Sulfide Nanotubes Research Articles

Se-doped nickel-cobalt sulfide nanotube arrays with 3D networks for high-performance hybrid supercapacitor

In this study, Se doped nickel-cobalt sulfide (Se–NiCoS) nanotube arrays with three-dimensional (3D) networks are prepared on nickel foam via a facile hydrothermal method combined with selenide reaction. The 3D networks are formed by interconnected nanosheets grown on the surface of nanotubes. Results show that the dopant amount of Se in nickel-cobalt sulfide (NiCoS) has obvious effects on both the structure and performance of the Se–NiCoS. The combined contribution of Se dopant and the unique 3D network structure can greatly improve the electrochemical performance of NiCoS. Compared with the pristine NiCoS nanotube array, the Se–NiCoS nanotube arrays demonstrate enhanced areal capacitance (2.00 and 1.48 F cm−2 at 1 and 20 mA cm−2, respectively) and cyclic stability (capacitance retention rate of 91.2% after 5000 cycles at 5 mA cm−2). Furthermore, the hybrid supercapacitor assembled with Se–NiCoS nanotube arrays and carbon nanotubes (CNTs) as positive electrode and negative electrode can deliver an energy density of 37.7 Wh kg−1 at a power density of 798.4 W kg−1. This study indicates that the 3D network structured Se–NiCoS nanotube arrays have a good practical application value in supercapacitor devices.

Synthesis of hierarchical nickel sulfide nanotubes for highly efficient electrocatalytic urea oxidation

It is a challenge to prepare high-efficiency and inexpensive electrocatalysts toward urea oxidation reaction (UOR). Herein, we report the fabrication of NiS nanotubes with hierarchical sheet-like surface morphology via a novel template-directed hydrothermal reaction as efficient UOR electrocatalyst. The unique hollow structure of NiS nanotubes provides the exposure of more active sites and excellent electron/mass transport properties, ensuring a superior UOR performance. The NiS nanotubes catalyst shows a very low potential at around 1.39 V vs. RHE at 100 mA cm−2 in 1 M KOH/0.33 M urea solution. And the UOR current density of the catalyst at 1.4 V vs. RHE reaches 135 mA cm−2, representing a superior UOR performance. The NiS nanotubes catalyst also possesses an excellent operational stability. Furthermore, a two-electrode urea-assisted overall water splitting (OWS) device assembled with NiS nanotubes as anode and Pt/C as cathode delivers a working voltage of 1.445 V to attain 10 mA cm−2, which is 188 mV less than that for the urea-free OWS electrolyzer, demonstrating its possibility to be applicable for energy efficient hydrogen production. This study provides a rationale to develop high-efficiency non-precious metal-based UOR catalysts for the efficient assistance of hydrogen fuel generation.

Construction of internal and external defect electrode materials based on hollow manganese-cobalt-nickel sulfide nanotube arrays

The deficient active sites and poor conductivity of transition metal sulfides result in low energy density of supercapacitors that limits their extensive application. In this work, hollow manganese-cobalt-nickel sulfide nanotube arrays with the pore diameter about 40 nm are synthesized by three steps, and then chemical reduction strategy is used to build hollow trimetallic electrode materials with internal and external defects. During the whole process, due to the strong reducibility and small radius of H−, metal ions, which locate inside and outside the tube, are partially reduced from high oxidation states to low oxidation states, then the corresponding metal-sulfur bonds are broken and sulfide ions escape from active materials to form sulfur vacancies. Enhanced electrochemical performance of the electrode with vacancy (from 2944F g−1 to 3794F g−1 at 1 A g−1) demonstrates that the introduce of vacancy can facilitate electrochemical reaction kinetics due to the increased electron density of metal ions and active sites. In addition, the assembled asymmetric supercapacitor has a maximum voltage window of 1.8 V and displays a high energy density of 85.2 Wh kg−1 under a power density of 1030 W kg−1, showing the promising application in electrochemical energy storage fields.

Self-Template Synthesis of Nickel Cobalt Sulfide Hollow Nanotubes for High-Performance Battery-Type Supercapacitors

In this work, nickel cobalt sulfide with hollow tubular structure was synthesized by solvothermal and subsequently anion-exchange processes. The nickel cobalt sulfide nanotubes processed high specific capacity (531.9 C g−1 at 0.5 A g−1) when it directly used as electrode material. Furthermore, an asymmetric supercapacitor was fabricated with nickel cobalt sulfide nanotubes as a positive electrode and active carbon as a negative electrode. The asymmetric device exhibited a maximum energy density of 25.7 Wh kg−1 and a maximum power density of 4315 W kg−1, and excellent cycling performance (84.3% capacity retention) over 10000 cycles. The excellent electrochemical behaviors indicated that nickel cobalt sulfide nanotubes were highly desirable for high capacity energy storage devices.

