Volume 239, Issue 4 - Special Issue: Solar Water Splitting And Artificial Photosynthesis (SWAP), Part 5; Guest Editors: Kevin Bethke, Jeyanthinath Mayandi and Smagul Karazhanov

The increase in the interest in electrical vehicles (EV) makes us to focus on the available resources of source materials for battery development and to improve the battery performance to achieve the complete EV domination over the others. Recent observations clearly tell us that EV and hybrid EVs are going to change the world market. As the demand is going to be high for the batteries, it is important to understand the number of reserves, production and supply of the source materials which can be used in batteries. Based on the data we must find alternatives, if there is a shortage of source material. This article briefly discusses the lithium reserves and production by the world. We also discussed the increasing demand on EV and the extraction of useful materials from the used battery for the sustainable environment and to follow the circular economy aspects.

This study focuses on converting iron particles from grinding sludge, after removing impurities, into Fe-nanoparticles using high-energy ball billing. The goal is to examine the corrosion behaviors and mechanical properties of these Fe-nanoparticles. Nanostructured Fe-powder was synthesized through a process involving 10 h of high-energy ball milling, followed by conventional hot pressing and sintering. Structural and microstructural properties were thoroughly examined using techniques such as X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and elemental diffraction spectroscopy. Upon sintering, SEM and TEM analyses unveiled the formation of a nanostructured alloy within the samples. Notably, the milled sample exhibited high hardness value, measuring at 155 HV. However, it is noteworthy that the un-milled sample demonstrated superior compression strength compared to its milled counterpart. Furthermore, the corrosion behavior of the samples was evaluated through electrochemical corrosion studies. Interestingly, the sample subjected to 10 h of milling (coin number 5) displayed a significantly lower corrosion rate, measuring at 1.3921 mm/year, suggesting enhanced corrosion resistance attributed to the nano structuring process.

In this present work we report the impact of employing the neodymium (Nd) to influence the structure and morphology of ZnO. To discern the efficiency of Nd doped ZnO in DSSCs, its properties are investigated. Undoped ZnO and Nd doped ZnO were prepared by hydrothermal synthesis method. Structural and morphological studies of the obtained samples were collected through XRD and HR-TEM. The change in the bandgap is observed from UV analysis due to the introduction of Nd ions on the surface of ZnO. Comparing to undoped ZnO, Nd doped ZnO sample exhibits better results. Dye sensitized solar cells were fabricated using N719 dye, redox electrolyte and counter electrode (platinum). The efficiencies of undoped and doped DSSCs were calculated. After the fabrication and simulation of DSSCs, the outcomes and efficiencies of the undoped and neodymium doped ZnO solar cells were studied to choose the better anode to fabricate dye sensitized solar cells.

This study aimed to examine the mechanical and physical characteristics of hybrid composite prepared using bio-epoxy reinforced with natural fibers extracted from pineapple leaf (PLF) and sisal (SF). The hand lay-up technique was utilized to fabricate the hybridized composite from bi-directional pineapple leaf fiber and sisal fibers using various stacking sequences. In order to understand the impact of hybridization on these composites, physical properties including density, percentage volume of fiber (PVF), and water absorption capacity were ascertained for hybrid composite. In addition, the mechanical characteristics like the tensile, fracture toughness, flexural, and interlaminar shear (ILSS) tests were investigated. Poly(furfuryl alcohol) was prepared and used as bioresin and it was apparent that the addition of more PLF in terms of PVF into hybridized composites, the properties flexural, tensile, and ILSS of the bio-epoxy composites were notably improved. The mechanical properties of hybridized composites were markedly impacted by the stacking order. Inference revealed that the composite attained the maximal tensile strength of 70.8 MPa for alternative sequence of SF and PLF. The composite which contained SF on the outside, had outperformed compared to other hybrid composites in terms of fracture toughness (3302.3 J/m 2 ) and interlaminar shear strength (16.1 MPa).

The textile industry contributes significantly to environmental pollution through the discharge of non-biodegradable colored dye effluents, emphasizing the need for effective wastewater treatment methods. Traditional approaches, including physical and biological treatments, face limitations, necessitating exploration into advanced oxidation processes (AOPs). Iron-based photocatalysts, particularly those synthesized through green methods, have shown promise in degrading organic pollutants. In this study, iron nanocomposites, including CSINCs, ASINCs, and ACINCs, are synthesized by mixing two different plant extract mixtures with an Iron precursor solution. XRD analysis confirms cubic structures for the prepared nanocomposites, with crystalline sizes of 14.21, 15.79, and 28.74 nm, respectively. UV–vis spectrophotometer shows characteristic absorption peaks in the 380–400 nm range. FESEM imaging reveals spherical particles, and EDX analysis detects typical signals of Fe, O, and C. FTIR spectra indicate various functional groups present in the nanocomposites. The study further focuses on optimizing the degradation of Reactive Blue 171 (RB 171) dye, considering factors such as pH, concentration of RB 171, and photocatalyst concentration. The results demonstrate that ACINCs, specifically at a concentration of 10 mg/100 mL in a mixture with Reactive Blue dye at a concentration of 50 ppm, exhibit enhanced degradation under UV irradiation. This detailed investigation contributes to the understanding of the structural and functional characteristics of Iron nanocomposites and their potential application in the efficient degradation of textile dyes, emphasizing the importance of optimizing key parameters for enhanced photocatalytic performance.

