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Abstract This comprehensive review extensively explores the potential applications of MXenes as versatile materials in the realm of photocatalysis, with a specific focus on their efficacy in mitigating hazardous dyes and CO2 to less harmful and friendly by-products. The review systematically investigates the unique properties that render MXenes well-suited for photocatalytic purposes and provides a thorough examination of their current state of research. It meticulously summarizes the successes and breakthroughs achieved thus far, offering insights into the advancements that have propelled these materials into the spotlight of photocatalytic research. In addition to highlighting achievements, the review critically addresses the challenges and hurdles that impede the full realization of the potential inherent in MXenes. Here, we have also highlighted the stability problem of MXenes and how to overcome this problem for efficient photocatalysis. The mechanism of photocatalysis was also the main theme of this review article and how to overcome the recombination of photogenerated charges. By identifying these challenges, the review serves as a valuable resource for researchers, providing a roadmap for future endeavours to unlock the untapped capabilities of these materials. It serves as a beacon for environmental researchers, offering valuable insights into the pivotal role these materials can play in creating a more environmentally friendly and safe world. Ultimately, this review contributes significantly to the collective knowledge base and will prove instrumental for researchers and professionals dedicated to environmental protection and sustainable living. Graphical Abstract

Fossil fuels resources are continually running out due to the rapid rise in industrialization and outgrowth. Moreover, the excessive utilization of fossil fuel has resulted in release of various toxic gases and global warming. Hence, it necessitates the demand to explore for an inexhaustible, renewable and eco-friendly energy sources. In this review, various waste biomasses which are abundantly available throughout the world have been reviewed as a feedstock for obtaining various value added products i.e. bio-oil, gases and biochar etc., using various pyrolysis techniques. The pyrolysis is considered to be the most effective conversion technique in which three stage degradation mechanism is observed leading to the production of valuable hydrocarbons from decomposition of hemicelluloses, cellulose and lignin. The bio-oil obtained if upgraded properly, is served as fuel for commercial use. The study also reviews the composition of lignocellulosic biomass, conversion techniques, and mechanism of conversion to various pyrolytic products, upgradation of bio-oil and effective utilization of biomass for energy generation. This review suggests utilization of lignocellulosic biomass waste as energy resource by converting it to value-added products by low-cost conversion methods which would ultimately lead to overcome the energy crises to some extent.

Abstract Herein, we report the synthesis, characterization, and application of TiO2/ZnO and La-doped ZnO nanocomposites for the detection and degradation studies of Malachite Green (MG). TiO2/ZnO and La-doped ZnO nanocomposites were synthesized by reflux and hydrothermal methods, respectively, and characterized by UV–visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analysis. A glassy carbon electrode modified with COOH-fMWCNTs and TiO2/ZnO nanocomposite demonstrated high sensitivity characteristics for the sensing of MG up to 0.34 nM limit of detection. The application of a photocatalytic method using 2% La-doped ZnO led to 99% degradation of MG in 40 min. The photocatalytic breakdown of MG followed first-order kinetics as revealed from the spectroscopic and electrochemical monitoring of the degradation process. Color variation offered naked-eye evidence of MG degradation in the specified time. The experimental findings helped in proposing the degradation mechanism. To the best of our knowledge, the current work presents the first example of a novel photocatalyst for almost absolute degradation of MG. Moreover, the electrode modifier as well as the approach adopted is novel and efficient for minute-level detection of MG and monitoring of its photocatalytic degradation.

Cadmium sulfide and zinc oxide nanoparticles were prepared, characterized and used as electrode modifiers for the sensing of two non-steroidal anti-inflammatory drugs (NSAIDs): naproxen and mobic. The structural and morphological characterization of the synthesized nanoparticles was carried out by XRD, UV-Vis spectroscopy, FTIR and scanning electron microscopy. The electrode’s enhanced surface area facilitated the signal amplification of the selected NSAIDs. The CdS-modified glassy carbon electrode (GCE) enhanced the electro-oxidation signals of naproxen to four times that of the bare GCE, while the ZnO-modified GCE led to a two-fold enhancement in the electro-oxidation signals of mobic. The oxidation of both NSAIDs occurred in a pH-dependent manner, suggesting the involvement of protons in their electron transfer reactions. The experimental conditions for the sensing of naproxen and mobic were optimized and, under optimized conditions, the modified electrode surface demonstrated the qualities of sensitivity and selectivity, and a fast responsiveness to the target NSAIDs.

In this study, bio-oil was produced from the pyrolysis of de-oiled karanja seed press cake in the presence of abandoned anthill as the catalyst. The anthill was characterised by SEM, EDX, XRF, XRD and surface area and pore size analysis. The pyrolysis experiments were carried out in an indigenously made furnace in a nitrogen atmosphere from 310 to 400 °C. The pyrolysis oil was collected at an optimised temperature and analysed through gas chromatography–mass spectrometry (GC-MS). The compounds identified via GC-MS of non-catalytic bio-oil were in the range of C5 to C19, and compounds identified from catalytic bio-oil were in the range of C2–C63. Furthermore, thermogravimetric analysis of the karanja seed press cake without and with anthill was carried out in a nitrogen atmosphere with temperature programme rates of 3, 12, 20 and 30 °C·min−1. Kinetic parameters were determined by applying the Kissinger equation. The activation energy (Ea) values for hemicelluloses, cellulose and lignin were obtained as 99.7 ± 0.4, 182.9 ± 0.5 and 199.5 ± 0.7 kJ·mol−1 without catalyst; and with catalyst, the Ea were lowered to 74.8 ± 0.2, 83.1 ± 0.4 and 108.0 ± 0.5 kJ·mol−1, respectively. From the results, it was concluded that the catalyst played a key role in lowering the activation energy for the pyrolysis reaction and enhanced the quality of the bio-oil obtained as well.

