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Metallic (1T) molybdenum disulfide (MoS

A novel electrocatalyst derived from a unique 3D hierarchical network of 2D Fe-doped NiSe nanosheets and CNTs on carbon paper exhibits enhanced OER performance with an overpotential of 282.0 mV to reach 10 mA cm−2 in 1.0 M KOH medium.

The development of sensitive and selective sensors using facile and low-cost methods for detecting neurotransmitter molecules is a critical factor in the health care system in regard to early diagnosis. In this research, an electrocatalyst derived from Mo,Zn dual-doped CuxO nanocrystals-based layer coating over one-dimensional copper nanowire arrays (Mo,Zn-CuxO/CuNWs) was successfully designed using a facile electrodeposition approach and used as an electrochemical sensor for non-enzymatic dopamine (DA) neurotransmitter detection. The synergistic effect caused by the dual-doping effect along with its excellent conductivity produced a large electroactive surface area and an improved hetero-charge transfer, thereby boosting DA sensing ability with a low limit detection of 0.32 µM, wide-range of detection (0.5 µM − 3.9 mM), long-term stability (5 weeks), and high selectivity in phosphate buffer solution (pH 7.4). Also, the sensor accurately determined DA in real blood serum-spiked solutions. The achieved results evidenced that the Mo,Zn-CuxO/CuNWs derived sensor is highly suitable for DA detection. Therefore, it also opens new windows for the development of low-cost, accurate, high-performance, and stable sensors for other neurotransmitter sensing for the purposes of better health care and early diagnosis.

Fabrication of hybrid trimetallic-organic framework-derived N, C co-doped Ni–Fe–Mn–P ultrathin nanosheet electrocatalyst demonstrating excellent performance with low overpotentials and cell voltage for HER, OER and overall water splitting.

The GO-BN hybrid nanofiller reinforced TPU/epoxy semi-interpenetrating network provided an excellent H2barrier coating along with superior adhesion for the nylon 6 based compressed H2storage vessels.

Electrochemical water-splitting is emerging as a promising pathway to produce pure and green hydrogen. Herein, we prepared a tungsten incorporated CoSe/Co3O4heterostructure and employed it as an efficient electrocatalyst for overall water splitting.

In this study, we prepared a three-dimensional self-supported electrocatalyst based on a thin layer of cerium oxide nanocrystals doped with cobalt heteroatoms (CeO2-Co) and then uniformly shelled over one-dimensional tin oxide (SnO2) nanorods supported by carbon cloth substrate. The material was used as a binder-free sensor that could nonenzymatically detect xanthine (XA) with an excellent sensitivity of 3.56 μA μM−1, wide linear range of 25 nM to 55 µM, low detection limit of 58 nM, and good selectivity. A screen-printed electrode based on the material accurately detected XA in food samples as well. The achievements were resulted from synergistic effects coming from the unique core@shell formation and Co-doping strategy, which efficiently modified electronic structure of the material to expose more electroactive site numbers/types and fast charge transfer, thereby producing intrinsic catalytic properties for XA oxidation. These results suggested that the SnO2@CeO2-Co is potential for developing efficient sensor to detect XA with good sensitivity and accuracy in food-quality monitoring.

A novel sulfur-doped vanadium-molybdenum oxide nanolayer shelling over two-dimensional cobalt nanosheets (2D Co@S-VMoOx NSs) was synthesized via a facile approach. The formation of such a unique 2D core@shell structure together with unusual sulfur doping effect increased the electrochemically active surface area and provided excellent electric conductivity, thereby boosting the activities for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). As a result, only low overpotentials of 73 and 274 mV were required to achieve a current response of 10 mA cm-2 toward HER and OER, respectively. Using the 2D Co@S-VMoOx NSs on nickel foam as both cathode and anode electrode, the fabricated electrolyzer showed superior performance with a small cell voltage of 1.55 V at 10 mA cm-2 and excellent stability. These results suggested that the 2D Co@S-VMoOx NSs material might be a potential bifunctional catalyst for green hydrogen production via electrochemical water splitting.

