A hydrothermal etching route to synthesis of 2D MXene (Ti3C2, Nb2C): Enhanced exfoliation and improved adsorption performance

Peng, Chao; Wei, Ping; Chen, Xin; Zhang, Yongli; Zhu, Feng; Cao, Yonghai; Wang, Hongjuan; Peng, Feng

doi:10.1016/j.ceramint.2018.07.124

Cited by 340 publications

(163 citation statements)

References 46 publications

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“…The (002) reflection shifts from 9.55 (MAX phase) to 9.00 and 9.10 2θ deg, for the samples Ti 3 C 2 T x _HF high and Ti 3 C 2 T x _HF low , respectively, determining a corresponding expansion of planes along the c parameters (Table S1, Supporting Information). [16,20] This expansion, therefore, changes with the acid concentration and the treatment times and it is related to a different ratio of O/OH/F terminations [38] and to the presence of small molecules in the layers (H 2 O, H 2 ). This latter circumstance is verified for the Ti 3 C 2 T x _HF high sample, as demonstrated by TGA-MS analysis (see next section), wherein water molecules are trapped between layers during the fast etching reaction.…”

Section: Resultsmentioning

confidence: 99%

“…[16,17] After the etching and washing process, the titanium is functionalized with different groups (-O, -OH, -F, or -Cl) depending on the acid kind and concentration. [18][19][20] The T terminating groups have an effect on the materials structural and functional properties, density functional theory (DFT) calculations have shown that the functionalization influences the spacing of the M n+1 X n T x layers. [4] As widely demonstrated in literature, the etching can be carried out in hydrofluoric acid; the higher the acid concentration the faster the reaction rate and it is possible to obtain MXene from MAX phase in 2 h with hydrofluoric (HF) 50 wt%.…”

Section: Introductionmentioning

confidence: 99%

“…Given the toxicity (HF vapors) and the corrosiveness of the highly concentrated HF solutions, [20] milder etching methods have been developed using HF in lower concentration (5-10%) or forming HF in situ by mixing a fluoride salt (LiF) with other acids (HCl). [16,23] The MXene Ti 3 C 2 T x phase has a high electronic conductivity, an hydrophilic surface, [4] and a good mechanical stability, [24] and for these reasons it can be used as transparent conductor, [24] membranes for selective passage by cations, [25] H 2 storage, [26] catalyst for hydrogen evolution reaction, [27,28] electromagnetic interference shield, [29] and electrode in both supercapacitors [30] and batteries.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Functional Properties of Ti₃C₂T_x MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

et al. 2020

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The large implementation of electrochemical energy storage devices requires the development of new chemistries tailored for specific uses. Sodium‐ion batteries (SIBs) can cover different application fields, however the state‐of‐the‐art negative material, hard carbon, suffers from poor cyclability and rate capability. MXenes are a vast class of 2D‐materials of the general formula Mn+1XnTx (M = transition metal, X = C or N, and T = M‐terminating group) with peculiar structural features able to reversible intercalate chemical species, such as alkaline cations. The MXene compound Ti3C2Tx is one of the most investigated, thanks to the easy preparation route by etching of the pristine compound Ti3AlC2. In this work, the effect of the etching conditions and of the postsynthesis thermal treatments on the chemical, morphological, and structural properties of Ti3C2Tx are investigated, and in turn the correlation between its features and the functional properties as negative materials in SIBs are studied. The Ti3C2Tx obtained in high hydrofluoric concentration and after a 300 °C thermal treatment shows 110 mAh g−1 at 30 mA g−1 with an average potential of 1.33 V versus Na+/Na, 100% and good rate capability, since it is still able to deliver 73 mAh g−1 at 1500 mA g−1.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhanced Functional Properties of Ti₃C₂T_x MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

et al. 2020

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“…Examples include MXenes, Ti 3 C 2 and Nb 2 AlC, reported to have higher interlayer distance and large specific surface area, which could affect its accommodation of more cations in between layers. Thus, increasing the storage capacity for supercapacitor application . Furthermore, hydrothermal surface functionalisation of MXene also contributes to improving yield of 2D MXene sheets.…”

Section: Synthetic Methodsologies Of 2d Materialsmentioning

confidence: 99%

Chemical Functionalisation of 2D Materials by Batch and Continuous Hydrothermal Flow Synthesis

Alli

Hettiarachchi

Kellici

2020

Chemistry A European J

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2D materials are single or few layered materials consisting of one or several elements with a thickness of a few nanometres. Their unique, tuneable physical and chemical properties including ease of chemical functionalisation makes this class of materials useful in a variety of technological applications. The feasibility of 2D materials strongly depends on better synthetic approaches to improve properties, increase performance, durability and reduce costs. As such, in the synthesis of nanomaterials, hydrothermal processes are widely adopted through a precursor–product synthesis route. This method includes batch or continuous flow systems, both employing water at elevated temperatures (above boiling point) and pressures to fine‐tune the physical, chemical, optical and electronic properties of the nanomaterial. Both techniques yield particles with different morphology, size and surface area due to different mechanisms of particle formation. In this Minireview, we present batch and continuous hydrothermal flow synthesis of a selection of 2D derivatives (graphene, MXene and molybdenum disulfide), their chemical functionalisation as an advantageous approach in exploring properties of these materials as well as the benefits and challenges of employing these processes, and an outlook for further research.