Water splitting has emerged as a sustainable, renewable and zero-carbon-based energy source. Water undergoes hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) during electrolysis. However, among these half-cell reactions, OER is more energy demanding. Hence, the development of efficient catalysts for speeding up OER is a key for boosting up the commercial viability of electrolyzers. Typical binders like Nafion and PVDF are not preferred for designing commercial electrocatalysts as they can compromise conductivity. Thus, we have designed a novel and cost-effective binder-free tetra-metallic (Co-Cu-Zn-Fe) oxide catalyst that efficiently catalyzes OER. This catalyst was grown over the surface of Fluorine doped tin oxide (FTO) transducer by a facile potentiodynamic method. The structure and morphology of the modified electrode were characterized by X-ray diffraction (XRD), scanning electron microscopy, and energy dispersive X-ray spectroscopy. XRD analysis confirmed the deposition of CoFe2O4 and CuCo2O4 along with alloy formation of Co-Fe and Co-Cu. Similarly, EDX and SEM results show the presence of metals at the surface of FTO in accordance with the results of XRD. Linear scan voltammetry was employed for testing the performance of the catalyst towards accelerating OER in strongly alkaline medium of pH-13. The catalyst demonstrated stunning OER catalytic performance, with an overpotential of just 216 mV at 10 mA cm−2 current density. Moreover, the chronopotentiometric response revealed that the designed catalyst was stable at a potential of 1.80 V for 16 h. Thus, the designed catalyst is the first example of a highly stable, efficient, and inexpensive catalyst that catalyzes OER at the lowest overpotential.

In this study pyrolysis of polypropylene (PP) was performed with and without cobalt oxide from 355 to 445 °C in inert conditions in an indigenously manufactured furnace. No oil was produced from non-catalytic reaction; however, the catalytic reaction resulted in production of oil in sufficient quantity. Optimum conditions for the maximum oil yield were explored and 100 min reaction time, 430 °C temperature and 5% of catalyst in continuous flow of nitrogen were observed as the most appropriate conditions for maximum oil production. Gas chromatography-mass spectrometry (GC-MS) of the obtained oil was performed for determining the composition of the oil. Moreover, fuel properties of the oil were examined and found comparable with commercial fuel. Furthermore, thermal degradation of polypropylene with and without cobalt oxide catalyst was performed in a thermobalance under nitrogen environment in the temperature ranging from 30 to 600 °C at temperature programmed rate of 5, 10, 15 and 20 °C/min. Using Kissinger-Akahira-Sunnose (KAS) kinetic model, the average activation energy (Ea) of non-catalytic reaction was found to be 83.14 kJ/mol, while in the presence of cobalt oxide the average Ea was observed as 63.55 kJ/mol. It was observed from the comparison of both the results that use of cobalt oxide has not only reduced Ea but also resulted in the production of oil having resemblance with fuel grade oil. Hence, cobalt oxide was found to be an efficient catalyst for the conversion of polypropylene into valuable products and the study performed on model polypropylene can be extended to polypropylene waste on industrial scale.

The progress in nanotechnology has effectively tackled and overcome numerous global issues, including climate change, environmental contamination, and various lethal diseases. The nanostructures being a vital part of nanotechnology have been synthesized employing different physicochemical methods. However, these methods are expensive, polluting, eco-unfriendly, and produce toxic byproducts. Green chemistry having exceptional attributes, such as cost-effectiveness, non-toxicity, higher stability, environment friendliness, ability to control size and shape, and superior performance, has emerged as a promising alternative to address the drawbacks of conventional approaches. Plant extracts are recognized as the best option for the biosynthesis of nanoparticles due to adherence to the environmentally benign route and sustainability agenda 2030 of the United Nations. In recent decades, phytosynthesized nanoparticles have gained much attention for different scientific applications. Eucalyptus globulus (blue gum) is an evergreen plant belonging to the family Myrtaceae, which is the targeted point of this review article. Herein, we mainly focus on the fabrication of nanoparticles, such as zinc oxide, copper oxide, iron oxide, lanthanum oxide, titanium dioxide, magnesium oxide, lead oxide, nickel oxide, gold, silver, and zirconium oxide, by utilizing Eucalyptus globulus extract and its essential oils. This review article aims to provide an overview of the synthesis, characterization results, and biomedical applications of nanoparticles synthesized using Eucalyptus globulus. The present study will be a better contribution to the readers and the students of environmental research.

Herein, we report an electrochemical scaffold consisting of functionalized multiwalled carbon nanotubes (COOH-fMWCNTs) and iron-doped zinc oxide nanoparticles (Fe-ZnO) for the detection of a hazardous textile dye safranin T (ST) and monitoring of its photocatalytic degradation. Prior to the detection and degradation analysis, Fe-ZnO NPs were synthesized by the sol-gel method and characterized by a number of structural and morphological techniques. The carboxyl moiety of COOH-fMWCNTs possessing a strong affinity for the amino functionality of ST led to significant enhancement of the current response at the designed electrochemical platform, whereas the electrocatalytic role, surface area enhancement, and the provision of binding sites of Fe-ZnO led to a further increase in the peak current intensity of ST. Electrochemical impedance spectroscopy showed that the sensing scaffold made of the glassy carbon electrode modified with COOH-fMWCNTs and Fe-ZnO efficiently transfers charge between the transducer and the redox probe. Under optimized conditions, the developed sensor showed a 2.3 nM limit of detection for ST. Moreover, recovery experiments and anti-interference tests qualified the sensing platform for practical applications. The dye was photocatalytically degraded using Fe-ZnO NPs up to 99% in 60 min with a rate constant of 0.068 min−1. The designed sensor was used to probe the degradation kinetics of the target dye, and the results were found consistent with the findings obtained from electronic absorption method. To the best of our knowledge, the present work is the first approach for the efficient detection and almost absolute degradation of ST.