The current article reviews the construction of thin films comprising carbon-based nanomaterials for application in electrical and electronic fields. Carbon-based materials such as carbon nanotubes, graphene, and fullerene are known to possess excellent electrical and electronic properties, which makes them desirable materials for the fabrication of micro- and nano-electromechanical devices. The fabrication process of thin films, including the deposition of several layers, removal of layers, solution processing methods, inkjet printing, micro-emulsion polymerization methods, deposition through filtration processes, spin coating, dip coating, pen lithography, vacuum-assisted flocculation, vacuum-assisted layer-by-layer assembly laser writing, etc., has been extensively reviewed. It is evident from the past findings that the fabricated thin films constituting carbon nanomaterials shows predominant alteration in electrical and electronic properties like sheet resistance, ionic transport, potential difference, conductivity, electro-rheological, transparency, trans-conductance, transmittance, bending stability, etc. In view of the referred properties, the developed materials find wide applications in charge-trap flash memories, flexible organic resistive memory devices, photovoltaic devices, flexible and transparent electronics, heat sinks in electronic materials, liquid crystal displays (LCDs), thin-film solar cells, flexible touch-screen panels, electronic papers, micro-batteries, electrochemical micro-capacitors, humidity sensors, optoelectronic devices, etc. We expect that the current review article will be a valuable asset for the researchers working in the field of carbon nanomaterials.

The development of a rapid, selective, and sensitive sensor to precisely monitor nitrite oxidation is of growing importance, given the strong interest in the protection of drinking water quality, treatment of wastewater, food production, and control of remediation processes. In this research, we successfully fabricated a hybrid originated from worm-like gold nanowires (Au WNWs) assembled on a high-quality carbon nanofibers-graphene (CNFs–Gr) hybrid network through a facile synthesis method. The hybrid as a binder-free sensor exhibited excellent activity towards nitrite detection in phosphate buffer solution (pH of 7.4) with a wide linear detection range of (1.98 µM – 3.77 mM), excellent sensitivity of 836 μA cm−2 mM−1, low detection limit of 1.24 µM, and long-term durability. The results were attributed to a special synergistic effect originating from unique hybridization of Au WNWs with large-area CNFs–Gr network to produce more electroactive sites and excellent conductivity, favorably boosting catalytic performance of the sensor. The successful fabrication of Au WNWs/CNFs–Gr suggested an interesting candidate for practically determining low-level nitrite in analytical applications.

Rechargeable zinc–air batteries (ZABs) have emerged as promising alternatives for conventional Li-ion batteries due to their high energy density and low manufacturing cost. However, Pt/C and RuO2-based conventional rechargeable ZABs are mainly constrained by the sluggish kinetics of oxygen reduction/oxygen evolution reactions (ORR/OER), limiting commercialization possibilities. Herein, a new type of oxygen vacancies enriched cobalt-doped molybdenum oxynitride quantum dot-anchored N-doped carbon nanosheets (VO-CMON@NCNs) was demonstrated as an advanced air-cathode for long-life rechargeable ZABs. Such VO-CMON@NCN catalyst has an exceptional ORR performance with a high half-wave potential of 0.857 V and tremendous OER performance with an ultrasmall overpotential of 240 mV at a current density of 10 mA cm−2, outperforming conventional Pt/C and RuO2 catalysts. As proof of concept, rechargeable ZABs with an optimal VO-CMON@NCN-800 air-cathode showed an ultrahigh specific capacity of 721.2 mA h gZn−1 at a current density of 5 mA cm−2, a tremendous peak power density of 143.7 mW cm−2, and ultralong cycling life of 500 h. These consequences suggest that the oxygen vacancies enriched VO-CMON@NCN can serve as promising bifunctional catalysts for next-generation metal–air batteries and other energy-related applications.

