CuS Nanosheets Research Articles

Multilayer Core-Sheath Wires with Cus Nanosheet Arrays and Pedot Sheaths for High-Performance Fiber-Shaped Asymmetric Supercapacitors

Multilayer Core-Sheath Wires with Cus Nanosheet Arrays and Pedot Sheaths for High-Performance Fiber-Shaped Asymmetric Supercapacitors

Engineering kinetics-favorable 2D graphene@CuS with long-term cycling stability for rechargeable magnesium batteries

Rechargeable magnesium batteries (rMBs) are regarded as one of the most promising next-generation energy storage devices due to their safe, cost-effective, and dendrite-free Mg deposition advantages. However, a great challenge still continues for the development of rMBs due to lacking capable cathodes with favorable electrochemical reaction kinetics and excellent structural stability. To achieve high electrochemical performances in rMBs, electrochemical reaction kinetics and structural stability of cathode materials should be enhanced by material design and optimization. Herein, the graphene-supported CuS nanosheets (CuS@rGO) with surface-to-surface two-dimensional architecture are fabricated by a facile microwave inorganic chemical synthesis method. By stacking CuS nanosheets on reduced graphene oxide, it is found that the Mg2+ cations storage performances can be significantly improved. The CuS@rGO positive-electrode can deliver a high discharge capacity of 421 mAh g−1 at 50 mA g−1 current density. A specific capacity of 51 mAh g−1 is maintained after 500 cycles at 1000 mA g−1 current density. Such excellent electrochemical performances could be ascribed to the conductive network construction of the two-dimensional CuS@rGO. The CuS@rGO can serve as a promising cathode material for rechargeable magnesium batteries.

Ultrathin CuSe nanosheets as the anode for sodium ion battery with high rate performance and long cycle life

Sodium-ion batteries (SIBs) have quickly developed to be important alternative energy storage devices other than lithium-ion batteries in the explosively growing market of large-scale grid storage and low-speed electric vehicles, thanks to their low cost and the abundance of sodium resources. However, the sluggish sodiation kinetics remains major concerns in design of competent anode materials for SIBs. Herein, by using a one-step, facile hydrothermal synthesis, well-defined ultrathin CuSe nanosheets (thickness of ∼5 nm) were fabricated, leading to a narrow bandgap, flexible Cu–Se bonding and abundant electrochemically active sites. As a result, the product presents high rate performance: a high capacity of 404 mAh g–1 is achieved at a current density of 0.1 A g–1 after 100 operation cycles, and the capacity can be maintained to 276 mAh g–1 even at a high current density of 20 A g–1. According to kinetics analysis, surface capacitance contributes dominatly in the electrochemical process, facilitating fast sodiation. Moreover, coordinated the ultrathin thickness and two-dimensional morphology of the nanosheets with their three-dimensional open framework, the volume expansion-related issues during charge/discharge processes have been well addressed, resulting in ultrahigh cycling stability (with 100% capacity maintenance after 500 cycles at 0.5 A g–1) together with ultralong cycle life (up to 10,000 working cycles) at 20 A g–1.

Facile low temperature synthesis of homogeneous CuS nanosheets: An effect of Ga loading on structural, optical, nonlinear and antimicrobial properties

Herein, we report the facile synthesis and characterization of gallium (Ga) doped copper sulfide (CuS) nanosheets (Ga:CuS NSs) via chemical co-precipitation (CCP) route. The phase was studied by XRD, Raman and XPS analyses. Furthermore, from applications point of view, the UV–Vis–NIR, Z-scan measurements, and antibacterial studies were performed on the prepared NSs. XRD/Raman analysis reveals hexagonal structure of NSs and the crystallite size was calculated in range of 6–13 nm. SEM images unveiled an increase in grains size with Ga contents. The band gap values of Ga:CuS NSs were calculated from diffuse reflectance spectra (DRS) using Kubelka-Munk (K-M) theory, which are found in the range of 2.2 – 2.4 eV. The nonlinear absorption coefficient (β) and nonlinear refractive index (n2) were found in range of 1.73 × 10−8 – 1.85 × 10−8 cm/W and 2.61 × 10−13 – 2.15 × 10−13 cm2/W, respectively. The antimicrobial findings showed that the tested Ga:CuS NSs are most effective against Gram positive bacteria. The outcomes spotlight the multifunctional nature of the prepared Ga:CuS NSs for a wide-range of applications.

