Nanosheets Nanocomposites Research Articles

Visible/near-infrared light response VOPc/carbon nitride nanocomposites: VOPc sensitizing carbon nitride to improve photo-to-current conversion efficiency for fabricating photoelectrochemical diclofenac aptasensor

A novel photoelectrochemical (PEC) aptasensor for diclofenac detection, based on visible/near-infrared (vis/NIR) light-responsive vanadyl-phthalocyanine/graphitic carbon nitrid nanosheet (VOPc/CN) nanocomposites, was successfully fabricated. In this work, the first coupling of CN and VOPc with a facile solution–phase method was prepared and applied to PEC sensing. The UV–vis diff ;use reflection spectra (DRS) indicated that VOPc is an excellent photosensitizer when applied to the surface of CN. It promoted CN light absorption to the visible-NIR region, which greatly enhanced the light excitation capability. The PEC signal of the VOPc/CN nanocomposites improved 2.7 and 12.42-fold compared with pure VOPc and CN, respectively, indicating that VOPc/CN nanocomposites have good photoelectric activity and enhanced photo-to-current conversion efficiency. As a result, VOPc sensitized CN was introduced as a covalent immobilizing PEC aptasensor for the sensitive and selective determination of diclofenac (DCF). Under optimal conditions, the fabricated PEC biosensor exhibited good PEC performances with high sensitivity, a low detection limit of 0.03 nM (S/N = 3) and a wide linear response, in the range of 0.1-500 nM. This was due to the specific interaction between DCF and the aptamer. It is concluded that VOPc/CN nanocomposites are potentially promising photoactive materials for applications in PEC biosensors, as well as for photocatalysis and other related fields.

Constructing highly dispersed 0D Co3S4 quantum dots/2D g-C3N4 nanosheets nanocomposites for excellent photocatalytic performance

The development of noble-metal-free catalysts with high efficiency photocatalytic properties is critical to the heterogeneous catalysis. Herein, zero-dimensional (0D) metal sulfide quantum dots/two-dimensional (2D) g-C3N4 nanosheets (Co3S4/CNNS) nanocomposites are synthesized by a two-step method, including the ways of in-situ deposition and water bath. The highly dispersed Co3S4 quantum dots (particle size is 2–4 nm) are evenly and tightly fixed on CNNS, which can be used as co-catalyst to effectively replace noble metals to improve the photocatalytic properties of CNNS. Co3S4/CNNS-900 has the apparent quantum efficiency, which is up to 7.85% at 400 nm. At the same time, the H2 evolution rate of Co3S4/CNNS-900 is 20,536.4 μmol g−1 h−1, which is 555 times than CNNS. The excellent photocatalytic performance is due to the highly dispersed Co3S4 quantum dots on 2D CNNS, which facilitate the formation of more active sites, Co3S4/CNNS promotes the separation and migration of photogenerated carriers, shortens the migration distance of photogenerated carriers, and eventually leads to an increase of the photocatalytic performance.

Facile synthesis of SnSe2 nanoparticles supported on graphite nanosheets for improved sodium storage and hydrogen evolution

SnSe2 attract enormous attention in sodium-ion batteries since it has a high theoretical specific capacity of 756 mAh g−1. However, the large volume expansion of SnSe2 during Na+ insertion/extraction processes seriously affects the cyclic stability of SnSe2-based electrodes. Herein, 5 nm SnSe2 nanoparticles supported on the graphite nanosheets are synthesized by two-step high-energy ball milling to obtain SnSe2/graphite nanosheet nanocomposite. By virtue of the ultrafine SnSe2 nanoparticles and the porous carbon skeleton constructed by highly conductive graphite nanosheets, the as-obtained SnSe2/graphite nanosheet nanocomposite presents a high specific capacity of 638.6 mAh g−1 at 200 mA g−1, excellent rate capacity of 517.8 mAh g−1 at 5 A g−1, and ultralong cyclic life (252.9 mAh g−1 after 4000 cycles at 2 A g−1), which are superior to the previously reported SnSe2-based composites. Ex-situ X-ray diffraction, Raman mapping, high-resolution transmission electron microscope, and X-ray photoelectron spectroscopy characterizations show that the crystal structure of SnSe2 is reversible during sodium ions insertion/extraction processes and the distribution of SnSe2 nanoparticles on graphite nanosheets remains uniform. Moreover, this nanocomposite can not only be used as a high-performance anode for sodium-ion full cells, but also as an improved electrocatalyst for hydrogen evolution reaction.

