Single-step Hydrothermal Method Research Articles

Enhanced ethylenediamine detection using WO3-BiVO4 nanoflakes heterostructure with exceptional adsorption capabilities: Experimental and theoretical studies.

The present work describes the synthesis of WO3-BiVO4- nanoflakes heterostructure (NFHs) by a single step hydrothermal method. The analysis of crystalline phases and structural behavior deduced the formation of good crystal quality WO3-BiVO4 NFHs. Under microscopic observation, the as-prepared WO3-BiVO4 displayed uniform and conspicuous nanoflakes like structures. The extensive density functional theory (DFT) was studied to examine the electronic and band structures of as-prepared WO3-BiVO4 NFHs in terms of formation energy, charge density, density of state (DOS) and band structures. The synthesized WO3-BiVO4 NFHs was used as sensing electrode towards the detection of ethylenediamine (EDA) chemical that displayed a good sensitivity of ~318.52 mA.mM-1cm-2, excellent dynamic range of 1 μM - 1 mM with detection limit (LOD) of ~94.51 nM and retention coefficient of ~0.9929. WO3-BiVO4 NFHs electrode possessed the good reproducibility, stability, and repeatability towards EDA chemical. To the best of our knowledge, for the first time, the fabricated chemical sensor fabricated with WO3-BiVO4 NFHs electrode could be promising electrode materials to identify dangerous chemicals at very low concentration in environment. Importantly, the fabricated chemical sensor can be effective for environmental monitoring.
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Engineered oxygen vacancies in NiCo2O4/BiOI heterostructures for enhanced photocatalytic pollutant degradation.

To address the bottleneck issue of poor carrier separation and transfer efficiency in NiCo2O4 photocatalyst, a novel 1D/2D-rod-on-rose-like NiCO2O4/BiOI nanohybrid with abundant OV's was successfully synthesized using a single-step hydrothermal method and employed to the photocatalytic degradation of Rhodamine B (RhB). The study revealed that the optimized NiCo2O4-OV/BiOI hybrid could possess superior photocatalytic degradation efficiency towards RhB degradation under visible light with a rate constant that was 3.8 and 3.03 times greater than that of BiOI and NiCo2O4-OV. Experimental findings indicated that the formation of NiCo2CO4-OV/BiOI heterojunction significantly improved the charge separation efficiency and facilitated the formation of surface OV's. These OVs enhanced photogenerated e--h+ separation and increased catalytic efficiency. Quenching experiments results confirmed that both holes and superoxide radicals are playing crucial roles in the degradation process. Thus, an oxygen vacancy and engineering NiCo2CO4-OV/BiOI heterojunction-enhanced degradation mechanism was proposed, offering insights for the integration of advanced oxidation technologies and the development of catalytic materials to enhance pollutant degradation efficiency.

Co3O4/rGO based nanocomposite architectures as electrodes for advanced energy storage and their pseudocapacitive attributes

In response to escalating global challenges in energy storage, this study embarked on captivating exploration of electrochemically proficient Co3O4 composites, seamlessly integrated with varying concentrations of reduced graphene oxide (5 %, 10 %, and 15 %). Using a single-step hydrothermal method, Co3O4 was synthesized, followed by a solvothermal process to produce Co3O4/rGO composites. These composites were then applied to Nickel Foam to fabricate electrodes. The structural properties of these novel Co3O4/rGO/NF electrodes were analyzed using X-ray Diffractometer, which confirmed the distinctive crystalline structure of Co3O4 and indicated no phase transformation after the introduction of rGO. Morphological analysis through a Field Emission Electron Microscope and Transmission Electron Microscope revealed layered structures and increasing porosity correlated with higher rGO concentrations. Electrochemical performance was rigorously tested through cyclic voltammetry, which verified the pseudocapacitive attributes of the samples. Additionally, galvanostatic charge-discharge studies highlighted that the electrode containing 15 % rGO demonstrated highest (Cs = 1360 Fg−1) at 1.7 Ag−1, with 86 % of cyclic retention after 5000 cycles. Electrochemical impedance spectroscopy further demonstrated superior conductivity, underscoring the potential of these electrodes'for supercapacitor applications.