Near-infrared responsive sulfur vacancy-rich CuS nanosheets for efficient antibacterial activity via synergistic photothermal and photodynamic pathways

Defect engineering has been proven to be an effective approach for electronic structure modulation and plays an important role in the photocatalytic performance of nanomaterials. In this study, a series of CuS nanosheet sulfur vacancies (VS) are constructed by a simple hydrothermal synthesis method. The CuS with the highest VS concentration exhibits strong antibacterial performance, achieving bactericidal rates of 99.9% against the Gram-positive Bacillus subtilis and Gram-negative Escherichia coli bacteria under 808 nm laser irradiation. Under illumination, the temperature of the catalyst increases from 23.5 °C to 53.3 °C, and with a high photothermal conversion efficiency of 41.8%. For E. coli and B. subtilis, the reactive oxygen species (ROS) production that is induced by the CuS group is 8.6 and 9.6 times greater, respectively, than that of the control group. The presence of VS facilitates the enhancement of the light absorption capacity and the separation efficiency of electron-hole pairs, thereby resulting in improved photocatalytic performance. The synergistic effect of photothermal therapy (PTT) and photodynamic therapy (PDT) is aimed at causing oxidative damage and leading to bacterial death. Our findings provide an effective antibacterial strategy and offer new horizons for the application of CuS catalysts with VS in the NIR region.

Copper sulfide with morphology-dependent photodynamic and photothermal antibacterial activities

Metal chalcogenides have been intensively investigated as antibacterial agents due to their unique structures and superior photoactivities. Herein, various structures of copper sulfide (CuS), a metal chalcogenide, such as microspheres (MSs), nanosheets (NSs), and nanoparticles (NPs), were developed in this work for antibacterial applications. A hydrothermal process was utilized to synthesize CuS MSs, CuS NSs, and CuS NPs. Under simulated solar light and near-infrared (NIR) light irradiation, the antibacterial behaviors, reactive oxygen species (ROS) production, and light-driven antibacterial mechanisms of CuS MSs, CuS NSs, and CuS NPs were demonstrated with the bacterium Escherichia coli (E. coli). Bacterial growth curves and ROS generation tests indicated that CuS NSs and CuS NPs had higher light-driven antibacterial activities than that of CuS MSs. ROS of hydroxyl (·OH) and superoxide anion radicals (O2−) were investigated via an electron spin resonance (ESR) spectroscopic analysis by respectively incubating CuS MSs, CuS NSs, and CuS NPs with E. coli under simulated solar light irradiation. Furthermore, E. coli incubated with CuS NPs and CuS NSs showed substantial bacterial degradation after NIR laser irradiation, which was attributed to their photothermal killing effects. Light-driven antibacterial mechanisms of CuS NSs and CuS NPs were investigated, and we discovered that under simulated solar and NIR light irradiation, CuS NSs and CuS NPs produced photoinduced electrons, and the copper ions and photoinduced electrons then reacted with atmospheric moisture to produce hydroxide and superoxide anion radicals and heat, resulting in bacterial mortality.

Plasmonic AuPt@CuS Heterostructure with Enhanced Synergistic Efficacy for Radiophotothermal Therapy.

Integrating multifunctional nanostructures capable of radiotherapy and photothermal ablation is an emerging alternative in killing cancer cells. In this work, we report a novel plasmonic heterostructure formed by decorating AuPt nanoparticles (NPs) onto the surfaces of CuS nanosheets (AuPt@CuS NSs) as a highly effective nanotheranostic toward dual-modal photoacoustic/computed tomography imaging and enhanced synergistic radiophotothermal therapy. These heterostructures can confer higher photothermal conversion efficiency via the local electromagnetic enhancement as well as a greater radiation dose deposition in the form of glutathione depletion and reactive oxygen species generation. As a result, the depth of tissue penetration is improved, and hypoxia of the tumor microenvironment is alleviated. With synergistic enhancement in the efficacy of photothermal ablation and radiotherapy, the tumor can be eliminated without later recurrence. It is believed that these multifunctional heterostructures will play a vital role in future oncotherapy with the enhanced synergistic effects of radiotherapy and photothermal ablation under the guided imaging of a potential dual-modality system.

