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Nickel-manganese-cobalt (NMC) is a type of cathode material widely used in lithium-ion batteries (LiBs). It performs well on high energy density and thermal stability, but after several charged-discharged cycles, its capacity significantly degrades and becomes waste. Leaching methods with strong inorganic acids are widely used to prevent the release of valuable metals into the environment. Still, these methods must be effectively achieved regarding the low selectivity of specific metals and environmental emissions. This study presents a selective leaching treatment for Ni metals extraction with the organic acid combination of H3PO4–H2C2O4 as a leaching agent. The research started with preparation, including discharge, dismantling, calcination steps, leaching, and precipitation. Ni, Mn, and Co leaching efficiency can reach up to 99.90 %, 3.29 %, and 43.65 %, respectively. The leaching experiment shows that a combination system contributes to obtaining excellent selectivity towards Ni metals compared to the others. The optimum conditions for selectively recovering Ni metals were an H3PO4–H2C2O4 volume ratio of 8:2 and a liquid-solid ratio of 25 mL/g, leaching at 60 °C for 1.5 h. The thermodynamics and kinetics of the leaching reactions were analyzed to determine the feasibility of leaching three metals. Leachate, which is Ni-saturated from cathode powder, was added with Cyanex272 to facilitate the precipitation of Ni3(PO4)2 with a yield of up to 40 %. This study presents a potential ''waste-to-wealth'' approach to lead the efficient and environmental recycling of spent NMC cathode LIBs.

A nanocomposite of hydroxyapatite-supported Ag3PO4 (Ag3PO4/HA) was prepared by in-situ co-precipitation followed by hydrothermal method by utilizing cockle (Anadara granosa) shell as biogenic calcium source. The obtained nanocomposite was characterized by different instrumental analyses. X-ray diffraction spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses confirmed the formation of dispersed Ag3PO4 on HA structure with the particles size ranging at 10–40 nm. The material has band gap energy of 2.3 eV which support the activity as photocatalyst for rhodamine B degradation. The removal efficiency of 99.87% was expressed by the nanocomposite for 120 min of treatment, and reusability was demonstrated by insignificant change of the removal and kinetics constant for 5 cycles. The nanocomposite showed antibacterial activity against E. Coli, S. aureus, K. Pneumonia, and S. pyogenes.

The objectives of this study were to determine the optimum phosphoric acid concentration that produces a PO4–ZrO2 catalyst with the best acidity and examine its performance in the catalytic hydroconversion of used palm cooking oil. The catalysts were characterized by XRD, FTIR, NH3–TPD, SAA, and FESEM–EDX Mapping. The results showed that at 550 °C, the PZ 2 (the best acidity) catalyst produced liquid product and bio-jet fuel selectivity of 39.44% and 33.92%, respectively. On the other hand, a pure ZrO2 catalyst can only have liquid product and bio-jet fuel selectivity of 36.00% and 29.32%, respectively.

A plasma-reduced graphene oxide/lithium titanate oxide (PrGO/LTO) composite is prepared as an anode material to enhance the performance of lithium-ion capacitors (LICs). The PrGO/LTO composite is synthesized by mixing graphene oxide (GO) and LTO, followed by a series of freeze-drying and plasma-treatment processes. PrGO forms a porous three-dimensional (3D) structure with a large surface area, effectively preventing the restacking of PrGO while covering LTO. The GO/LTO mixing ratio is controlled to optimize the final structure for LIC applications. In lithium-ion half-cell assembly, the PrGO/LTO-based anode with an 80% mixing ratio exhibits the highest specific capacity of 73.0 mAh g−1 at 20 C. This is attributed to the optimized ratio for achieving high energy density from LTO and high power density from PrGO. In a LIC full-cell comprising PrGO/LTO as the anode and activated carbon as the cathode, the energy and power densities at 1 A g−1 are 40.3 Wh kg−1 and 2000 W kg−1, respectively, with a specific capacitance of 36.3 F g−1 and capacitance retention of 94.1% after 2000 cycles. Its outstanding performance, obtained from incorporating 3D-structured PrGO with LTO at an optimized ratio, lowers the cell resistance and provides efficient lithium-ion diffusion pathways.

Abstract A novel tungsten disulfide-molybdenum copper oxide composite supported with graphene quantum dots (WM@GQDs) has been synthesized as a counter electrode (CE) for dye-sensitized solar cells (DSSCs) using a simple and low-cost ultrasonication method. The unique structure of WM@GQDs exhibits excellent power conversion efficiency due to its high catalytic activity and charge transport properties. In addition, the graphene quantum dots (GQDs) provide more active sites in the zero-dimensional materials for an I/I3 − redox reaction which can improve the electrical and optical properties of the composite. The results indicate that the amount of GQDs in the composite affect the effectiveness of solar devices. When 0.9%wt of GQDs was used, the WM@GQDs composite achieved an efficiency of 10.38%, which is higher than that of the expensive platinum CE under the same conditions. The mechanism behind the improved power conversion efficiency (PCE) of the composite sample is also discussed in detail. Therefore, WM@GQDs can be an efficient material to replace platinum in DSSCs as a CE.

Abstract Novel MoWO4 with ZnO nanoflowers was synthesized on multi-walled carbon nanotubes (MW-Z@MWCNTs) through a simple hydrothermal method, and this unique structure was applied as a counter electrode (CE) for dye-sensitized solar cells (DSSC) for the first time. The synergetic effect of ZnO nanoflowers and MoWO4 on MWCNTs was systematically investigated by different techniques. The amount of MWCNTs was optimized to achieve the best DSSC performance. It was found that the 1.5% MW-Z@MWCNTs composite structure had the highest power conversion efficiency of 9.96%, which is greater than that of traditional Pt CE. Therefore, MW-Z@MWCNTs-based CE can be used to replace traditional Pt-based electrodes in the future.

