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Aqueous Zn ion batteries (AZIBs) represent a promising candidate for the next‐generation energy storage and conversion systems due to their high safety and cost‐effectiveness. However, sluggish kinetics arising from interface desolvation processes pose challenges in achieving high‐power density and long cycle life for AZIBs. Here, it is discovered for the first time that heterostructures utilize built‐in electric field forces to promote the desolvation process at the electrode‐electrolyte interface. Density functional theory (DFT) calculations and structural characterization demonstrate that heterogeneous structures simultaneously accelerate the desolvation process and enhance ion diffusion, resulting in the outstanding rate performance (160.9 mA h g−1 at 5 A g−1) of TiS2‐TiO2 heterostructures, far exceeding that of a conventional TiS2 electrode with 14.2% capacity retention. Meanwhile, the insertion/extraction of the desolvated charge carriers reduced the volume change of TiS2‐TiO2 material during the charging/discharging processes, enabling the long‐lasting cycling stability (108.6 mA h g−1 after 2000 cycles at 0.5 A g−1). This study provides instructive electrode design strategies for the construction of fast‐charging electrochemical energy storage systems. [ABSTRACT FROM AUTHOR]

TiS2 has received significant attention as a promising anode for "Rocking‐Chair"‐type aqueous Zn‐ion batteries due to the large interlayer spacing and low discharge plateau. However, the structural distortion caused by the embedding of divalent Zn2+ as well as the undesirable hydrogen evolution reaction (HER) severely affects their cycling stability. Herein, a facet‐dependent mechanism is first deeply investigated to understand charge storage behaviors of TiS2 via differential electrochemical mass spectrometry, in situ electrochemical quartz crystal microbalance, and in situ X‐ray diffraction characterizations. By regulating the exposed crystal facets of TiS2 from (001) (TS (001)) to (011) (TS(011)), HER can be effectively inhibited, and the charge storage mechanism is transformed from Zn2+ insertion/extraction dominating to H+ insertion/extraction dominating, resulting in faster charge transfer kinetics and strong structure stability during long‐term cycling. Hence, TS(011) delivers a higher reversible capacity of 212.9 mAh g−1 at 0.1 A g−1 and a strong cycling stability of 74% capacity retention over 1000 cycles, much better than that of TS (001) with a reversible capacity of 164.7 mAh g−1 at 0.1 A g−1, a capacity retention of 17% after 1000 cycles. These new findings can provide deep insight into the rational design of high‐performance intercalation‐type electrode materials for energy storage applications. [ABSTRACT FROM AUTHOR]

A two‐dimensional titanium disulfide (TiS2) nanosheet film is prepared on a YAG crystal substrate. The saturated absorption behavior of TiS2 on the YAG substrate is investigated. Then, TiS2 is successfully employed as a modulation element to develop a Tm:YAG ceramic eye‐safe pulsed laser. With a 7.04 W absorbed pump light and a 3% transmission of output coupler, the greatest average optical power, and the least pulse width (PD) are 233 mW and 524 ns, separately. The pulse repeated frequency of 69 kHz is generated, while the single pulse energy (SPE) is 3.38 µJ. Based on the experimental results, TiS2 nanosheet films possess the practical value as saturable absorbers for 2.0 μm eye‐safe pulsed lasers. [ABSTRACT FROM AUTHOR]

This study explores the potential of titanium disulfide (TiS2) as an active material for aqueous calcium-ion batteries (CIBs). We investigate the electrochemical redox reactions of calcium ions within TiS2 and assess its suitability for use in aqueous CIBs. Additionally, we examine the impact of varying electrolyte concentrations, ranging from 1.0 to 8.0 mol dm−3, on TiS2 electrode reactions. Our findings reveal that TiS2 exhibits distinct charge–discharge behaviors in various aqueous calcium-ion electrolytes. Notably, at higher electrolyte concentrations, TiS2 effectively suppresses the hydrogen generation reaction caused by water decomposition. In situ X-ray diffraction analysis confirms the intercalation of Ca2+ ions between the TiS2 layers during charging, which is a groundbreaking discovery, signifying TiS2's applicability in aqueous CIBs. X-ray photoelectron spectroscopy analysis further supports the formation of a solid electrolyte interphase (SEI) on the TiS2 electrode surface, contributing to the suppression of electrolyte decomposition reactions. Furthermore, we investigate the influence of anions in the electrolyte on charge–discharge behavior. Our findings suggest that the choice of anion coordinated with Ca2+ ions affects the SEI formation and cycling performance. Understanding the role of anions in SEI formation is crucial for optimizing aqueous CIBs. In conclusion, this research underscores TiS2's potential as an active material for aqueous calcium-ion batteries and emphasizes the importance of the electrolyte composition in influencing SEI formation and battery performance, contributing to sustainable and efficient energy storage technologies. [ABSTRACT FROM AUTHOR]