Preparation of electroactive shape memory polyurethane/graphene nanocomposites and investigation of relationship between rheology, morphology and electrical properties

In this study, electroactive shape-memory polyurethane/graphene nanosheets nanocomposites were prepared. Shape-memory polyurethane (SMPU) was synthesized from polycaprolactone-diols (PCL-diols) with a molecular weight of 4000 g/mol, hexamethylene diisocyanate (HDI), and 1,4-butanediol (BDO) with a molar ratio of 5 (HDI)/4 (BDO)/1 (PCL) via solution polymerization. Nanocomposites were prepared from neat SMPU and mono-layered fluffy graphene nanosheets through solution mixing method. Electrical resistivity test was employed to investigate the electrical conductivity threshold of the nanocomposites. The results showed that the nanocomposites with graphene content higher than 1.5 wt% had a reasonable conductivity to respond to the electrical current. Fourier transform infrared (FTIR) spectroscopy confirmed the interaction between graphene nanosheets and SMPU chains by variation of hydrogen bonding content. Differential scanning calorimetry (DSC) thermograms and X-ray diffraction (XRD) patterns showed that the crystalline structures of SMPU have been changed by incorporating of graphene nanosheets. Rheological examination showed that the percolation threshold to create a graphene network structure was 1.5 wt%. Field emission scanning electron microscopy (FE-SEM) images revealed percolation of graphene nanosheets in the electrically conductive nanocomposites. Mechanical and shape-memory tests revealed that the mechanical properties and shape-memory parameters were improved by the addition of graphene nanosheets. The changes in surface temperature under the examination with voltage of 75 V indicated that the temperature of the electrically conductive samples was significantly increased by flowing of electrical current. This increase in temperature led responsivity to the electrical current in SMPU nanocomposites containing 2 and 3 wt% graphene nanosheets.

Adsorption of Anionic Dye on Graphene Nanosheets Doped with Ag Nanoparticles: Kinetics and Thermodynamic Study

AgNPs doped graphene nanosheets (Ag@GNs) nanocomposites were prepared using an environment-friendly one-pot hydrothermal method. The performance in the removal of anionic dye methyl orange (MO) onto graphene-based materials, such as graphene oxide (GO), graphene nanosheets (GNs) and Ag@GNs were investigated extensively. Ag@GNs displays a relative high adsorption capacity of 75.87 mg g–1 at 318 K, and can be easily recycled from liquid-phase owing to the hydrophobicity of GNs. On the base of XRD, FTIR and UV–Vis analysis, the excellent ability of Ag@GNs to MO is mainly due to the high dispersion of AgNPs, which can result in strong π–π interactions, electrostatic interactions between the dye molecules and GNs. Furthermore, SEM results show that the doped AgNPs effectively avid the aggregation of GNs, which is necessary for the adsorption of MO molecules. Finally, the kinetics, isotherm and thermodynamics results demonstrate that the adsorption of MO on Ag@GNs are mainly controlled by chemisorption and endothermic in nature, which matches well with Langmuir isotherm model and kinetic data reveal a good correlation to a pseudo-second-order equation.

Facile synthesis of oxidized multi-walled carbon nanotubes functionalized with 5-sulfosalicylic acid/MoS2 nanosheets nanocomposites for electrochemical detection of copper ions

Copper is one of the essential trace elements in human body which plays a vital role in the processes of fundamental physiology. Therefore, analysis and detection of copper ions has attracted tremendous attention. In this paper, an electrochemical sensor was successfully developed based on 5-sulfosalicylic acid modified nanocomposite of molybdenum disulfide nanosheets and oxidized multi-walled carbon nanotubes (SSA/MoS2/o-MWCNTs). The nanocomposite was characterized by scanning electron microscopy, transmission electron microscopy, element mapping, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and electrochemical measurements. Then, nanocomposite-modified glassy carbon electrode was used for the detection of Cu2+. Electrochemical analysis of Cu2+ was performed by differential pulse voltammetry, and the effects of pH, deposition potential, and deposition time were investigated. The results showed that the peak current increased linearly with increasing Cu2+ concentration over the range of 0.1–11 μM and a detection limit of 0.057 μM (S/N = 3). Finally, the developed sensor was applied for the analysis of Cu2+ in lake water and dairy products, and the results were consistent with the results of ICP-MS analysis. Therefore, this work demonstrates that the proposed electrochemical sensor can be easily used for the daily monitoring of Cu2+.