Abstract The gas sensing ability of a pure β-SiC fiber is limited due to its low-sensitivity and selectivity with poor recovery time during a gas sensing test. The combination of functional β-SiC fibers with metal-oxide (MO) can lead to excellent electronic conductivity, boosted chemical activity, and high reaction activity with the target gas and β-SiC–In2O3 sensor material. Influence factors such as amounts of MO, current collectors, and gas species (CO2, O2 and without gas) for the gas sensing ability of β-SiC–In2O3 nanocomposite were determined at standard room temperature (25 °C) and high temperature (350 °C) conditions. The gas sensing ability of the functional β-SiC fiber was significantly enhanced by the loading of In2O3 metal-oxide. In addition, the MO junction on the β-SiC fiber was mainly subjected to the Si–C–O–In bond sensor layer with an effective electron-transfer ability. The gas sensing mechanism was based on the transfer of charges, in which the sensing material acted as an absorber or a donor of charges. The sensor material could use different current- collectors to support the electron transfer and gas sensing ability of the material. A 1:0.5M SiC–In2O3 coated Ni-foil current collector sensor showed better sensing ability for CO2 and O2 gases than other gas sensors at room temperature and high temperature conditions. The sensing result of the electrode was obtained with different current density values without or with gas purging conditions because CO2 and O2 gases had electron acceptor properties. During the gas sensing test, the sensor material donated electrons to target gases. The current value on the CV graph then significantly changed. Our obtained sample analysis data and the gas sensing test adequately demonstrated that MO junctions on functional β-SiC fibers could improve the sensitivity of a sensor material and particularly upgrade the sensor material for gas sensing.

Abstract Photocatalytic degradation is essential for the successful removal of organic contaminants from wastewater, which is important for ecological and environmental safety. The advanced oxidation process of photocatalysis has become a hot topic in recent years for the remediation of water. Cadmium sulphide (CdS) nanostructures doped with Titanium oxide (CdS/TiO2) nanocomposites has manufactured under ambient conditions using a simple and modified Chemical Precipitation technique. The nanocomposites crystal structure, thermal stability, recombination of photo-generated charge carriers, bandgap, surface morphology, particle size, molar ratio, and charge transfer properties are determined. The production of nanocomposites (CdS-TiO2) and their efficient photocatalytic capabilities are observed. The goal of the experiment is to improve the photocatalytic efficiency of TiO2 in the visible region by doping CdS nanocomposites. The results showed that as-prepared CdS-TiO2 nanocomposites has exhibited the highest photocatalytic activity in the process of photocatalytic degradation of AB-29 dye, and its degradation efficiency is 84%. After 1 h 30 min of visible light irradiation, while CdS and TiO2 showed only 68% and 09%, respectively. The observed decolorization rate of AB-29 is also higher in the case of CdS-TiO2 photocatalyst ~ 5.8 × 10−4mol L−1 min−1) as compared to the reported decolorization rate of CdS ~ 4.5 × 10−4mol L−1 min−1 and TiO2 ~ 0.67 × 10−4mol L−1 min−1. This increased photocatalytic effectiveness of CdS-TiO2 has been accomplished by reduced charge carrier recombination as a result of improved charge separation and extension of TiO2 in response to visible light.

Gas-sensing technology has witnessed significant advancements that have been driven by the emergence of graphene quantum dots (GQDs) and their tailored nanocomposites. This comprehensive review surveys the recent progress made in the construction methods and applications of functionalized GQDs and GQD-based nanocomposites for gas sensing. The gas-sensing mechanisms, based on the Fermi-level control and charge carrier depletion layer theory, are briefly explained through the formation of heterojunctions and the adsorption/desorption principle. Furthermore, this review explores the enhancements achieved through the incorporation of GQDs into nanocomposites with diverse matrices, including polymers, metal oxides, and 2D materials. We also provide an overview of the key progress in various hazardous gas sensing applications using functionalized GQDs and GQD-based nanocomposites, focusing on key detection parameters such as sensitivity, selectivity, stability, response and recovery time, repeatability, and limit of detection (LOD). According to the most recent data, the normally reported values for the LOD of various toxic gases using GQD-based sensors are in the range of 1–10 ppm. Remarkably, some GQD-based sensors exhibit extremely low detection limits, such as N-GQDs/SnO2 (0.01 ppb for formaldehyde) and GQD@SnO2 (0.10 ppb for NO2). This review provides an up-to-date perspective on the evolving landscape of functionalized GQDs and their nanocomposites as pivotal components in the development of advanced gas sensors.

The use of plate-like materials to induce a percolation gel-like effect in electrorheological (ER) fluids is sparsely documented. Hence, we dispersed plate-like materials, namely natural mica, synthetic mica, and glass, as well as their pulverized particles, in various concentrations in silicone oil to form ER fluids. Subsequently, the rheological properties of the fluids were evaluated and compared to identify the threshold concentration for percolating a gel-like state. The shear stress and viscoelastic moduli under zero-field conditions confirmed that plate-like materials can be used to induce percolation gel-like effects in ER fluids. This is because of the high aspect ratio of the materials, which enhances their physical stability. In practical ER investigations, ER fluids based on synthetic mica (30.0 wt%) showed the highest yield stress of 516.2 Pa under an electric field strength of 3.0 kV mm−1. This was attributed to the formation of large-cluster networks and additional polarization induced by the ions. This study provides a practical approach for developing a new type of gel-like ER fluid.

TiO2@Pt nanocomposite was synthesized using a simple one-step coprecipitation method as an electrocatalyst for methanol oxidation. Pt nanoparticles were supported by using TiO2 as a support material, thereby providing strong metal-support interactions. The TiO2@Pt nanocomposite characterized by Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-ray analysis (EDX) revealed the spherical shape of TiO2 crystalline matrix with finely dispersed Pt nanoparticles. In the powder X-ray diffraction (XRD) analysis, the diffraction peaks observed for the TiO2 and TiO2@Pt nanocomposites were composed of mixed phases of anatase and rutile. Electrochemical performances are evaluated in an aqueous 0.1 M KOH electrolyte and 0.1 M CH3OH as a target analyte. The Pt@TiO2 nanocomposite showed high electrocatalytic activity towards methanol oxidation, the results indicated that the bare Pt electrode has catalyzed the oxidation of methanol with a strongly weak oxidation peak (J = 0.25 mA/cm2), while TiO2 modified Pt electrode which showed higher catalytic activity towards methanol oxidation with a current density of 0.48 mA/cm2. The methanol oxidation was increased compared to a commercially available Pt/C reference catalyst, as shown by a shifted methanol oxidation peak potential and an increased peak current density. As demonstrated by cyclic voltammetry, these increased activities have been clarified by enhanced methanol oxidation activities. An enhanced methanol oxidation activity is attributed to the metal support interaction due to TiO2 nanoparticles, therefore resulting in a weak CO chemisorption on the surface of Pt. Finally, with such valuable features of electrochemical sensitivity and great catalytic activity, the synthesized TiO2@Pt-3 nanocomposite is used as the anode material for methanol fuel cell application.