The rational design of free-standing hierarchic core–shell nanoporous architectures is a good strategy for fabricating next-generation electrode materials for application to electrochemical energy conversion/storage systems. Herein, hierarchical core–shell 3D Co9S8@Nix:Moy–Se nanowire arrays (NWAs) are constructed by a low-cost, straightforward two-step hydrothermal method and an effective electrodeposition process. The optimal 3D Co9S8@Ni0.5Mo0.5–Se NWAs electrode displays the excellent specific capacity of 460.81 mAh g-1 with a corresponding areal capacity of 0.93 mA h cm-2 at 1.5 mA cm-2. It also demonstrates superb rate capability (~68.4 % capacity retention at 20 mA cm-2) and remarkable cyclic stability (~ 94.3 % capacity retention after 10,000 charge and discharge cycles). Additionally, an asymmetric supercapacitor (ASC) is assembled using the hierarchical 3D Co9S8@Ni0.5Mo0.5–Se NWAs as the positive electrode, and the as-obtained Fe2O3@PANNFs/N-rGO aerogel as the negative electrode. The assembled Co9S8@Ni0.5Mo0.5–Se//Fe2O3@PANNFs/N-rGO ASC shows a larger operating voltage range of 1.7 V, a high electrochemical energy storage capability (96.90 W h kg−1 at 1,158 W kg−1), and excellent cyclic stability (capacity remained ~ 94.47 % of the original capacity before 10,000 cycles). The all-solid-state ASC device that is also fabricated exhibits a high export working potential window of ~1.8 V, and an outstanding energy density of ~ 102.94 W h kg−1 at ~1,534 W kg−1, demonstrating that the hierarchical 3D Co9S8@Ni0.5Mo0.5–Se NWAs electrode materials are potential candidates for the high-performance energy storage device.

Supercapacitors possess minimum energy density, lower rate capability, and inferior long-term cycling stability performance, and these issues have restricted their practical applications. In these ...

We have prepared the flexible and transparent symmetric solid-state supercapacitors based on the nanofiber-based composite (NFC) electrodes decorated with NiO nanoparticles which exhibit better ele...

Transparent and flexible energy-storage devices have currently gained a lot of attention as wearable and portable electronics. Herein, we develop a one-step electrodeposited MoS2 nanosheet@Ni-mesh core–shell network nanostructure as a transparent negative electrode for the flexible and transparent asymmetric solid-state supercapacitor (FT-ASSc). In the fabricated core–shell nanosheet network architecture, the junctionless interconnected Ni-mesh network with excellent conductivity contributes to superior electron transport pathways, and the nanostructure of the MoS2 over the Ni-mesh provides effective interface contact between the active material and current collector. As a result, the MoS2@Ni-mesh network negative electrode provides an areal capacitance of 7.31 mF cm−2 at the scan rate of 10 mV s−1 with an 80% capacity retention rate after 5000 GCD cycles. Moreover, the fabricated FT-ASSc with a transmittance of 51% can operate up to a maximum working potential window of 1.6 V and also provide a maximum volumetric capacitance of 48.32 mF cm−3 at 0.4 mA cm−3 current density. This work might provide a new strategy for improving the electrochemical performance of transparent and flexible energy-storage devices for next-generation integrated electronic gadgets.

In recent years, much effort has been devoted to developing hybrid supercapacitors due to their capability to deliver both high energy and power density. The hybrid approach is advantageous in terms of reinforcing the synergic combination of the properties of different components in a hybrid composite. However, a large kinetic mismatch existing between the fast capacitive and sluggish battery-type electrodes greatly hinders its advancement. In this work, we report the fabrication of a solid-state hybrid supercapacitor (SSHSC) device using metal–organic framework (MOF)-derived cobalt-embedded N-doped carbon nanofibers (Co–N-CNFs) and Co2−xFexP–N–C micropillar arrays grown on Ni foam (Co2−xFexP–N–C/NF) as multi-component hybrid electrodes with improved charge storage kinetics. Such Co–N-CNFs (negative electrode) exhibited a remarkable specific capacitance of 280 F g−1 at a current density of 1 A g−1, while Co2−xFexP–N–C/NF (positive electrode) exhibited a high specific capacity of 345 mA h g−1 at a current density of 1 A g−1 due to the synergistic combinations of different components in a single hybrid composite. The assembled Co2−xFexP–N–C/NF(+)//Co–N-CNFs(−) SSHSC device demonstrated a high specific capacity of 104 mA h g−1 at a current density of 1 A g−1 with a maximum energy density of 84.7 W h kg−1 at a power density of 706 W kg−1. It also exhibited excellent stability and reversibility with a capacity retention of 93% and coulombic efficiency of 99.6% after 10 000 galvanostatic charge–discharge (GCD) cycles. Two SSHSC devices connected in series after being charged could easily light up a red LED bulb. These excellent performances indicate that Co–N-CNFs(−) and Co2−xFexP–N–C/NF(+) materials could be considered as potential electrodes for high energy density storage systems.