Preparation and characterization of silicone rubber/graphene nanosheets nanocomposites by in-situ loading of the coupling agent

Inexpensive approach to fully disperse graphene nanosheet (GNS) in silicone rubber (SR) by the addition of (3-Aminopropyl) triethoxysilane (APTES) as the coupling agent is presented in this study. The effects of GNS loading and presence of APTES on the cure characteristics, dynamic-mechanical, rheological and mechanical properties of the resulting SR compounds were systematically studied by rheometry, DMTA and tensile testing, respectively. The obtained results were correlated with the microstructure of the samples investigated by SEM and TEM analyses. Vulcanization curves revealed that the GNS and the coupling agent had an accelerating effect on the cure kinetics of the SR compounds leading to a steady decrease in scorch time and optimum cure time along with a gradual increase in the effective torque value. Morphological results showed that the GNSs could disperse more homogeneously within SR matrix using a simple solution mixing approach by in-situ loading of APTES. DMTA results showed restricted relaxation processes in GNS-reinforced SR systems in comparison with the pure SR, with more pronounced effect for the system containing APTES owing to improved interactions between graphene and SR which prevented the molecular mobility of neighboring chains of SR matrix. The tensile data demonstrated about 20% rise of modulus in the GNS-filled rubber nanocomposites in the presence of APTES. Low-frequency rheological properties including the storage modulus (G′), the loss modulus (G″), and complex shear viscosity (η*) showed a significant increase of about 10-fold, 75% and 20%, respectively, with the incorporation of APTES and GNS. Thus it could be expected that APTES had a substantial potential to be applied in-situ as the coupling agent to fabricate SR/GNS nanocomposites with exfoliated GNS morphology and increased the rheological and mechanical properties.

A facile preparation of FePt-loaded few-layer MoS2 nanosheets nanocomposites (F-MoS2-FePt NCs) and their application for colorimetric detection of H2O2 in living cells

BackgroundRapid and sensitive detection of H2O2 especially endogenous H2O2 is of great importance for series of industries including disease diagnosis and therapy. In this work, uniform FePt nanoparticles are successfully anchored onto Few-layer molybdenum disulfide nanosheets (F-MoS2 NSs). The powder X-ray diffraction, transmission electron microscopy, UV–Vis spectra and atomic force microscopy were employed to confirm the structure of the obtained nanocomposites (F-MoS2-FePt NCs). The prepared nanocomposites show efficient peroxidase-like catalytic activities verified by catalyzing the peroxidation substrate 4,4′-diamino-3,3′,5,5′-tetramethylbiphenyl (TMB) with the existence of H2O2.ResultsThe optimal conditions of the constructed colorimetric sensing platform is proved as 35 °C and pH 4.2. Under optimal catalytic conditions, the detection limit for H2O2 detection reaches 2.24 μM and the linear ranger is 8 μM to 300 μM. Furthermore, the proposed colorimetric sensing platform was successfully utilized to detect the intracellular H2O2 of cancer cells (MCF-7).ConclusionsThese findings indicated that the F-MoS2-FePt-TMB-H2O2 system provides a potential sensing platform for hydrogen peroxide monitoring in living cells.

Low- and High-Index Faceted Pd Nanocrystals Embedded in Various Oxygen-Deficient WO x Nanostructures for Electrocatalytic Oxidation of Alcohol (EOA) and Carbon Monoxide (CO).

This work suggests a modest hydrothermal method applied for the synthesis of oxygen-deficient WO x ( x = 2.75, 2.83, and 2.94) nanomaterials with various morphologies, such as bundled nanorods (NR), nanobelts (NB), and nanosheets (NS), by changing the inorganic additives, such as HCl, NaHSO4, and HNO3. In addition, WO x-supported high- and low-index faceted Pd nanoparticles (Pd-WO2.75 NB, Pd-WO2.83 NR, and Pd-WO2.94 NS) have been successfully synthesized by a facile sonochemical method to enhance the high electrocatalytic activity of electrocatalysts for alcohol electrooxidation, including ethanol, ethylene glycol, and glycerol. Among the three different electrocatalysts, the versatile high-index {520} faceted Pd nanoparticles on WO2.75 NB (Pd-WO2.75 NB) show better electrocatalytic performance compared to low-index {100} faceted Pd-WO2.83 NR and Pd-WO2.94 NS nanocomposites. This work has identified that the high-density low-coordinated surface atom of Pd strongly interacts with alcohol, which facilitates C-C bond cleavage and may prevent the CO poisoning of nanoparticles. Furthermore, the high concentration of oxygen-deficient nano compositesprovided additional benefit for the generation of OH species and boosted the electrocatalytic performance of alcohols as well.