We fabricated a novel nanocomposite composed of graphene-La2CrFeW6 perovskite compounds with an organic-inorganic counter electrode based on CdSe, gallic acid, urea and sulfate in dye-sensitized solar cells (DSSCs) by a simple hydrothermal technique. The nanocomposite shows an excellent electro–catalytic activity with low charge-transfer resistance, due to the synergetic catalytic effects of the graphene sheets and La2CrFeW6 perovskite with organic-inorganic materials. The special structure of this nanocomposite also improves the active sites for reduction of triiodide ions on the counter electrodes. The photo-conversion efficiency of the DSSC fabricated using a gallic-based counter electrode reached a higher value of 10.40% under standard illumination (1 sun, 100 mW cm−2, AM 1.5), as compared to the traditional Pt electrode (7.49%). The graphene-La2CrFeW6 fabricated with an organic-inorganic based CE was also found to be more efficient than those reported in previous works, in which graphene, produced by various methods, was used as a CE material. Therefore, the present nanocomposite is considered an environmentally friendly, low-cost, and highly efficient CE material for DSSCs.

High demand for energy consumption forced the exploration of renewable energy resources, and in this context, biodiesel has received intensive attention. The process of biodiesel production itself needs to be optimized in order to make it an eco-friendly and high-performance energy resource. Within this scheme, development of low-cost and reusable heterogeneous catalysts has received much attention. Mesoporous silica materials with the characteristics of having a high surface area and being modifiable, tunable, and chemical/thermally stable have emerged as potential solid support of powerful catalysts in biodiesel production. This review highlights the latest updates on mesoporous silica modifications including acidic, basic, enzyme, and bifunctional catalysts derived from varied functionalization. In addition, the future outlook for progression is also discussed in detail.

Herein, unique three-dimensional (3D) hierarchically structured carbon nanofiber (CNF)/metal oxide/conducting polymer composite materials were successfully synthesized by combinations of various experimental methods. Firstly, base CNFs were synthesized by carbonization of electrospun PAN/PVP fibers to attain electric double-layer capacitor (EDLC) characteristics. To further enhance the capacitance, tin oxide (SnO2) and iron oxide (Fe2O3) were coated onto the CNFs via facile hydrothermal treatment. Finally, polypyrrole (PPy) was introduced as the outermost layer by a dispersion polymerization method under static condition to obtain 3D-structured CNF/SnO2/PPy and CNF/Fe2O3/PPy materials. With each synthesis step, the morphology and dimension of materials were transformed, which also added the benign characteristic for supercapacitor application. For the practical application, as-synthesized CNF/SnO2/PPy and CNF/Fe2O3/PPy were applied as active materials for supercapacitor electrodes, and superb specific capacitances of 508.1 and 426.8 F g−1 (at 1 A g−1) were obtained (three-electrode system). Furthermore, an asymmetric supercapacitor (ASC) device was assembled using CNF/SnO2/PPy as the positive electrode and CNF/Fe2O3/PPy as the negative electrode. The resulting CNF/SnO2/PPy//CNF/Fe2O3/PPy device exhibited excellent specific capacitance of 101.2 F g−1 (at 1 A g−1). Notably, the ASC device displayed a long-term cyclability (at 2000 cycles) with a retention rate of 81.1%, compared to a CNF/SnO2//CNF/Fe2O3 device of 70.3% without an outermost PPy layer. By introducing the outermost PPy layer, metal oxide detachment from CNFs were prevented to facilitate long-term cyclability of electrodes. Accordingly, this study provides an effective method for manufacturing a high-performance and stable supercapacitor by utilizing unique 3D hierarchical materials, comprised of CNF, metal oxide, and conducting polymer.

Abstract Herein, we manufactured the positive and negative electrodes for the hybrid capacitor. The Mn-doped High surface area of Activated carbon composite used for the positive electrode and as-prepared composite was calcined at 600 °C and 800 °C. The morphological structures and pore-size distributions of MnYP-600HTT and MnYP-800HTT were characterized by means of XRD, SEM, EDAX, TEM, and BET. According to the BET specific surface-area evaluation, MnYP-600HTT and MnYP-800HTT were 1272.6 and 1388.1 m2/g, respectively. Total pore volumes were 0.627 and 0.687 cm3/g, which is beneficial for forming ion-transport channels in electrochemical reactions. The MnYP-600HTT electrode had a high specific capacity of 177.2 mAh/g at 20C, and the capacity retention was 64.8%. During the entire cycling, MnYP-600HTT had excellent cyclic stability in 500 cycles along with high efficiency. The robust design of the MnYP-600HTT and MnYP-800HTT cathode materials introduced in this work pave the way for designing next-generation supercapacitors operating at ultra-high C rates. The Mn-doped high surface of activated carbon had stable energy density and superior cycling stability that were demonstrated in supercapacitor systems.

SnO2 nanoparticles were synthesized utilizing Tinospora cordifolia stem extract. The effects of the concentration of the extract and the utilization of ultrasound irradiation on different chemical properties, mainly surface morphology, were studied. To determine the instrumental characteristics, X-ray diffraction, Fourier-Transform-Infra Red, scanning electron microscopy, and transmission electron microscope analyses were used. The optical properties of the material were studied using ultraviolet UV–visible diffuse reflectance spectrophotometry and photocatalytic activity tests on rhodamine B photodegradation. The results summarized the effect of T. cordifolia stem extract on the nucleation process during SnO2 crystallization, as a higher concentration leads to polymorphic forms with a greater particle size and an additional SnO phase. In addition, ultrasound-assisted reduction tended to produce a smaller particle size. The optical properties were found to be correlated with the particle size, as the higher particle size gave a smaller band gap energy and less photocatalytic activity for rhodamine B degradation.

