Enhancing hydrogen evolution reaction activity through defects and strain engineering in monolayer MoS.

Molybdenum disulfide (MoS) has recently emerged as a promising electrocatalyst for the hydrogen evolution reaction (HER). However, the poor in-plane electrical conductivity and inert basal plane activity pose major challenges in realizing its practical application. Herein, we demonstrate a new approach to induce biaxial strain into CVD-grown MoS monolayers by draping it over an array of patterned gold nanopillar arrays (AuNAs) as an efficient strategy to enhance its HER activity.

Two-Dimensional Materials/Biopolymer-Based Antimicrobial Coatings to Thwart Biofilm Formation on Medical Implants.

Infections associated with medical implants due to bacterial adhesion and biofilm formation are a serious problem, leading to acute health risks to patients by compromising their immune system. Therefore, suppressing biofilm formation on biomedical implants is a challenging task, especially for overcoming the drug resistance of bacterial biofilms. Herein, a synergistic efficient surface coating method was developed to inhibit biofilm formation on a model medical implant by combining the antimicrobial property of trimethyl chitosan (TMC) with either 2D material graphene oxide (GO) or black phosphorus (BP) sheets using layer-by-layer (LbL) self-assembly.

Polyimide-Based Aqueous Potassium Energy Storage Systems Using Concentrated WiSE Electrolyte.

Aqueous batteries are considered as promising alternative power sources due to their eco-friendly, cost-effective, and nonflammable attributes. Employing organic-based electrode materials offers further advantages toward building greener and sustainable systems, owing to their tunability and environmental friendliness. In order to enhance the energy and power densities, superconcentrated aqueous electrolytes, such as water-in-salt electrolytes (WiSE), have renewed the interest in aqueous batteries due to their enhanced stability and much wider electrochemical stability window (>1.

Heterointerface engineering of cobalt molybdenum suboxide for overall water splitting.

Highly active and earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are of great significance for sustainable hydrogen generation through alkaline water electrolysis. Here, with an aim to enhance the bifunctional electrocatalytic activity of cobalt molybdate towards overall water splitting, we demonstrate a simple method involving the modulation of the cobalt to molybdenum ratio and creation of phase-modulated heterointerfaces. Samples with varying Co/Mo molar ratios are obtained a microwave-assisted synthesis method using appropriate starting precursors.

Anomalously polarised emission from a MoS/WS heterostructure.

We report circularly polarised emission, with helicity opposite to the optical excitation, from a van der Waals heterostructure (HS) consisting of a monolayer MoS and three-layer WS. Selective excitation of the MoS layer confirms that this cross-polarized emission is due to the charge transfer from the WS layers to the MoS layer. We propose that the high levels of n-doping in the constituent layers due to sulphur vacancies and defects give rise to an enhanced transition rate of electrons from the valley of WS to the ' valley of MoS, which leads to the emission, counter polarized to the excitation.

Mass Balancing of Hybrid Ion Capacitor Electrodes: A Simple and Generalized Semiempirical Approach.

Hybrid ion capacitors (HICs) are emerging as promising energy-storage devices exhibiting the advantages of both batteries and supercapacitors. However, the difference in the electrodes' specific capacities and rate capabilities makes it extremely challenging to achieve optimum mass balancing for a full-cell HIC device. Here, we demonstrate a method to predict well-performing mass ratios of electrodes for a Na-HIC by analyzing the capacities of anodes and cathodes as a function of the actual current densities experienced by the individual electrodes.

Engineering of Exciton-Plasmon Coupling Using 2D-WS Nanosheets for 1000-Fold Fluorescence Enhancement in Surface Plasmon-Coupled Emission Platforms.

Enhancement of fluorescence emission from single-photon quantum emitters on plasmonic nanomaterials using surface plasmon-coupled emission (SPCE) platforms has seen significant advancements. In parallel, there has also been an exponential rise in applications involving two-dimensional (2D) transition-metal dichalcogenides (TMDs) that exhibit unique exciton-plasmon interactions. Although both these Frontier research areas have impacted the development of sensor and sensing technologies, no study coalesces these two arenas for translational applications.

Hierarchically Engineered Nanocarbon Florets as Bifunctional Electrode Materials for Adsorptive and Intercalative Energy Storage.

Three-dimensional dendritic nanostructured carbon florets (NCFs) with tailored porosity are demonstrated as electrochemically versatile electrodes for both adsorptive and intercalative energy storage pathways. Achieved through a single-step template-driven approach, the NCFs exhibit turbostratic graphitic lamellae in a floral assembly leading to high specific surface area and multi-modal pore distribution (920 m/g). The synergism in structural and chemical frameworks, along with open-ended morphology, enables bifunctionality of hard carbon NCFs as symmetric adsorptive electrodes for supercapacitors (SCs) and intercalation anodes for hybrid potassium-ion capacitors (KICs).

Oxygen incorporated WS nanoclusters with superior electrocatalytic properties for hydrogen evolution reaction.

Transition metal dichalcogenides (TMDs) exhibit unique properties and show potential for promising applications in energy conversion. Mono/few-layered TMDs have been widely explored as active electrocatalysts for the hydrogen evolution reaction (HER). A controlled synthesis of TMD nanostructures with unique structural and electronic properties, leading to highly active sites or higher conductivity, is essential to achieve enhanced HER activity.

Exfoliation of Reduced Graphene Oxide with Self-Assembled π-Gelators for Improved Electrochemical Performance.