The unavailability of non-poisonous and hygienic food substances is the most challenging issue of the modern era. The uncontrolled usage of toxic colorant moieties in cosmetics and food manufacturing units leads to major threats to human life. The selection of environmentally benign approaches for the removal of these toxic dyes has gained the utmost attention from researchers in recent decades. This review article’s main aim is the focus on the application of green-synthesized nanoparticles (NPs) for the photocatalytic degradation of toxic food dyes. The use of synthetic dyes in the food industry is a growing concern due to their harmful effects on human health and the environment. In recent years, photocatalytic degradation has emerged as an effective and eco-friendly method for the removal of these dyes from wastewater. This review discusses the various types of green-synthesized NPs that have been used for photocatalytic degradation (without the production of any secondary pollutant), including metal and metal oxide NPs. It also highlights the synthesis methods, characterization techniques, and photocatalytic efficiency of these NPs. Furthermore, the review explores the mechanisms involved in the photocatalytic degradation of toxic food dyes using green-synthesized NPs. Different factors that responsible for the photodegradation, are also highlighted. Advantages and disadvantages, as well as economic cost, are also discussed briefly. This review will be advantageous for the readers because it covers all aspects of dyes photodegradation. The future feature and limitations are also part of this review article. Overall, this review provides valuable insights into the potential of green-synthesized NPs as a promising alternative for the removal of toxic food dyes from wastewater.

Fossil fuels are the major source of energy in the world, which are being depleted day by day. Fossil fuels are also polluting the environment by releasing greenhouse gases such as carbon dioxide. To overcome environmental pollution as well as energy crisis, exploration of new ways of storing energy is the need of the time. In the presented work, reduced graphene oxide/Strontium selenate nanocomposite has been synthesized as an electrode material for energy storage devices. The structure of rGO/ SrSeO4 nanocomposite was confirmed by x-ray diffraction while the morphology was investigated by scanning electron microscopy. The electrochemical measurements, such as cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy and cyclic stability, were also carried out. The synthesized nanocomposite showed excellent specific power of 684.16 W/kg with 3.67 Wh/kg specific energy, which is significantly much better than already reported metal selenide materials.

Silver-coated ZrO2 and individual ZrO2 nanoparticles have been synthesized using the simple reduction and co-precipitation methods, respectively. The synthesized products were examined using the X-ray diffraction, energy-dispersive X-ray and UV–visible spectroscopy, which confirmed the successful synthesis of materials. Scanning electron microscopy and transmission electron microscopy revealed the round-shaped nanoparticles of both materials. The cyclic voltammograms revealed the well-defined redox peaks and recommended the pseudocapacitive nature of the electrodes. The silver-coated zirconia showed higher specific capacitance of 792 F/g at 10 mV/s as compared to individual zirconia (10.22 F/g). Silver-coated ZrO2 also showed good power density of 274.5 W/kg at current density of 5 mA/cm2 through the galvanostatic charge discharge profile. Hence, the results suggest that silver-coated ZrO2 showed improved electrochemical performance as compared individual ZrO2 due to higher electrical conductivity and specific surface area. Hence, silvercoated ZrO2 nanoparticles can be employed as an electrode material for supercapacitor applications.

The increase in industrialization and development has tremendously diminished fossil fuel resources. Moreover, the excessive use of fossil fuels has resulted in the release of various toxic gases and an increase in global warming. Hence, necessitating the need to search for a renewable energy source. In this study, sesame waste biomass (SWB), which is abundantly available in Pakistan, has been used as feedstock for obtaining bio-oil using the pyrolysis technique. Pyrolysis was carried out using thermogravimetry and a pyrolysis chamber. Firstly, thermogravimetric analysis was performed on biomass with/without a laboratory synthesized catalyst Ni/Co/MCM-41 in nitrogen at different temperature programmed rates of 5, 10, 15, and 20 °C/min. A four-stage weight loss was observed that pointed toward the vaporization of water, and degradation of hemicelluloses, cellulose, and lignin. The kinetics parameters were determined using the Kissinger equation. The activation energy for the decomposition reaction of hemicelluloses, cellulose, and lignin, without catalyst, was observed as 133.02, 141.33, and 191.22 kJ/mol, respectively, however, with catalyst it was found as 91.45, 99.76, and 149.65 kJ/mol, respectively. In the catalyzed reaction the results showed the lowest activation energy, which is an indication of the fact that the catalyst is successful in reducing the activation energy to a sufficient level. As the TG/DTG showed active degradation between 200 and 400 °C, therefore, the waste sesame biomass over Ni-Co/MCM-41 was pyrolyzed within the same temperature range in the pyrolysis chamber. Temperature and time were optimized for maximum oil yield. A maximum oil yield of 38% was achieved at 330 °C and 20 min. The oil obtained was studied using GCMS. The physicochemical characteristics of the oil were assessed, and it was found that if the oil was upgraded properly, it could serve as a fuel for commercial use.

Biosensors are analytical tools that can be used as simple, real-time, and effective devices in clinical diagnosis, food analysis, and environmental monitoring. Nanoscale functional materials possess unique properties such as a large surface-to-volume ratio, making them useful for biomedical diagnostic purposes. Nanoengineering has resulted in the increased use of nanoscale functional materials in biosensors. Various types of nanostructures i.e., 0D, 1D, 2D, and 3D, have been intensively employed to enhance biosensor selectivity, limit of detection, sensitivity, and speed of response time to display results. In particular, carbon nanotubes and nanofibers have been extensively employed in electrochemical biosensors, which have become an interdisciplinary frontier between material science and viral disease detection. This review provides an overview of the current research activities in nanofiber-based electrochemical biosensors for diagnostic purposes. The clinical applications of these nanobiosensors are also highlighted, along with a discussion of the future directions for these materials in diagnostics. The aim of this review is to stimulate a broader interest in developing nanofiber-based electrochemical biosensors and improving their applications in disease diagnosis. In this review, we summarize some of the most recent advances achieved in point of care (PoC) electrochemical biosensor applications, focusing on new materials and modifiers enabling biorecognition that have led to improved sensitivity, specificity, stability, and response time.

