfoliated at 100 h etching time at a thickness of 1 mm exhibited EMI shielding effectiveness of about 44.09 ± 1.99 dB at 12 GHz, and its EMI attenuation mechanism explained by conduction and eddy current loss. The combined action of few-layer and lamellar Nb 2 CT x nanostructures could be interesting for making novel shielding materials; open a new avenue for niobium series in the MXene family for elaborated applications.

An efficient peroxymonosulfate activation by Nb2CTx-MXene mediated with CQDs composite catalyst for carbamazepine degradation: Kinetics and mechanistic insights

Muhammad Adnan,Zhenhua Zhao,Liling Xia,Ghulam Abbas Ashraf,Arslan Tauqeer,Muhammad Usman,Saqib Bashir,Thamer Alomayri,Akmal Abilkasimov

Nb2CTx-MXene with CQDs-modified catalyst was rationally designed and synthesized. • The composite exhibited highly efficient PMS activation for CBZ degradation. • Synergistic radical and non-radical oxidation pathways were experimentally validated. • Identifying key active sites and the degradation pathways improved understanding of Nb2CTx@CQDs catalytic performance. Persistent organic pollutants present long-term risks to aquatic ecosystems, calling for oxidation processes with well-defined activation mechanisms. In this work, an Nb 2 CTx- MXene composite decorated with ginger-derived carbon quantum dots (Nb 2 CTx@CQDs) was constructed to investigate interfacial peroxymonosulfate (PMS) activation for carbamazepine (CBZ) degradation in water. The surface chemistry, textural properties, and electronic features of the composite were systematically characterized. The Nb 2 CTx@CQDs(5 wt.%)/PMS system achieved 94.7 % CBZ removal within 50 min, corresponding to a pseudo-first-order rate constant k of 0.0598 min -1 under optimized conditions. Density functional theory calculations, together with Liquid chromatography-mass spectrometry (LC-MS) analysis, revealed the evolution of key intermediates and supported a stepwise CBZ degradation pathway. Mechanistic results indicate that PMS activation is governed by coupled radical and non-radical processes, promoted by CQDs-modified Nb 2 CTx surfaces playing a decisive role while, the evaluation of ecotoxicity analysis of CBZ intermediates suggested that they are much less harmful for ecosystem. This study highlights the importance of MXene surface modulation with CQDs for regulating PMS activation pathways and provides mechanistic insights relevant to advanced oxidation processes for the degradation of organic pollutants. Download: Download high-res image (291KB) Download: Download full-size image

Construction of 2D/2D ZnIn2S4/Nb2CTx (MXene) hybrid with hole transport highway and active facet exposure boost photocatalytic hydrogen evolution

Chao Peng,Yiming Chen,Xingyue Gao,Ping Wei,Yihao Lin,Li Fu,Bingpu Zhou,Mengchen Zhang,Jianbo Jia,Tiangang Luan

In this study, leveraging the tunable surface groups of MXene , the two-dimensional (2D) Nb 2 C T x with OH terminal (NC) was synthesized. 2D ZnIn 2 S 4 (ZIS) nanosheets were prepared with the aid of sodium citrate, enhancing the exposure ratio of active (1   1   0) facet. On this basis, 2D/2D ZnIn 2 S 4 /Nb 2 C T x heterojunctions were fabricated to improve photocatalytic hydrogen evolution reaction (HER) performance. The optimized 6 wt%Nb 2 C T x /ZnIn 2 S 4 -450 (6NC/ZIS-450) photocatalyt exhibits a remarkable HER rate of 3603 μmol g −1 h −1 , which is 10 times superior to that of the original ZnIn 2 S 4 . Its apparent quantum efficiency (AQE) at 380 nm reaches 14.9 %. Meanwhile, even after 5 rounds of HER, the activity of 2D/2D ZnIn 2 S 4 /Nb 2 C T x heterojunction remained at 90 %, far superior to that of pure ZnIn 2 S 4 (34 % and 31 %). Energy band structure analysis and density functional theory (DFT) calculation indicate that Nb 2 C T x adsorbed with OH exhibit a low work function . By serving as a hole cocatalyst, it effectively boosts the photocatalytic HER rate of ZnIn 2 S 4 /Nb 2 C T x heterojunction and inhibits the photocorrosion of ZnIn 2 S 4 . This unique insight, via hole transport highways and increased exposure of active facets, effectively enhances the activity and stability of sulfides photocatalysts .

