Active Edge Research Articles

Tuberculosis Extra Pulmonary Bacilli Detection System Based on Ziehl Neelsen Images with Segmentation

Tuberculosis Extra Pulmonary (TBEP) is one of the infectious diseases that can cause death. The bacterium Mycobacterium tuberculosis is the cause of this disease. Patients suffering from this disease must be treated quickly. Currently, patients need a long time and a large cost in detecting the bacteria that cause this disease. The technique used is to take the patient's lung fluid by biopsy and given Ziehl Neelsen chemical dye and then observed using a microscope. This study aims to help detect bacteria quickly and precisely by processing the image produced by the microscope. The technique used is to develop the segmentation method. The segmentation process carried out is to develop a Hue Saturation Value (HSV) color space transformation technique with Active Contour, Edge Detection, and Otsu techniques. The images used in this research are 51 images taken from H. Adam Malik Hospital, Medan and have been validated by an expert. Of the several segmentation methods used in this study, the maximum or best result in detecting Tuberculosis Extra Pulmonary (TBEP) bacilli is the Otsu method. So the method developed is very helpful in accelerating the detection of TBEP.

Porous carbon foam loaded CoSe2 nanoparticles based on inkjet-printing technology as self-supporting electrodes for efficient water splitting

Reasonable design of self-supporting electrocatalyst with porous structure and flexibility is very important for hydrogen and oxygen evolution reactions. Herein, we constructed porous carbon foam loaded CoSe2 (CoSe2/CMF) as self-supporting electrode by combining inkjet printing, pyrolysis and selenization technologies. The non-contact and precise control characteristics of inkjet printing nano-deposition technology reduces the accumulation of CoSe2 nanoparticles on porous carbon foam, having access to full exposure for active edge sites. Due to the outstanding intrinsic catalytic activity, abundant electrochemical active sites and high electrical conductivity, in alkaline media, CoSe2/CMF exhibits outstanding electrocatalytic behavior in hydrogen evolution and oxygen evolution reactions, with low overpotentials of 122.6 and 400.0 mV at 10 mA cm−2, respectively, lower than CoP/CMF and CoO/CMF, highlighting the advance of selenides in electrocatalysis. This study is helpful to the design of high-efficiency self-supporting electrocatalysts for water splitting.

Efficient Lithium/Sodium-Ion Storage by Core-Shell Carbon Nanospheres@TiO2 Decorate by Epitaxial WSe2 Nanosheets Derived from Bimetallic Polydopamine Composites.

Metal-polydopamine coordination chemistry attracts great attention owing to the synergistic effect of adjustable components and advantageous structures. However, few efforts have been devoted to exploring bimetal-polydopamine composites, especially for multistructural composites with high-capacity components and high stability. In this regard, the TiO2 @C-WSe2 core-shell nanospheres are designed and fabricated based on Ti-W-polydopamine composites after selenization, in which the TiO2 nanoparticles are encapsulated or embedded in the carbon nanospheres and the external WSe2 nanosheets are grown epitaxially on the carbon surfaces, featuring multiple channels for ion diffusion and abundant active edges for electrochemical reactions. The introduction of WSe2 not only greatly improves the capacity but also results in exponential growth of the active edge. As a result, the as-prepared TiO2 @C-WSe2 displayed long-term cycling performance in lithium-ion batteries. Furthermore, the anode is assembled into sodium-ion batteries, manifesting a stable capacity of 352mA h g-1 at 1.0 A g-1 even after 2000 cycles, one of the best performances for polydopamine-based composites. Enhanced performance can be attributed to the synergies of high-capacity components and different dimensional materials. This work highlights that the rational design of functional structures provides a novel inspiration for electrodes with effective nanoarchitectures.

A Stable Rechargeable Aqueous Zn-Air Battery Enabled by Heterogeneous MoS2 Cathode Catalysts.