Among several methodologies to improve the solution processing of graphene-based materials, noncovalent functionalization has been considered as the simplest and nondestructive method. Herein, we show that molecular self-assembly process can be used as a useful tool to exfoliate reduced graphene oxide (RGO), resulting in hybrid materials with improved physical properties. Upon interacting with a π-gelator, the dispersing ability of the RGO increased significantly in most of nonpolar and polar aprotic solvents when compared to the bare one.

Highly Ordered Vertical Arrays of TiO2/ZnO Hybrid Nanowires: Synthesis and Electrochemical Characterization.

We report the fabrication of vertically aligned hierarchical arrays of TiO2/ZnO hybrid nanowires, consisting of ZnO nanowires grown directly from within the pores of TiO2 nanotubes, through a combination of electrochemical anodization and hydrothermal techniques. These novel nano-architectured hybrid nanowires with its unique properties show promise as high performance supercapacitor electrodes. The electrochemical behaviour of these hybrid nanowires has been studied using Cyclic voltammetry, Galvanostatic charge-discharge and Electrochemical impedance spectroscopy (EIS) measurements using 1.

Electrochemical synthesis of luminescent MoS2 quantum dots.

Size-controlled synthesis of luminescent quantum dots of MoS2 (≤2 layers) with narrow size distribution, ranging from 2.5 to 6 nm, from their bulk material using a unique electrochemical etching of bulk MoS2 is demonstrated. Excitation-dependent photoluminescence emission is observed in the MoS2 QDs.

MoS2 quantum dot-interspersed exfoliated MoS2 nanosheets.

We report the synthesis of heterodimensional nanostructures of MoS2 quantum dots interspersed in few-layered sheets of MoS2, using a liquid exfoliation technique in organic solvents. This unique hybrid morphology results from the optimized experimental conditions involving bath sonication followed by ultrasound probe sonication. We show that such heterodimensional hybrid materials could easily be extracted from the solvent as precipitates when post-treated with less polar volatile solvents such as chloroform.

Covalently interconnected three-dimensional graphene oxide solids.

The creation of three-dimensionally engineered nanoporous architectures via covalently interconnected nanoscale building blocks remains one of the fundamental challenges in nanotechnology. Here we report the synthesis of ordered, stacked macroscopic three-dimensional (3D) solid scaffolds of graphene oxide (GO) fabricated via chemical cross-linking of two-dimensional GO building blocks. The resulting 3D GO network solids form highly porous interconnected structures, and the controlled reduction of these structures leads to formation of 3D conductive graphene scaffolds.

Hybrid nanostructures for energy storage applications.

Materials engineering plays a key role in the field of energy storage. In particular, engineering materials at the nanoscale offers unique properties resulting in high performance electrodes and electrolytes in various energy storage devices. Consequently, considerable efforts have been made in recent years to fulfill the future requirements of electrochemical energy storage using these advanced materials.

Conformal coating of thin polymer electrolyte layer on nanostructured electrode materials for three-dimensional battery applications.

Various three-dimensional (3D) battery architectures have been proposed to address effective power delivery in micro/nanoscale devices and for increasing the stored energy per electrode footprint area. One step toward obtaining 3D configurations in batteries is the formation of core-shell nanowires that combines electrode and electrolyte materials. One of the major challenges however in creating such architectures has been the coating of conformal thin nanolayers of polymer electrolytes around nanostructured electrodes.

Coaxial MnO2/carbon nanotube array electrodes for high-performance lithium batteries.

Coaxial manganese oxide/carbon nanotube (CNT) arrays deposited inside porous alumina templates were used as cathodes in a lithium battery. Excellent cyclic stability and capacity of MnO2/CNT coaxial nanotube electrodes resulted from the hybrid nature of the electrodes with improved electronic conductivity and dual mechanism of lithium storage. The reversible capacity of the battery was increased by an order compared to template grown MnO2 nanotubes, making them suitable electrodes for advanced Li ion batteries.

Controlled manipulation of giant hybrid inorganic nanowire assemblies.

The ultimate goal of nanotechnology is the design and fabrication of nanosize building blocks with multiple functionalities and their assembly into large-scale functional structures that can be controllably manipulated. Here we show that hybrid inorganic multisegmented nanowires, with hydrophobic carbon nanotube tails and hydrophilic metal nanowire heads, allow the assembly and manipulation of massive ordered structures in solution, reminiscent of the organic molecular micellar assembly. Further, properly designed assemblies can be manipulated using external stimuli such as magnetic field and light.

Synthesis of hybrid nanowire arrays and their application as high power supercapacitor electrodes.

Arrays of multi-segmented hybrid nanostructures of carbon nanotube and gold nanowires have been synthesized using a combination of chemical vapour deposition and electrodeposition methods and we further demonstrate that ultra-high power electrochemical double layer capacitors can be engineered using these hybrid nanowires, resulting in very high power densities.

Flexible energy storage devices based on nanocomposite paper.

There is strong recent interest in ultrathin, flexible, safe energy storage devices to meet the various design and power needs of modern gadgets. To build such fully flexible and robust electrochemical devices, multiple components with specific electrochemical and interfacial properties need to be integrated into single units. Here we show that these basic components, the electrode, separator, and electrolyte, can all be integrated into single contiguous nanocomposite units that can serve as building blocks for a variety of thin mechanically flexible energy storage devices.