The co‐intercalation of solvent molecules along with Na+ into the crystal lattice of electrode materials is an undesired process in sodium batteries. An exception is the intercalation of ether solvated alkali ions into graphite, a fast and highly reversible process. Here, reversible co‐intercalation is shown to also be possible for other layered materials, namely titanium disulfide. Operando X‐ray diffraction and dilatometry are used to demonstrate different storage mechanisms for different electrolyte solvents. Diglyme is found to co‐intercalate into the TiS2 leading to a change in the voltage profile and an increase in the interlayer spacing (≈150%). This behavior is different compared to other solvents, which expand much less during Na storage (24% for tetrahydrofuran [THF] and for a carbonate mixture). For all solvents, specific capacities (2nd cycle) exceed 250 mAh g−1 whereas THF exhibited the best stability after 100 cycles. The solvent co‐intercalation is rationalized by density functional theory and linked to the stability of the solvation shells, which is largest for diglyme. Finally, the TiS2 electrode with diglyme electrolyte is paired with a graphite electrode to realize the first proof‐of‐concept solvent co‐intercalation battery, that is, a battery with two electrodes that both rely on reversible co‐intercalation of solvent molecules. [ABSTRACT FROM AUTHOR]

[Display omitted] • SECM imaging of redox species for hydrogen evolution on 2D materials surface. • Localized in situ imaging of corrosion to electrocatalyst on layered metal dichalcogenides. • Imaging the localized selectivity of hydrogen evolution reaction on TMDs. Among the vast field of 2D materials, transition metal dichalcogenides (TMDs) have emerged as promising materials for electrocatalysis. Many of them, such as MoS 2 , were found to be potent electrocatalysts for the hydrogen evolution reaction (HER), which is vital for making electrochemical water splitting, a green route for obtaining hydrogen, economically feasible. In this work, we investigated the morphological and (electro)chemical changes undergoing in synthetic bulk crystals of MoS 2 , TiS 2 , and TiSe 2 during HER. Local electrochemical changes were observed using scanning electrochemical microscopy (SECM). Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were utilized to monitor morphological changes. Furthermore, the chemical composition of the materials was analyzed using X-ray photoelectron spectroscopy (XPS) and electron dispersive X-ray spectroscopy (EDS). Changes in the atomic structure were studied using X-ray diffraction (XRD). Our experiments showed different degrees of corrosion occurring in these materials, with the magnitude of corrosion decreasing in the order TiSe 2 > TiS 2 > MoS 2. These findings are of tremendous importance for the development of transition metal dichalcogenide electrocatalysts, which are touted to replace platinum for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

This study explores the potential of titanium disulfide (TiS2) as an active material for aqueous calcium-ion batteries (CIBs). We investigate the electrochemical redox reactions of calcium ions within TiS2 and assess its suitability for use in aqueous CIBs. Additionally, we examine the impact of varying electrolyte concentrations, ranging from 1.0 to 8.0 mol dm−3, on TiS2 electrode reactions. Our findings reveal that TiS2 exhibits distinct charge–discharge behaviors in various aqueous calcium-ion electrolytes. Notably, at higher electrolyte concentrations, TiS2 effectively suppresses the hydrogen generation reaction caused by water decomposition. In situ X-ray diffraction analysis confirms the intercalation of Ca2+ ions between the TiS2 layers during charging, which is a groundbreaking discovery, signifying TiS2’s applicability in aqueous CIBs. X-ray photoelectron spectroscopy analysis further supports the formation of a solid electrolyte interphase (SEI) on the TiS2 electrode surface, contributing to the suppression of electrolyte decomposition reactions. Furthermore, we investigate the influence of anions in the electrolyte on charge–discharge behavior. Our findings suggest that the choice of anion coordinated with Ca2+ ions affects the SEI formation and cycling performance. Understanding the role of anions in SEI formation is crucial for optimizing aqueous CIBs. In conclusion, this research underscores TiS2’s potential as an active material for aqueous calcium-ion batteries and emphasizes the importance of the electrolyte composition in influencing SEI formation and battery performance, contributing to sustainable and efficient energy storage technologies.

