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This paper demonstrates the exfoliation of naturally occurring silicates into two-dimensional structures. Moving the d-silicate device repeatedly in a vertical direction causes it to react robotically and generate up to ∼400 mV of voltage.

Radiofrequency (RF) energy harvesting is receiving increased attention in today's digital era due to its potential to replace or improve the longevity of energy storage devices in low-power IoT devices.

For many biomedical applications, high-precision CO2 detection with a rapid response is essential. Due to the superior surface-active characteristics, 2D materials are particularly crucial for electrochemical sensors. The liquid phase exfoliation method of 2D Co2Te3 production is used to achieve the electrochemical sensing of CO2. The Co2Te3 electrode performs better than other CO2 detectors in terms of linearity, low detection limit, and high sensitivity. The outstanding physical characteristics of the electrocatalyst, including its large specific surface area, quick electron transport, and presence of a surface charge, can be credited for its extraordinary electrocatalytic activity. More importantly, the suggested electrochemical sensor has great repeatability, strong stability, and outstanding selectivity. Additionally, the electrochemical sensor based on Co2Te3 could be used to monitor respiratory alkalosis.

We report an eco-friendly, economical and green approach to synthesize few-layers of functionalised graphene from large graphite flakes and chunks without the aid of any external mechanical forces. Here, we demonstrate a fermentation process aided by friendly microbes like yeast to effortlessly exfoliate graphite to graphene with a high yield. The evident flaking and delamination of graphene layers, characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and Raman spectroscopy, confirmed the successful exfoliation of graphite to few-layer graphene (~10 nm in thickness). The gate-to-gate life cycle assessment of the developed method identified the environmental hotspots of the process. The biofunctionalized graphene (as suggested by Fourier transform infrared (FTIR) spectroscopy) was explored for its application in NH4+ sensing, where it exhibited the limit of detection to be ~20 ppm. The detection mechanism was explained based on Raman and FTIR spectroscopy which revealed the functional state and lattice changes introduced in the graphene layers by NH4+ ions. Our study demonstrates a novel, cost-effective exfoliation of graphite using off-the-shelf materials in laboratories or kitchens and has the potential to be scaled up to industry levels. The yeast cells also exhibited their potential in flaking off the bulk MoS2 structure into few-layer MoS2 sheets.

Additive manufacturing allows to produce parts with complex geometries is an essential tool in materials science. Schwarzites is a class of carbon allotropes with interesting mechanical properties. However, most of the schwarzite studies are theoretical until now because the synthesis of large schwarzite fragments remains elusive. In this work, we have carried out molecular dynamics simulations, and extensive experimental tests of 3D printed schwarzites to study their mechanical behavior. Our results show that this behavior does not strongly depend on printed used material, model size, or the number of structural unit cells. We also observed a strong correlation between the stress‐strain curves of 3D printed and the ones obtained from fully atomistic molecular dynamics simulations. Both results show the same trends for almost all investigated schwarzites, suggesting that topological features and scale‐size invariant dominate some deformation mechanisms. Our results further validate the use of atomic models of materials with complex geometries that are impractical or very difficult to synthesize, translated into macro models that can be 3D printed, and offer an innovative engineered approach to produce new materials with tunable mechanical behavior.

The efficient monitoring and early detection of viruses may provide essential information about the disease. In this work, we have highlighted the interaction between DNA and a two-dimensional (2D) metal...

Two-dimensional (2D) materials are at the forefront of current materials research due to their exciting and unique properties. 2D tellurides are emerging materials which are yet to be fully explored. To provide an overview of this emergent field, in this review, we discuss the structure, properties, synthesis methods, and applications of selected 2D tellurides, with stoichiometry of MxTey, and MxNyTez, (M, N are metal atoms). We present a summary of the latest advances in modeling, experimental synthesis, and characterization of 2D tellurides. Additionally, stress and strain-induced tunability of the physical properties have been reviewed, with a focus on the application of 2D tellurides in electronic, optoelectronic, and magnetic devices. We have discussed many emergent quantum properties of these materials. Finally, we conclude with a perspective on the future of 2D metal tellurides.

Hydrazine electrooxidation is an important reaction as it assists in decreasing the OER overvoltage. Herein, we report the utilization of high entropy nano-catalyst alloy for the electrooxidation of hydrazine. High entropy nano-catalyst comprising five elements (Ag, Au, Pt, Pd, Cu) shows profound activity towards this molecule at low overvoltage. An intriguingly high entropy nano-catalyst prepared by the casting-cum-cryomilling method is endowed with unique catalytic activity for HzOR. Detailed analysis of gaseous product points to the formation of nitrogen as well as oxygen as the oxidation product, a sign of accompanying oxygen evolution reaction (OER). Interestingly, significant oxygen is detected at 1.13 V (RHE) in a neutral buffered medium, confirming that OER is functional at a voltage near to the thermodynamic voltage of 1.23V (RHE). The quantitative contribution of each hydrazine and OER reaction is ascertained which explains a vital insight into this reaction. Density functional theory calculations showed that both HzOR and OER assist each other where the electron-donating effect of H2O to the surface can reduce the endothermicity of the HzOR. Whereas, the electron acceptance of *NHNH2 helps in the favorable overlap of the HEA Fermi level and vacant states with the HOMO of H2O.