Derivatives (Cu/CuO, Cu/Cu2O, and CuS) of Cu superstructures reduced by biomass reductants

Metallic Cu is considered as the promising functional material owing to its high conductivity and harmlessness. Here, metallic Cu which presents a unique interconnected and continuous structure (Cu superstructure) is prepared using Magnolia grandiflora leaves as the biomass reductant, a green process which avoided the release of harmful gases and massive energy consumption. What's more, Cu/CuO, Cu/Cu2O, and CuS nanosheets with different sizes were fabricated using Cu superstructure as the substrate via facile methods, and the morphology is regulated by controlling the relevant factors. The electrochemical sensors based on the three derivations were fabricated to study the sensing performance of glucose. The unique structure of nanosheets encapsulating Cu superstructure guarantees the excellent conductivity of Cu/CuO and Cu/Cu2O composites. Moreover, the electrochemical stability is improved owing to the nanosheet protective layer. Although no metallic Cu was maintained in CuS, the integrated multilayer nanosheets endow CuS with short channels for fast interlayer electronic transmission and with structural stability.

Highly efficient field emission properties of vertically aligned 2D CuSe nanosheets: An experimental and theoretical investigation

We report the synthesis of klockmannite (CuSe) via a three-probe electrochemical set-up (chronoampereometry). The structural properties are examined by X-ray diffraction and Raman spectroscopy. Field emission scanning electron microscopy (FESEM) analysis revealed the formation of vertically aligned CuSe nanosheets with an average thickness of 34 nm and an average lateral size of 700 nm. The CuSe nanosheets exhibit impressive field electron emission characteristics with a turn-on field of 1.4 V/µm for 10 µA/cm2 emission current density. Also, a high current density of 5.8 mA/cm2 is observed at a relatively low applied field of 3.1 V/µm. Complementary first-principles DFT calculations show that CuSe displays metallic conductivity, and the (001) surface has a low work function of 5.12 eV, which is believed to be responsible for the impressive field emission characteristics.

Iron Doped in the Subsurface of CuS Nanosheets by Interionic Redox: Highly Efficient Electrocatalysts toward the Oxygen Evolution Reaction.

Modifying the electronic structure of electrocatalysts by metal doping is favorable to their electrocatalytic activity. Herein, by a facile one-pot redox process of Fe(III) and Cu(I), Fe(II) was successfully doped into the subsurface of CuS nanosheets (NSs) for the first time to obtain a novel electrocatalyst (Fesub-CuS NSs) that possesses not only subtle lattice defects but also an atomic-level coupled nanointerface, greatly enhancing the oxygen evolution reaction (OER) performances. Meanwhile, Fe(II) and Fe(III) coexisting in Fesub-CuS nanosheets are favorable to OER through valence regulation. As expected, by simultaneously controlling the abovementioned three factors to optimize Fesub-CuS nanosheets, they display a lower overpotential of 252 mV at a current density of 20 mA cm-2 for OER, better than 389 mV for pristine CuS nanosheets. This discovery furnishes low-cost and efficient Cu-based electrocatalysts by metal doping. Density functional theory (DFT) calculations further verify that Fesub-CuS(100) is thermodynamically stable and is more active for OER. This research provides a strategy for the atomic-scale engineering of nanocatalysts and also sheds light on the design of novel and efficient electrocatalysts.