Solar-driven co-production of freshwater and electricity using Janus Nb2CTX/graphene aerogels

Ya'’nan Zhao,Liyang Zhao,Yi'’na Yang,Tianran Zhao,Chunna Yu,Chang Zhao,Guangjian Xing

Freshwater scarcity and energy shortages stand as two of the most pressing global challenges confronting modern society. The integration of solar-driven interfacial evaporation with the hydrovoltaic effect emerges as a highly promising strategy to address both issues simultaneously. In this study, we report the development of Janus Nb 2 CT X /graphene aerogels (NGAs) specifically engineered to synergistically facilitate solar-driven seawater evaporation and hydrovoltaic power generation. The Janus NGAs were fabricated via a combination of hydrothermal reaction, freeze-drying, and surface modification techniques, yielding a three-dimensional porous architecture with distinct hydrophilic-hydrophobic asymmetry—a key structural feature for their dual-functional performance. Under 1 sun irradiation, the optimized NGA-3 sample achieved a high seawater evaporation rate of 1.64 kg·m −2  h −1 and an exceptional photothermal conversion efficiency of 86.61 %, attributed to the reduced water evaporation enthalpy (1904 kJ·kg −1 ) induced by the formation of intermediate water within the aerogel's porous structure. Meanwhile, the Nb 2 CT X MXene component enhances broadband sunlight absorption through the localized surface plasmon resonance (LSPR) effect, further boosting photothermal conversion. Concurrently, the NGAs exhibit robust hydrovoltaic performance: in NaCl solution, NGA-3 generated a stable output voltage of 147 mV under 1 sun and 236 mV under 3 sun. A peak power density of 197 μW·cm −2 was achieved in 10 wt% NaCl solution, demonstrating its adaptability to high-salinity environments. Additionally, the NGAs maintain excellent salt resistance and long-term operational stability. The synergistic integration of efficient photothermal conversion and electricity harvesting in the Janus NGAs offers a viable solution to alleviate global freshwater and energy pressures.

Nb2CTx MXene boosting PEO polymer electrolyte for all-solid-state Li-S batteries: two birds with one stone strategy to enhance Li+ conductivity and polysulfide adsorptivity

Liu Si-Ming,Chen Meng-Xun,Xie Ying,Liu Deng-Hua,Zheng Jin-Fei,Xiong Xiang,Jiang Heng,Wang Li-Chang,Luo Heng,Han Kai

All-solid-state lithium-sulfur (Li-S) battery is regarded as next-generation high energy density and safety battery system. The key challenge is to develop a compatible high-performance solid-state electrolyte. Herein, a two birds with one stone strategy is proposed to simultaneously enhance Li + conductivity and polysulfide adsorptivity of poly(ethylene oxide) (PEO)-based polymer electrolyte via the integration of Nb 2 CT x MXene. Moreover, the sheet size of Nb 2 CT x MXene is crucial for the enhancement of Li + conductivity and polysulfide adsorptivity, attributing to the difference in a specific surface area related to the percolation effect. By tuning the sheet size of Nb 2 CT x MXene from 500–300 nm to below 100 nm, the ionic conductivity of the PEO electrolyte is increased to 2.62 × 10 −4 S·cm −1 with improved Li + transference number of 0.37 at 60 °C. Furthermore, theoretical calculation and X-ray photoelectron spectroscopy (XPS) conjointly prove that polysulfides could be effectively adsorbed by Nb 2 CT x nanosheets via forming Nb−S bonding to inhibit their shuttle in the PEO framework. As a result, the all-solid-state Li-S cell exhibits an initial capacity of 1149 mAh·g −1 at 0.5C and good cycling stability with 491 mAh·g −1 after 200 cycles. The results demonstrate the necessity of polysulfide inhibition and the application of Nb 2 CT x MXene in PEO-based electrolytes for all-solid-state Li-S batteries. Graphic