Innovating efficient and robust electrocatalysts with economical production cost for the oxygen reduction reaction (ORR) is of utmost significance for enhancing the energy efficiency of fuel cells and metal–air batteries. Herein, a single-step doping/annealing strategy has been developed for fabricating an Fe–N–C/Fe3C/C–S–C nanohybrid with a high N-doping level, well-defined mesoporous/microporous architecture, and high density of efficient active sites. The importance of tuning the S-doping into the electrocatalyst carbon framework has been fully elaborated for the first time. Under alkaline conditions, the nanohybrid displayed an exceptional onset potential (E0) and half-wave potential (E1/2) of 1.078 and 0.929 V vs. reversible hydrogen electrode (RHE). Furthermore, it manifests a dominant four-electron transfer reaction, marvelous selectivity for the ORR in the presence of methanol, and excellent durability after 15 000 potential cycles with almost zero degradation in performance under both acidic and alkaline conditions. The superb performance is due to the high density of active sites, like FeNx, FeSx, Fe3C, pyridinic-N, graphitic-N, C–S–C, and C–SOx–C, that efficiently catalyze the ORR. In addition, the high graphitization degree boosts the electron conductivity and corrosion resistance; meanwhile, the high surface area and ideal mesoporosity enhance the mass transfer and facilitate the maximum exposure of the active sites to the electrolyte and reactants.

The development of highly efficient electrocatalysts for simultaneous evolution of hydrogen and oxygen is a vital concern in water splitting. In this study, a novel catalyst derived from a porous interconnected network of nickel cobalt oxysulfide interfacial assembled Cu@Cu2S nanowires was rationally designed. It was recognized that the formation of multi-integrated active centers and a higher number of active sites, together with an adjusted adsorption energy towards reactants caused by the modulated surface and crystalline distortion of the NiCo oxide layer due to S insertion synergistically promoted both HER and OER. In addition, such 3D innovative core–shell structure effectively fine-tuned conductive properties and maximized interfacial contact to improve charge/mass transfer, thereby boosting catalytic activity and durability towards hydrogen and oxygen evolution. The catalyst only required an overpotential of 203 mV to achieve a current response of 20 mA cm−2 for the HER and 295 mV to reach 50 mA cm−2 for the OER in 1.0 M KOH medium. A developed electrolyzer enabled a small cell voltage of 1.61 V at 20 mA cm−2 without performance decay upon long-term operation. This result suggested an exciting prospect for developing new bifunctional electrocatalysts, which could effectively accelerate both hydrogen and oxygen evolution for water splitting applications.

The electrocatalytic water-splitting performance of MoS2 nanostructures can be improved by increasing the edge density, activating basal planes, expanding the interlayer spacing and stabilizing the 1T-phase. In this work, for the first time, we have studied the synchronous involvement of all these driving factors to achieve the highest bifunctional performance of MoS2 for water-splitting following doping and intercalation of nickel (Ni) and phosphorus (P) in a single-step reaction. Two nanostructures, nanoflowers (1T-Ni0.2Mo0.8S1.8P0.2 NFs, powder) for large scale synthesis and freestanding nanosheets on carbon-cloth (1T-Ni0.2Mo0.8S1.8P0.2 NS/CC) as binder-free electrodes, are fabricated. Co-doping of Ni and P enriches the 1T-phase, expands the interlayer spacing by 24%, activates basal planes significantly and increases the edge density of MoS2 in the 2D-nanostructures. The 1T-Ni0.2Mo0.8S1.8P0.2 NS/CC and 1T-Ni0.2Mo0.8S1.8P0.2 NFs exhibit significantly low overpotentials of 55 and 99 mV at the current density of 10 mA cm−2 for the hydrogen evolution reaction (HER) and 286 and 305 mV at 40 mA cm−2 for the oxygen evolution reaction (OER), respectively. Further, 1T-Ni0.2Mo0.8S1.8P0.2-NS/CC (±) and 1T-Ni0.2Mo0.8S1.8P0.2-NF (±) alkaline electrolyzers require only 1.52 and 1.53 V, respectively, to generate a current density of 20 mA cm−2 with robust stability, and are much superior to recently reported electrocatalysts, indicating the immense potential of the employed strategy for developing highly efficient and low-cost electrocatalysts for water-splitting.