Green synthesis of carbon dots (CDs) and their use for selective determination of Pb2+

Carbon dots were synthesized from fenugreek seeds through a single step hydrothermal method. The method is simple, fast, pleasant to the environment and cheaper. The CDs were characterized by Fourier Transform Infrared (FTIR), UV–visible spectrophotometer, X-ray diffraction (XRD), High Resolution Transmission electron microscopy (HR-TEM), and fluorescence. The CDs obtained were extremely fluorescent. The fluorescent carbon dots exhibited excitation-dependent behavior with the maximum excitation at 372 nm. The interaction of CDs was studied with different selected cations Al3+, Ca2+, Cd2+, Cr3+, Co2+, Cu2+, Cu+, Fe2+, Fe3+, K+, Sn4+, Na+, Ni2+, Pb2+, Mn2+, Zn2+, Sr2+, (NH4)6Mo7O24, 4H2O, Cr6+, Sb3+, Ba2+, Li+, and Mg2+. None of the ions studied showed any effect on its fluorescence intensity except Pb2+ which decreased its intensity. A direct relationship was found between Pb2+ concentrations and quenching of CDs intensity. Detection limit (DL) and quantification limits (QL) were determined as three and ten times of the standard deviation of the blank for ten number of measurements. DL and QL were found in the order 9.345 μM and 31.15 μM respectively. This linear behavior between quenching and Pb2+ concentration is useful for analytical purpose.

In-situ constructed NiCoZnS composite on nickel foam with hierarchical structures as bifunctional electrocatalysts for oxygen evolution reaction (OER) and supercapacitors

Transition metal sulfides have shown promise as candidates for energy storage and conversion devices, but the limited electroactive sites may greatly hinder further improvement. The novel nanostructured morphologies enhance active sites and surface area, thereby increasing overall electrochemical performance. Herein, we successfully synthesized various morphologies such as ZnS spheres, CoS star anise spice-like structures, and NiS flakes-like structures, which were directly grown on Ni foam using a single-step hydrothermal method. Additionally, the novel nanostructured morphologies were combined as a heterojunction NiCoZnS electrode to further utilize electronic and junction properties, thereby enhancing performance. This combination of morphologies—spheres, star anise spice, and flakes-like structures with ultrathin thickness and large surface areas—effectively increases the number of active sites, resulting in enhanced supercapacitor and oxygen evolution reaction (OER) performance. Moreover, directly growing nanostructures on conductive Ni foam endows the electrode materials with higher conductivity and richer active sites. In terms of supercapacitor performance, the NiCoZnS electrode exhibits a specific capacity of 1171.3 C g−1 at 0.5 A g−1 and remarkable rate performance. Furthermore, NiCoZnS maintains a capacitance retention of 94.9 % after 5000 cycles. As an electrocatalyst, NiCoZnS undergoes a rapid self-reconstruction process during the oxygen evolution reaction (OER), producing rich oxygen vacancies and thus demonstrating remarkable long-term stability. The NiCoZnS nanocomposites exhibit small overpotential (157 mV at 100 mA cm−2) and a Tafel slope of 128 mV dec−1. NiCoZnS's unique hierarchical nanostructures, doping-optimized electronic structural configuration, and specific surface lead to high catalytic performance. These remarkable performances of mixed morphologies like NiCoZnS hold great promise for energy storage and conversion devices.

Porphyrin-based carbon dots as fluorescence probe for sensing of Fe3+ ion and S2- anion in aqueous solution