Inorganic nanomaterials with high photothermal effects have received immense interest for photothermal therapy of tumors, while most of them suffer from long-term safety concerns due to their non-degradability. To address this issue, we have reported the PEGylated titanium disulfide (TiS2-PEG) nanoplates as degradable photothermal agents. The oleylamine-capped TiS2 nanoplates with an average size of ∼200 nm have been prepared via a high-temperature liquid-phase route, and they can be easily dispersed in nonpolar solvents and remain high stability for at least one month. To confer hydrophilicity, the oleylamine-capped TiS2 nanoplates are then surface-modified with amphiphilic PEGylated lipids through Van der Waals interactions. When dispersed in saline solution at 37 °C, the TiS2-PEG are unstable and they can be gradually decomposed into Ti(OH)4/TiO2 sol ultrasmall particles (

The potential energy surfaces (PESs) and band gap landscapes (BGLs) of MoS2 and TiS2 monolayers were studied with a set of density functional methods. For our best knowledge, the PESs for transition metal dichalcogenides as a function of sulfur atom coordinates were studied for the first time. It is found that the energy differences between chemically meaningful points of the PESs are quite stable with respect to the density functional choice. The BGLs are characterized by "wavelike" structure with maxima that refer to 2H forms and minima that refer to 1T forms and ripples between them. It is shown that thermal vibrations may reduce the band gap in 2H form of MoS2. [ABSTRACT FROM AUTHOR]

The precise modulation of electrical activity in specific neuronal populations is paramount for rectifying abnormal neurological functions and is a critical element in the therapeutic arsenal for neurological disorders. However, achieving a balance between minimal invasiveness and robust neuroprotection poses a considerable challenge. Herein, we present a nanoneuromodulation strategy integrating neuroprotective features to effectively address epilepsy with minimal invasiveness and enable wireless functionality. Strategically engineered nanotransducer, adorned with platinum (Pt) decoration with titanium disulfide (TiS 2 ) (TiS 2 /Pt), enables precise modulation of neuronal electrical activity in vitro and in vivo , ensuring exceptional temporal fidelity under millisecond-precision near-infrared (NIR) light pulses irradiation. Concurrently, TiS 2 /Pt showcase a pronounced enhancement in enzyme-mimicking activity, offering a robust defense against oxidative neurological injury in vitro . Nanotransducer-enabled wireless neuromodulation with biocatalytic neuroprotective capacity is highly effective in alleviating epileptic high-frequency neural activity and diminishing oxidative stress levels, thereby restoring redox equilibrium. This integrated therapeutic approach reduces the severity of epilepsy, demonstrating minimal invasiveness and obviating the requirements for genetic manipulation and optical fiber implantation, while providing an alternative avenue for neurological disorder treatment.

Titanium disulfide (TiS 2 ) is a promising anode material for sodium-ion batteries due to its high theoretical capacity, but it suffers from severe volume variation and shuttle effect of the intermediate polysulfides. To overcome the drawbacks, herein the successful fabrication of TiS 2 @N,S-codoped C (denoted as TiS 2 @NSC) through a chemical vapor reaction between Ti-based metal-organic framework (NH 2 -MIL-125) and carbon disulfide (CS 2 ) is demonstrated. The C─N bonds enhance the electronic/ionic conductivity of the TiS 2 @NSC electrode, while the C─S bonds provide extra sodium storage capacity, and both polar bonds synergistically suppress the shuttle effect of polysulfides. Consequently, the TiS 2 @NSC electrode demonstrates outstanding cycling stability and rate performance, delivering reversible capacities of 418/392 mAh g -1 after 1000 cycles at 2/5 A g -1 . Ex situ X-ray photoelectron spectroscopy and transmission electron microscope analyses reveal that TiS 2 undergoes an intercalation-conversion ion storage mechanism with the generation of metallic Ti in a deeper sodiation state, and the pristine hexagonal TiS 2 is electrochemically transformed into cubic rock-salt TiS 2 as a reversible phase with enhanced reaction kinetics upon sodiation/desodiation cycling. The strategy to encapsulate TiS 2 in N,S-codoped porous carbon matrices efficiently realizes superior conductivity and physical/chemical confinement of the soluble polysulfides, which can be generally applied for the rational design of advanced electrodes., (© 2024 Wiley‐VCH GmbH.)