Radiation-induced synthesis of copper sulfide nanotubes with improved catalytic and antibacterial activities.

In the current paper, copper sulfide nanotubes have been successfully synthesized via the green, simple, and effective gamma-radiolysis method without adding any capping or reducing agents. The structural and morphological characteristics of the as-prepared CuS nanotubes were investigated by X-ray diffraction (XRD), N2 adsorption-desorption measurements at 77K, transmission electron microscopy (TEM), and ultraviolet-visible (UV-vis) spectroscopy, which all demonstrated the formation of pure CuS covellite phase with tubular morphology. The synthesized CuS nanotubes possessed not only high activity towards the reduction of both cationic (methylene blue) and anionic (Congo red) dyes in the presence of NaBH4 but also exhibited excellent reusability. In addition, the pseudo-first-order kinetic model represented the reduction of MB very well, and the value of the normalized rate constant (2.4 × 10-2s-1mg-1) was higher than those of other solid catalysts reported in the literature. Ultimately, CuS nanotubes were found to have a broad-spectrum microbicidal action against the common microbiota, such as Gram-positive (exemplified by Bacillus subtilis and Staphylococcus aureus), Gram-negative bacteria (exemplified by Pseudomonas aeruginosa and Escherichia coli), yeast (exemplified by Candida albicans), and plant pathogenic fungi (exemplified by Aspergillus niger).

Supercapacitor Performance of Nickel-Cobalt Sulfide Nanotubes Decorated Using Ni Co-Layered Double Hydroxide Nanosheets Grown in Situ on Ni Foam.

In this study, to fabricate a non-binder electrode, we grew nickel–cobalt sulfide (NCS) nanotubes (NTs) on a Ni foam substrate using a hydrothermal method through a two-step approach, namely in situ growth and an anion-exchange reaction. This was followed by the electrodeposition of double-layered nickel-cobalt hydroxide (NCOH) over a nanotube-coated substrate to fabricate NCOH core-shell nanotubes. The final product is called NCS@NCOH herein. Structural and morphological analyses of the synthesized electrode materials were conducted via SEM and XRD. Different electrodeposition times were selected, including 10, 20, 40, and 80 s. The results indicate that the NCSNTs electrodeposited with NCOH nanosheets for 40 s have the highest specific capacitance (SC), cycling stability (2105 Fg−1 at a current density of 2 Ag−1), and capacitance retention (65.1% after 3,000 cycles), in comparison with those electrodeposited for 10, 20, and 80 s. Furthermore, for practical applications, a device with negative and positive electrodes made of active carbon and NCS@NCOH was fabricated, achieving a high-energy density of 23.73 Whkg−1 at a power density of 400 Wkg−1.

Hierarchical materials constructed by 1D hollow nickel–cobalt sulfide nanotubes supported on 2D ultrathin MXenes nanosheets for high-performance supercapacitor

To design and prepare novel composites with strong electrode structure and superior electrochemical performances via a facile and convenient synthesis method is a significant challenge to develop the high-performance materials for energy storage and conversion devices. Herein, we fabricated a novel hybridization of two dimensional (2D) Ti3C2-MXenes nanosheets and one dimensional (1D) nickel-cobalt sulfide (NiCo2S4) hollow nanotubes though the favorable electrostatic interaction between the negatively charged Ti3C2 and positively charged NiCo2S4 nanotubes. The electrode combined the good metallic conductivity of Ti3C2-MXenes and high pseudo-capacitance of NiCo2S4 demonstrated the outstanding electrochemical performance for supercapacitors. Herein, 2D Ti3C2-MXenes/1D NiCo2S4 hybrid electrode achieved an excellent specific capacitance of 1927 F g-1 at 2 mV s-1, long cycling stability for 4000 cycles and charming rate performances, which is mainly ascribed to the synergistic effect and interfacial interaction between two components. Particularly, the novel hybrid material with 1D and 2D hierarchical structures can provide additional electrochemical reaction sites, supply shorter paths for ions diffusion and electron transport, and effectively raise the charge transfer kinetics during the electrochemical process, which explores a new strategy aimed to develop 2D Ti3C2-MXenes energy storage devices with high electrochemical performance, and is possible potential for expansion into other application fields.