In this work, a facile bottom-up approach was employed to synthesize the porphyrin-citric acid-derived fluorescent carbon dots (Por-CA-CDs) using a single-step hydrothermal method. As-prepared Por-CA-CDs were well characterized using spectroscopic techniques such as FT-IR, high-resolution transmission electron microscopy, P-XRD, UV-Vis absorption, and photoluminescence spectroscopy. The synthesized Por-CA-CDs exhibited blue fluorescence with excellent photostability and diameter ranging from 2.4 to 6.4 nm. Por-CA-CDs show excitation-dependent emission behavior, with a quantum yield of 26% and were used for sensing of Fe3+ and S2− ions in an aqueous solution. Por-CA-CDs demonstrated a robust and selective reaction to Fe3+ compared to the other cations utilized in this investigation. The sensing capability of Por-CA-CDs with Fe3+ ions was evaluated with fluorescence spectroscopy, and results show a “Turn-Off” emission mode upon binding of Fe3+ with Por-CA-CDs. In metal ion sensing studies, the fluorescence intensity of Por-CA-CDs exhibited significant quenching upon the addition of Fe3+ at concentrations ranging from 0 to 230 μM, with a detection limit (LOD) of 3.2 × 10−8 M. The quenching efficiency and Stern-Volmer quenching constant were computed as 99.45% and 4.4 × 106 M−1, respectively. Interestingly, fluorescence of Por-CA-CDs can be regained with the addition of S2− (0-160 µM) with LOD of 4.3 × 10−6 M and Stern-Volmer quenching constant of 6 × 105 M−1. Most importantly, the toxicity assay revealed good reliability for samples in deionized, tap, and river water, suggesting applications for Fe3+ monitoring in complex environments.

Enhanced hydrogen gas sensing performance with Ag-doped WO3 thin film

The paper reports the fabrication of a device, based on the thin film of Ag-doped WO3 nanoparticles, to enhance the hydrogen gas sensing performance. The synthesis of thin films of pristine and Ag-doped WO3 nanoparticles were carried out using the single-step hydrothermal method, followed by the spin coating deposition process. The characterization of the samples was carried out with XRD, FESEM, TEM, FTIR and UV–vis spectroscopy. The consistent pattern observed from the microstructure analysis of data from XRD, UV–vis spectrometer and FTIR validates effective incorporation of Ag into the WO₃ structure. The XRD patterns confirmed the formation of the monoclinic phase of WO3 nanoparticles. The crystallite size and the value of band gap decreased on increasing the Ag doping percentage in WO3. This reduction with Ag-doping could be attributed to the proper substitution of the W with Ag due to their similar sizes. The gas sensing performances of the fabricated sensing devices were analyzed by exposing different concentrations of hydrogen gas ranging from 12.5 ppm to 75 ppm. The device based on the thin film of Ag-doped WO3 performed much better than the device based on the thin film of pristine WO3 nanoparticles. The device with 4% Ag-doped WO3 showed the best sensor response of 98 % for 75 ppm H2 gas concentration with response and recovery time of 76 and 100 s, respectively at 100 °C. The improved response of the device with Ag doping compared to the pristine device could be attributed to the better charge transfer, more defect creation, and the ability of Ag to work as a catalyst to make reaction kinetics faster. The selectivity of the device was tested using the oxidizing and reducing gasses of NO2, H2, and NH3 at 100 °C for 75 ppm gas concentration. The recorded response of the device for NO2, H2, NH3 were 38%, 98%, and 43%, respectively.

One-step formation of synergistic ZnO/SnO2 composite nanostructures derived from annealing of crystalline ZnSn(OH)6 nanocubes for enhanced catalytic degradation of organic pollutants

Binary metal oxides/hydroxides derived primary metal oxide composites have a pivotal role in diverse applications because of the beneficial interfacial contact, good synergism, high porous nature, and high stability. The current work deals with the derived ZnO/SnO2 composite nanostructures from post-annealing crystalline ZnSn(OH)6 (ZTO-RT) nanocubes, initially synthesized via a single-step hydrothermal synthesis method. First, the pristine ZTO-RT is synthesized @ 180 °C in a hydrothermal autoclave. Further, the transformation of ZTO-RT to ZnO/SnO2 composite nanostructures is performed at two different annealing temperatures of 500 °C (ZTO-DV-500) and 750 °C (ZTO-DV-750) in the vacuum. The respective samples' physical characterization was studied and compared using various analytical techniques. The X-ray diffraction analysis affirms the amorphous nature of ZTO-DV-500 and the poly-crystalline nature of ZTO-DV-750. The nanocube morphologies of the samples are retained even at high-temperature sintering. The existence of metal-oxygen bonds on the surface of the ZnO/SnO2 composite is sustained by X-ray photoelectron spectroscopy. ZTO-DV-750 has larger pores (pore volume - 0.091 cm3 g−1) than the ZTO-DV-500 (0.051 cm3 g−1). In the presence of NaBH4 aqueous solution, the enhanced rhodamine B dye degradations of ZTO-DV-750 are observed. At low RhB concentrations (5 mg L−1), the ZTO-DV-500 and ZTO-DV-750 rate constants are determined to be 0.099 and 0.156 min−1, respectively, while at high concentration (10 mg L−1), these values are 0.043, and 0.091 min−1. Therefore, the ZTO-DV-750 composite has shown potent catalytic activity with NaBH4 over ZTO-DV-500 to decolourise organic dyes.