Aqueous rechargeable zinc (Zn)-air batteries have recently attracted extensive research interest due to their low cost, environmental benignity, safety, and high energy density. However, the sluggish kinetics of oxygen (O2) evolution reaction (OER) and the oxygen reduction reaction (ORR) of cathode catalysts in the batteries result in the high over-potential that impedes the practical application of Zn-air batteries. Here, we report a stable rechargeable aqueous Zn-air battery by use of a heterogeneous two-dimensional molybdenum sulfide (2D MoS2) cathode catalyst that consists of a heterogeneous interface and defects-embedded active edge sites. Compared to commercial Pt/C-RuO2, the low cost MoS2 cathode catalyst shows decent oxygen evolution and acceptable oxygen reduction catalytic activity. The assembled aqueous Zn-air battery using hybrid MoS2 catalysts demonstrates a specific capacity of 330 mAh g-1 and a durability of 500 cycles (~180 h) at 0.5 mA cm-2. In particular, the hybrid MoS2 catalysts outperform commercial Pt/C in the practically meaningful high-current region (>5 mA cm-2). This work paves the way for research on improving the performance of aqueous Zn-air batteries by constructing their own heterogeneous surfaces or interfaces instead of constructing bifunctional catalysts by compounding other materials.

Enhancing Hydrogen Evolution Reaction via Synergistic Interaction between the [Mo3S13]2- Cluster Co-Catalyst and WSe2 Photocathode.

A thiomolybdate [Mo3S13]2- nanocluster is a promising catalyst for hydrogen evolution reaction (HER) due to the high number of active edge sites. In this work, thiomolybdate cluster films are prepared by spin-coating of a (NH4)2Mo3S13 solution both on FTO glass substrates as hydrogen evolving electrodes and on highly 00.1-textured WSe2 for photoelectrochemical water splitting. As an electrocatalyst, [Mo3S13]2- clusters demonstrate a low overpotential of 220 mV at 10 mA cm-2 in 0.5 M H2SO4 electrolyte (pH 0.3) and remain structurally stable during the electrochemical cycling as revealed by in situ Raman spectroscopy. Moreover, as a co-catalyst on WSe2, [Mo3S13]2- clusters enhance the photocurrent substantially by more than two orders of magnitude (from 0.02 to 2.8 mA cm-2 at 0 V vs RHE). The synergistic interactions between the photoelectrode and catalyst, i.e., surface passivation and band bending modification by the [Mo3S13]2- cluster film, promoted HER catalytic activity of [Mo3S13]2- clusters influenced by the WSe2 support, are revealed by intensity-modulated photocurrent spectroscopy and density functional theory calculations, respectively. The band alignment of the WSe2/[Mo3S13]2- heterojunction, which facilitates the electron injection, is determined by correlating UV-vis with photoelectron yield spectroscopy results.

Design, Manufacture and Assembly of 3D Integrated Optical Transceiver Module Based on an Active Photonic Interposer

The new generation of data centers is further evolving towards the direction of high speed and intelligence, which puts forward a great demand for the iteration of optical interconnection technology. Three-dimensional integration based on active photonic interposers can achieve the advantages of high integration, high bandwidth and low power consumption, which has become the main direction for next generation optical module technology. The fabrication and assembly of 3D optical modules based on active interposer-integrated edge couplers and TSV are realized in this paper. Different active interposer processes with integrated edge couplers and RDL-TSV-RDL structures are discussed, manufactured, analyzed and evaluated. The problem of the co-fabrication of the TSV and edge coupler was solved, and perfect electrical and optical characteristics were also achieved. Finally, the fabrication of the substrate and the assembly of the 3D optical module were completed. This paper lays a solid foundation for the further research and large-scale application of 3D optical modules in the future.

Ceria and gold co-decorated porous MoS2@graphene nanocomposite electrochemical electrode integrated with smartphone-controlled microstation for simultaneous dual metal ions detection

Continuous increase in release of toxic metals into ecosystem posed a threat to public ecology, leading to demand for the portable monitoring system to control contamination source and monitor disease progression. Herein, ceria and gold co-decorated porous MoS2@graphene nanocomposite was synthesized to construct electrochemical chip and integrate with smartphone-controlled hand-held microstation for simultaneous detecting Zn(II) and Cu(II). Concretely, MoS2 nanosheets coated polyimide were firstly laser-induced into 3D frame-structured MoS2/graphene with abundant oxygen-containing groups and active breaking edges, thereby accelerating the electron transfer and improving the absorptivity and reductive affinity for divalent ions. Double electro-deposition of ceria and gold provide vast oxygen vacancies for sensing, and Ce(III)/Ce(IV) cycle inhibit the recombination of electrons and holes, prolonging the life of carriers to enhance its electro-conductibility. The hydroxylation of ceria under acidic conditions is favorable for ions adsorption. Benefitting from synergetic effect among materials, the smartphone-controlled sensing system exhibits high sensitivity and low detection limit for Cu(II) of 2.8 ppt and Zn(II) of 103.6 ppt. Low energy barrier of target plating/stripping kinetics were also substantiated via calculating activation energy upon composite using Arrhenius formula. Furthermore, its outstanding flexibility, reusability, and anti-interference performance was verified, indicating the potential implementation possibilities in complex environment.

