Single-step Hydrothermal Method Research Articles

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.

Temperature-driven enhancement in pseudocapacitive charge storage of Sn-doped WO3 nanoflowers and its high-performance quasi-solid-state asymmetric supercapacitor

The substitution of another metal cations in the WO3 matrix enhances their electrochemical performance due to the synergistic effect. In this report, Sn-doped WO3 nanoflowers are synthesized via a facile single-step hydrothermal method. Further, the temperature-dependent pseudocapacitive behavior of Sn-doped WO3 nanoflowers is investigated for quasi-solid state asymmetric supercapacitors (QSSAC). The electrochemical study reveals that the specific capacitance values of WO3 increase from 72 F g−1 to 138 F g−1 (Sn-doped WO3) at 1 A g−1. The temperature-dependent specific capacitance values of Sn-doped WO3 nanoflowers demonstrating six times enhancement with rising temperature, from 109 F g−1, 139 F g−1, 194 F g−1, 301 F g−1, to 603 F g−1 at 10 °C, 20 °C, 30 °C, 40 °C, to 50 °C respectively. Furthermore, the QSSAC exhibits better stability of 97.51 % up to 2500th cycles with an energy density of 8 W h kg−1 and a power density of 6400 W kg−1, attributed to enhanced conductivity, large diffusion capability, and high strength with multiple redox active sites. The experimental results emphasize the promising electrochemical features of the Sn-doped WO3 matrix, which is an effective approach for electrode materials development.

Flower-like FeCoNi ternary composite formed by interweaving nano needles for positive electrode material of supercapacitor

Ternary layered double hydroxide (LDH) are potential electrode material choices for supercapacitors (SCs) due to their various oxidation states and high theoretical specific capacitance. In this paper, FeCoNi-LDH composite with cross-braided flowers of nanoneedles has been prepared by a single-step hydrothermal method. By highlighting the structural and morphological advantages, the obtained ternary LDH shows lower resistivity in comparison with the binary LDH. As electrode material, the ternary LDH exhibits excellent electrochemical properties, such as superb specific capacitance of 2163.3 F·g−1 at 0.5 A·g−1 and good cycle retention rate of 93.8% after 5000 cycles at 20 A·g−1. Meanwhile, the assembled asymmetric flexible solid-state supercapacitor device can provide 44.8 Wh·kg−1 energy density at 807.5 W·kg−1. Moreover, two devices in series can also light up miniature light bulbs of different hues and maintain them for a long period when they are connected in series.

Citric acid-cross linked with magnetic metal-organic framework composite sponge for superior adsorption of indigo carmine blue dye from aqueous solutions: Characterization and adsorption optimization via Box–Behnken design

A novel sponge composite (Fe3O4@Pd-MOF/CSC) capable of effectively eliminating indigo carmine blue (ICB) dye from water, was synthesized using an effective single-step hydrothermal method under acidic conditions, employing citrate crosslinking chitosan. The adsorbent was thoroughly characterized using various techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Brunauer–Emmett–Teller surface area (BET) analysis. Our research indicated that the Fe3O4@Pd-MOF/CSC composite sponge possesses an impressive surface area of 1076.8 m2/g and the highest adsorption capacity (qmax) of 778.8 mg/g. The study delved into various factors influencing the adsorption process, including pH levels, indigo carmine blue concentration, adsorbent dosage, and temperature. Both the adsorption isotherm and kinetics were aligned with the Langmuir equation and the pseudo-second-order equation, respectively, for comprehensive analysis. The adsorption energy was determined to be 18.22 kJ/mol, indicating a chemisorption adsorption mechanism. According to adsorption thermodynamics, the process was observed to be both endothermic and spontaneous. Additionally, the material absorption increased with rising temperatures. Moreover, the Fe3O4@Pd-MOF/CSC composite sponge demonstrated magnetic properties, allowing for easy extraction from the solution after the adsorption process. The adsorbent displayed satisfactory efficiency even after being reused six times, demonstrating no alteration in chemical composition. Furthermore, X-ray diffraction (XRD) pattern showed consistent results before and after the reuse process. Electrostatic contact, π-π interaction, hydrogen bonding, and pore filling were identified as the primary mechanisms through which the Fe3O4@Pd-MOF/CSC composite sponge interacted with ICB. The adsorption outcomes were optimized using Box–Behnken-design (BBD).