Ultra-Small Fe₃O₄ Nanoparticles Decorated WS₂ Nanosheets with Superior Electrochemical Properties for Supercapacitors.

Fe₃O₄ nanoparticles/WS₂ nanosheets nanocomposite was successfully synthesized in this study by a one-step hydrothermal method. Three different contents of Fe₃O₄ in the nanocomposite were prepared by changing the quantity of FeCl₃·6H₂O, ascorbic acid and NaHCO₃. Fe₃O₄ nanoparticles are about 3 nm in diameter and combined with WS₂ to form stable heterojunctions, which are good for releasing the volume change of electrode materials in charge/discharge procedure. Because of the large theory capacitance of Fe₃O₄ nanoparticle, the specific capacitance of the Fe₃O₄ nanoparticles/WS₂ nanosheets nanocomposites increase with increasing content of Fe₃O₄ nanoparticles. When the weight ratio for Fe₃O₄ nanoparticles to WS₂ nanosheets is up to 8:10, the specific capacitances of the nanocomposite are 83.85 F g-1 and 149.25 F g-1 as the scanning rate at 20 mV s-1 and the current density at 0.5 A g-1, respectively. Both of them of Fe₃O₄ nanoparticles/WS₂ nanosheets are as almost 7 times high as that of WS₂ nanosheets under the same measurement condition. This work shows that the Fe₃O₄ nanoparticles/WS₂ nanosheets nanocomposite will be a kind of potential electrode materials for supercapacitors.

Controlling the phenolic resin-based amorphous carbon content for enhancing cycling stability of Si nanosheets@C anodes for lithium-ion batteries

Carbon-coated Si nanosheets (Si NSs@C) nanocomposites with different carbon contents are successfully controlled and synthesized by the method of DC arc-discharge plasma, followed by phenolic resin pyrolysis at high temperature. The electrochemical performances of these nanocomposites as the anodes of lithium-ion batteries (LIBs) are investigated. The Si NSs with an average size of 31 nm and a thickness of 2.4 nm are surrounded by phenolic resin-derived amorphous carbon, forming a cladding structure. In the nanocomposites, Si NSs play a leading role in the reaction with Li+ ions, while the amorphous carbon mainly provides a highly conductive matrix for good contact among Si NSs active phases, which further facilitates the diffusion and transport of Li+ ions and electrons. The carbon matrix can also protect Si NSs from direct contact with the electrolyte, to ensure the formation of stable SEI films in cycles. Electrochemical performances indicate that the Si NSs@C nanocomposite electrode with the carbon content of 66.4 wt% delivers a stable discharge specific capacity of 822 mAh g−1 at a current density of 100 mA g−1 after 200 cycles and a better rate capability, confirming the predominant role of the controlled carbon content in the enhancement of the cycling stability of such Si-based anodes for LIBs.

Synthesis and characterization of an Au nanoparticles/graphene nanosheet nanocomposite and its application for the simultaneous determination of tramadol and acetaminophen

Here, we aimed to prepare a selective and sensitive electro-chemical sensor through modifying a carbon paste electrode (CPE) with a gold nanoparticle graphene nanosheet (AuNPs/GN) nanocomposite and 4-hydroxyl-2-(triphenylphosphonio)phenolate (HTP).

A dual-modal nanoprobe based on Eu(iii) complex-MnO2 nanosheet nanocomposites for time-gated luminescence-magnetic resonance imaging of glutathione in vitro and in vivo.

Dual-modal fluorescence-magnetic resonance imaging (MRI) techniques have gained great interest in biomedical research and clinical practice, since they integrate the advantages of both imaging techniques and provide a useful approach to simultaneously investigate both molecular and anatomical information at the same biological structures. Herein, we report the construction of a dual-modal time-gated luminescence (TGL)/MRI nanoprobe, BHHBB-Eu3+@MnO2, for glutathione (GSH) by anchoring luminescent β-diketone-Eu3+ complexes on layered MnO2 nanosheets. The fabricated nanoprobe exhibited very week luminescence and MR signals since the luminescence of the Eu3+ complex was quenched by MnO2 nanosheets and Mn atoms were isolated from water. Upon exposure to GSH, the MnO2 nanosheets were rapidly and selectively reduced to Mn2+ ions, resulting in remarkable enhancements of TGL and MR signals simultaneously. The combination of TGL and MR detection modes enables the nanoprobe to be used for detecting GSH in a wide concentration range (1-1000 μM) and imaging GSH at different resolutions and depths ranging from the subcellular level to the whole body. Furthermore, the as-prepared nanoprobe exhibited a low cytotoxicity and good biocompatibility, rapid response rate, long-lived luminescence, and high sensitivity and selectivity for responding to GSH. These features allowed it to be successfully used for the TGL detection of GSH in human sera, TGL imaging of GSH in living cells and zebrafish, as well as dual-modal TGL/MR imaging of GSH in tumor-bearing mice. All of these results highlighted the applicability and advantages of the nanoprobe for detecting GSH in vitro and in vivo.