Carbothermal-reduction-assisted CVD synthesis of layered MoS2 nanosheets on activated carbon support: Implication for photocatalysis

The photocatalytic activity of MoS2-based heterostructures largely depends on the thickness and orientation of the MoS2 components. We report a new facile two-step carbothermal-reduction-assisted CVD synthesis protocol to produce horizontally and vertically aligned MoS2 nanosheets (NSs) on activated carbon (AC) granules. MoO3/AC pellets were first prepared by sonicating MoO3 and AC powders and then used as a substrate and Mo source to obtain MoS2/AC composites. A feature of the process is that MoO3 particles, prior to interaction with sulfur, undergo carbothermal reduction with the formation of Mo suboxides favorable for MoS2 growth. The thickness and orientation of MoS2 NSs strongly depend on the synthesis temperature. At 600 °C, horizontally oriented triangular MoS2 NSs are formed on the surface of molybdenum oxide particles, and at 700 °C, thin vertically oriented MoS2 NSs with a high aspect ratio (with a thickness and a lateral size of 20 × 5000 nm2) are grown. The high photocatalytic activity of MoS2/AC composites during the decompositions of organic dyes under UV radiation is associated with the thickness and orientation of MoS2 NSs. The vertical arrangement of the active edges intensifies the chemical interaction with the reagents, and the small NS thickness prevents the recombination of charge carriers and facilitates their transfer to the surface. The obtained results open up new possibilities for the development of cost-effective and scalable MoS2-based photocatalysts with tunable thickness and orientation of MoS2 NSs on commercially available AC substrates using a carbothermal-reduction-assisted CVD approach.

Role of dopants and defects on the photocatalytic performance of g-C3N4 under visible light and sub-band gap excitation

Here, we report the photocatalytic (PC) activity of graphitic carbon nitride (g-C3N4) doped with potassium (K), magnesium (Mg), and boron (B) under visible (>390 nm), green (532 nm), and red (660 nm) light. Doped g-C3N4 has an improved band structure, high carrier density, and tunable band-edge absorption as compared to pure g-C3N4. An atomic force microscope shows a decrease in layer thickness that follows the order: g-C3N4 > K/g-C3N4 > Mg/g-C3N4 > B/g-C3N4. The evolution of nitrogen vacancies in doped g-C3N4 was identified via x-ray photoelectron spectroscopy (XPS) and CHNS/O analyses. The red-shift in the absorption spectrum of K/g-C3N4 and the emission spectrum of B/g-C3N4 is caused by the band gap renormalization (BGR) effect. Quantum confinement and a possible Burstein–Moss (BM) effect both contribute to the spectral blue shift in the absorption spectra of Mg/g-C3N4 and B/g-C3N4. The BM effect, quantum confinement, and dopant-induced lattice strain might all alter the band structure and move the conduction band edge away from the valence band zone centre, causing an above band gap emission in K/g-C3N4 and Mg/g-C3N4. All samples degraded methylene blue (MB) under visible light with outstanding results, but they responded poorly to methyl orange (MO) and rhodamine B (RhB). With 83.59% MB degradation at a rate constant of 1.1 × 10−2 min−1, Mg/g-C3N4 recorded the best PC, which was three times quicker than g-C3N4 (3.7 × 10−3 min−1). When compared to g-C3N4, the doped samples’ current density (both anodic and cathodic) and carrier density were almost two times greater. The mechanism demonstrated how active edge sites, defects, and dopants contributed to the remarkable PC activity in the doped samples.