High photocatalytic and photoelectrochemical performances of the CuSe/MoSe2 2D/2D face-to-face heterojunction photocatalyst

Photocatalysis and photoelectrochemistry are effective approaches to solve the energy and environmental crises. The suitable catalyst is the key for photocatalysis and photoelectrochemistry. Metal selenides have good prospects for their narrow band gap, low internal resistance, and related high photoelectric performance. In this work, a novel CuSe/MoSe2 2D/2D face-to-face heterojunction photocatalyst was obtained through a simple hydrothermal route. These CuSe/MoSe2 2D/2D heterojunction photocatalysts show excellent performance in photocatalytic degradation and photoelectrochemistry. With an optimized CuSe loading ratio of 2.5%, the heterojunction photocatalyst displays an improved degradation rate by 4.5 times and increased photocurrent by 7.6 times than the pristine MoSe2. The large improvement in photocatalysis and photoelectrochemistry can be ascribed to the 2D/2D face-to-face contact between MoSe2 nanoplates and CuSe nanosheets. Given this mode, the interface between CuSe and MoSe2 can be maximized, and good binding can be obtained. The electrochemical impedance and the fluorescence emission spectroscopic methods confirm that the internal resistance is reduced, whereas the separation efficiency is improved. This work demonstrates the prospect of metal selenides used in environmental treatment and hydrogen energy utilization.

An Energetic CuS-Cu Battery System Based on CuS Nanosheet Arrays.

The development of low-cost and high-energy aqueous battery technologies is of significance for renewable and stationary energy applications. However, this development has been bottlenecked by poor conductivity, low capacity, and limited cycling stability of existing electrode materials. In this work, we report on an energetic aqueous copper ion system based on CuS nanosheet arrays, taking profit of high conductivity of CuS and efficient charge carrier of copper ions. Electrochemical results reveal a high capacity of 510 mAh g-1, robust rate capability of 497 mAh g-1 at a high rate of 7.5 A g-1, and ultrastable cycling by retaining 91% of the initial capacity over 2500 cycles. The charge-storage mechanism was systematically investigated by ex situ and in situ techniques involving a reversible transition from CuS to Cu7S4 and to Cu2S through the redox of Cu2+/Cu+. Moreover, we demonstrate a hybrid ion battery consisting of CuS positive electrode and Zn negative electrode, which affords an energy and power of 286 Wh kg-1 and 900 W kg-1, respectively, on the basis of both electrodes, exceeding many aqueous battery systems.

CuS Nanosheet Arrays for Electrochemical CO2 Reduction with Surface Reconstruction and the Effect on Selective Formation of Formate

Copper-based catalysts have shown excellent performance in electrochemical CO2 reduction, but there has not been much study on copper sulfides. In our work, a simple and low-temperature chemical ba...

Metal–Organic Framework-Derived CuS Nanocages for Selective CO 2 Electroreduction to Formate

Electroreduction of CO2 to target products with high activity and selectivity has techno-economic importance for renewable energy storage and CO2 utilization. Herein, we report a hierarchical CuS h...

Room Temperature Wafer-Scale Synthesis of Highly Transparent, Conductive CuS Nanosheet Films via a Simple Sulfur Adsorption-Corrosion Method.

The development of highly conductive electrodes with robust mechanical durability and clear transmittance in the visible to IR spectral range is of great importance for future wearable/flexible electronic applications. In particular, low resistivity, robust flexibility, and wide spectral transparency have a significant impact on optoelectronic performance. Herein, we introduce a new class of covellite copper monosulfide (CuS) nanosheet films as a promising candidate for soft transparent conductive electrodes (TCEs). An atmospheric sulfur adsorption-corrosion phenomenon represents a key approach in our work for the achievement of wafer-scale CuS nanosheet films through systematic control of the neat Cu layer thickness ranging from 2 to 10 nm multilayers at room temperature. These nanosheet films provide outstanding conductivity (∼25 Ω sq-1) and high transparency (> 80%) in the visible to infrared region as well as distinct flexibility and long stability under air exposure, yielding a high figure-of-merit (∼60) that is comparable to that of conventional rigid metal oxide material-based TCEs. Our unique room temperature synthesis process delivers high quality CuS nanosheets on any arbitrary substrates in a short time (< 1 min) scale, thus guaranteeing the widespread use of highly producible and scalable device fabrication.