Hexagonal boron nitride nanosheet/carbon nanocomposite as a high-performance cathode material towards aqueous asymmetric supercapacitors

The two-dimensional hexagonal boron nitride (h-BN) has garnered tremendous interest due to its unique mechanical, thermal and electronic properties. However, the application of h-BN has been restricted as electrode materials for supercapacitors because of its wide band gap and rather low conductivity. Herein, a carbon-modified hexagonal boron nitride nanosheet (h-BN/C) nanocomposite is prepared through a facile and scalable solid-state reaction. Interestingly, the h-BN/C nanocomposite as cathode material exhibits a pair of distinct and reversible redox peaks in 2 M KOH aqueous electrolyte. Because of the enhanced electrical conductivity derived from the modified carbon and the increased specific surface area, the h-BN/C nanocomposite presents a high specific capacitance of 250 F g−1 at the current density of 0.5 A g−1. More importantly, the fabricated aqueous asymmetric supercapacitor with the h-BN/C as cathode and activated carbon as anode displays an operating voltage of 1.45 V, an energy density of 17 Wh kg−1 at a power density of 245 W kg−1, and high stability up to 1000 cycles. Therefore, h-BN/C nanocomposite would promisingly be a cathode material for aqueous asymmetric supercapacitors.

Facile fabrication of multi-walled carbon nanotubes (MWCNTs)/α-Bi2O3 nanosheets composite with enhanced photocatalytic activity for doxycycline degradation under visible light irradiation

In this work, multi-walled carbon nanotubes (MWCNTs)/α-Bi2O3 nanosheets nanocomposites were firstly fabricated and used for photocatalytic degradation of doxycycline (DOX) under visible light. These nanocomposites were characterized by a series of techniques. XRD patterns illustrated α-Bi2O3 and MWCNTs/α-Bi2O3 composites were successfully synthesized. The nanotubular structure of MWCNTs and the nanosheet structure of α-Bi2O3 were determined by SEM and TEM. The compositional analysis of as-synthesized materials was obtained by XPS, and the results showed that MWCNTs and α-Bi2O3 were tightly combined. DRS spectra indicated that the introduction of MWCNTs broadened the light absorption range of the photocatalysts. The BET tests and photocatalysis experiments confirmed that the introduction of MWCNTs not only increases the specific surface area of the photocatalyst, but also increases its photocatalytic activity. When mass ratio of MWCNTs to α-Bi2O3 was 0.15, the catalyst showed the best degradation ability with 91% DOX was degraded at 120 min. The trapping experiments and electron spin resonance tests demonstrated that the ·O2− and ·OH radicals were the main reactive species in DOX degradation process. This work has prepared an economical MWCNTs/α-Bi2O3 photocatalyst by a simple solvothermal–calcination method, which has the potential application of pharmaceutical pollutants removal in water.

Simultaneous formation of carbon nanosheet and loading of platinum nanoparticle to form platinum/carbon nanosheet composite and its electrocatalytic activity

Platinum (Pt)/two-dimensional (2D) carbon nanocomposites with high catalytic performance and stability are mostly fabricated through two-step route, in which the 2D carbon supports are pre-prepared and then Pt nanoparticles are disposed on the surface of 2D carbon supports. Such method needs tedious processes to pre-prepare 2D carbon substrates and the binding between Pt and carbon might be weak. Herein, we report the synthesis of the Pt/carbon nanosheet (Pt/CNS) nanocomposites via a hydrothermal method, in which the formation of CNSs and the loading of Pt nanoparticles occurred almost simultaneously. We find that hydrogen bond can promote Pt nanoparticles anchored and dispersed uniformly on the surface of CNS. The good synergistic effect between Pt and CNS greatly improved the electrocatalytic performance for ethanol oxidation.