Titanium disulfide (TiS2) was synthesized by a simple solid phase method. The physical properties of TiS2 were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDX). Scanning and transmission electron microscopy (SEM and TEM) were used to study the structural and morphological characteristics. The synthesized TiS2 was applied as negative electrode material for TiS2/graphite electric storage devices with organic electrolytes based on Na+-ions. The electrochemical methods were used to characterize the charge storage mechanism of TiS2. The TiS2/graphite electric energy storage device possessed a working voltage of 3.5 V. The fabricated device showed relatively high performance rate and excellent cycle stability in electrochemical tests. [ABSTRACT FROM AUTHOR]

Abstract A subcellular organelle-targeted delivery of anti-cancer drugs is a promising strategy to maximize the anti-cancer effects and minimize the adverse effects. Herein, we prepared a mitochondria-targeted drug delivery nanoplatform based on IR780 iodide (IR780) and titanium disulfide (TiS2) nanosheets. Due to the large specific surface area of TiS2 nanosheets, the nanoplatform could highly load anti-cancer drug resveratrol (RV). The as-prepared nanocomposite (IR780-TiS2/RV) was used for an efficacious photothermal-triggered tumor chemotherapy. IR780-TiS2/RV showed satisfactory stability and biocompatibility, and the loading ratio of RV and IR780 was about 112% and 56%, respectively. Upon the near-infrared (NIR) irradiation, the heat generated by IR780-TiS2/RV could trigger the RV release. Due to the conjugation with the mitochondria-specific IR780, IR780-TiS2/RV could target and accumulate in mitochondria and release RV when triggered by NIR to decrease the mitochondrial membrane potential, rapidly induce the upregulation of key intrinsic apoptotic factors such as cytochrome c, and initiate the caspase cascade, thereby achieving the chemotherapeutic effect. The IR780-TiS2/RV nanocomposite was demonstrated to have a high anti-tumor efficacy in vitro and in vivo as well as no remarkable tissue toxicity. We believe our study demonstrates that the NIR-triggered IR780-TiS2/RV nanoplatform could be a promising chemotherapeutic agent in clinical practice.

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The scalable and conformal synthesis of two-dimensional (2D) transition metal dichalcogenide (TMDC) heterostructures is a persisting challenge for their implementation in next-generation devices. In this work, we report the synthesis of nanometer-thick 2D TMDC heterostructures consisting of TiSx-NbSx on both planar and 3D structures using atomic layer deposition (ALD) at low temperatures (200–300 °C). To this end, a process was developed for the growth of 2D NbSx by thermal ALD using (tert-butylimido)-tris-(diethylamino)-niobium (TBTDEN) and H2S gas. This process complemented the TiSx thermal ALD process for the growth of 2D TiSx-NbSx heterostructures. Precise thickness control of the individual TMDC material layers was demonstrated by fabricating multilayer (5-layer) TiSx-NbSx heterostructures with independently varied layer thicknesses. The heterostructures were successfully deposited on large-area planar substrates as well as over a 3D nanowire array for demonstrating the scalability and conformality of the heterostructure growth process. The current study demonstrates the advantages of ALD for the scalable synthesis of 2D heterostructures conformally over a 3D substrate with precise thickness control of the individual material layers at low temperatures. This makes the application of 2D TMDC heterostructures for nanoelectronics promising in both BEOL and FEOL containing high-aspect-ratio 3D structures. [ABSTRACT FROM AUTHOR]