Constructing a novel type-Ⅱ ZnO/BiOCOOH heterojunction microspheres for the degradation of tetracycline and bacterial inactivation

A novel ZnO/BiOCOOH microsphere photocatalyst with a type-Ⅱ mechanism was developed for the first time. This strategy was accomplished by immobilizing ZnO onto 3D BiOCOOH microspheres via a single-step hydrothermal synthesis method. The ability to degrade tetracycline (TC) in water under visible light and inactivate bacteria of as-catalyst were analyzed. Among the prepared samples, the ZnO/BiOCOOH composite, with a mass ratio of 40%(Zn/Bi), exhibited the highest photocatalytic activity, which was able to degrade 98.22% of TC in just 90 min and completely eradicated Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in 48 h, and had potential application in solving water resource environmental pollution. The photoelectric characteristics of the photocatalysts were examined by means of electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectroscopy. The findings indicated that the superior photocatalytic performance could be credited to the dissociation of electrons (e−) and holes (h+) in heterojunction composites. Finally, electron paramagnetic resonance (EPR) and capture experiments were conducted to confirm the photocatalytic mechanism of the type-Ⅱ heterojunction. This work provides a new Bi-base photocatalyst for aqueous environmental control.

Incorporated ferrocene-derivatives endow Ni-based MOF with high-performance for electrochemical detection

Metal-organic frameworks (MOFs) exhibit structural diversity and functional tunability, rendering them a versatile platform for a wide range of applications. Specifically, defects or function groups induced by exotic ligands is an efficient strategy to adjust the catalytic performance. In this study, we explore the impact of incorporating ferrocene derivatives into two Ni-based MOFs and examine their suitability as potential glucose sensors. One strategy involves introducing bidentate 1,1′-ferrocenedicarboxylic acid (1,1′-Fc) into the 3D Ni-1,4-benzenedicarboxylic acid MOF (Fc-Ni-BDC) using a simple single-step hydrothermal method. Another approach involves encapsulating ferrocenemethylamine (Fc-NH2) inside the cavity of 2D conductive Ni-HHTP MOF (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) driven by electrostatic attraction to form Fc-Ni-HHTP. On account of the synergy between ferrocene derivatives and MOFs, the hybrid MOFs demonstrated remarkable electrochemical performance, characterized by pronounced electrocatalytic reactivity towards glucose oxidation. It is showed that the doped ferrocene derivatives act as electron donors to the MOF active sites, modifying the electronic structure and facilitating the kinetics of the reactions, then an augmentation in the catalytic efficiency has been achieved. This work demonstrates a simple strategy to improve MOF-based electrochemical sensors by incorporating metallocene ligands.

Green synthesis of fluorescent carbon dots from Robinia hispida L. leaves for selective detection of Hg (II)

In this study, Robinia hispida L leaves (RH) was used as a precursor for the first time to synthesize fluorescent carbon dots (CDs) with stable blue fluorescence by a single-step hydrothermal synthesis method. Notably, the innovative approach eliminates the necessity for toxic chemicals or hazardous substances, marking a significant advancement in the field. The synthesized CDs demonstrate CDs demonstrates the predominance of spherical shapes with an average size of 11.63 ± 1.92 nm. The CDs not only exhibit an enhanced fluorescent efficiency with a relatively high quantum yield of up to 6.8%, but they also possess the potential for direct utilization in the selective determination of Hg(II) through fluorescence quenching, even without any functionalization. Under the optimized conditions at a pH of 7.0, a robust linear correlation was found to exist between the fluorescence intensity and the concentration of Hg (II) within the range of 5–17.5 μM, exhibiting a detection limit (3σ) of 1.5 μM. Additionally, this methodology was effectively employed to successfully detect Hg (II) ions in various aqueous samples, including tap water, spring water, drinking water, and a certified reference material (CRM-SA-C Sandy Soil C). The spike recoveries of 97.6%–101.6% with less than 2.7% variability were performed on all samples.