In-situ growth of hierarchical trifunctional Co4S3/Ni3S2@MoS2 core-shell nanosheet array on nickel foam for overall water splitting and supercapacitor

It is an enormous challenge to construct the cheap and effective multifunctional electrocatalysts for energy storage and conversion applications. Herein, a ZIF-67 derived Co4S3/Ni3S2@MoS2 core-shell nanosheet arrays were successfully developed on nickel foam via a simple two-step hydrothermal vulcanization method for electrocatalytic water splitting and supercapacitors. For overall water splitting, CNM 0.5 required the overpotentials of 96 and 269 mV at 10 mA cm−2 and 100 mA cm−2 for HER and OER in 1 M KOH. The dual-electrode electrolytic cell assembled from CNM 0.5 required only 1.447 V at 10 mA cm−2, and had nearly 100% Faraday efficiency and long-term stability (40 h). When used as the electrode for supercapacitors, CNM 0.5 had a large specific capacitance of 1238 F g−1 at 1 A g−1 current density and exceptional durability (85% retention after 2000 cycles). The ASC device assembled with CNM 0.5 provided the high-energy density of 41.2 W h kg−1 and long cycle-life (87% after 2000 cycles). The unique core-shell morphology with abundant active reactive edge sites would be beneficial for charge reduction and the volume shrinking/swelling during the rapid charge/discharge process. The well-ordered and vertically aligned nanosheet arrays possessed good conductivity and small interface resistance, which would facilitate the electron transfer and electrolyte penetration, ion insertion and de-intercalation.

Development of self-supporting catalyst based on bionic honeycomb communication channel from biomass cork waste for hydrogen evolution

It is a great challenge to achieve an efficient hydrogen evolution reaction (HER) in the alkaline medium. Multi-layer functional carbon can provide abundant anchor points for metal nanostructures, showing great potential in improving the catalytic activity of electrolyzed water in the alkaline medium. Inspired by honeybee hives, an efficient hydrogen evolution electrode (RuNi-LMH@NCNT/CW) is developed by structuring multi-directional N-doped carbon nanotubes on porous carbonized cork (CW), which encapsulates Ru/RuNi nanoparticles uniformly grown on NiO/Ni(OH)2 nanostructures. Interestingly, the whole encapsulation of NiO/Ni(OH)2 nanostructured doped Ru/RuNi nanoparticles by carbon nanotubes are obtained. The exposed active edges of multilayer porous nanostructures and the high conductivity of the carbonized cork jointly improve the electrocatalytic performance of HER. Specifically, the RuNi-LMH@NCNT/CW electrode shows an over potential as low as 67 mV, achieves excellent HER activity with a current density of 10 mA cm−2 in 1 M KOH solution, and illustrates a low Tafel slope of 41.3 mV dec−1, having excellent stability in alkaline medium. This study provides a bionic composite structure for electrolyzing water to produce hydrogen. In addition, to a certain extent, this study solves the problem that it is difficult to load active particles caused by the cork sealing cell structure.

Electrocatalytic Applications of 2D Molybdenum Dichalcogenides By Atomic Layer Deposition

2D semiconductor transition metal dichalcogenides have attracted considerable attention due to their layered structure, suitable band gap, electrochemically active unsaturated edges and relatively good stability against photocorrosion. These properties result promising for different applications including, Li-ion batteries, photocatalysis and hydrogen evolution reaction (HER). Apart from the widely studied 2D MoS2, 2D selenide and telluride equivalents, MoSe2 and MoTe2, have recently gained considerable interest due to their higher electrical conductivity, wider inter-layer distance and narrower bandgap as compared to MoS2, high surface area and close to zero Gibbs free energy edges for hydrogen adsorption.Unlike sulfide dichalcogenides, the lack of Se and Te precursors have prevented the synthesis of selenide and telluride dichalcogenides by ALD. In order to surpass such impediment, we present a set of novel in-house synthesized Se and Te compounds, which were successfully combined with commercial Mo precursor to synthesize MoSe2 and MoTe2 by ALD [1-5]. The as-deposited ALD MoSe2 and MoTe2 on substrates of different nature were extensively characterized by different techniques, which confirmed the chemical composition and revealed the growth of 2D flaky nano-crystalline MoSe2 and MoTe2.In parallel, MoSe2 and MoTe2@TiO2 nanotube layers (TNTs) heterostructures were fabricated in a simple and fast fashion to explore and exploit the MoSe2 and MoTe2 photo- and electrocatalytic properties. TNTs act as excellent photoactive supporting material providing a high surface area, unique directionality for charge separation, and highly effective charge collection.The presentation will introduce and describe the synthesis of the 2D Mo dichalcogenides, the corresponding physical and electrochemical characterization and encouraging results obtained in HER [4,5], photocatalysis [4-6] and Li-ion batteries [7].[1] R. Zazpe et al, FlatChem (2020) 21 100166[2] J. Charvot et al, Chempluschem (2020) 85 576[3] J. Charvot et al, RSC Adv. (2021) 11 22140[4] R. Zazpe et al, ACS Appl. Nano Mater. (2021) 3 12 12034[5] R. Zazpe et al, Appl. Mater. Today (2021) 23 101017[6] M. Motola et al, Nanoscale (2019) 11 23126[7] H. Sopha et al FlatChem (2019) 17 100130