Dual-defect surface engineering of bimetallic sulfide nanotubes towards flexible asymmetric solid-state supercapacitors

Nickel cobalt sulfide (NiCo2S4) is a promising battery-type material for electrochemical energy storage.

Correction: Dual-defect surface engineering of bimetallic sulfide nanotubes towards flexible asymmetric solid-state supercapacitors

Correction for ‘Dual-defect surface engineering of bimetallic sulfide nanotubes towards flexible asymmetric solid-state supercapacitors’ by Ling Kang et al., J. Mater. Chem. A, 2020, DOI: 10.1039/d0ta08979f.

Indium sulfide nanotubes with sulfur vacancies as an efficient photocatalyst for nitrogen fixation

We have designed and manufactured In2S3 nanotubes containing sulfur vacancies as effective and stable photocatalysts for nitrogen fixation and ammonia production. In the preparation process of In2S3, a self-templated strategy was used to obtain the nanotubes. The sulfur vacancies were then manufactured by calcination under a nitrogen atmosphere. The existence of sulfur vacancies enhances the light absorption and promotes the separation and migration of the photoinduced charge carriers. In addition, sulfur vacancies can serve as the active sites to achieve strong N2 adsorption and activation. Thus the obtained samples show enhanced photocatalytic performance with a high NH3 generation rate (52.49 μmol h−1 g−1) and excellent stability under UV-vis light.

Tuning the Optical Properties of Zinc Sulfide Nanotube

Optical properties of zinc sulfide (ZnS) nanotube (NT) are tuned by changing its chirality and adsorbing phosphorous. It is found that Armchair (4, 4) ZnS NT results in largest absorption coefficient in ultraviolet region in comparison to zigzag and chiral ZnS NTS. Zigzag (5, 0), (6, 0) and chiral (4, 2) ZnS NTS have larger bandgap and lower absorption in comparison to armchair (3, 3), (4, 4), and (5, 5) ZnS NTs. On changing the chirality of armchair ZnS NTS from (3, 3) to (4, 4) and then to (5, 5), it is found that absorption can be tuned to higher values in an ultraviolet region in the case of (4, 4) NTS which has a higher absorption coefficient in ultraviolet region than (3, 3) and (5, 5) NTS. The absorption in armchair ZnS NTs can be tuned to increase with increase in nanotube bandgap and can also be tuned to increase with decrease in bandgap in ziz-zag NTs. Furthermore, adsorption of phosphorous over ZnS NT results in lower formation energies, thus making it more stable. The magnitude of absorption coefficient peak reduces in the ultraviolet region, and the absorption peaks spread over infrared and visible regions as well in phosphorous-adsorbed NTs.

A smart architecture of nickel-cobalt sulfide nanotubes assembled nanoclusters for high-performance pseudocapacitor

To develop a high-performance capacitive material with both superior power density and energy density, it is very important to construct a nanomaterial with a well-controlled structure. In this work, we report the preparation of NiCo2S4 nanotubes-assembled nanoclusters with a combination of hydrothermal and ion exchange processes. By optimizing the ion-exchange temperature, the tubular morphology can be both achieved and optimized. By tuning the conditions of the synthesis process, the diameter of the primary 1D structure can be increased, which leads to a compact cluster with decreased surface area. In particular, the sample prepared at 180 °C (NCS2) shows the morphology of nanoclusters assembled nanotubes with a wall thickness of about 7 nm. Such an architecture shows excellent electrochemical performance as a pseudocapacitor. It shows an initial specific capacitance of 1005 F g−1 at the current density of 1 A g−1 and remains 896 F g−1 at a current density of 20 A g−1. Moreover, it displays a favorable capacitance retention of 79.34% after 5000 cycles at a current density of 10 A g−1. Furthermore, the NCS2//AC asymmetric supercapacitor exhibits excellent rate performance (retaining 81% of the initial capacity when the current density increases from 1 A g−1 to 20 A g−1) and a high energy density of 52 Wh kg−1 at a power density of 9288 W kg−1. This work lays the foundation for the design and optimization of NiCo2S4 based nanostructured materials for energy storage.