In present investigation, Pure Tin (Sn), Zirconia (Zr) and Silver (Ag) doped Sn thin films are prepared by jet nebuliser spray technique and utilised for possible photovoltaic application. A simple soft chemical technique used to create Zr and Ag doped SnO 2 nanocrystalline nanoparticles. As shown by the results of the XRD analysis, the nanoparticles found a tetragonal structure with P 42/ mnm symmetry, in accordance with the appearance of highly crystalline SnO 2 . The optical properties were performed, and their bandgap energies were found to be 2.8, 3.1 and 3.2 eV, respectively. Particles of prepared SnO 2 were analysed using FT-IR and XRD spectroscopy, which confirmed the presence of Zr and Ag. The photocatalytic performance of Sn–Zr–Ag NPs was examined by degradation of cationic Safranin dye under sunlight radiations with an interval of 15 min up to 90 min. UV–Vis spectrum analysis and a pseudo-first-order kinetics model were used to study nano catalytic dye degradation. High photocatalytic activities were observed after Zr and Ag doping, which may be enhanced further by adding H 2 O 2 . The surface characteristics of the prepared thin films are evaluated by AFM analysis. The electrochemical behaviour and photovoltaic properties are evaluated by EIS and IV characteristic studies.

In this work, MgNiO 2 material is prepared by a facile sol–gel method as an electrode material for supercapacitor application. The prepared MgNiO 2 material is characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and elemental analysis (EDS). The electronics conductivity is 1.9 × 10 −4  S cm −1 . The electrochemical performance of the prepared MgNiO 2 material was examined in an aqueous electrolyte of 1 M KOH. The electrochemical reaction of the prepared MgNiO 2 material shows the EDLC behaviour from the shapes of the CV curves. The prepared MgNiO 2 nanomaterial revealed good electrochemical performance with a maximum specific capacitance of 78 F/g at a rate of current density of 0.1 A/g. The above result delivered a simple, low cost and high-performance approach for a supercapacitor application.

This study pioneers the synthesis of porous Ag/ZnO nanosheets, focusing on their role as a catalyst in Knoevenagel condensation. Notably, these nanosheets display exceptional catalytic efficacy and captivating antibacterial properties. The research delves into the Ag/ZnO catalyst’s recyclability and proposes a potential reaction mechanism, marking the first comprehensive exploration of Knoevenagel condensation on porous Ag/ZnO nanosheets. Key findings underscore the successful synthesis of coumarin derivatives using various o-hydroxy benzaldehyde and 1,3-dicarbonyl compounds, with nano-Ag/ZnO serving as a catalyst via a monomode microwave-assisted approach. X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM) and UV–Vis spectroscopy were used in conjunction with other physicochemical methods to characterize the synthesized catalytic samples. The method boasts advantages such as high product yields, brief reaction durations, and the ability to reuse the catalyst for multiple cycles. The Ag/ZnO nanosheets, functioning as an acid catalyst, activate carbonyl groups and facilitate their interaction with methylene-containing active molecules. In addition, antibacterial activity assessments demonstrate the superior effectiveness of Ag/ZnO nanocomposites compared to ZnO nanosheets against Staphylococcus aureus germs. This multifaceted study not only advances catalytic synthesis but also unveils promising biological applications of porous Ag/ZnO nanosheets.

Zirconium oxide (ZrO 2 ) nanoparticles doped with silver (Ag) were synthesized utilizing Vitis vinifera leaf extract, offering a non-toxic and cost-effective production method. These nanoparticles were evaluated for their photocatalytic activity against both cationic (CR, EY, MO) and anionic (CV, MG, MB) dyes, alongside electrochemical impedance spectroscopy studies. The incorporation of silver into ZrO 2 aimed to enhance the photocatalytic efficiency, particularly under visible light activation, for the significant removal of toxic contaminants. Analysis employing UV-vis spectroscopy and a pseudo-first-order kinetics model revealed that sunlight exposure notably improved dye degradation. Various techniques were employed to assess the physicochemical characteristics, indicating the reduction process in the chemical reaction and confirming nanoparticle formation through chemical bonding, as evidenced by peaks in the IR spectrum ranging from 450 to 660 cm −1 . Furthermore, analysis of the UV–vis spectrum revealed bandgaps of 5.1 eV and 4.56 eV, confirming tetragonal and cubic crystal structures with crystalline sizes of approximately 15.7 nm and 17 nm for ZrO 2 and Ag–ZrO 2 nanoparticles, respectively. Electrochemical impedance spectra demonstrated that the addition of Ag to Zr notably improved charge transfer and electron separation processes.

The present work elucidates on a facile hydrothermal synthesis method for producing highly fluorescent carbon dots using corn flour as a natural carbon source. The structural confirmation was validated through XRD (X-ray Diffraction), HR-TEM (High-Resolution Transmission Electron Microscope), and FTIR (Fourier Transform Infra-Red) studies. The synthesized carbon dots exhibited an excitation-dependent photoluminescence (PL) emission. The optical band gap of as-synthesized carbon dots was estimated using UV-absorption spectral analysis. The variation in optical and luminescent response of the carbon dot suspension with the rate of centrifugation was also monitored. Furthermore, investigations on the photocatalytic response of as-synthesized carbon dots towards degradation of methylene blue and its activity as a potential antimicrobial agent against Escherichia coli are also presented.