Si@SiOx/Graphene Nanosheets Composite: Ball Milling Synthesis and Enhanced Lithium Storage Performance

Si@SiOx/Graphene nanosheet (GNS) nanocomposites as high performance anode materials for lithium-ion batteries are synthesized by mechanically blending the mixture of expanded graphite with Si nanoparticles, and characterized by X-ray diffraction, Raman spectrum, field emission scanning electron microscopy and transmission electron microscopy. During the ball milling process, the size of Si nanoparticles will decrease, and the layer of expanded graphite can be peeled off to thin multilayers. Electrochemical performances reveal that the obtained Si@SiOx/GNS nanocomposites exhibit improved cycling stability, high reversible lithium storage capacity and superior rate capability, e.g. the discharge capacity is kept as high as 1055 mAh g-1 within 50 cycles at a current density of 200 mA g-1, retaining 63.6% of the initial value. The high performance of the obtained nanocomposites can be ascribed to GNS prepared through heat-treat and ball-milling methods, the decrease in the size of Si nanoparticles and SiOx layer on Si surface, which enhance the interactions between Si and GNS.

CoFe2O4 derived-from bi-metal organic frameworks wrapped with graphene nanosheets as advanced anode for high-performance lithium ion batteries

CoFe2O4/graphene nanosheets (GNS) nanocomposites derived from bi-metal organic frameworks and graphene oxides were firstly synthesized via a facile one-pot chemical precipitation with subsequent thermal decomposition method. The as-prepared CoFe2O4/GNS were characterized by XRD, Raman, SEM, TEM and BET adsorption-desorption. As an anode for lithium ion batteries, the CoFe2O4/GNS nanocomposites exhibited an obvious enhancement electrochemical property in terms of a higher discharge capacity of 1061.7 mAh g−1 after 100 cycles at 100 mA g−1 with 75.1% capacity retention and the excellent reversible capacity of 956.2 mAh g−1 when the charge-discharge rate returned from 2 A g−1 to 0.1 A g−1 after 60 cycles. This enhancement could be attributed to the synergistic effects between Co and Fe oxides, and the graphene nanosheets which could not only accommodate the volume variations of CoFe2O4 nanoparticles during cycling, but also improve the contact area between electrolyte and electrodes.

Fe2O3/nitrogen-doped graphene nanosheet nanocomposites as anode materials for sodium-ion batteries with enhanced electrochemical performance

Fe2O3 anode suffers from drastic volume change during cycling and poor electronic conductivity, resulting in inferior electrochemical performance. To address these problems, Fe2O3/nitrogen-doped graphene nanosheet nanocomposites (Fe2O3/N-GNS) were synthesized via a simple, effective and convenient hydrothermal method, and the resulting nanocomposites were applied as anodes of sodium-ion batteries (SIBs). The electrochemical test shows that the Fe2O3/N-GNS deliver a reversible capacity of ∼306 mA h g−1 at 50 mA g−1 after 50 cycles and with a good cyclability in SIBs, indicating that N-GNS can improve electrical conductivity and stabilize the structure changes during cycling. It suggests a potential feasibility to use these metal oxide composites as low-cost and high capacity anode materials for SIBs.

In situ grown Ni9S8 nanorod/O-MoS2 nanosheet nanocomposite on carbon cloth as a free binder supercapacitor electrode and hydrogen evolution catalyst

Transition metal sulfide nanostructure composites have received significant attention as energy conversion and storage devices. In this work, we report a three-dimension (3D) nanostructure with the Ni9S8 nanorods embedded in oxygen-incorporated MoS2 (O-MoS2) nanosheets for supercapacitors and hydrogen evolution catalysts. The in situ grown Ni9S8/O-MoS2 nanocomposite on carbon cloth can be used as a free binder supercapacitor electrode and hydrogen evolution catalyst. The Ni9S8/O-MoS2 nanocomposite exhibits electrochemical behaviors with a specific capacitance of 907 F g−1 (at 2 A g−1) and good cycle stability after 1200 cycles due to its unique mutual embedding 3D nanostructure. Furthermore, the Ni9S8/O-MoS2 nanocomposite also shows highly electrocatalytic features for hydrogen production with an onset overpotential of ∼150 mV and a low Tafel slope of ∼81 mV dec−1. The oxygen incorporation of MoS2 provides more active sites to participate in the catalytic process for the hydrogen evolution reaction.