In recent years, two-dimensional layered materials have attracted extensive attention due to their unique physical and chemical properties. In this paper, a solution method is utilized to obtain ultra-thin two-dimensional layered titanium disulfide nanosheets ( NSs) with controlled thickness. The obtained titanium disulfide NSs s how a few atomic layers in the thickness. Moreover, the T iS2 NSs exhibit excellent photothermal performance compared to conventional photothermal silver nanoparticles. Our results s how that the temperature of the TiS2 NSs aqueous solution (500 µg/ mL) can be increased to 54 . 41 'C under the irradiation of infrared 808 nm laser with a power density of 1 W / cm2,and its photothermal stability is excellent. Through theoretical calculation, the photo thermal con version efficiency is 42 . 14 % . This study shows that two-dimensional layered TiS2 NSs is a promise photothermal material, which has potential application value for the treatment of cancer. [ABSTRACT FROM AUTHOR]

Nanobactericides are employed as a promising class of nanomaterials for eradicating microbial infections, considering the rapid resistance risks of conventional antibiotics. Herein, we present a pioneering approach, reporting the synthesis of two-dimensional titanium disulfide nanosheets coated by nitrogen/sulfur-codoped carbon nanosheets (2D-TiS 2 @NSC LAA hybrid NSs) using a rapid l-ascorbic acid-assisted sulfurization of Ti 3 C 2 T x -MXene to achieve efficient alternative bactericides. The as-developed materials were systematically characterized using a suite of different spectroscopy and microscopy techniques, in which the X-ray diffraction/Raman spectroscopy/X-ray photoelectron spectroscopy data confirm the existence of TiS 2 and C, while the morphological investigation reveals single- to few-layered TiS 2 NSs confined by N,S-doped C, suggesting the successful synthesis of the ultrathin hybrid NSs. From in vitro evaluation, the resultant product demonstrates impressive bactericidal potential against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria, achieving a substantial decrease in the bacterial viability under a 1.2 J dose of visible-light irradiation at the lowest concentration of 5 μg·mL -1 compared to Ti 3 C 2 T x (15 μg·mL -1 ), TiS 2 -C (10 μg·mL -1 ), and standard antibiotic ciprofloxacin (15 μg·mL -1 ), respectively. The enhanced degradation efficiency is attributed to the ultrathin TiS 2 NSs encapsulated within heteroatom N,S-doped C, facilitating effective photogenerated charge-carrier separation that generates multiple reactive oxygen species (ROS) and induced physical stress as well as piercing action due to its ultrathin structure, resulting in multimechanistic cytotoxicity and damage to bacterial cells. Furthermore, the obtained results from molecular docking studies conducted via computational simulation ( in silico ) of the as-synthesized materials against selected proteins (β-lactamas E. coli /DNA-Gyras E. coli ) are well-consistent with the in vitro antibacterial results, providing strong and consistent validation. Thus, this sophisticated study presents a simple and effective synthesis technique for the structural engineering of metal sulfide-based hybrids as functionalized synthetic bactericides.

Two-dimensional transition metal dichalcogenides (2D TMDCs) are considered promising alternatives to Si as channel materials because of the possibility of retaining their superior electronic transport properties even at atomic body thicknesses. However, the realization of high-performance 2D TMDC field-effect transistors remains a challenge owing to Fermi-level pinning (FLP) caused by gap states and the inherent high Schottky barrier height (SBH) within the metal contact and channel layer. This study demonstrates that high-quality van der Waals (vdW) heterojunction-based contacts can be formed by depositing semimetallic TiS 2 onto monolayer (ML) MoS 2 . After confirming the successful formation of a TiS 2 /ML MoS 2 heterojunction, the contact properties of vdW semimetal TiS 2 were thoroughly investigated. With clean interfaces of the TiS 2 /ML MoS 2 heterojunctions, atomic-layer-deposited TiS 2 can induce gap-state saturation and suppress FLP. Consequently, compared with conventional evaporated metal electrodes, the TiS 2 /ML MoS 2 heterojunctions exhibit a lower SBH of 8.54 meV and better contact properties. This, in turn, substantially improves the overall performance of the device, including its on-current, subthreshold swing, and threshold voltage. Furthermore, we believe that our proposed strategy for vdW-based contact formation will contribute to the development of 2D materials used in next-generation electronics.