In-situ synthesis of SnO/CuSnO3 nanostructures to catalyze azo dye degradation, CO2 reduction, and amines direct alkylation reactions under visible light

The extensive use of photocatalysis to address environmental concerns, energy production, and organic transformations has attracted attention in recent decades. The SnO/CSO photocatalytic materials were fabricated through a single-step hydrothermal method and comprehensively characterized using a muti-technique approach to demonstrate the physicochemical, morphological, and electronic features. According to the photocatalytic experiments, the SnO/CSO could remove >96 % of acid blue 92 (AB92) azo dye under optimum conditions, with rate constant 2.37 × 10−2 min−1. Furthermore, the photocatalyst significantly outperformed commercial TiO2 (P25), in reducing CO2 to CO and CH4 with a production rate of 10.8 and 1.18 μmol g−1 h−1, respectively, under visible light irradiation. The successful direct alkylation of amines to valuable organic compounds within 10 min of the reaction time with a conversion selectivity of >90 % was another capability of the materials, making it a good candidate for pharmaceutical synthesis purposes.

Synergistic electrocatalytic activity unveiled: Cu–Mo bimetal sulfo-selenide nanocomposite for hydrogen evolution reaction

Developing an affordable and abundant electrocatalyst for generating green hydrogen is crucial for achieving sustainable energy with zero carbon emissions. In this context, nanostructured transition metal chalcogenides were seen as ideal cathode materials for water splitting due to their tuneable structure, large surface area, strong conductivity, and widespread availability. Herein, we have developed Cu–Mo Bimetal Sulfo-Selenide Nanocomposite (CuMoSSe) by incorporating Cu into the MoSSe system through a single-step hydrothermal method and explored it as a catalyst for electrochemical hydrogen evolution. The Cu0.25Mo0.75SSe, consisting of a Cu2Se/MoSSe composite structure, exhibited excellent electrochemical HER activity with an overpotential of 290 mV vs. RHE at 10 mA/cm2 compared to its various compositions and pristine counterparts, with remarkable stability for more than 1500 cycles and 12 h in an acidic medium. The enhanced electrochemical activity with smaller charge-transfer resistance (47.8 Ω) and larger double-layer capacitance (14.74 mF/cm2) values with a low Tafel slope of 79.1 mV/dec can be attributed to the effective kinetics and enhanced electrical conductivity of the composite due to the hybrid structure which is backed by the decrease in Gibbs free energy value calculated through theoretical studies. These discoveries open the door to creating new electrocatalysts using combinations of MoSSe and Cu or other metals. This approach aims to design electrode materials that are not only low cost but also mechanically strong and electrically conductive for the process of electrocatalytic water splitting.

Synthesis and Electrochemical Characterization of ZnMoS4 Nanorods on Nickel Foam Substrate for Advanced Hybrid Supercapacitor Applications.

A single-step hydrothermal method was utilized to grow ZnMoS4 (ZMS) nanorods uniformly. Initially, [MoS4]2- and Zn2+ ions interacted to create active nucleation centers, which then led to the formation of primary particles. These particles then underwent spontaneous aggregation and self-assembly on the nickel foam (NF) substrate, which served as a superior 3D interconnecting network template. This aggregation occurred nearly perpendicular to the NF and promoted the uniform growth of ZMS nanorods. The nanorods structure ensures efficient and rapid electrolyte accessibility and ion diffusion, resulting in an increased specific capacitance (Cs) of 2,116 Fg1- (846.4 C g-1) at 1 A g-1 and maintaining about 90% of their capacitance after 10,000 cycles of galvanic charge-discharge (GCD). In a hybrid supercapacitor configuration, ZMS@NF//AC@NF achieved a peak specific power of 7.2 kW.kg-1 and a specific energy of 40.3 Wh.kg-1. Remarkably, it preserved 93% of its initial capacitance after more than 20,000 cycles. These findings affirm the potential of binder-free ZMS nanorods as effective positive electrodes in advanced hybrid supercapacitors.