Engineered Tubular Nanocomposite Electrocatalysts Based on CuS for High-Performance, Durable Glucose Fuel Cells and Their Stack

Exploring the electrochemically active and robust nanocatalysts for the efficient glucose oxidation reaction (GOR) and oxygen reduction reaction (ORR) garners enormous interest in the development of high performance glucose fuel cells (GFCs). The bifunctional copper sulfide (CuS) nanotubes and their specific surface engineering modification with nickel hydroxide (Ni(OH)2) and manganese dioxide (MnO2) nanostructures evade the constrains of existing GOR and ORR catalysts, respectively. On the basis of a systematic electrochemical analysis, the fundamental intrigue on the optimization and influences of core and shell nanostructures toward GFC performances is realized. Under alkaline conditions, CuS@Ni(OH)2 and CuS@MnO2 as GOR and ORR catalysts, respectively, demonstrate the maximum GFC power density of 1.25 mW cm–2 with 300 h of durability. Furthermore, the energy harvest from a GFC stack without any major performance loss in comparison with a single cell enunciate the excellent energetic capabilities of a stack design. These findings thus provide the compatible solutions for the thriving research areas of GOR and ORR, and by coupling the aforesaid research efforts, high performance and durable GFCs are established.

Facile Synthesis of Mesoporous and Thin-Walled Ni–Co Sulfide Nanotubes as Efficient Electrocatalysts for Oxygen Evolution Reaction

Development of high-performance and inexpensive electrocatalysts for oxygen evolution reaction (OER) is of important significance for sustainable energy conversion technologies. In this work, mesoporous Co and Ni–Co sulfide nanotubes with ultrathin nanowalls are designed and fabricated by a facile and template-free solvothermal method. The obtained CoS1.097 nanotubes can be used as an OER electrocatalyst, and the incorporation of Ni into the CoS1.097 lattice could further enhance the catalytic activity of the catalysts. The best-performing Ni0.13Co0.87S1.097 nanotubes exhibit high performance for OER with a small overpotential of 316 mV to achieve a current density of 10 mA cm–2 and excellent stability, which outperform those of commercial IrO2 and most of the studied Co-based OER catalysts. Our work demonstrates a new strategy to design highly efficient non-previous-metal OER electrocatalysts with unique structures and can be extended to other transition-metal-based systems.

Reaction temperature‐dependent growth of ZnS nanomaterials

Zinc sulphide (ZnS) nanobelts and nanotubes with high yield are prepared by a simple chemical vapour deposition approach at different reaction temperature. The as-prepared products are characterised by several characterisation methods such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Raman spectrum and photoluminescence spectrum. It shows that the as-prepared ZnS products possess well-hexagonal wurtzite structures. Possible growth mechanisms of ZnS nanomaterials are proposed based on nucleation and oriental attachment. Photoluminescence spectrum of ZnS nanobelts shows a blue emission peak centred at 425 nm, which could be attributed to the defects associated with oxygen vacancies. Finally, the wettability of ZnS nanobelts is also investigated by water contact angle characterisation.

Facile synthesis of hierarchical porous manganese nickel cobalt sulfide nanotube arrays with enhanced electrochemical performance for ultrahigh energy density fiber-shaped asymmetric supercapacitors

Hierarchical porous manganese–nickel–cobalt sulfide multi-tripod nanotube arrays on carbon nanotube fibers are prepared by a simple, cost-effective synthesis process.

One-dimensional cadmium sulphide nanotubes for photocatalytic water splitting.

Recently, a two-dimensional (2D) stable CdS monolayer with remarkable visible-light photocatalytic activity for water splitting has been proposed via theoretical calculations. It is also interesting to explore the photocatalytic activity of one-dimensional (1D) CdS nanotubes (CSNTs). In the present study, we have designed atomic models for CSNTs in the 5.2-19.2 Å outer diameter range and investigated the basic properties using density functional theory. It is shown that the CSNTs have negative strain energies when the diameter is beyond 6.4 Å; this indicates that they can possibly be folded from 2D CdS nanosheets. Moreover, all the CSNTs are direct-energy-gap semiconductors, and their energy gaps monotonically increase as the outer diameter increases. Tunable band gaps provide strong evidence for the effectiveness of nanostructuring on the electronic properties of CSNTs. Due to their perfect band gaps and band energies for photocatalytic activity, CSNTs exhibit potential application in visible light photocatalysis for water splitting. Because of their better photooxidation capabilities and smaller effective masses of holes, CSNTs are more promising photocatalytic materials for the oxygen evolution reaction in Z-scheme systems than monolayer CdS. In addition, the designed CdS nanotube-planar (CSNTP) hetero-dimension junction can be used as a direct Z-scheme photocatalyst. Electron transfer is observed in the interface region, which induces an internal electric field that effectively promotes the separation of charge carriers at the interface and reduces the probability of recombination. This study helps to further understand the advanced strategies to design and improve potentially efficient photocatalysts for the overall water splitting reaction.