In this study, the pyrolysis procedure was used to extract oil from pomegranate peels (PP) utilizing biomass-derived sulfonated tea waste as a catalyst. FTIR, SAA, SEM, and XRD were used to characterize the catalyst. Thermo-catalytic decomposition was carried out in a salt bath reactor and the bio-oil composition was determined through GC-MS. The oil obtained from virgin PP was observed to contain compounds in the range of C5–C13, whereas from the catalyzed reaction it was found to be rich in C5–C23. For the calculation of kinetic parameters, TG analysis was performed of virgin PP and with the catalyst at different heating rates. TG/DTG indicated weight loss in four steps. The first weight loss below 100 °C is due to the physically adsorbed water molecule evaporation. The second weight loss is attributed to hemicellulose decomposition and the third one to cellulose degradation. The fourth weight loss is due to lignin degradation. Kissinger model was used for measuring the activation energy (Ea) of the decomposition reaction. The activation energy of hemicellulose, cellulose, and lignin for non-catalytic reactions was observed as 199, 249, and 299 kJmol−1, while in the case of the loaded tea waste catalyst, the Ea was reduced to 122, 163, and 207 kJmol−1, respectively, confirming the effectiveness of the catalyst. From these findings, it can be concluded that sulfonated tea waste catalyst has not only lowered the pyrolysis temperature and Ea but also brought a change in oil quality by enhancing value-added compounds in the bio-oil.

In the current work surface of a glassy carbon electrode (GCE) is purposely modified with a suitable modifier to enhance its sensing characteristics. A composite of surfactant 1-(2, 4-initrophenyl)-dodecanoylthiourea (DAN) and gold nanoparticles (AuNPs) was employed as modified for the sensitive detection of oxoplatin (OXP), an extensively used anticancer drug. It enters into water bodies through improper handling in underdeveloped countries where drug disposal precautions are not fully respected. The designed platform (DAN/AuNPs/GCE) displays remarkable sensitivity 6.35 μ A nM ^−1 and senses OXP with LOD of 14.5 pM under optimized conditions. The sensor was characterized by electrochemical techniques mainly cyclic voltammetry, electrochemical impedance spectroscopy, and square wave voltammetry. The response of OXP was also examined in the artificial serum sample. The modified electrode was found to have extraordinary discrimination ability for the selected drug even in the presence of a 100-fold higher concentration of several interfering agents and displayed remarkable repeatability and reproducibility with RSD up to 3%. The role of the electrode modifier in enhancing the concentration of OXP near the transducer surface and consequently intensifying the oxidation signal of OXP was validated from experimental and computational studies.

In the current study, plain and lignin loaded with Zeolite Y, hydrogen was decomposed in a pyrolysis chamber. The reaction parameters were optimized and 390 °C, 3% catalyst with a reaction time of 40 min were observed as the most suitable conditions for better oil yield. The bio-oil collected from the catalyzed and non-catalyzed pyrolytic reactions was analyzed by gas chromatography mass spectrometry (GCMS). Catalytic pyrolysis resulted in the production of bio-oil consisting of 15 components ranging from C3 to C18 with a high percentage of fuel range benzene derivatives. Non-catalytic pyrolysis produced bio-oil that consists of 58 components ranging from C3 to C24; however, the number and quantity of fuel range hydrocarbons were lower than in the catalyzed products. The pyrolysis reaction was studied kinetically for both samples using thermogravimetry at heating rates of 5, 10, 15 and 20 °C/min in the temperature range 20–600 °C. The activation energies and pre-exponential factors were calculated using the Kissinger equation for both non-catalytic and catalytic decomposition and found to be 157.96 kJ/mol, 141.33 kJ/mol, 2.66 × 1013 min−1 and 2.17 × 1010 min−1, respectively. It was concluded that Zeolite Y, hydrogen worked well as a catalyst to decrease activation energy and enhance the quality of the bio-oil generated.

The current work presents a sensitive, selective, cost-effective, and environmentally benign protocol for the detection of ibuprofen (IBP) by an electrochemical probe made of a glassy carbon electrode modified with Ag-ZnO and MWCNTs. Under optimized conditions, the designed sensing platform was found to sense IBP up to a 28 nM limit of detection. The interaction of IBP with bovine serum albumin (BSA) was investigated by differential pulse voltammetry. IBP−BSA binding parameters such as the binding constant and the stoichiometry of complexation were calculated. The results revealed that IBP and BSA form a single strong complex with a binding constant value of 8.7 × 1013. To the best of our knowledge, this is the first example that reports not only IBP detection but also its BSA complexation.

A Schiff base 1-((3-nitrophenylimino)methyl)naphthalen-2-olate (HL) and its two novel complexes with Zn(II) and Co(II) metals were successfully synthesized and characterized by FTIR, 1H NMR, 13C NMR, elemental analysis, magnetic susceptibility, TGA and EIS-MS. Crystal of Schiff base was also characterized by X-ray analysis and experimental parameters were found in line with the theoretical parameters. Quantum mechanical approach was also used to compare structural and calculated parameters and to ensure the geometry of metal complexes. The photometric behaviors of all the synthesized compounds were investigated in a wide pH range using BR buffers. Appearance of isosbestic point suggested the existence of Schiff base molecules in different tautomeric forms. Binding of synthesized complexes with calf thymus DNA was explored by photometric and voltammetric titrations and binding constants were calculated. The results indicated that ligand and its metal complexes bind to DNA by intercalation mode. Docking studies indicate their binding possibilities with topoisomerase II. Moreover, all these prepared compounds were screened for enzyme inhibition, antibacterial, cytotoxic and in vivo antidiabetic activities and found active against one or other activity. This effort just provides preliminary data for some biological properties and which can act as foundation stone for their application in drug development. Keywords: Schiff base-metal complexes, Spectroscopy, X-ray analysis, DNA binding, Molecular docking