High-efficiency sustainable energy driven alkaline/seawater electrolysis using a novel hetero-structured non-noble bimetal telluride nanorods

The development of non-noble, economical, and efficient electrocatalysts for water electrolysis will be inevitable for the upcoming green hydrogen economy. In consideration of this, we developed non-noble dual transition metal telluride nanorods through a facile single step hydrothermal method. The optimized CoMnTe2-1 nanorods requires a minimum overpotential of about 120 mV to reach a current density of 10 mA cm−2 in 1.0 M KOH towards the hydrogen evolution reaction (HER). Additionally, we evaluated the theoretical coordination calculations and investigated mechanistic HER pathways using density functional theory calculations. Furthermore, the fabricated water splitting device with CoMnTe2-1 anode displays a cell voltage of 1.60 V and 1.64 V to attain a current density of 10 mA cm−2 in alkaline and alkaline/seawater electrolytes, respectively. As a prototype, we also utilized renewable heat and mechanical energy to drive a self-powered water electrolysis device. This provides a promising path forward in designing an active and efficient bimetal telluride based electrocatalysts for green hydrogen production via alkaline/seawater electrolysis.

Molybdenum disulfide (MoS[formula omitted]) and reduced graphene oxide (rGO) nanocomposite based electrochemical sensor for detecting mercury(II) ions

In this study, a two-dimensional (2D) layered nanocomposite of molybdenum disulfide and reduced graphene oxide (rGO) was synthesized through a facile single-step hydrothermal method. Internal structure and morphological studies have shown that the vertical layered structure of MoS2 has grown over the horizontally aligned layer of reduced graphene oxide. The XRD analysis proved that the structure is multi-layered with 68.8 % crystallinity. Despite the highly crystalline nanocomposite structure, very few defects are also present in the network, as shown through Raman spectroscopy. Further, the presence of CS, RSR, CO, CO, MoO and MoS bonds, identified through XPS, indicates the successful synthesis of the MoS2-rGO nanocomposite. The nanocomposite was further evaluated for its electrochemical properties and applications regarding the sensing of mercury ions. Cyclic voltammetry shows that the oxidation peak current response increased by ∼103 % with the MoS2-rGO modified electrode compared to a bare electrode. The sensor has shown an excellent detection limit (LOD) of 1.6 μM, while the sensitivity and limit of quantification obtained from the sensor are 76.302 μM μA−1 cm−2 and 5.4 μM, respectively. The enhanced sensing performance of the MoS2-rGO modified sensor is attributed to the synergistic effect of MoS2 and rGO. The as-synthesized sensor also exhibits excellent stability, as only a 13% drop in current was observed after 60 days. This work proves that MoS2-rGO possesses enormous potential for developing next-generation heavy metal ion sensors.

Direct construction of cobalt selenate-cobalt phosphide composite with exalted energy storage for hybrid supercapacitor cells