Cation exchange on colloidal copper selenide nanosheets: a route to two-dimensional metal selenide nanomaterials

Up to 5 μm largeca.5 nm thick PbSe, HgSe, SnCuSe, ZnCuSe, and Cu–Zn–Sn–Se nanosheets (NSs) were synthesizedviacation exchange starting from CuSe NSs, offering a universal platform for the synthesis of other metal selenide 2D nanomaterials.

Functional integration of hierarchical core–shell architectures via vertically arrayed ultrathin CuSe nanosheets decorated on hollow CuS microcages targeting highly effective sodium-ion storage

A hierarchical core–shell architecture of vertically arrayed ultrathin CuSe nanosheets decorating on hollow CuS microcages affords exceptional sodium storage performance with an admirable 303.1 mA h g−1 at 20.0 A g−1 after 1500 cycles.

CuS Nanosheet Decorated Bi5O7I Composite for the Enhanced Photocatalytic Reduction Activity of Aqueous Cr(VI)

CuS Nanosheet Decorated Bi₅O₇I Composite for the Enhanced Photocatalytic Reduction Activity of Aqueous Cr(VI)

Facile microwave-assisted synthesis and characterization of CuSe nanosheets: effect of EDTA concentration

A facile microwave-assisted synthesis approach was used to synthesize a high-quality CuSe nanosheets at different concentration of ethylenediaminetetraacetic acid (EDTA). Analysis of the XRD result revealed the formation of single-phase CuSe with hexagonal (Klockmannite) crystal structure. The crystallite size was found to decrease from 73.10 to 8.40 nm with an increase in EDTA concentration. EDX analysis revealed that all the samples were of the pure phase CuSe corresponding to a 1:1 atomic ratio. Three Raman vibrational modes ascribed to the vibrational bands of CuSe were detected from the Raman spectroscopy. TEM result revealed that a well-tailored layered hexagonal structure was achieved at higher EDTA concentration. The particle size obtained from FESEM micrographs was found to decrease from 75.10 to 12.20 nm with an increase in EDTA concentration. Moreover, the optical bandgap obtained from the UV–Visible diffuse reflectance spectroscopy was found to increase alongside an increase in EDTA concentration, which is attributed to the decrease in the particle size of the as-synthesized CuSe nanosheets. The maximum PL emission of all the samples was centered at 600 nm under an excitation wavelength of 400 nm. Therefore, CuSe nanosheets obtained by the described method could be of great benefit in many applications particularly in optoelectronics and solar cell applications.

Facile synthesis of 3D/2D Cu2Se cauliflower/CuS nanosheets composite as a binder-free electrode for high-performance asymmetric solid-state supercapacitors

In this work, we demonstrate a facile, binder-free technique to fabricate 3D Cu2Se nano-cauliflower with 2D CuS nanosheets as a composite on Ni foam by co-electrodeposition technique for high-performance solid-state supercapacitor. The morphology of the composite (Cu2Se@CuS) was confirmed by the scanning electron microscope and the crystal phases of monoclinic Cu2Se and hexagonal CuS were obtained using X-ray diffraction technique. The Cu2Se@CuS composite delivered an ultra-high specific capacitance of 2727 F g−1, compared to its single compound material Cu2Se (1925 F g−1) and CuS (1156 F g−1), respectively at current density of 2.5 mA cm−2 in three-electrode configuration. Ni foam, as a binder-free conducting substrate, acts as uniform growth point for electrode materials and accelerates the transportation of ions throughout the electrode while the synergistic effect of Cu2Se and CuS and their efficient redox properties contribute to faster diffusion path for both electrolyte ions and electrons. Moreover, the assembled asymmetric solid-state supercapacitor Cu2Se@CuS//AC with PVA-KOH gel as supporting electrolyte delivered an excellent specific energy of 42.7 Wh Kg−1 (1.95 Wh cm−3) at specific power of 381 W kg−1 (17.55 W cm−3). The solid-state device achieved a good cyclic stability of 70.2% capacitance retention even after 8000 cycles. This technique of a simple co-electrodeposition method outlined in this work to engineer 3D/2D nanostructured electrode provides a potential strategy for fabricating high performance, free-standing energy storage devices.