The substituted strontium Y-type hexaferrites Sr2Co2GexMnxFe12−2xO22 (X = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) was synthesized by sol–gel auto-combustion method. The crystal structures of the present materials were identified using X-ray diffraction analysis. The XRD patterns of the prepared samples pointed out the successful formation of Y-type hexagonal phase. The dielectric and magnetic properties have been studied for Ge-Mn substituted Y-type hexaferrites. The results showed that the dielectric parameters decrease with increasing frequencies. The values of magnetic parameters such as saturation magnetization, remanent magnetization and magnetic moment were found to decrease which are attributed to the weakening of super-exchange interactions. The values of Squareness ratio are found to be 0.48–0.56, which shows that the fabricated materials are multi domain. With decreasing dielectric parameters and increasing coercivity support these investigated samples have appealing applications in micro-wave devices, and Multilayer chip inductors. Keywords: XRD, EDX, Dielectric loss, Coercivity, Multilayer chip inductors

A stable bimetallic catalyst composed of Co–Pd@Al2O3 was synthesized using a wet impregnation method, followed by calcination and H2 reduction. The synthesized catalyst was thoroughly characterized using XRD, BET, SEM, EDX, and TPR techniques. The catalyst was then drop-casted on a glassy carbon electrode (Co–Pd@Al2O3/GCE) and applied for the sensitive and selective electrochemical determination of a common antidepressant drug, venlafaxine (VEN). The proposed sensor (Co–Pd@Al2O3/GCE) demonstrated a remarkable catalytic activity for the electro-oxidation of VEN, with a decent repeatability and reproducibility. The pH dependent responsiveness of the electro-oxidation of VEN helped in proposing the redox mechanism. A linear relationship between the peak current and concentration of VEN was observed in the range of 1.95 nM to 0.5 µM, with LOD and LOQ of 1.86 pM and 6.20 pM, respectively. The designed sensor demonstrated an adequate selectivity and significant stability. Moreover, the sensor was found to be quite promising for determining the VEN in biological specimens.

The results of cyclic, differential pulse and square wave voltammetric studies of four ferrocene derivatives, i.e., 4-ferrocenyl-3-methyl aniline (FMA), 3-Chloro-4-ferrocenyl aniline (CFA), 4-ferrocenyl aniline (FA) and ferrocenyl benzoic acid (FBA) on carbon electrode, revealed that the redox behavior of these compounds is sensitive to pH, concentration, scan number and scan rate. One electron, diffusion controlled, with a quasi-reversible redox signal displaying ferrocene/ferrocenium couple was observed for each of the studied ferrocenyl derivatives. Quasi-reversibility of this signal is evidenced by ∆Ep, Ia/Ic current ratio and ksh values. Another one electron and one proton irreversible oxidation signal was noticed in the voltammograms of these compounds except FBA. This signal corresponds to the electro-oxidation of the amine group and its irreversibility, as supported by ∆Ep, Ia/Ic current ratio and ksh values, is due to the influence of the electron donating nature of the amine group. A number of electrochemical parameters such as D, ksh, LOD and LOQ were evaluated for the targeted ferrocene derivatives. The obtained parameters are expected to provide insights into the redox mechanism for understanding their biochemical actions. The electrochemistry presented in this work is done using a unique environmentally benign and cost-effective droplet electrochemical approach.

The present study is aimed to determine the efficacy and dose response of the nuciferine (1), norcoclaurine (2) and crude extract of Nelumbo nucifera in managements of diabetes, Alzheimer disease and related allergies. Experimentally, alloxan (100 mg/kg body weight (b.w.))-induced diabetic rats (200–250 g) were divided into seven groups (n = 6). Group I: normal control, Group II: diabetic control, Group III: standard treated with glibenclamide and Group lV-VII: treated with methanolic crude extracts (100, 200 mg/kg), nuciferine and norcoclaurine (10 mg/kg b.w.) for 15 days. Different tests were performed, including blood glucose, body weights and antioxidant enzyme assays, i.e., superoxide dismutase (SOD), catalase test (CAT), lipid peroxidation assay (TBARS), glutathione assay (GSH) and acetylcholinesterase (AChE) assay. Nuciferine and norcoclaurine significantly reduced blood glucose (p < 0.05) and restored body weight in diabetic rats. Moreover, nuciferine and norcoclaurine (10 mg/kg) significantly recovered the antioxidant enzymes (SOD, CAT, GPx and GSH) which decreased during induced diabetes. Significant increase in TBARS was also observed in the diabetic group and nuciferine as well as norcoclaurine (10 mg/kg) inhibited the increase in TBARS in diabetic animals (p < 0.05), as compared to glibenclamide. AChE activity was significantly recovered by nuciferine and norcoclaurine (10 mg/kg) both in the blood and brain of the diabetic group (p < 0.05). Nuciferine and norcoclaurine showed potent inhibitory effects against α-glucosidase and α-amylase with IC50, 19.06 ± 0.03, 15.03 ± 0.09 μM and 24.07 ± 0.05, 18.04 ± 0.021 μM, as confirmed by molecular docking studies. This study concludes that nuciferine and norcoclaurine significantly improve memory and could be considered as an effective phytomedicine for diabetes, Alzheimer’s disease (AD) and oxidative stress.

Hydrogen is contemplated as a promising renewable source of energy as compared to the fast depleting fossil fuels. The splitting of water for the generation of hydrogen is a perspective approach to produce sustainable fuel. Titanium dioxide is the most commonly used catalyst, the performance of which depends upon its electronic surface structure, bandgap, and type of radiation. This review article summarizes the state of the art developments about the photocatalytic activity of titanium dioxide for hydrogen production from the splitting of water. Special attention has been devoted to the addition of sacrificial reagents, metal/non-metal doping ions, and composite semiconductors in titania for absorbing visible light and enhancing charge separation on a catalyst surface for efficient energy generation of hydrogen fuel from water splitting.