Polylactic acid (PLA), although has many interesting physicochemical characteristics, the strong hydrophobicity and a lack of antibacterial activity restricting its widespread application in the medical sector. In a view of addressing some of the limitations of PLA, the current study aimed to test the antibacterial efficacy of active metal-doped bioceramic/PLA composite formed by the fused deposition manufacturing (FDM) technique. For the testing, we prepared polyvinyl alcohol (PVA) bound silver-hydroxyapatite (Ag-HAp) composite and further applied as a low-temperature coating onto the PLA scaffold designed for the appropriate cell development, differentiation, and bio-mineral establishment. From the analysis, we revealed that the larger surface area of three-dimensional (3D) printed composite material having the matrix porosity makes it a perfect biocompatible material with no loss to its mechanical potency. The HAp/PLA and Ag-HAp/PLA composites were tested for the hemocompatibility, and antibacterial activity (gram-positive and gram-negative bacteria). Further, the mechanical property of the Ag-HAp/PLA scaffold was tested. The results demonstrated that the Ag-HAp/PLA composite offers the biocompatibility and antibacterial ability and therefore can serve as the potential bone implant material.

The present study was aimed to use of N doped graphene quantum dots (N-GQDs) and N,K co-doped graphene quantum dots (N,K-GQDs) as a fluorescence quenching sensor to determine both mercury and copper in water sample, simultaneously using simple fluorescence protocol. Each of N-GQDs or N,K-GQDs was optimized separately with 1–5% (w/v) HNO3 or KNO3, respectively, and their quantum yields were determined and compared. It was found that N-GQDs, obtained from 3% (w/v) HNO3 doped resulted higher fluorescence intensity at the maximum excitation and emission wavelengths of 370 and 460 nm, respectively, with higher quantum yield (QY = 83.42%) compared with that of undoped GQDs (QY = 16.35%). While N,K-GQDs obtained from 5%(w/v) KNO3 gave somewhat different fluorescence spectrum, but still had the same maximum excitation and emission wavelengths with rather highest QY (94.07%). However, it is interesting that detection sensitivity expressed as slope of their calibration curve (y = 5.43x − 19.48; r2 = 0.9971) of the N-GQDs is rather higher than that (y = 1.29x + 17.66; r2 = 0.9977) of the N,K-GQDs for Hg2+ fluorescence quenching sensor, and the fluorescence intensity of N-GQDs had better selectively quenching effect only by both Hg2+ and Cu2+. Thus, their quenching effects were selected to develop the fluorescence turn-off sensor for trace level of both metal ions in real water samples. For method validation, the N-GQDs exhibited high sensitivity to detect both Hg2+ and Cu2+ with wide linear ranges of 20–100 μM and 100–500 μM, respectively. Limit of detection (LOD) and limit of quantitation (LOQ) were 0.42 μM & 1.41 μM for Hg2+ and 13.19 μM & 43.97 μM for Cu2+, respectively, with their precision expressed as an intra-day and an inter-day analysis of 6.98% & 11.35% for Hg2+ and 11.78% & 9.43% for Cu2+, respectively. Also the study of matrix analysis of the water samples (drinking water and tap water), was carried out using N-GQDs and N,K-GQDs resulted good percentage recoveries in comparison with those using undoped GQDs under the same optimum conditions. Keywords: Graphene quantum dots, N doped GQDs, N,K co-doped GQDs, Fluorescence quenching sensor, Copper (II), Mercury (II)

MXene is a type of two-dimensional (2D) transition metal carbide and nitride, and its promising energy storage materials highlight its characteristics of high density, high metal-like conductivity, tunable terminals, and charge storage mechanisms known as pseudo-alternative capacitance. MXenes are a class of 2D materials synthesized by chemical etching of the A element in MAX phases. Since they were first discovered more than 10 years ago, the number of distinct MXenes has grown substantially to include numerous MnXn−1 (n = 1, 2, 3, 4, or 5), solid solutions (ordered and disordered), and vacancy solids. To date, MXenes used in energy storage system applications have been broadly synthesized, and this paper summarizes the current developments, successes, and challenges of using MXenes in supercapacitors. This paper also reports the synthesis approaches, various compositional issues, material and electrode topology, chemistry, and hybridization of MXene with other active materials. The present study also summarizes MXene’s electrochemical properties, applicability in pliant-structured electrodes, and energy storage capabilities when using aqueous/non-aqueous electrolytes. Finally, we conclude by discussing how to reshape the face of the latest MXene and what to consider when designing the next generation of MXene-based capacitors and supercapacitors.

Zinc oxide (ZnO) nanorods have attracted considerable attention in recent years owing to their piezoelectric properties and potential applications in energy harvesting, sensing, and nanogenerators. Piezoelectric energy harvesting-based nanogenerators have emerged as promising new devices capable of converting mechanical energy into electric energy via nanoscale characterizations such as piezoresponse force microscopy (PFM). This technique was used to study the piezoresponse generated when an electric field was applied to the nanorods using a PFM probe. However, this work focuses on intensive studies that have been reported on the synthesis of ZnO nanostructures with controlled morphologies and their subsequent influence on piezoelectric nanogenerators. It is important to note that the diatomic nature of zinc oxide as a potential solid semiconductor and its electromechanical influence are the two main phenomena that drive the mechanism of any piezoelectric device. The results of our findings confirm that the performance of piezoelectric devices can be significantly improved by controlling the morphology and initial growth conditions of ZnO nanorods, particularly in terms of the magnitude of the piezoelectric coefficient factor (d33). Moreover, from this review, a proposed facile synthesis of ZnO nanorods, suitably produced to improve coupling and switchable polarization in piezoelectric devices, has been reported.