Enhanced Electrocatalytic Activity for Hydrogen Evolution Reaction from Electrophoretically-Deposited BiSbSe3 Nanoparticles

For the development of renewable energy conversion and storage systems, it is vital to investigate earth-abundant, noble-metal-free, and highly efficient electrocatalysts for the hydrogen evolution process (HER). Platinum and other precious metals-based electrocatalysts show better HER activity in acidic conditions than other electrocatalysts due to their fast kinetics and lower Tafel slope.[1] However, because they are rare and costly, they are challenging to deploy in practical applications. As a result, there has been an ongoing search for low-cost and earth-abundant materials that may be used as an efficient alternative for platinum-based electrocatalysts, with the goal of developing more cost-effective and inexpensive H2 manufacturing processes. The layered 2D nanomaterials have sparked a lot of scientific attention because of their tremendous potential for both fundamental and practical investigations. Natural minerals of the group V-VI (V = Bi, Sb; VI = S, Se) have exceptional optical and electrical characteristics.[2] Because of their availability, low cost, and tunable characteristics, antimony/bismuth-based chalcogenides are garnering a lot of attention as potential candidates as electrocatalysts for acidic HER. We have shown an efficient and straightforward approach for the electrochemical exfoliation of BiSbSe3 nanostructures from the ball-milled BiSbSe3 sample; the process parameters were adjusted in terms of time and applied voltage. Furthermore, a simple and straightforward electrophoretic deposition process was used to synthesize BiSbSe3 nanoparticles from exfoliated BiSbSe3 nanostructures. A DC voltage was supplied between the two inert electrodes in an aqueous electrolyte for the electrophoretic deposition of BiSbSe3 nanostructures directly onto a gold substrate. Charged particles or sheets suspended in the electrolyte are activated to migrate toward the electrode and deposit when a voltage is applied. The BiSbSe3 nanoparticles were deposited onto the positive electrode because the exfoliated BiSbSe3 nanostructures in water had a negative zeta potential. BiSbSe3 nanostructures prepared through electrochemical exfoliation method are electrophoretically deposited onto the gold substrate to obtain BiSbSe3 nanoparticles, were investigated as active electrocatalysts for HER in 0.5 M H2SO4 solution using a three-electrode set up. The optimized BiSbSe3 catalyst (10V10M-Au-7.5) is identified as highly active HER activity, having a low overpotential of 72 mV @ 10 mA cm−2 and a low Tafel slope of 31.6 mV dec-1, which far better than the antimony/bismuth chalcogenide system and very close to the state-of-the-art Pt/C catalyst. We demonstrate that the electrocatalytic HER activity is enhanced by highly active edge sites, large available surface active sites, defects created and partial oxidization of material during electrodeposition, and a synergistic effect between BiSbSe3 and the substrate.

Heterostructure Induced S p‐Band Center Shift for Activating 1T‐MoS2 Basal Plane towards Hydrogen Evolution Reaction

AbstractDespite the benefits of metallic conductivity and highly active edge Mo sites of 1T phase molybdenum disulfide (1T‐MoS2) as an electrocatalyst, its overall catalytic efficiency for hydrogen evolution reaction (HER) is still limited by the less active S sites on the basal plane with a considerable positive ΔGH*. As a result, activating the basal plane S atoms is a viable solution for increasing catalytic activity. In this work, we modulated the electronic structure of 1T‐MoS2 by constructing a heterostructure with CoS2 nanoparticles deposited on the 1T‐MoS2 basal plane. This heterostructure demonstrated excellent HER activity as well as robust stability. Theoretical calculations indicate that the bridge S atoms connecting 1T‐MoS2 and CoS2 have an up‐shifted p‐band center relative to the S atoms on the basal plane, so the ΔGH* of the bridge S atoms is optimized to thermal neutrality and the 1T‐MoS2 basal plane is activated with enhanced hydrogen evolution activity. This work provides a novel strategy for activating the basal plane S atoms of 1T‐MoS2.