Temperature driven pseudocapactive performance of WO3/MXene nanocomposite for asymmetric aqueous supercapacitors

The WO3 nanostructured materials are widely used as a pseudocapacitive charge storage electrodes. However it is restricted by poor cyclic stability. To overcome it, hybrid nanocomposites materialization of WO3 with fascinating 2D MXene is an excellent strategy. Though both materials consumes acid based electrolytes and possesses layered structures, WO3 protects MXene from self-restacking and/or aggregation of their adjacent layers owing to its strong van-der Waals interaction. Moreover layered structure of MXene offers synergistic action of various metal elements, fast diffusion of ions, increase the voltage window and cycle life. Herein we report hybrid nanocomposite of orthorhombic WO3 nanoplates with 2D MXene nanoflakes prepared by a single-step hydrothermal method. The electrochemical investigations exhibits the specific capacitances of 21 F g−1 (MXene), 112 F g−1 (WO3), and 290 F g−1 (WO3/MXene-20) at 0.5 A g−1 in 1 M H2SO4 aqueous electrolyte. Furthermore temperature dependent investigation of a hybrid nanocomposite (WO3/MXene-20) demonstrates consistent enhancement in the specific capacitance with the increasing temperature and a maximum capacitance of 376 F g−1 at 0.5 A g−1 is achieved at 50 °C. Eventually an asymmetric aqueous supercapacitor (AASC) fabricated using hybrid nanocomposite (WO3/MXene-20) demonstrates an outstanding cyclic stability up to 20,000 cycles at 5 A g−1 upholding 72 % capacitance retention and 73 % coulombic efficiency. The exceptional cyclic stability of the AASC configuration emphasizes the prospective of WO3/MXene hybrid nanocomposites for durable energy storage applications.

Biocompatible polymer-coated magneto-fluorescent super nanoparticles for the homing of mesenchymal stem cells

Stem cell plays an important role in the clinical field. However, the effective delivery of stem cells to the targeted site relies on the efficient homing of the cells to the site of injury. In view of that, fluorescent magnetic nanoparticles stick out due to their wide range of enabling functions including cellular homing and tracking. The present study unravels the synthesis of polymer-coated biocompatible and fluorescent magnetic nanoparticles (FMNPs) by a single-step hydrothermal synthesis method. Importantly, the facile method developed the biological super nanoparticles consisting of the magnetic core, which is surrounded by the fluorescent nanodot-decorated polymeric shell. The synthesized particles showed an amorphous nature, and superparamagnetic properties, with efficient fluorescence properties of emission at the blue range (̴ 410 nm). The FMNP labeling showed the mesenchymal stem cell (MSC) homing to the desired site in the presence of an external magnetic field. The in-house synthesized nanoparticles showed significant cytocompatibility and hemocompatibility in vitro as well as in vivo conditions owing to their surface coating. This unprecedented work advances the efficient internalization of FMNPs in MSCs and their enhanced migration potential provides a breakthrough in stem cell delivery for therapeutic applications. Statement of significanceThe bi-modal fluorescent magnetic nanoparticles hold a promising role in the biomedical field for mesenchymal stem cell homing and tracking. Hence, in this study, for the first time, we have synthesized the fluorescent magnetic nanoparticle with polymer coating via an easy single-step method. The nanoparticle with a polymer coat enhanced the biocompatibility and effortless internalization of the nanoparticle into mesenchymal stem cells without hampering the native stem cell properties. Furthermore, the enhanced migration potential of such magnetized stem cells and their homing at the target site by applying an external magnetic field opened up avenues for the smart delivery of mesenchymal stem cells at complex sites such as retina for the tissue regeneration.