High performance colloid flake of carbon is gaining interest due importance in meeting the challenges of the globe. To make novel superior materials, the pulverized fuel ash-green adhesive based construction materials modified with the flake of carbon and the colloid flake of carbon were evaluated in view of synthesis, physico-mechanical properties, and material processing and models. For better understanding, such experimental samples as green adhesive plaster and green adhesive grout were made of the pulverized fuel ash of class C, the common adhesive, the flake of carbon, the colloid flake of carbon, fine sand, and the distilled water to compare with the structural material properties each other. The results of the adsorption spectra of optical atomic spectroscopy of the colloid flake carbon, the thickening-period of plaster, the spread and the consolidating level, the apparent unit volume mass, the apparent porosity, the apparent compacity, and the compressive stress of green grouts were reported in the research. It was concluded that the flake of carbon and the colloid flake of carbon led to important progress in the novel superior materials, e.g., accelerating of the thickening-period of plasters and increasing of the compressive stress of grouts. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

The aim of this study is to evaluate the usability of new cement (NC) made by the burning of quinary by-product to make commercial binders. Chemical analysis of the by-products and NC as well as X-ray diffraction (XRD) analysis of NC, fineness, density, consistency, and setting time of NC paste, and slump in addition to compressive strength (CS) and splitting tensile strength (STS) of NC concrete (NCC) were conducted. The results suggested that chemical composition of by-products is suitable to make NC binder. The NC contains Ca3SiO5, Ca2SiO5, Ca3Al2O6, and Ca3Al2FeO10. The particles passing through the 200 um Sieve were 56% compared with 52% for Portland cement (PC). The density of the of NC was similar to that of PC. The NC needed 48% more water than PC for normal consistency. The initial and final setting-time of NC was 105 min and 225 min respectively which is much higher than that of PC (15 and 45 min). The slump, compressive strength and splitting tensile strength were slightly lower for concrete containing NC compared with that pf PC concrete. Although the CS and STS of NCC are the lowest, the rate of the CS and STS gain of NCC is greater than that of PCC. It was concluded that NC is a viable alternative to PC for the production of greener concrete. (C) 2021 The Authors. Published by Elsevier B.V.

The incessant accumulation of pharmaceutically active compounds (PhACs) in various environmental compartments represents a global menace. Herein, an equimolar and environmentally benign FeCoNiCuZn HEA is synthesized via a facile and scalable method, and its effectiveness in eliminating four different PhACs from aqueous matrices is rigorously examined. Attributing to its relatively low bandgap and multielement active sites, the as synthesized quinary HEA demonstrates more pronounced photocatalytic decomposition efficiency, towards tetracycline (86%), sulfamethoxazole (94%), ibuprofen (80%), and diclofenac (99%), than conventional semiconductor-based photocatalysts, under visible light irradiation. Additionally, radical trapping assays are conducted, and the dissociation intermediates are identified, to probe the plausible photocatalytic degradation pathways. Further, the end-products of FeCoNiCuZn-mediated photocatalysis are eco-friendly, and the HEA can be successfully recycled repeatedly, with no obvious leaching of heavy metal ions. Overall, the findings of this study testify the applicability of FeCoNiCuZn HEA as a visible light-active photocatalyst, for treating wastewaters contaminated with PhACs.

In this study, an experimental and atomic-scale simulation-based investigation has been performed to investigate the possible stability of the nano-crystalline structure and thereby considerable st...

Oxygen evolution reaction (OER) is the key step involved both in water splitting devices and rechargeable metal-air batteries, and hence, there is an urgent need for a stable and low-cost material for efficient OER. In the present investigation, Co−Fe−Ga−Ni−Zn (CFGNZ) high entropy alloy (HEA) has been utilized as a low-cost electrocatalyst for OER. Herein, after cyclic voltammetry activation, CFGNZ-nanoparticles (NPs) are covered with oxidized surface and form high entropy (oxy) hydroxides (HEOs), exhibiting a low overpotential of 370 mV to achieve a current density of 10 mA/cm2 with a small Tafel slope of 71 mV/dec. CFGNZ alloy has higher electrochemical stability in comparison to state-of-the art RuO2 electrocatalyst as no degradation has been observed up to 10 h of chronoamperometry. Transmission electron microscopy (TEM) studies after 10 h of long-term chronoamperometry test showed no change in the crystal structure, which confirmed the high stability of CFGNZ. The density functional theory (DFT) based calculations show that the closeness of d(p)-band centers to the Fermi level (EF) plays a major role in determining active sites. This work highlights the tremendous potential of CFGNZ HEA for OER, which is the primary reaction involved in water splitting.