Novel core-shell structured electrocatalyst with 1D-NiTe2 over 3D metal structure for efficient hydrogen evolution reactions

Novel inexpensive materials are the focus of modern research for efficient hydrogen evolution reactions (HER) to substitute scarce and expensive platinum (Pt) based electrocatalysts. The ideal material should be durable, low-cost, efficient and possess high surface area. Earth abundant Transition metal dichalcogenides (TMDCs) are the potential group of materials for providing inexpensive source of durable HER catalysts with high surface area and active edges due to their layered structure. Here, we report a scalable single-step microwave-assisted solution phase synthesis of NiTe2 with core-shell configuration over porous three-dimensional nickel foam (3D-NF). This surface heterojunction catalyst possesses high surface area, unique needlelike morphology, and efficient performance for hydrogen evolution reactions. NiTe2 needles decorated on porous 3D-NF displayed fast HER kinetics with a reasonable overpotential of ~ −0.36 V to drive a current density of 100 mA cm−2. A small Tafel slope of ~55 mV dec−1 is observed. The catalyst showed higher stability with negligible performance degradation even after 8 h of potential cycling operation. It also demonstrated negligible current density variation at a constant applied potential for more than 15 h in 0.5 M sulfuric acid (H2SO4) solution. The 3D porous skeleton allowed high impregnation of electrolyte while the dense needlelike morphology provided high surface area and active edge sites for reactions. A thin 7 nm of amorphous oxide overlayer shell on highly crystalline NiTe2 core structure makes it a surface heterojunction catalyst (SHC) which is reported to facilitate hydrogen desorption upon charge take up and makes it an efficient electrocatalyst.

MoS2 nanocrystals embedded in hierarchical hollow carbon microspheres for efficient aerobic oxidative desulfurization

Aerobic oxidative desulfurization (AODS) is an emerging sustainable technology for deep desulfurization of petroleum fuels, which requires robust catalysts to boost the efficient aerobic oxidation of thiophenes. Here we report a self-assembly approach to anchor homogeneously dispersed MoS2 nanocrystals into hierarchical hollow carbon microspheres for the efficient AODS of thiophenic sulfides. We show that MoS2 nanocrystals are vertically embedded in carbon nanosheets with highly active edge sites exposed to the surface, which could activate the aerobic oxidation of dibenzothiophene at 100 °C, and achieves a turnover frequency of 7.53 h–1, higher than that of the reported metallic oxide catalysts. Through a combination of experimental research and theoretical calculations, we demonstrate that the Mo edge of MoS2 can effectively activate oxygen and strongly adsorb sulfides, which endows our catalyst with extraordinary performance. Moreover, the close coupling of MoS2 nanocrystals in carbon ensures their chemical stability, so that the catalyst maintains unattenuated activity and unchanged chemical structure over seven repeated uses. This work provides both fundamental and practical insights in the design of efficient and stable nanocrystal-based catalysts.

Advances on Understanding Coke Gasification Process with CO2: A Report from Density Functional Theory

AbstractCO2 gasification process on different active edges of a particular coke model surface has been explored computationally. It is observed that the adsorption through carbon and oxygen end of CO2 (CO‐mode) through formation of four‐ and five‐membered ring on the active sites is the favoured one. Our calculation also reveals that the strength of adsorption depends on nature and position of the active sites. The exergonic adsorption energy of CO‐mode drives the first CO release process and also makes it favoured compared to the adsorption mode where CO2 has been absorbed through its two‐oxygen end (OO‐mode). Among all the intermediates, intermediate having oxygen attached to the middle‐carbon of the coke (middle‐oxygenated coke) is found to be the most stable intermediate. The energy barrier for the second CO release also depends on the attachment sites of the oxygen on the coke surface. It is noteworthy that first principles investigations of coke gasification reactions with CO2 reported to date are found to consider different coke active sites separately on different coke model surfaces. In this context, our work is believed to be the first of its kind where complete characterization of CO2 gasification reactions has been performed considering all the active sites in a single coke model, thus providing a more coherent picture of it.