The recent research on aqueous zinc‐ion hybrid supercapacitors (ZHSCs) based on zinc metal anode has attracted great attention in energy storage systems due to the inherited merits of supercapacitors and batteries. However, the problems of sluggish diffusion of zinc ion, low utilization rate of zinc foil, and uncontrollable zinc dendrites limit the application of ZHSCs. In order to effectively solve the above problems, a ZHSC is constructed and investigated with a 2D layered titanium disulfide (TiS2) (de)intercalation battery‐type anode and an active carbon (AC) capacitor‐type cathode in 2 m ZnSO4 electrolyte. Notably, this ZHSC demonstrates a high specific capacitance of 249 F g−1 (0.2 A g−1), a superior energy density of 112 Wh kg−1 (180 W kg−1), and a high power density of 3600 W kg−1 (35 Wh kg−1) based on the total weight of the anode and cathode active materials. Furthermore, the ZHSC also shows long service life with a capacitance retention of 92% after 5000 cycles at a current density of 2 A g−1. This work provides a concept to design next‐generation high‐performance ZHSC by replacing the zinc foil anode with a (de)intercalation battery‐type anode. [ABSTRACT FROM AUTHOR]

The synthesis of large‐area TiS2 thin films is reported at temperatures as low as 500 °C using a scalable two‐step method of metal film deposition followed by sulfurization in an H2S gas furnace. It is demonstrated that the lowest‐achievable sulfurization temperature depends strongly on the oxygen background during sulfurization. This dependence arises because TiO bonds present a substantial kinetic and thermodynamic barrier to TiS2 formation. Lowering the sulfurization temperature is important to make smooth films, and to enable integration of TiS2 and related transition metal dichalcogenides—including metastable phases and alloys—into device technology. [ABSTRACT FROM AUTHOR]

In this paper, TiS2 nanosheet porous structure was prepared via a facile two-step process. The precursor, TiH1.924 nanoparticles, were prepared by DC arc-discharge plasma method in the mixed atmosphere of H2 and Ar with titanium bulk as the titanium source, then blended with sublimated sulfur and heated to obtain the TiS2 nanosheet porous structure. The samples were characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM）, scanning electron microscopy（SEM）, Raman and so on. XRD and Raman results showed that the as-synthesized TiS2 was fully crystallized. TEM and SEM results showed the nanosheet micro-morphology of the as-synthesized TiS2. The nanosheets grew in any direction to form a porous structure. The TiS2 nanosheet porous structure was used as the anode material of lithium-ion batteries to study its electrochemical lithium storage performance. The first charge-discharge specific capacities under the current density of 500 mA/g were 816.0 mAh/g and 1193.0 mAh/g, respectively. After 50 cycles, the capacity remained a capacity of 550 mAh/g. Even under a high current density of 5 A/g, it still maintained a capacity of 100 mAh/g, showing excellent cycle stability and charge-discharge reversibility. [ABSTRACT FROM AUTHOR]

Titanium disulfide (TiS2) was adopted as a negative electrode material for the asymmetric sodium-ion supercapattery of TiS2/activated carbon using Na+-based organic electrolytes. This type of supercapattery possesses a working voltage as high as 3 V. The physical properties of the negative electrode were characterized by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical performance tests revealed that the supercapattery had a relatively high rate performance and good cycle stability, displaying 77% capacity retention after 1000 cycles at a current density of 0.2 A g−1. [ABSTRACT FROM AUTHOR]

A detailed study of temperature‐dependent phonon properties of exfoliated titanium disulphide (TiS2) nanosheets probed by Raman spectroscopy in the 80‐ to 450‐K temperature range is reported here. The TiS2 Raman mode (Eg, A1g, and Sh) positions exhibit linear shift dependences; however, in contradiction to typical behavior, the Sh mode surprisingly exhibits positive first‐order temperature coefficient (χ=0.0592 cm‐1/K) with increase of the temperature. In addition, the widths of studied peaks typically increase with temperature and peak intensity ratio shows no changes proving that relative phonon population is not affected by temperature. Our findings can be useful for further analysis of phonon properties and determination of thermal conductivity of supported TiS2 thin films for advanced electronics devices. [ABSTRACT FROM AUTHOR]