Freestanding, Binder-Free Metal Sulfide Nanotubes Array As High Efficient Cathode for High Performance Lithium-O2 Batteries

Lithium-O2 battery as a novel energy conversion and storage device has attracted increasing attention [1]. However, it’s still facing great challenges for practical applications, including of large over potentials, poor cycling life [2]. Many reports have shown that a suitable cathode catalyst may could solve these problems [3]. Herein, metal sulfide (NiCo2S4) nanotube arrays on carbon paper were synthesized through a two-step hydrothermal method and then applied as a freestanding, binder-free cathode for lithium-O2 batteries directly. This novel air electrode could deliver a high initial discharge capacity of 12348.5 mAh g-1 with coulomb efficiency of 88.9% (Fig. 1a). Specifically, the discharge/charge over-potentials gap has been reduced to 0.73V, which is much lower than that of the counterpart metal oxide catalyst (NiCo2O4 NWs, 1.24 V)(Fig. 1b). Furthermore, this NiCo2S4 NTs@CFPs air electrode shows excellent long cycling life (485 cycles). This novel air electrode also exhibited great stability and reversibility. Interestingly, the discharge product of the air electrode with NiCo2S4 NTs is film-like amorphous Li2O2, which owns higher charge-transport properties and could be decomposed at a much lower potential than the common crystalline Li2O2. The excellent cell performances could be ascribed to the intrinsic properties of NiCo2S4, including high electrical conductivity and redox activity, the special hollow nanotubes structure, which could provide larger specific surface area and more active sites as well as enough space to accommodate the discharge products. The numerous pores distributed on the nanotube wall could also facilitate the transport of oxygen and electrolyte during the cell operation. This novel freestanding, binder-free air electrode sheds light on the application of metal sulfides not only on Lithium-air batteries, but also other metal-air batteries and fuel cells. This work was supported by National Natural Science Foundation of China (21673153, 21303114，51272167 and 51572181 ), National Key Research and Development Program of China (2016YFB0100200), Natural Science Foundation of the Higher Education Institutions of Jiangsu Province, China (15KJB480001) and Natural Science Foundation of Jiangsu Province, China (BK20161207).

A Hollow Tube‐on‐Tube Architecture of Carbon‐Tube‐Supported Nickel Cobalt Sulfide Nanotubes for Advanced Supercapacitors

AbstractThe nanotube structure has unique advantages, such as a large electroactive surface area and shorter diffusion pathway for ions/electrons for energy storage. In this paper, we fabricated a novel supercapacitor electrode material based on a composite material with a hollow tube‐on‐tube architecture. This architecture, which was derived from the sustainable Juncus roemerianus, consisted of nickel cobalt sulfide nanotubes coating the exterior and interior of carbon tubes. The obtained hollow tube‐on‐tube structure is similar to a reservoir, in which ions/electrons can diffuse via a bi‐directional method and supply and transfer to the carbon tube interface. Consequently, this structure can probably provide more electrochemically active sites for its application in high‐performance asymmetric supercapacitors (ASCs). The assembled ASC device also presents superior specific capacitance (83 F g−1 at the current density of 0.5 A g−1), high energy density (27.7 Wh kg−1 at a power density of 263.6 W kg−1), and good cycling stability (72.23 % capacitance retention after 3000 cycles). Therefore, the NiCo2S4/bio‐carbon electrode with hollow tube‐on‐tube structure is not only a promising electrode material, but also can be applicable to energy storage and conversion devices.

Influence of curvature strain and Van der Waals force on the inter-layer vibration mode of WS2 nanotubes: A confocal micro-Raman spectroscopic study

Transition-metal dichalcogenides (TMDs) nanostructures including nanotubes and monolayers have attracted great interests in materials science, chemistry to condensed matter physics. We present an interesting study of the vibration modes in multi-walled tungsten sulfide (WS2) nanotubes prepared via sulfurizing tungsten oxide (WO3) nanowires which are investigated by confocal micro-Raman spectroscopy. The inter-layer vibration mode of WS2 nanotubes, A1g, is found to be sensitive to the diameter and curvature strain, while the in-plane vibration mode, E12g, is not. A1g mode frequency shows a redshift by 2.5 cm−1 for the multi-layered nanotubes with small outer-diameters, which is an outcome of the competition between the Van der Waals force stiffening and the curvature strain softening. We also show that the Raman peak intensity ratio is significantly different between the 1–2 wall layered nanotubes and monolayer flat sheets.