Creating Edge Sites within the 2D Metal‐Organic Framework Boosts Redox Kinetics in Lithium–Sulfur Batteries

AbstractLithium–sulfur batteries have received extensive interest owing to their exceptionally high energy density. Nonetheless, their practical implementation is still impeded by the shuttle effect of polysulfides and sluggish conversion kinetics. Considering that, a porous 2D defective zeolitic imidazolate framework‐7 (ZIF‐7) with abundant active edges is rationally designed as multifunctional sulfur carriers for Li–S batteries. The 2D ZIF‐7 enables uniform distribution of sulfur and rapid Li‐ion diffusion, while rich edges facilitate sufficient exposure to active sites capturing and catalyzing polysulfides. In addition, the nitrogen defects on edge sites can further accelerate the transformation of polysulfides and decrease the energy barrier of Li2S decomposition. Consequently, the Li–S batteries demonstrate surprisingly practical prospects with a stable capacity of 676.9 mAh g−1 over 500 cycles at 1 C (capacity retention rate = 72.3%). When assembled into a pouch cell at 2.3 mg cm−2, it still exhibits a high capacity of 901.1 mAh g−1 after 100 cycles at 0.1 C. This work offers a rational structural design strategy to tackle the challenges of the sulfur cathode.

Synthesis and characterization of in-situ MoS2-graphene hybrid nanostructured material

Nowadays, it has been challenging to develop novel techniques and synthesis processes for hybrid two-dimensional materials. Hence, this research presents an innovative technique for the fabrication of MoS2-Graphene (MoS2-Gr) hybrid nanostructured materials. The graphene was effectively generated in-situ and incorporated into the interlayer spacing of MoS2, which was synthesized by using a co-precipitation process with diethyl glycol as the solvent, followed by annealing the as-synthesized MoS2 at 800 oC for two hours in an inert atmosphere. The integrated graphene enhanced the width of MoS2 interlayers, exposing a substantial concentration of active edge sites in the hybrid material, according to SEM, XRD, HR-TEM, and other characterizations. This research might lead to the development of viable hybrid structured materials for various applications. In addition, this study outlines a novel advanced approach for creating hybrid 2D nanostructured materials with superior characteristics.

Interface modulation induced by the 1T Co-WS2 shell nanosheet layer at the metallic NiTe2/Ni core–nanoskeleton: Glib electrode-kinetics for HER, OER, and ORR

The metallic (1T) transition metal dichalcogenides (TMDCs) are known for their superior electrocatalytic performance, due to their high conductivity, active basal-planes, and exposed edges. Our novel approach of coupling a metallic-NiTe2/Ni nano-skeleton with 1T-Co-WS2 nanosheet in a core–shell arrangement to develop a hybrid heterostructure (1T Co-WS2/NiTe2/Ni) has helped to outperform the trifunctional-electrocatalytic activity (HER, OER, and ORR). 1T-Co-WS2/NiTe2/Ni only requires ultralow overpotential (ηHER = 88 mV@10, ηOER = 290 mV@30), higher half-wave potential for ORR (E1/2 = 0.781 V vs RHE), small Tafel slopes (HER = 68 mV dec-1, OER = 98 mV dec-1, and ORR = 63 mV dec-1) with high electrocatalytic surface area and robust stability in corresponding half-cell reactions. The designed heterostructured electrocatalyst (1T Co-WS2/NiTe2/Ni) presented exceptional total water-splitting performance, requiring a low voltage of 1.521 V to yield 10 mA cm−2 current with extensive structural and electrochemical durability. Such performance could be attributed towards improved nanochannel morphology with exposed active edge, fluent electrode-kinetics, facile adsorption–desorption of reaction intermediates owing to the intrinsically tuned 1T-WS2 by cobalt-doping, and hybridized NiTe2/Ni nano-skeleton. The DFT study confirmed that the incorporation of Co atoms in basal plane and the edge sites of WS2 lattice induces the redistribution and modulation of electronic structure for fast electron/charge transfer and the synergistic coupling of 1T NiTe2 heterostructures bolstered the electrocatalytic activity of the as-prepared catalysts. These outcomes provide a prospect towards the design and application of efficient 2D/2D heterostructured electrocatalyst for zero emission energy goal.