Real-time and high-performance monitoring of trace carbon dioxide (CO 2 ) has become a necessity due to its substantial impact on the global climate, human health, indoor occupancy, and crop productivity. Two-dimensional materials such as transition metal dichalcogenides (TMDs) have gained significant interest in gas sensing applications owing to their intrinsically high surface-to-volume ratio. However, the research has been limited to prominent TMDs such as WS 2 and MoS 2 . Specifically, the chemiresistive sensing performance of titanium disulfide (TiS 2 ) has rarely been investigated. We present an electric-field-assisted TiS 2 nanodisc assembly for the fabrication of a low-cost, low-power CO 2 gas sensor based on charge transfer between physisorbed CO 2 analyte molecules and TiS 2 nanodiscs operating at room temperature. The physiochemical properties of the synthesized TiS 2 nanodiscs were investigated via scanning electron microscopy (SEM), electron diffraction spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy. The fabricated sensor demonstrated an ultra-high sensor response of 60%, a fast response time of 37 s toward 500 ppm CO 2 gas, and the lowest detection limit of 5 ppm under ambient conditions. The low adsorption energies and vdW interaction between CO 2 molecules and TiS 2 resulted in easy desorption, allowing the sensor to self-recover without the need for external stimuli, which is hardly been witnessed in other 2D material analogues. Furthermore, the sensor has excellent reproducibility and stability for successive analyte exposures, as well as excellent selectivity for CO 2 over other interfering gases. This reported sensor based on 2D TMDs is the first of its type to integrate such a broad range of sensor characteristics (such as high sensor response and sensitivity, rapid response and recovery times, a high signal-to-noise ratio, and excellent selectivity at room temperature) into a single, revolutionary device for CO 2 detection.

Abstract: The selective removal of ions by an electrochemical process is a promising approach to enable various water‐treatment applications such as water softening or heavy‐metal removal. Ion intercalation materials have been investigated for their intrinsic ability to prefer one specific ion over others, showing a preference for (small) monovalent ions over multivalent species. In this work, we present a fundamentally different approach: tunable ion selectivity not by modifying the electrode material, but by changing the operational voltage. We used titanium disulfide, which shows distinctly different potentials for the intercalation of different cations and formed binder‐free composite electrodes with carbon nanotubes. Capitalizing on this potential difference, we demonstrated controllable cation selectivity by online monitoring the effluent stream during electrochemical operation by inductively coupled plasma optical emission spectrometry of aqueous 50 m m CsCl and MgCl2. We obtained a molar selectivity of Mg2+ over Cs+ of 31 (strong Mg preference) in the potential range between −396 mV and −220 mV versus Ag/AgCl. By adjusting the operational potential window from −219 mV to +26 mV versus Ag/AgCl, Cs+ was preferred over Mg2+ by 1.7 times (Cs preference). [ABSTRACT FROM AUTHOR]

2017 is the 50th anniversary of the discovery of fast ion transport in β-alumina. This discovery led to a revolution in the study of solid materials that might exhibit ionic motion as fast as that found in liquids. The need for materials with both fast ionic and electronic conductivity and a wide stoichiometry range to measure the ionic conductivity of beta alumina led to the intercalation concept for rechargeable alkali metal batteries. These discoveries and the resulting development of the lithium battery are described. [ABSTRACT FROM AUTHOR]

Abstract: 2D titanium disulfide (TiS2) is recently found to have strong light absorption properties from visible to infrared (IR) region. This feature is highly attractive for applications in nonlinear photonics; however, the mechanism of broadband light–matter interaction is yet to be determined and nonlinear photonic devices are not developed. Here, for the first time, the experimental evidence supporting the mechanism of the broadband nonlinear photoresponse in ultrathin TiS2 nanosheets ranging from 400 nm to 1390 nm is reported through laser Z‐scan measurements. High‐performance nonlinear photonic devices operating in the telecommunication band are also demonstrated. A novel saturable absorber (SA) device is successfully fabricated based on a 2D TiS2‐decorated fiber, which exhibits outstanding ultrashort pulse generation performance with pulse duration of ≈1.04 ps centered at 1569.5 nm. Furthermore, as a stable all‐optical thresholding component, the device can effectively attenuate noise and boost the signal‐to‐noise ratio of the pulse from 1.90 to 10.68 dB. The findings indicate that TiS2‐based SA devices can be developed into excellent highly nonlinear photonic devices, which may advance the development of TiS2‐based optical communication technologies in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Aqueous ionic liquids solutions are used to exfoliate TiS 2 nanosheets from bulk TiS 2 powder. • The yield of TiS 2 nanosheets is up to 57.6%. • The thickness of TiS 2 nanosheets is mainly in the range from 1 to 2 nm. • The geometric size and anionic basicity of the ILs play critical roles in the exfoliation process. • The Faradaic efficiency of CO catalyzed by TiS 2 nanosheets is 6 times that of the bulk TiS 2 powder. Titanium disulfide nanosheets (TiS 2 NSs) have attracted considerable research interest due to their eco-friendliness and outstanding electrical transport properties. However, the large scale preparation of TiS 2 NSs usually is plagued by the employ of poisonous solvents and low production. Herein, we develop a green, highly efficient and scalable tactic to exfoliate bulk TiS 2 powders in aqueous ionic liquids solutions under ambient conditions. This result shows that the exfoliation yield can reach 57.6 %, which surpasses the most values for the liquid-phase exfoliation of TiS 2 reported in literatures. The thickness of TiS 2 NSs is mainly in the range of 1 nm to 2 nm, and the lateral dimension is up to a few hundreds of nanometers. The molecular geometry and anionic alkalinity of the ionic liquids play key roles in the delamination and stability of TiS 2 NSs. In addition, TiS 2 NSs have been used as catalysts in the electrocatalytic CO 2 to CO conversion with the faradaic efficiency of 68.7 %, which is six times that by the bulk TiS 2 powder. Thus, the liquid phase delamination approach reported in this work has a great potential in manufacturing 2D layer materials for high activity electrocatalysis. [ABSTRACT FROM AUTHOR]