To efficiently design improved therapeutic agent, study of molecule-DNA interaction is a crucial step. In our previous study, we investigated comprehensive mechanism of some 1,2,4 triazol-4-ylimino derivatives, and they exhibited excellent in vitro anti-cancer activities. Out of all compounds studied previously (E)-3-((4H-1,2,4 triazol-4-ylimino) methyl) benzene-1,2-diol (TMB) demonstrated the best anti-cancer activity. This prompted us to explore its action mechanism by interacting the compound with the Salmon Sperm DNA. UV–Vis spectroscopic technique was employed as a tool to study this mechanism at two different temperatures. A slight bathochromic shift along with a noticeable hypochromic effect appears signaling interaction of the molecules with DNA. Thus, it clearly depicts that compound was bound to DNA. To interpret the TMB-DNA interaction mechanism, adsorption of TMB on various concentrations of salmon sperm DNA was investigated. It was found that the adsorption of TMB decreased with increased concentrations of DNA. Electrostatic attraction between TMB and DNA, and interactions among TMB molecules deemed to play a role in the interaction mechanism. Thermodynamic data obtained indicates the thermodynamic feasibility of overall process. This work offered an insight to molecular mechanism of the interaction between TMB and tumor cells. It further offered a valuable standpoint to the design novel 1,2,4 triazol-4-ylimino derivatives based anticancer compounds.

Plastic has made our lives comfortable as a result of its widespread use in today’s world due to its low cost, longevity, adaptability, light weight and hardness; however, at the same time, it has made our lives miserable due to its non-biodegradable nature, which has resulted in environmental pollution. Therefore, the focus of this research work was on an environmentally friendly process. This research work investigated the decomposition of polypropylene waste using florisil as the catalyst in a salt bath over a temperature range of 350–430 °C. A maximum oil yield of 57.41% was recovered at 410 °C and a 40 min reaction time. The oil collected from the decomposition of polypropylene waste was examined using gas chromatography-mass spectrometry (GC-MS). The kinetic parameters of the reaction process were calculated from thermogravimetric data at temperature program rates of 3, 12, 20 and 30 °C·min−1 using the Ozawa–Flynn–Wall (OFW) and Kissinger–Akahira–Sunnose (KAS) equations. The activation energy (Ea) and pre-exponential factor (A) for the thermo-catalytic degradation of polypropylene waste were observed in the range of 102.74–173.08 kJ·mol−1 and 7.1 × 108–9.3 × 1011 min−1 for the OFW method and 99.77–166.28 kJ·mol−1 and 1.1 × 108–5.3 × 1011 min−1 for the KAS method at a percent conversion (α) of 0.1 to 0.9, respectively. Moreover, the fuel properties of the oil were assessed and matched with the ASTM values of diesel, gasoline and kerosene oil. The oil was found to have a close resemblance to the commercial fuel. Therefore, it was concluded that utilizing florisil as the catalyst for the decomposition of waste polypropylene not only lowered the activation energy of the pyrolysis reaction but also upgraded the quantity and quality of the oil.

Over the past decade, layered double hydroxides (LDH) have been the subject of extensive investigations owing to their remarkable water splitting catalytic activity. Stability and porosity are several of the features of LDH which help them to serve as efficient oxygen evolution reaction (OER) catalysts. Based on these considerations, we synthesized NiCo(OH)2 LDH and probed its OER electrocatalytic performance. The synthesized catalyst was subjected to X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy for structural analysis and investigation of its surface morphology, surface composition, and oxidation states. The LDH-NiCo(OH)2 was anchored over the FTO surface and the fabricated electrode was found to exhibit a much lower OER onset potential of 265 mV, a much higher current density of 300 mAcm−2 and a smaller Tafel slope of 41 mVdec−1. Moreover, the designed catalyst was found to be stable up to 2500 repeated voltametric scans. These figures of merit regarding the structure and performance of the designed LDH are expected to provide useful insights into the fundamental understanding of the OER catalysts and their mechanisms of action, thus enabling the more rational design of cost effective and highly efficient electrocatalysts for use in water splitting.

The electrochemical reduction of carbon dioxide (CO2) on copper electrode derived from cupric oxide (CuO), named oxide derived copper (ODCu), was studied thoroughly in the potential range of −1.0 V to −1.5 V versus RHE. The CuO nanoparticles were prepared by the hydrothermal method. The ODCu electrode was used for carbon dioxide reduction and the results revealed that this electrode is highly selective for C2+ products with enhanced current density at significantly less overpotential. This catalyst shifts the selectivity towards C2+ products with the highest Faradaic efficiency up to 58% at −0.95 V. In addition, C2 product formation at the lowest onset potential of −0.1 V is achieved with the proposed catalyst. X-ray diffraction and scanning electron microscopy revealed the reduction of CuO to Cu (111) nanoparticles during the CO2 RR. The intrinsic property of the synthesized catalyst and its surface reduction are suggested to induce sites or edges for facilitating the dimerization and coupling of intermediates to ethanol and ethylene.