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“…Apart from HF, other etchants were used to selectively etch the A layers and produce MXenes. Most of them comprised an acid and a source of fluoride ions, such as NH4HF2 (used in paper I), LiF + HCl (used in paper II), NaBF4 + HCl [85], molten baths of KF, LiF and NaF in the case of Ti4AlN3 to produce Ti4N3Tz [27]. Whereas, for selectively removing Si layers from Ti3SiC2 and producing Ti3C2Tz, a mixture of HF and an oxidant such as H2O2, (NH4)2S2O8, HNO3, KMnO4, FeCl3 was used [30].…”

Section: Factors Influencing the Production Of Mxenesmentioning

confidence: 99%

Synthesis and transport properties of 2D transition metal carbides (MXenes)

Halim¹

2018

Linköping Studies in Science and Technology. Dissertations

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Since the isolation and characterization of graphene, there has been a growing interest in 2D materials owing to their unique properties compared to their 3D counterparts. Recently, a family of 2D materials of early transition metal carbides and nitrides, labelled MXenes, has been discovered (Ti2CTz, Ti3C2Tz, Mo2TiC2Tz, Ti3CNTz, Ta4C3Tz, Ti4N3Tz among many others), where T stands for surface-terminating groups (O, OH, and F). MXenes are mostly produced by selectively etching A layers (where A stands for group A elements, mostly groups 13 and 14) from the MAX phases. The latter are a family of layered ternary carbides and/or nitrides and have a general formula of Mn+1AXn (n = 1-3), where M is a transition metal and X is carbon and/or nitrogen. The produced MXenes have a conductive carbide core and a non-conductive O-, OH-and/or F-terminated surface, which allows them to work as electrodes for energy storage applications, such as Li-ion batteries and supercapacitors. Prior to this work, MXenes were produced in the form of flakes of lateral dimension of about 1 to 2 microns; such dimensions and form are not suitable for electronic characterization and applications. I have synthesized various MXenes (Ti3C2Tz, Ti2CTz and Nb2CTz) as epitaxial thin films, a more suitable form for electronic and photonic applications. These films were produced by HF, NH4HF2 or LiF + HCl etching of magnetron sputtered epitaxial Ti3AlC2, Ti2AlC, and Nb2AlC thin films. For transport properties of the Ti-based MXenes, Ti2CTz and Ti3C2Tz, changing n from 1 to 2 resulted in an increase in conductivity but had no effect on the transport mechanism (i.e. both Ti3C2Tx and Ti2CTx were metallic). In order to examine whether the electronic properties of MXenes differ when going from a few layers to a single flake, similar to graphene, the electrical characterization of a single Ti3C2Tz flake with a lateral size of about 10 µm was performed. These measurements, the first for MXene, demonstrated its metallic nature, along with determining the nature of the charge carriers and their mobility. This indicates that Ti3C2Tz is inherently of 2D nature independent of the number of stacked layers, unlike graphene, where the electronic properties change based on the number of stacked layers. Changing the transition metal from Ti to Nb, viz. comparing Ti2CTz and Nb2CTz thin films, the electronic properties and electronic conduction mechanism differ. Ti2CTz showed metallic-like behavior (resistivity increases with increasing temperature) unlike Nb2CTz where the conduction occurs via variable range hopping mechanism (VRH)where resistivity decreases with increasing temperature.

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A hydrothermal etching route to synthesis of 2D MXene (Ti3C2, Nb2C): Enhanced exfoliation and improved adsorption performance

Cited by 340 publications

References 46 publications

Enhanced Functional Properties of Ti₃C₂T_x MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

Enhanced Functional Properties of Ti₃C₂T_x MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

Chemical Functionalisation of 2D Materials by Batch and Continuous Hydrothermal Flow Synthesis

Synthesis and transport properties of 2D transition metal carbides (MXenes)

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A hydrothermal etching route to synthesis of 2D MXene (Ti3C2, Nb2C): Enhanced exfoliation and improved adsorption performance

Cited by 340 publications

References 46 publications

Enhanced Functional Properties of Ti3C2Tx MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

Enhanced Functional Properties of Ti3C2Tx MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

Chemical Functionalisation of 2D Materials by Batch and Continuous Hydrothermal Flow Synthesis

Synthesis and transport properties of 2D transition metal carbides (MXenes)

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Product

Resources

About

Enhanced Functional Properties of Ti₃C₂T_x MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning

Enhanced Functional Properties of Ti₃C₂T_x MXenes as Negative Electrodes in Sodium‐Ion Batteries by Chemical Tuning