Enhancing toluene gas sensing performance using Co3O4/ZnO hollow porous flower-like material

ZnO is widely used in semiconductor oxide gas sensors due to its remarkable physical and chemical properties. However, ZnO-based gas sensors face several challenges in practical applications, including limited selectivity, reduced sensitivity, and the requirement for high operating temperatures. In this study, a three-dimensional hollow porous flower-like Co3O4/ZnO material was synthesized by single-step hydrothermal method, exhibiting an average diameter ranging from 4 to 5 μm. The presence of Co3O4 within ZnO was confirmed through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Through the detection of different gases, the results indicate that the ZnO-based gas sensor, doped with 0.5 at% Co3O4, exhibits exceptional sensitivity towards toluene gas, with the limit of detection (LOD) (1 ppb). The sensor's response values Ra/Rg to 0.1–200 ppm toluene at 260 °C range from 2 to 225, respectively. In the presence of toluene gas at a concentration of 100 ppm, the sensor demonstrated a high response value of 130, with response and recovery times of 30 s and 50 s, respectively. Furthermore, the response value of this sensor type was tested over a period of 15 days, confirming the device's excellent long-term stability.

Green Synthesis of CQDs via the Trunks of Bauhinia purpurea as Fluorescence Probes for Rapid and Accurate Detection of Quinoline Yellow.

Carbon quantum dots (CQDs) were greenly synthesized via a single-step hydrothermal method, using the trunks of Bauhinia purpurea as the carbon source. They exhibited good dispersibility, water solubility, high sensitivity, and great stability with a spherical form and a particle size of 2.68 ± 0.32 nm. By utilizing the inner filter effect and dynamic quenching effect, the fluorescence quenching of CQDs can be induced to detect quinoline yellow. Detailed experimental results showed that the change rate of fluorescence intensity of CQDshadagood linearrelationshipwith varying concentrations of quinoline yellow (2-128 µmol/L). It can be clearly observed that the fluorescence quenching occurred within 1 min, its correlation coefficient (R2) is 0.9912, and the detection limit (DL) is 1.7884 μmol/L, substantially lower than the maximum concentration stipulated by the national standard of 209.5 µmol/L. Furthermore, quinoline yellow had been successfully detected in real beverage samples using CQDs, with the recovery rates of 90.6%-110.4% and the relative standard deviation (RSD) ≤ 6.3% and it also showed great anti-interference and selectivity. These findings indicate that the detected quinoline yellow of CQDs possess substantial promise for a wide range of applications within the detected artificial food colors field.

Hydrothermal synthesis of NiS2@SnS2 nanohybrid for the water splitting application

The potential capabilities of stannous sulphide (SS) in the domain of the hydrogen evolution process (HER) have attracted significant interest. By employing a straightforward single-step hydrothermal method, we successfully boosted the HER performance of SnS2. This was achieved by fabricating a nanocomposite consisting of nickel sulphide (NS) and tin sulphide (SS) nanostructure. The resulting NS@SS nanocomposite shows the superior electrocatalytic behavior for the HER compared to pristine NS and SS material. The composite exhibited a morphology with two distinct phases, such as nanoparticles and nanorod structures that are responsible for good electrochemical properties. The NS@SS nanocomposite has several advantages for enhancing HER electroactivity, including a greater active surface area, increased edge-terminated structures, and better conductivity. The catalyst has high stability in alkaline solutions and demonstrates a low overpotential (ɳ) of 155 mV@ 10 mA cm−2 with a Tafel slope of 34 mV dec−1. The current results show that the NS@SS nanocomposites are a potential candidate for the energy production materials and energy conversion system.

Graphene quantum dot-based hydrogel microspheres for sensitive detection of caffeic acid

In this investigation, blue-emitting graphene quantum dots (B,N-GQDs) were synthesized via a single-step hydrothermal method in an ethanol/water mixture utilizing 3-APBA as the nitrogen and boron sources. These B,N-GQDs showcased a highly graphitized structure, complemented by surface-functionalized boronic acid and amino groups that bestowed upon them remarkable optical attributes and water solubility. Leveraging the interplay of internal filtering and dynamic quenching effects, the sensor demonstrated remarkable selectivity and sensitivity in detecting caffeic acid (CA) within the range of 0–840 μM, achieving a limit of detection (LOD) of 0.63 μM. Moreover, the fluorescent gel microspheres engineered with B,N-GQDs exhibited robust CA sensing capabilities and portability. As such, the application potential of B,N-GQDs expands to encompass drug metabolism monitoring, alongside the assessment of food and environmental safety.