In this study, a flexible all-solid-state asymmetric supercapacitor (FASC) device has been successfully fabricated via full recycling of heated tobacco waste (HTW). Tobacco leaves and cellulose acetate tubes have been successfully carbonized (HTW-C) and mixed with metal oxides (MnO2 and Fe3O4) to obtain highly active materials for supercapacitors. Moreover, poly(lactic acid) (PLA) filters have been successfully dissolved in an organic solvent and mixed with the as-prepared active materials using a simple paste mixing method. In addition, flexible MnO2- and Fe3O4-mixed HTW-C/PLA electrodes (C-MnO2/PLA and C-Fe3O4/PLA) have been successfully fabricated using the drop-casting method. The as-synthesized flexible C-MnO2/PLA and C-Fe3O4/PLA electrodes have exhibited excellent electrical conductivity of 378 and 660 μS cm−1, and high specific capacitance of 34.8 and 47.9 mF cm−2 at 1 mA cm−2, respectively. A practical FASC device (C-MnO2/PLA//C-Fe3O4/PLA) has been assembled by employing the C-MnO2/PLA as the positive electrode and C-Fe3O4/PLA as the negative electrode. The as-prepared FASC device showed a remarkable capacitance of 5.80 mF cm−2 at 1 mA cm−2. Additionally, the FASC device manifests stable electrochemical performance under harsh bending conditions, verifying the superb flexibility and sustainability of the device. To the best of our knowledge, this is the first study to report complete recycling of heated tobacco waste to prepare the practical FASC devices. With excellent electrochemical performance, the experiments described in this study successfully demonstrate the possibility of recycling new types of biomass in the future.

Novel visible-light photocatalyst (titanium-dioxide-functionalized graphene/strontium-hexaferrites) TiO2-FG/Sr-hexaferrite nanocomposites were fabricated using a simple hydrothermal technique. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), Raman spectroscopic analysis, and atomic force microscopy were used to analyze the composites as prepared. The unique TiO2-FG/Sr-hexaferrite-based composite catalyst reveals superior photocatalytic properties for the disintegration of organic dyes methylene blue (MB) and rhodamine B (Rh. B) under visible-light irradiation. The result showed that the functionalized graphene with ternary structure improved the catalytic behavior of the composite due to the synergistic effect of the TiO2-FG boosted by the graphene surface to provide a fast conducting path to the photogenerated charge carrier. The markedly high photocatalytic behavior has been ascribed to the formation of the ternary structure between TiO2, FG, and Sr-hexaferrites through interface interaction. The prepared photocatalyst composite exhibited better recyclability, which further confirms its future uses as a photocatalyst in industrial waste products.

In this work, a novel ternary nanocomposites AgZnS-TiO2-reduced graphene oxide (RGO) was successfully synthesized by a facile soft ultrasonic-reduction condition as low as 70 °C. During the ultrasound reaction, the reduction of GO and the growth of AgZnS and TiO2 crystals occurred simultaneously in conjunction with the deposition of AgZnS and TiO2 crystals onto the surface of the graphene. The synthesized nanocatalysts were characterized by XRD, SEM, TEM, EDX, Raman spectroscopy, XPS, UV–Vis DRS, photoluminescence spectrometer, and photocurrent and CV. The AgZnS-G-T was shown as catalytic HER with some synnegetic factors such as pH-universal, temperature, and ultrasonic condition. After 4 h, it was observed that AgZnS-TiO2-RGO has the highest efficiency of photocatalytic activity through hydrogen production by water splitting, which achieved the highest hydrogen evolution rate of 930.45 μmol/g at buffer solution (pH = 5), which was superior to AgZnS-G (790.1 µmole/g) and AgZnS (701.2 µmole/g). Such a significant hydrogen evolution amount far exceeded that of undoped TiO2 and RGO. The H2 evolution amounts increased significantly at ultrasonic irradiation power of 80 MHz. AgZnS-G-T demonstrates the higher H2 evolution amounts of 985 µmole/g at 80 MHz. Its photocatalytic hydrogen-evolution activity remained at a high level over four cycles (16 h) nanoparticle.

Light detection and ranging (LiDAR) sensors utilize a near-infrared (NIR) laser with a wavelength of 905 nm. However, LiDAR sensors have weakness in detecting black or dark-tone materials with light-absorbing properties. In this study, SiO2/black TiO2 core/shell nanoparticles (SBT CSNs) were designed as LiDAR-detectable black materials. The SBT CSNs, with sizes of 140, 170, and 200 nm, were fabricated by a series of Stöber, TTIP sol-gel, and modified NaBH4 reduction methods. These SBT CSNs are detectable by a LiDAR sensor and, owing to their core/shell structure with intrapores on the shell (ca. 2–6 nm), they can effectively function as both color and NIR-reflective materials. Moreover, the LiDAR-detectable SBT CSNs exhibited high NIR reflectance (28.2 R%) in a monolayer system and true blackness (L* < 20), along with ecofriendliness and hydrophilicity, making them highly suitable for use in autonomous vehicles.

Extremely short-sized multi-wall carbon nanotube (CNT) and high surface area activated carbon were used to increase the electrical performance of lithium-ion capacitors (LIC). After electrodes were synthesized using extremely short-sized CNTs and high specific surface area activated carbon, their electrochemical characteristics were evaluated by XRD, SEM, TEM, cyclic voltammetry, EIS, BET, adoption isotherm, t-plot, and pore size distribution. In the process of electrode preparation using extremely short-sized CNTs and high specific surface area activated carbon, CNTs certainly caused a space-filling effect between these two materials, which had a significant effect on the evaluation of electrical characteristics. These relationships were demonstrated by the results of adsorption–desorption isotherm, pore size distribution, t-plot, and BJH plot. Particularly, in the electrochemical cyclic test, as the content of CNT increased, the current density significantly increased with the formation of a near-perfect rectangular shape. This tendency also exhibited excellent characteristics in a t-I plot, Tafel plot, and LSV plot, which clearly affected the electrochemical oxidation–reduction reaction due to the densification of filling density and space structure by adding extremely short-sized CNTs to the active material. In addition, YP80_CNT3 formed a specific resistance value in the range of 7.2 to 6.2 Ω/cm2, showing significantly reduced values compared to other samples. This research presented herein offers a promising route for the rational design of MWCNT and stable electrochemical reaction with LIC working mechanism.