Recently, metal selenides/phosphides have attracted increasing interest as electrode candidates for energy storage devices due to their high conductivity, redox activity, and specific capacity. Herein, we report the cobalt selenate-cobalt phosphide (CoSeO3-CoP3) composite materials by a two-step synthesis method. Initially, the CoSeO3 was rapidly synthesized via a facile single-step hydrothermal method for 30 min (CSO-30). Benefitting from rich redox-activity and morphological advantages, the CSO-30 electrode exhibited a higher areal capacity (CA) of 351 µAh cm−2 (specific capacity (CS) of 159.5 mAh g−1) at 2 mA cm−2 than those of the CSO electrodes obtained for 15 and 45 min. In the next step, the phosphorization process was performed to modify/alter the CSO-30 crystal structure by incorporating the phosphorus element, which leads to the formation of CoSeO3-CoP3 (CSO-CP) composite. The resultant CSO-CP electrode delivered an improved CA of 627.7 µAh cm−2 (CS of 179.3 mAh g−1) at 2 mA cm−2 compared to the CSO-30 electrode. Furthermore, a hybrid supercapacitor (HSC) cell was fabricated with CSO-CP and activated carbon electrodes. The HSC revealed a maximum energy density of 0.43 mWh cm−2 and a maximum power density of 18.1 mW cm−2. Moreover, the feasibility of the HSC was verified by powering various electronic devices.

Improved N,N-Dimethylformamide vapor sensing using WSe[formula omitted]/MWCNTs composite at room-temperature

The detection of air contaminating volatile organic compounds (VOCs) like N,N-Dimethylformamide (DMF) under room temperature and highly humid conditions is a tough task to accomplish. Herein, we demonstrate a high-performance chemiresistive gas sensor which was fabricated using composite of layered nanosheets of WSe2 and multiwalled carbon nanotubes prepared using facile single-step hydrothermal method. Structural analysis via various material characterization techniques not only established the composite formation but also indicated the presence of stacking faults and enhanced specific-surface area for the composite, which collectively determine the improved sensing performance of the device. Composite has shown nearly three times enhancement (4.3%) in sensing response compared with WSe2 (1.5%) alone. Sensor has displayed clear noise free signal for DMF detection down to 2 parts per million (ppm) with faster response (1.37 min), recovery rates (0.82 min) and theoretical limit of detection around ≈ 440 parts per billion (ppb). Sensor has shown a reasonable selective behavior towards DMF as compared with other eleven analytes. This was further corroborated via principal component analysis method. Reproducibility of device fabrication and response transients were successfully performed at different humidity levels. Stable and reproducible sensing characteristics over a wider range of relative humidity justify the potential use of WSe2 based composites for various sensing applications.

BaTiO3 is a novel adsorbent for solid-phase extraction of copper at trace levels in food and water samples before HR-CS-FAAS detection

A simple, precise, and rapid method for preconcentration and determination of copper in food and water samples, based on sonication/vortex-free solid phase extraction with high resolution-continuum source flame atomic absorption spectrometry has been developed. In this study, BaTiO3 was synthesized using a single-step hydrothermal method and used as an adsorbent. BaTiO3 was characterized by FT-IR, SEM-EDX, STEM, XRD, and BET methods. The significant feature of the adsorbent is its high surface-to-volume ratio (177.4 m²/g). Important parameters (pH, adsorbent amount, eluent type and volume, adsorption and desorption time, model solution volume, and matrix effects) were optimized. The linear working range (5 – 250 µg L-1) and the detection limit (1.6 µg L-1) were calculated. The presented method was validated with certified reference material and the addition-recovery tests. The application of the method was evaluated for the extraction and determination of Cu(II) in selected food and water samples and quantitative data were obtained.

One-Pot Hydrothermal Synthesis of SnMnS Nanosheets for Dielectric Energy Storage Applications