Harnessing enhanced stability and high-rate capability in lithium-ion batteries using synergistic SnS2/MoS2 2D nanostructures with optimized conversion/alloying reactions

Recently, there has been a significant interest in the application of SnS2/MoS2 2D nanostructure composites in lithium-ion batteries (LIBs) due to their advantageous conversion, intercalation, and alloying reactions, leading to high capacity during charge and discharge cycles. In this study, we successfully synthesized SnS2/MoS2 composites with a 2D-nanoplate morphology using a single-step hydrothermal method. Specifically, the optimized SnS2/MoS2-3:1 composite was tested as anodes in coin cell LIBs, demonstrating an impressive capacity of 710 mAh/g at a current density of 500 mA/g, along with outstanding stability (800 cycles) and remarkable rate capability compared to other composites. The excellent electrochemical performance of the SnS2/MoS2-3:1 composite can be attributed to the moderately coupled SnS2 and MoS2 2D-nanosheets, which provide short lithium-ion transportation lengths, low charge transfer resistance, and dominant capacitive behavior.

Ni and P co-doped WS2 nanosheets decorated on MWCNTs as an efficient counter electrode for dye-sensitized solar cells

Designing of inexpensive and robust counter electrode (CE) material without noble metals is of great essential for improving the overall power conversion efficiency (PCE) of dye-sensitized solar cells (DSSCs). Herein, nickel (Ni) and phosphorus (P) co-doped WS2 nanosheets decorated on multi-walled carbon nanotubes (Ni/P-WS2 @MWCNTs) was fabricated via single-step hydrothermal method and used as CE for DSSC. According to the electrochemical studies, the Ni/P-WS2 @MWCNTs CE displayed remarkable catalytic activities, great electron transfer ability, and high durability in the I−/I3− electrolyte. More importantly, the device equipped with Ni/P-WS2 @MWCNTs CE yielded an outstanding PCE of 8.62%, surpassing that of standard Pt (PCE=6.61%) and other corresponding counterparts. Such notable photovoltaic performance can be ascribed to the synergistic coupling effect of heteroatom doping and support role of conductive carbon network, which offer abundant catalytic active sites, high porosity, and exceptional electrical conductivity. Our work suggests a novel strategy to fabricate Pt-like CE materials based on metal and nonmetal heteroatoms co-doped in metal chalcogenides with excellent performances for large-scale energy conversion devices to reach the consumer market.

Novel structured carbon nanotubes fiber based microelectrodes for efficient electrochemical water splitting and glucose sensing

An efficient electrocatalyst composed of nickel and cobalt selenide over unique structure carbon nanotubes (NiCo-Se@CNTs) fiber has been fabricated via a single-step hydrothermal method which showed efficient electrocatalytic performance towards electrochemical non-enzymatic glucose sensing and overall water splitting applications. The structural and elemental composition of a modified electrode (NiCo-Se@CNTs) was ascertained via transmission electron microscopy (TEM), X-rays diffraction (XRD) pattern, X-rays photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDX) techniques. Modified fiber-based electrode was used for the electrochemical water splitting which showed a low overpotential value (η10 = 260 mV) with a corresponding Tafel slope of 138 mV dec−1. These values are far superior in contrast with pristine CNTs fiber, having 384 mV overpotential and 318 mV dec−1 of Tafel slope. In extension, while studying overall water splitting by engaging both modified CNTs fiber as anode and cathode, it exhibited excellent performance with an overpotential (η10) of 297 mV and corresponding Tafel slop of 159 mV dec−1. The fabricated electrode was further investigated for electrochemical glucose sensing which exhibited excellent performance towards the glucose detection with a linear dynamic range of up to 10 mM, a detection limit of 0.59 μM in an alkaline condition (pH=13) and high sensitivity of 813 mAmM−1cm−2. The outcomes demonstrated that fabricated fiber (NiCo-Se@CNTs) might be a promising material in future as a multifunctional electrocatalyst for flexible and wearable energy and sensing related applications.