Hollow TiO2 nanoparticles (HNPs) capped with conducting polymers, such as polythiophene (PT), polypyrrole (PPy), and polyaniline (PANI), have been studied to be used as polarizability-tunable electrorheological (ER) fluids. The hollow shape of TiO2 nanoparticles, achieved by the removal of the SiO2 template, offers colloidal dispersion stability in silicone oil owing to the high number density. Conducting polymer shells, introduced on the nanoparticle surface using vapor deposition polymerization method, improve the yield stress of the corresponding ER fluids in the order of PANI < PPy < PT. PT-HNPs exhibited the highest yield stress of ca. 94.2 Pa, which is 5.0-, 1.5-, and 9.6-times higher than that of PANI-, PPy-, and bare HNPs, respectively. The improved ER response upon tuning with polymer shells is attributed to the space charge contribution arising from the movement of the charge carriers trapped by the heterogeneous interface. The ER response of studied ER fluids is consistent with the corresponding polarizability results as indicated by the permittivity and electrophoretic mobility measurements. In conclusion, the synergistic effect of hollow nanostructures and conducting polymer capping effectively enhanced the ER performance.

Herein, the electrorheological (ER) performances of ER fluids were correlated with their colors to allow for the visual selection of the appropriate fluid for a specific application using naked eyes. A series of TiO2-coated synthetic mica materials colored white, yellow, red, violet, blue, and green (referred to as color mica/TiO2 materials) were fabricated via a facile sol–gel method. The colors were controlled by varying the thickness of the TiO2 coating layer, as the coatings with different thicknesses exhibited different light interference effects. The synthesized color mica/TiO2 materials were mixed with silicone oil to prepare colored ER fluids. The ER performances of the fluids decreased with increasing thickness of the TiO2 layer in the order of white, yellow, red, violet, blue, and green materials. The ER performance of differently colored ER fluids was also affected by the electrical conductivity, dispersion stability, and concentrations of Na+ and Ca2+ ions. This pioneering study may provide a practical strategy for developing new ER fluid systems in future.

In this study, carbon quantum dots (CQDs) from Magnolia Grandiflora flower as a carbon precursor were obtained using a hydrothermal method under the optimized conditions affected by various heating times (14, 16, 18, and 20 min) and various electric power inputs (900–1400 W). Then, hydrogen sulfide (H2S) was added to dope the CQDs under the same manner. The aqueous solution of the S-CQDs were characterized by FTIR, XPS, EDX/SEM, and TEM, with nanoparticle size at around 4 nm. Then, the as-prepared S-CQDs were successfully applied with fine corn starch for detection of minutiae latent fingerprints on non-porous surface materials. It is demonstrated that the minutiae pattern is more clearly seen under commercial UV lamps with a bright blue fluorescence intensity. Therefore, this research has proved that the S-CQDs derived from plant material have a better potential as fluorescent probes for latent fingerprint detection.

Zn-Al Layered Double Hydroxides (Zn-Al LDHs) and its calcined form were successfully prepared and utilized for the removal of methyl violet (MV) and treatment of peat water by photocatalytic oxidation. The research was aimed to evaluate the effect of calcination to Zn-Al LDHs for the effect on the physicochemical character and the capability as a photocatalyst. The characterization of the samples was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmet–Teller specific surface area (BET), and X-ray photoelectron spectroscopy (XPS). The results showed that the increased BET specific surface area along with the enhanced porous structure was achieved by the calcination procedure, which is associated with the enhanced interlayer space of d003 identified by XRD analysis. Thermal conversion showed an influence to the increased band gap energy from 3.10 eV in the uncalcined Zn-Al LDHs into 3.16 eV for the calcined material. These character changes contributed to the enhanced photocatalytic activity of the Zn-AL LDHs by calcination, which was proposed and verified by experiments. It was observed that photocatalytic activity of the material for MV gave about a 45.57% removal of MV and a 68% removal for the natural organic material of the peat water.

Photocatalytic degradation can be increased by improving photo-generated electrons and broadening the region of light absorption through conductive polymers. In that view, we have synthesized Polyaniline (PANI) with CdS, CdS-ZnS, and CdS-TiO2 nanocomposites using the chemical precipitation method, characterized and verified for the photo-degradation of Acid blue-29 dye. This paper provides a methodical conception about in what way conductive polymers “PANI” enhances the performance rate of composite photocatalysts (CdS, CdS-ZnS and CdS-TiO2). The nanocomposites charge transfer, molar ratio, surface morphology, particle size, diffraction pattern, thermal stability, optical and recombination of photo-generated charge carrier properties were determined. The production of nanocomposites and their efficient photocatalytic capabilities were observed. The mechanism of photocatalysis involved with PC, CZP and CTP nanocomposites are well presented by suitable diagrams representing the exchange of electrons and protons among themselves with supported equations. We discovered that increasing the number of nanocomposites in the membranes boosted both photocatalytic activity and degradation rate. CdS-Zinc-PANI (CZP) and CdS-TiO2-PANI(CTP) nanocomposites show entrapment at the surface defects of Zinc and TiO2 nanoparticles due to the demolition of unfavorable electron kinetics, and by reducing the charge recombination, greater photocatalytic activity than CdS-PANI (CP) with the same nanoparticle loading was achieved. With repeated use, the photocatalysts’ efficiency dropped very little, hinting that they may be used to remove organic pollutants from water. The photocatalytic activity of CZP and CTP photocatalytic membranes was greater when compared to CdS-PANI, which may be due to the good compatibility between CdS and Zinc and TiO2, as well efficient charge carrier separation. PANI can also increase the split-up of photo-excited charge carriers and extend the absorption zone when combined with these nanoparticles. As a result, the development of outrageous performance photocatalysts and their potential uses in ecological purification and solar power conversion has been facilitated. The novelty of this article is to present the degradation of AB-29 Dye using nanocomposites with polymers and study the enhanced degradation rate. Few studies have been carried out on polymer nanocomposites and their application in the degradation of AB-29 dyes and remediation of water purposes. Nanoparticle CdS is a very effective photocatalyst, commonly used for water purification along with nanoparticle ZnS and TiO2; but cadmium ion-leaching makes it ineffective for practical and commercial use. In the present work, we have reduced the leaching of hazardous cadmium ions by trapping them in a polyaniline matrix, hence making it suitable for commercial use. We have embedded ZnS and TiO2 along with CdS in a polyaniline matrix and compared their photocatalytic activity, stability, and reusability, proving our nano-composites suitable for commercial purposes with enhanced activities and stabilities, which is a novelty. All synthesized nanocomposites are active within the near-ultraviolet to deep infrared (i.e., 340–850 nm). This gives us full efficiency of the photocatalysts in the sunlight and further proves the commercial utility of our nanocomposites.