Recently, dielectric materials with high energy storage capacity, low loss, and good temperature stability are highly desired for the rapidly growing field of power electronics. In the current work, we have investigated the change in electrical, optical, and dielectric properties by varying the concentration of compositional elements Sn and Mn. We have prepared the Sn1–xMnxS (0.1, 0.3, 0.5, 0.7, and 0.9) matrix by using the simple single-step hydrothermal method. The samples show that the reflectance percentage increased with the increase of the Mn amount in the composition. The samples exhibit narrow band gap values, which further increase with the Mn content. The band gap value increases from 0.43 to 0.56 eV. The structural analysis shows that the prepared samples are polycrystalline in nature, having SnS and MnS phases. Furthermore, the crystallite sizes increase with an increase in Mn addition, whereas dislocation density and strain decrease simultaneously. The refractive index is calculated from optical band gap values by using the Dimitrov and Sakka equation. The morphological study reveals the uniformity in size and shape of the prepared composition throughout the sample. The presence of compositional elements Sn, Mn, and S is confirmed by EDX analysis. The electrical study reveals that the sample shows good electrical properties, which increase with the Mn contents. The dielectric behavior as a function of frequency and temperature was investigated, and the parameters like dielectric constant, AC conductivity, impedance spectroscopy, and electric modulus were deeply analyzed. All the above optical, electrical, and dielectric properties of the SnMnS matrix have potential use in the field of electronic and energy storage device applications.

The performance of heteroatom-doped carbon nanotubes synthesized via a hydrothermal method on the oxygen reduction reaction and specific capacitance

Due to the increasing demand for electrochemical energy storage, various novel electrode and catalysis materials for supercapacitors and rechargeable batteries have developed over the last decade. The structure and characteristics of these catalyst materials have a major effect on the device's performance. In order to lower the costs associated with electrochemical systems, electrochemical systems, metal-free catalysis materials can be employed. In this study, metal-free catalysts composed of nitrogen (N) and sulfur (S) dual-doped multi-walled carbon nanotubes were synthesized using a straightforward and cost-effective single-step hydrothermal method. Carbon nanotubes served as the carbon source, while l-cysteine amino acid and thiourea acted as doping elements. As a result of the physicochemical characterization, many defects and a porous structure were noted, along with the successful insertion of nitrogen and sulfur into the carbon nanotube was confirmed. According to the cyclic voltammetry tests for the dual-doped samples in alkaline conditions, the D-CNT2 catalyst exhibited onset potentials of -0.30 V higher than the -0.37 V observed for the D-CNT3 catalyst. This indicates enhanced oxygen–reduction reaction due to the synergistic effects of the heteroatoms in the structure and the presence of chemically active sites. Moreover, the outstanding specific capacitance of the D-CNT2 catalyst (214.12 F g-1 at scanning rates of 1 mV s-1) reflects the effective porosity of the proposed catalyst. These findings highlight the potential of N/S dual–doped carbon nanotubes for electrocatalytic applications, contributing to efficient energy conversion.

Synergetic effect of ternary MnVMo-oxide electrode by hydrothermal method for high-performance asymmetric supercapacitor

The binder-free deposition facilitates fast electron transfer and smoothens the diffusion path of electrolyte ions into the matrix of electrode material. Herein, the ternary metal oxides, such as manganese vanadium molybdenum oxide (MnVMo-oxide) is directly deposited on nickel foam by a single-step hydrothermal method. X-ray diffraction study confirms formation of MnVMo-oxide phase. The X-ray photoelectron spectroscopy confirms the Mn, V, and Mo are in the +2 (and +3), +5, and +6 oxidation states. Deposition time variation results, change in nanostructures from nanoparticle-assembled sheets to rectangular nanosheets, also the size of micro rods. The porous microrods formed with uneven quasi-rectangular shaped nanosheets of MnVMo-oxide exhibit high areal capacitance of 814.5 mFcm−2 (as compared to other electrodes) measured in 1 M KOH electrolyte at 3 mAcm−2 current density. The enhanced capacitance of the MnVMo-8 electrode is due to the dominance of the diffusion process over the capacitive-controlled contribution and high diffusion coefficient. The fabricated asymmetric supercapacitor device MnVMo-oxide//activated carbon shows good areal capacitance of 40 mFcm−2 with 0.025 mWhcm−2 energy at 1.5 mWcm−2 power density measured at 2 mAcm−2 current density, and cyclic stability of about 71.45 % (Coulombic efficiency of 98 %) quantified up to ∼9000 consecutive cycles.