Reaction with n-butyl lithium (BuLi) is commonly used to study the kinetics of intercalation of lithium in electrode materials for batteries. We performed lithium isotope exchange experiments on TiS2 single crystals as model system to determine the irreversible step in the intercalation process. Single crystals of TiS2 were prepared by chemical vapor transport and intercalated by lithium with natural isotopic signature (7% 6Li 93% 7Li) using a 2.5 molar solution of BuLi in hexane. Crystals were homogenized at 313 K in a dry argon atmosphere for 1-2 months and then exposed for several days to ~1 molar BuLi solution enriched in the light lithium isotope (95% 6Li, 5% 7Li). After the isotopic exchange experiments concentration profiles of the isotopes were measured parallel to the a/b-plane of the crystal using Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS). Profiles show that already intercalated lithium isotopes can be completely exchanged without significant increase in total lithium content. This observation implies that, after adsorption of BuLi at the crystal surface, the butyl radical can freely jump from one lithium atom to a neighbouring one. The jump sequence is either finished by desorption of a BuLi molecule or by combination of two adjacent butyl radicals forming an octane molecule or other kinds of deactivation of butyl radicals. The latter step is irreversible. Self diffusion coefficients determined by fitting of the lithium isotope profiles are in good agreement with chemical diffusivities determined by lithium intercalation experiments. [ABSTRACT FROM AUTHOR]

Although the LiMn 1.5 Ni 0.5 O 4 spinel operating at 4.7 V presents some beneficial characteristics over more traditional positive electrode materials, instability issues at elevated temperature have limited its practical use so far. While we previously proposed Li 1+y Mn 1.5 Ni 0.5 O 4−x F x (LMNOF) spinel that is intrinsically stable at elevated temperatures in Li-excess half-cell configuration, we investigate herein fixed, non-excess Li-content window-shifted Li-ion systems. By utilizing Li 4 Ti 5 O 12 (LTO) or TiS 2 negative electrodes stable in broad electrolyte compositions instead of carbonaceous electrodes, we aim at limiting the Li-consuming side reactions such as the formation of solid-electrolyte interphase and enable a focus on the exploration of electrolyte compositions including additives. Utilizing such an approach, excellent fundamental stability of LMNOF in a fixed Li-content Li-ion environment is demonstrated at 55 °C with the use of relatively common electrolyte components. [ABSTRACT FROM AUTHOR]

The adsorption of TiO nanoclusters onto a TiS2 single layer surface is investigated via the density functional theory in combination with random structure searching algorithms. The nanoclusters are Ti—O dipoles and their orientation in the electrostatic field is induced by S atoms near the TiS2 single layer surface. The binding energy of nanoclusters with a TiS2 single layer surface is found to be 4.713 eV. Another curious observation is the creation of a nanocluster with an S–S–S–O anionic tetrahedron by Ti atoms, where the O anion is located at the maximum distance from the surface. [ABSTRACT FROM AUTHOR]