We described the novel nanocomposite of silver doped ZrO2 combined graphene-based mesoporous silica (ZrO2-Ag-G-SiO2,) in bases of low-cost and self-assembly strategy. Synthesized ZrO2-Ag-G-SiO2 were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, Nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and Diffuse Reflectance Spectroscopy (DRS). The ZrO2-Ag-G-SiO2 as an enzyme-free glucose sensor active material toward coordinate electro-oxidation of glucose was considered through cyclic voltammetry in significant electrolytes, such as phosphate buffer (PBS) at pH 7.4 and commercial urine. Utilizing ZrO2-Ag-G-SiO2, glucose detecting may well be finished with effective electrocatalytic performance toward organically important concentrations with the current reaction of 9.0 × 10−3 mAcm−2 and 0.05 mmol/L at the lowest potential of +0.2 V, thus fulfilling the elemental prerequisites for glucose detecting within the urine. Likewise, the ZrO2-Ag-G-SiO2 electrode can be worked for glucose detecting within the interferometer substances (e.g., ascorbic corrosive, lactose, fructose, and starch) in urine at proper pH conditions. Our results highlight the potential usages for qualitative and quantitative electrochemical investigation of glucose through the ZrO2-Ag-G-SiO2 sensor for glucose detecting within the urine concentration.

This study aims to synthesize carbon dots from a natural resource and will be used to detect a latent fingerprint on a non-porous surface. The carbon dots (CDs) were prepared by adding luminol to coconut water and ethanol via a hydrothermal method. Luminol enhances the chemiluminescence of the CDs, which show more distinct blue light under a UV lamp compared with bare CDs. To detect the latent fingerprint, luminol carbon dots (N-CDs) were combined with commercial starch and stirred at room temperature for 24 h. Their characteristics and optical properties were measured using EDX-SEM, HR-TEM, FTIR, XPS, UV–visible absorption, and fluorescence. In this research, it was found that the N-CDs had a d-spacing of 0.5 nm and a size of 12.9 nm. The N-CDs had a fluorescence intensity 551% higher than the standard normally used. N-CDs can be used to detect latent fingerprints on a non-porous surface and are easy to detect under a UV lamp at 395 nm. Therefore, luminol has a high potential to increase sensitive and stable traces of chemiluminescence from the green CDs for forensic latent fingerprint detection.

In this work, photoactive nanocomposites of ZnO/SiO2 porous heterostructures (PCHs) were prepared from montmorillonite clay. The effects of preparation methods and Zn content on the physicochemical features and photocatalytic properties were investigated. Briefly, a comparison of the use of hydrothermal and microwave-assisted methods was done. The Zn content was varied between 5 and 15 wt% and the characteristics of the nanomaterials were also examined. The physical and chemical properties of the materials were characterized using X-ray diffraction, diffuse-reflectance UV-Vis, X-ray photoelectron spectroscopy, and gas sorption analyses. The morphology of the synthesized materials was characterized through scanning electron microscopy and transmission electron microscopy. The photocatalytic performance of the prepared materials was quantified through the photocatalytic degradation of methyl violet (MV) under irradiation with UV and visible light. It was found that PCHs exhibit greatly improved physicochemical characteristics as photocatalysts, resulting in boosting photocatalytic activity for the degradation of MV. It was found that varied synthesis methods and Zn content strongly affected the specific surface area, pore distribution, and band gap energy of PCHs. In addition, the band gap energy was found to govern the photoactivity. Additionally, the surface parameters of the PCHs were found to contribute to the degradation mechanism. It was found that the prepared PCHs demonstrated excellent photocatalytic activity and reusability, as seen in the high degradation efficiency attained at high concentrations. No significant changes in activity were seen until five cycles of photodegradation were done.

Aerospace equipages encounter potential radiation footprints through which soft errors occur in the memories onboard. Hence, robustness against radiation with reliability in memory cells is a crucial factor in aerospace electronic systems. This work proposes a novel Carbon nanotube field-effect transistor (CNTFET) in designing a robust memory cell to overcome these soft errors. Further, a petite driver circuit to test the SRAM cells which serve the purpose of precharge and sense amplifier, and has a reduction in threefold of transistor count is recommended. Additionally, analysis of robustness against radiation in varying memory cells is carried out using standard GPDK 90 nm, GPDK 45 nm, and 14 nm CNTFET. The reliability of memory cells depends on the critical charge of a device, and it is tested by striking an equivalent current charge of the cosmic ray’s linear energy transfer (LET) level. Also, the robustness of the memory cell is tested against the variation in process, voltage and temperature. Though CNTFET surges with high power consumption, it exhibits better noise margin and depleted access time. GPDK 45 nm has an average of 40% increase in SNM and 93% reduction of power compared to the 14 nm CNTFET with 96% of surge in write access time. Thus, the conventional MOSFET’s 45 nm node outperforms all the configurations in terms of static noise margin, power, and read delay which swaps with increased write access time.