This study focused on the thermal degradation of peanut shells in the presence and absence of a termite hill as the catalyst. EDX, XRF, SEM, SAA and XRD were employed for the characterization of the termite hill. The bio-oil obtained from peanut shell pyrolysis was analyzed by GC-MS. To ascertain the kinetic parameters of the reaction, thermogravimetric analysis of peanut shells was carried out with and without a termite hill at heating rates of 3, 12, 20 and 30 °C·min−1. TG/DTG of peanut shells revealed four steps of weight loss from 30 to 800 °C. The weight loss was attributed to the evaporation of water and degradation of hemicellulose, cellulose and lignin. The Kissinger method was applied for the evaluation of kinetic parameters. The activation energy (E) for the non-catalyzed degradation reactions of hemicellulose, cellulose and lignin was evaluated as 108.082, 116.396 and 182.908 kJ/mol, with a pre-exponential factor (A) of 1.9 × 108, 2.42 × 109 and 2.98 × 1011 min−1, respectively. Similarly, for the catalyzed reaction, the values of E and A were calculated as 66.512, 74.826 and 133.024 kJ/mol and 5.83 × 106, 2.859 × 107 and 1.46 × 109 min−1, respectively. The termite hill not only reduced the degradation temperature and activation energy but also modified the composition of the bio-oil. In the case of the non-catalyzed reaction, the bio-oil was found to consist of C5-C24, while catalytic pyrolysis produced more components ranging from C4 to C31 hydrocarbons.

Water is obligatory for sustaining life on Earth. About 71% of the Earth’s surface is covered in water. However, only one percent of the total water is drinkable. The presence of contaminants in wastewater, surface water, groundwater, and drinking water is a serious threat to human and environmental health. Their toxic effects and resistance towards conventional water treatment methods have compelled the scientific community to search for an environmentally friendly method that could efficiently degrade toxic contaminants. In this regard, visible light active photocatalysts have proved to be efficient in eliminating a wide variety of water toxins. A plethora of research activities have been carried out and significant amounts of funds are spent on the monitoring and removal of water contaminants, but relatively little attention has been paid to the degradation of persistent water pollutants. In this regard, nanoparticles of doped ZnO are preferred options owing to their low recombination rate and excellent photocatalytic and antimicrobial activity under irradiation of solar light. The current article presents the roles of these nanomaterials for wastewater treatment from pollutants of emerging concern.

The screen-printed electrodes have gained increasing importance due to their advantages, such as robustness, portability, and easy handling. The manuscript presents the investigation of the interaction between double-strand deoxyribonucleic acid (dsDNA) and three anthracyclines: epirubicin (EPI), idarubicin (IDA), and doxorubicin (DOX) by differential pulse voltammetry on metal nanoparticles modified by screen-printed electrodes. In order to investigate the interaction, the voltammetric signals of dsDNA electroactive bases were used as an indicator. The effect of various metal nanomaterials on the signals of guanine and adenine was evaluated. Moreover, dsDNA/PtNPs/AgNPs/SPE (platinum nanoparticles/silver nanoparticles/screen-printed electrodes) was designed for anthracyclines–dsDNA interaction studies since the layer-by-layer modification strategy of metal nanoparticles increases the surface area. Using the signal of multi-layer calf thymus (ct)-dsDNA, the within-day reproducibility results (RSD%) for guanine and adenine peak currents were found as 0.58% and 0.73%, respectively, and the between-day reproducibility results (RSD%) for guanine and adenine peak currents were found as 1.04% and 1.26%, respectively. The effect of binding time and concentration of three anthracyclines on voltammetric signals of dsDNA bases were also evaluated. The response was examined in the range of 0.3–1.3 ppm EPI, 0.1–1.0 ppm IDA and DOX concentration on dsDNA/PtNPs/AgNPs/SPE. Electrochemical studies proposed that the interaction mechanism between three anthracyclines and dsDNA was an intercalation mode.

One of the challenges in improving the efficiency of hybrid solar cells is to remove crystal defects from the semiconducting nanoparticles. Here we report the synthesis, characterization and applications of transition metal doped ZnO nanorods in hybrid bulk heterojunction solar cells. MnxZn1−xO and NixZn1−xO with dopant concentrations ranging from x = 0.01–0.10 were successfully synthesized by a novel facile solution-processed wet chemical method, which gave better yield at low cost and temperature. The morphological and optical properties of the material were investigated by Transmission electron microscopy (TEM), UV–Visible and Fluorescence spectroscopies. TEM measurements confirmed the reduction in size of nanorods upon doping. UV–Visible spectra of doped nanorods showed blue shift with respect to the reference undoped ZnO. The defect emissions were completely disappeared from the fluorescence spectra upon doping at high concentrations. These doped nanorods in combination with P3HT were employed in the hybrid solar cells which gave better current densities than their corresponding undoped counterparts.

The main objective of this research is to study the adsorption behaviour of malachite green and methylene blue dyes onto the surfactant modified natural clays. The results of SEM, XRD, IR, and thermal analysis confirms the intercalation of organic moiety in to the clay. The adsorption results show that pseudo-first order kinetics best fitted for both the dyes adsorbed on organo-clay. The data also reveals that both dyes are in a good agreement with Langmuir isotherm in both types of modified clays. The value of separation factor, RL, from Langmuir equation and Freundlich constant, n, give an indication of favourable adsorption. The maximum adsorption capacity qm based on Langmuir model was found to be 294-303 mg/g at 25 ˚C, is in good agreement with the experimental values.

Abstract Electrochemical capacitors (ECs) are a vital class of electrical energy storage (EES) devices that display the capacity of rapid charging and provide high power density. In the current era, interest in using ionic liquids (ILs) in high‐performance EES devices has grown exponentially, as this novel versatile electrolyte media is associated with high thermal stability, excellent ionic conductivity, and the capability to withstand high voltages without undergoing decomposition. ILs are therefore potentially useful materials for improving the energy/power performances of ECs without compromising on safety, cyclic stability, and power density. The current review article underscores the importance of ILs as sustainable and high‐performance electrolytes for electrochemical capacitors.

Different fractions of root and stem of Derris scandens demonstrated good antibacterial (Escherichia coli, and Bacillus megaterium), antialgal (Chlorella fusca), and antifungal (Microbotryum violaceum) activities. Phytochemical investigation resulted in isolation of scandenin, scandenin A, betulinic acid, lupeol, β-amyran-3-one, β-amyrin, β-sitosterol and ß-sitosterol glucopyranoside. Study showed that scandenin has strong antibacterial activity against B. megaterium and good antifungal and antialgal properties. Scandenin A showed good antibacterial, antifungal and antialgal properties.