A novel Fe-Cr-V-C plasma transformed arc (PTA) coating of 4 mm thickness was successfully deposited on a mild steel substrate, which constitutes a relatively smaller amount of carbide-forming elements such as Cr and V compared to previous studies. PTA coating was found to be free of any surface or transverse crack and porosity. A detailed phase analysis was performed using XRD, optical and SEM coupled with EPMA analysis. Thermodynamic calculations were also performed to determine the volume fraction and type of the carbide phases formed because of the coating and substrate interaction. Hardness variation along the coating thickness was related to the carbide fraction and size distribution. The improvement in wear resistance of the coating is reported and explained based on the carbide size and distribution.

“Waste-to-wealth” is always a subject of significant interest due to several aspects, including effective utilization of a large amount of e-waste by recycling valuable materials and thereby protec...

Two-dimensional materials are becoming a new sensation in the chemical, electrical, energy storage, and biomedical industries. Since the invention of graphene, scientists worldwide have been attempting to explore novel 2D materials. High surface-to-volume ratio, lightweight, anisotropy, and multi-functionality are some special features of these 2D materials. Such characteristics can be merged with the fabrication flexibility of 3D printing to develop complex structures including shape, size, and functionality. These complex 3D-printed 2D materials can be used in novel biomedical applications, including the advancement of targeted drug delivery, cancer therapy, tissue engineering, and biosensors. This review article focuses on the recent development of 3D/4D printed complex structures from 2D nanomaterials in biomedical applications. We have assessed the concept of hybridization of existing 2D nanomaterials and discussed the significance of computational modeling in 2D nanomaterials. Current trends, challenges, and prospects of 3D/4D-printed 2D nanomaterials in the biomedical field are also delineated.

In the past decade, several different classes of two-dimensional (2D) materials beyond graphene such as layered polymorphs of group V elements (phophorene, arsenene), Metalenes (gallenene, stanene etc.), Transition Metal–Dichalcogenides (TMDs), group III monochalcogenides, transition metal carbides as well as nitrides have been thoroughly explored. These atomically thin materials have gathered significant focus due to their unique electronic, optical, and magnetic properties, which are seldom found in their bulk counterparts due to the high surface to volume ratios and quantum confined electronic structure. These properties have led to excitement in the research community due to their potential applications in various fields of optoelectronics, energy harvesting and storage, sensing, electronics, magneto-electronics, and thermo-electronic applications. However, there is another emerging class of layered oxide 2D materials, which has been sporadically explored and lacks a systematic compilation of the made progress, potential benefits and research opportunities that may lie ahead. This specific review provides a thorough and systematic summary of research carried out on layered 2D oxides both from an experimental and theoretical perspective. Due to ultra-thin nature of the 2D metal oxides, a majority of the atoms are accessible to the surfaces, which induces new properties and applications in comparison to traditional bulk oxides. We discuss several different classes of metal oxides in their 2D forms such as MO, MOx, MxOy (where M stands for metals; x and y possible oxidation states) as well as Perovskite type oxides in this review specifically focusing on optoelectronics, sensing and electrochemical storage applications. We further make critical comparisons with bulk metal oxides, and elaborate the specific advantages of 2D metal oxides as compared to their bulk counterparts in respective applications. Finally, we conclude by providing a critical assessment and outlook of technical challenges and research opportunities for future development of layered 2D oxides.

Atomically thin, few-layered membranes of oxides show unique physical and chemical properties compared to their bulk forms. We have exfoliated manganese oxide (Mn3O4) membranes from naturally occurring Hausmannite and used them to make flexible, high-performance nanogenerators. We observe an enhanced power density in the membrane nanogenerators (NG) with the best-performing device showing a power density of 7.20 µW cm-2 compared to 1.04 µW cm-2 obtained from NG made up of bulk Mn3O4. We also observe a sensitivity of 108 mV/kPa for applied forces < 10 N in the membrane NGs. We attribute the improved performance to enhanced flexoelectric response in few-layers Mn3O4. Using first-principles calculations, we calculate the flexoelectric coefficients of monolayer and bilayer Mn3O4, and find them to be 50 – 100 times larger than two-dimensional transition metal dichalcogenides. We also show the presence of a destructive interference between the bending and shear modes in bulk Mn3O4 that almost cancel the overall flexoelectric coefficients. Dimensional reduction in the Mn3O4 suppresses the response to the shear modes and results in large flexoelectric coefficients. As a proof-of-concept, we made flexible triboelectric nanogenerators (TENG) using exfoliated Mn3O4 membranes and used them in self-powered devices such as paper based TENG. This research paves the way for exploration of few-layer membranes of other centrosymmetric oxides for application as energy harvesters.

An easily scalable fabrication method has been explored to obtain atomically thin gallium telluride (GaTe), which opens up new prospective applications of this well-known material. Due to nanostruc...