The present study reported biofabrication of flower-like SnO2 nanoparticles using Pometia pinnata leaf extract. The study focused on the physicochemical characteristics of the prepared SnO2 nanoparticles and its activity as photocatalyst and antibacterial agent. The characterization was performed by XRD, SEM, TEM, UV-DRS and XPS analyses. Photocatalytic activity of the nanoparticles was examined on bromophenol blue photooxidation; meanwhile, the antibacterial activity was evaluated against Klebsiella pneumoniae, Escherichia coli Staphylococcus aureus and Streptococcus pyogenes. XRD and XPS analyses confirmed the single tetragonal SnO2 phase. The result from SEM analysis indicates the flower like morphology of SnO2 nanoparticles, and by TEM analysis, the nanoparticles were seen to be in uniform spherical shapes with a diameter ranging from 8 to 20 nm. SnO2 nanoparticles showed significant photocatalytic activity in photooxidation of bromophenol blue as the degradation efficiency reached 99.93%, and the photocatalyst exhibited the reusability as the degradation efficiency values were insignificantly changed until the fifth cycle. Antibacterial assay indicated that the synthesized SnO2 nanoparticles exhibit an inhibition of tested bacteria and showed a potential to be applied for further environmental and medical applications.

Abstract A nanowire-like WSe2-graphene catalyst was prepared via ultra-sonication and was tested in terms of the photocatalytic reduction of CO2 into CH3OH under irradiation with UV/visible light. The prepared nano-composite was further characterized via XRD, SEM, TEM, Raman and XPS. The photocurrent analysis was further tested for its photocatalytic reduction of CO2 using gas chromatography (GCMS-QP2010 SE). To further improve the the photo-catalytic efficiency, a sacrificial agent (Na2S/Na2SO3) was added to the WSe2-graphene nanocomposite and was found to improve the photo-catalytic efficiency, with the methanol yield reaching 5.0278 µmol g−1h−1. Our present work provides a convenient way to prepare nanomaterials various morphologies that have future applications for environmental remediation.

This study aimed to improve the performance of the activated carbon-based cathode by increasing the Li content and to analyze the effect of the combination of carbon and oxidizing agent. The crystal structure and chemical structure phase of Li-high surface area activated carbon material (Li-HSAC) was analyzed by X-ray diffraction (XRD) and Raman spectroscopy, the surface state and quantitative element by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and the surface properties with pore-size distribution by Brunauer–Emmett–Teller (BET), Barrett–Joyner–Halenda (BJH) and t-plot methods. The specific surface area of the Li-YP80F is 1063.2 m2/g, micropore volume value is 0.511 cm3/g and mesopore volume is 0.143 cm3/g, and these all values are higher than other LiOH-treated carbon. The surface functional group was analyzed by a Boehm titration, and the higher number of acidic groups compared to the target facilitated the improved electrolyte permeability, reduced the interface resistance and increased the electrochemical properties of the cathode. The oxidizing agent of LiOH treated high surface area of activated carbon was used for the cathode material for EDLC (electric double layer capacitor) to determine its electrochemical properties and the as-prepared electrode retained excellent performance after 10 cycles and 100 cycles. The anodic and cathodic peak current value and peak segregation of Li-YP80F were better than those of the other two samples, due to the micropore-size and physical properties of the sample. The oxidation peak current value appeared at 0.0055 mA/cm2 current density and the reduction peak value at –0.0014 mA/cm2, when the Li-YP80F sample used to the Cu-foil surface. The redox peaks appeared at 0.0025 mA/cm2 and –0.0009 mA/cm2, in the case of using a Nickel foil, after 10 cycling test. The electrochemical stability of cathode materials was tested by 100 recycling tests. After 100 recycling tests, peak current drop decreased the peak profile became stable. The LiOH-treated high surface area of activated carbon had synergistically upgraded electrochemical activity and superior cycling stability that were demonstrated in EDLC.

Porous carbon has been widely used for many applications e.g., adsorbents, catalysts, catalyst supports, energy storage and gas storage due to its outstanding properties. In this paper, characteristics of porous carbon prepared by carbonization of lignin from various biomasses are presented. Various biomasses, i.e., mangosteen peel, corncob and coconut shell, were processed using ethanol as an organosolv solvent. The obtained lignin was characterized using a Fourier transform infrared (FTIR) spectrophotometer and a viscosimeter to investigate the success of extraction and lignin properties. The results showed that high temperature is favorable for the extraction of lignin using the organosolv process. The FTIR spectra show the success of lignin extraction using the organosolv process because of its similarity to the standard lignin spectra. The carbonization process of lignin was performed at 600 and 850 °C to produce carbon from lignin, as well as to investigate the effect of temperature. A higher pyrolysis temperature will produce a porous carbon with a high specific surface area, but it will lower the yield of the produced carbon. At 850 °C temperature, the highest surface area up to 974 m2/g was achieved.

The mesoporous silica nanoparticles (MSNs), because of the synthesis, ease of surface functionalization, tunable pore size, large surface area, and biocompatibility, are being useful in many of the biomedical applications like drug delivery, theranostics, stem cell research, etc. It has been a potent nanocarrier for many different therapeutic agents, i.e., the surface functionalization of silica nanoparticles (SNs) with chemical agents, polymers, and supramolecular moieties enable the efficient delivery of therapeutic agents in a highly controlled manner. Also, the toxicity, biosafety, and in vivo efficiency involving biodistribution, pharmacokinetics, biodegradation, and excretion of MSNs play an important role in its involvement in the clinical applications. A coherence between chemistry and biological sciences extends its opportunities to a wide range in the field of nanomedicine such as smart drug delivery systems, functionalization and gating approach, controlled drug delivery systems, diagnostic and targeted theragnostic approach etc. Thus, taking advantage of the inbuilt properties of the MSNs applicable to the biomedical sector, the present review describes a panorama on the SNs which are presently used for the development of theragnostic probes and advanced drug delivery platforms.

Multiwall carbon nanotube (MWCNT), vanadyl acetylacetonate (V(acac)3), and titanium n-butoxide (TNB) were used as carbon, vanadium oxide, and titanium oxide precursor to prepare V2O3/CNT/TiO2 composite. The obtained composite was characterized by BET surface area measurement, X-ray diffraction, transmission electron microscopy, and energy dispersive X-ray analysis. In addition, we used methylene blue (MB) solution under condition of visible light irradiation to determine their photocatalytic degradation efficiency. In conclusion, the V2O3/CNT/TiO2 composite had excellent photocatalytic degradation for MB solution under visible light.