The aim of this study was to reduce the highly toxic hexavalent chromium Cr(VI) into less toxic chromium Cr(III) species by using nickel nanoparticles (Ni NPs) as catalysts in order to provide safety to the aqueous environment. In the first phase Ni NPs were synthesized in ethylene glycol and capped with l-cysteine by a modified microwave irradiation method using NaOH as the accelerator. The formed Ni NPs were characterized by various techniques such as UV-Visible spectroscopy, Fourier Transform Infra-red (FTIR) spectroscopy and Scanning Electron Microscopy (SEM). In the second phase the formed Ni NPs were immobilized on glass surfaces and employed as catalyst for the reduction of Cr(VI) ions. According to observations, 99% reduction of Cr(VI) ions was achieved in the presence of 0.5 mg of Ni NPs catalyst in just five minutes as compared to nickel powder that showed only 16% reduction in 15 minutes. The study has a great impact on the aqueous pollution control of Cr(VI) especially caused by the discharge of waste water from several industries utilizing Cr(VI) containing salt as one of the essential gradients.

The redox behaviour of two potential anticancer anthraquinones, 9,10-anthraquinone and 2-chloromethyl-9,10-anthraquinone was investigated in a wide pH range. Cyclic voltammetry based assay was developed for the assessment of the effect of medium, substituents, potential scan rate and number of scans on the voltammetric response of anthraquinones. The electrode reaction mechanism was suggested on the basis of cyclic and differential pulse voltammetric results. The effect of DNA on anthraquinones was also probed at physiological pH which could lead to further investigation of possible citotoxic activity in vitro. The results revealed that anthraquinones interact with DNA more strongly than the clinically used anticancer drug, epirubicin.

A faster, simpler and sensitive method was developed for determination of aliphatic phthalates using differential pulse polarography (DPP) as standard technique. The choice and concentration of base electrolyte, solvent, initial potential, effect of water addition and interference by other phthalates were the main parameters to optimize for enhancement of peak current and to obtain well-defined polarogram with lower background current using 1.3 x 10-4 M di-butyl phthalate (DBP) solution. Best results were obtained in the presence of tetra methyl ammonium bromide (TMAB) as electrolyte in methanol solvent with initial potential, -1.4 V. A linear calibration plot was observed in the range of 3 x 10-7 – 1.6 x 10-4 M DBP solution as aliphatic phthalates with lower detection limit of 5.9 x 10-8 M and linear regression coefficient of 0.9987. The developed polarographic method was successfully applied for analysis of aliphtaic phthalates in various samples of locally available polymer products such as baby toys, nipples, teethers, infusion blood bags and shopping bags. The results of the current method were compared with those obtained by a reported method and good agreement was found between them.

Au-Cu alloy nanoparticles were synthesized by a chemical reduction method. Five samples having different compositions of Au and Cu (Au-Cu 3 : 1, Au-Cu 2 : 1, Au-Cu 1 : 1, Au-Cu 1 : 2, and Au-Cu 1 : 3) were prepared. The newly synthesized nanoparticles were characterized by electronic absorption, fluorescence, and X-ray diffraction spectroscopy (XRD). These alloy nanoparticles were also analyzed by SEM and TEM. The particle size was determined by SEM and TEM and calculated by Debye Scherrer’s equation as well. The results revealed that the average diameter of nanoparticles gets lowered from 80 to 65 nm as the amount of Cu is increased in alloy nanoparticles. Some physical properties were found to change with change in molar composition of Au and Cu. Most of the properties showed optimum values for Au-Cu alloy nanoparticles of 1 : 3. Cu in Au-Cu alloy caused decrease in the intensity of the emission peak and acted as a quencher. The fluorescence data was utilized for the evaluation of number of binding sites, total number of atoms in alloy nanoparticle, binding constant, and free energy of binding while morphology was deduced from SEM and TEM.

Epirubicin, (7S,9S)-7-[(2R,4S,5R,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione, which is an antineoplastic in the anthracycline class, is a 4′-epi-isomer of the anthracycline antineoplastic doxorubicin. [...]

Essential and nonessential heavy metals like iron (Fe), nickel (Ni), manganese (Mn), zinc (Zn), copper (Cu), cadmium (Cd), chromium (Cr), and lead (Pb) were analyzed in four selected medicinal plants such as Capparis spinosa, Peganum harmala, Rhazya stricta, and Tamarix articulata by flame atomic absorption spectrophotometer (FAAS). These medicinal plants are extensively used as traditional medicine for treatment of various ailments by local physicians in the area from where these plants were collected. The concentration level of heavy metals in the selected plants was found in the decreasing order as Fe > Zn > Mn > Cu > Ni > Cr > Cd > Pb. The results revealed that the selected medicinal plants accumulate these elements at different concentrations. Monitoring such medicinal plants for heavy metals concentration is of great importance for physicians, health planners, health care professionals, and policymakers in protecting the public from the adverse effects of these heavy metals.

Preparation of colloidal silver nanoparticles has been carried out by salt reduction method and confirmed by the appearance of plasmon band in the visible region. The prepared nanoparticles were subjected to acidic and basic environments. The plasmon band was studied as a function of time under the described conditions and hence used as a stability check of silver nanoparticles in different media. The mechanism of plasmon band disappearance of silver colloids was found to depend strongly on the pH of the medium. Graphical abstract Research highlights ► Plasmon band of silver nanoparticles formed by citrate reduction method is strongly affected by the acidic and basic environments demonstrating effect of pH on the structure and stability of citrate caped silver nanoparticles. ► In acidic condition, an accelerated particle growth results only limited by the buffer action of citrate in solution. ► In the case of base Ag+ ions formation take place which ultimately deposit on the walls of test tube forming a silver mirror.