The effect of A-site substitution on the morphological and electrochemical properties of La1-xSrxMnO3 (x = 0, 0.25, 0.50) perovskites was investigated to evaluate their potential as electrode materials for supercapacitors. X-ray diffraction analysis confirmed the formation of the perovskite structure, with minor peak shifts and distortion of crystal structure induced by Sr substitution. Scanning electron microscopy analysis revealed irregularly shaped particulate morphology across all perovskite compositions. The increasing amount of Sr as in La0.5Sr0.5MnO3 (LSM-50) favored the formation of nanosized particles, and energy dispersive X-ray (EDX) analysis confirmed the presence of all constituent elements; EDX elemental mapping also showed a uniform distribution of all elements in the various perovskite compositions. Among all compositions, La0.75Sr0.25MnO3 (LSM-25) possessed the highest specific capacitance (Csp) of 483 Fg-1 at 1 Ag-1 current density in 3 M KOH electrolyte, as determined by electrochemical analysis. This perovskite material also exhibited a capacitance retention of 87.8% after 5000 charge-discharge cycles. Electrochemical impedance spectroscopy revealed that LSM-25 showed the lowest solution resistance (0.68 Omega*cm2) and charge transfer resistance (1.52 Omega*cm2), indicating strong electrode-electrolyte interaction. Detailed analysis of cyclic voltammetry data revealed that the predominant charge storage mechanism was diffusive in nature, with 88% of the diffusive contribution registered for LSM-25. These findings demonstrate that Sr substitution at the A-site significantly enhances the energy storage performance of LaMnO3, making it a promising candidate for supercapacitor applications.

Zinc oxide (ZnO) has emerged as a potential candidate for supercapacitors due to good electrical conductivity, cost-effectiveness, and nontoxicity. However, the drawback lies in its lower specific capacity compared to other metal oxides. To address this limitation, we have added cerium (Ce) as a dopant in ZnO, which simultaneously induces secondary phase CeO2 in a single step. This unique approach eliminated the need for a complex multistep synthesis and tailored the electrochemical properties of ZnO. The PL and Raman results showed the presence of defects. The CeO2 phase improved particle connectivity, as seen in SEM, and enhanced redox activity via the Ce+3/Ce+4 transition. As a result, the Ce-doped ZnO sample exhibited the highest specific capacity of 748 C/g (207 mAh/g) as compared to pure zinc, which is only 224 C/g (62 mAh/g) at 1 A/g current density. Hence, the effective doping engineering and secondary phase resulted in high-performance Ce-doped ZnO electrodes.

This research focuses on synthesizing MnO2 via a one-step hydrothermal method and evaluating its electrochemical performance for supercapacitor applications. MnO2 was directly coated on a Ni foam substrate to create binder-free electrodes. Varying hydrothermal conditions altered the morphology and crystallinity of MnO2, with semi-crystalline structures formed at intermediate temperatures and times-exhibiting enhanced charge storage due to higher surface area and active sites. SEM analysis revealed diverse morphologies, including particulate, spherical and rod-like structures. Among the samples, M2 (synthesized at 140 degrees C for 8h) showed the best performance, achieving a specific capacitance (Csp) of 780Fg-1 with energy and power densities of 39.99Whkg-1 and 0.29kWkg-1, respectively. To further improve performance, M2 was combined with varying concentrations of graphene oxide (GO). The M2-5GO composite electrode delivered a high Csp of 1145Fg-1, an energy density of 58.06Whkg-1 and maintained 94.6% capacitance over 5000 cycles. The enhanced performance was attributed to the synergistic effect offered by a higher surface area of MnO2 and the layered structure of GO. Analysis indicated that while M2 relied mainly on diffusive charge storage, while GO addition increased capacitive contribution by 11%. The study demonstrates MnO2 has a potential for high-performance supercapacitors, especially when used with GO. Furthermore, M2-5GO was used to develop a symmetric two-electrode device. Electrochemical characterization of the device revealed that it possessed Csp of 333Fg-1 at 1mVs-1 with energy and power density of 44.42Whkg-1 and 0.50kWkg-1, respectively, at 1Ag-1 current density.

Supercapacitors have gained considerable focus for storage and utilization of renewable energy. The performance of supercapacitors is strongly dependent on the properties and design of electrode materials. The present research focuses on development of non-toxic, low-cost and environmentally-friendly magnesium aluminate (MAL) spinel compound-based electrode materials for supercapacitor applications. Three MAL samples were synthesized by solution combustion technique at different precursor salt to fuel (glycine) ratios (1:1, 1:3 and 1:6), and one sample was produced by incorporating cetyltrimethylammonium bromide (CTAB) surfactant in the precursor solution, labelled as MAL-3G-CT. XRD analysis showed the variation in salt to fuel ratio resulted in the formation of secondary phase, whereas the addition of CTAB resulted in a pure spinel phase. The morphology of MAL changes from chunks to crumpled-sheet-like due to CTAB as confirmed by SEM. Photoluminescence confirmed an increase in defect density for MAL-CTAB sample compared to other MAL samples. Due to the low crystallite size, increased defect density and distinct morphology, MAL-CTAB displayed the highest specific capacity of 1265 Cg-1 at 2 Ag-1 current density. The study widely explored the synthesis condition, especially the usefulness of surfactant addition during solution combustion synthesis of electrode materials for supercapacitor applications.

Aluminate-based spinel compounds are interesting materials for optical and energy storage devices owing to their exceptional chemical stability, non-toxicity and mechanical strength. However, their performance is limited due to low electrical conductivity. The present work is focused on improving photoluminescence and electrochemical performance of zinc aluminates by doping with small quantities of strontium (Sr). The Zn1-xSrxAl2O4, where x = 0, 0.1, 0.25 and 0.5, compounds were synthesized by solution combustion route. For optimum concentration (x = 0.1), the addition of Sr in spinel lattice not only increased its electrical conductivity but also introduced porosity in its structure. The electrodes were subjected to optical as well as electrochemical testing. For both characterizations, the best results were obtained for 0.1 wt.% Sr addition. Hence, alkali earth metal addition in the zinc aluminate proved promising for functional applications.

This study provides insights into nanocellulose production using 1-butyl-3-methylimidazolium hydrogen sulphate ([Bmim]HSO4) as a green solvent, utilizing cellulose derived from date palm waste. Critical hydrolysis parameters were optimized through analysis of variance and response surface methodology. The predicted nanocellulose yield (Y) followed a quadric equation represented by Y=55.48-0.57pH-0.478ST+0.997T-0.006721T2+0.0681pH×ST-0.0681pH×T+0.003833ST×T. The developed empirical model showed excellent predictive accuracy (R2>0.95). The optimized hydrolysis parameters were pH 1, a temperature of 80 °C, and a stirring time of 45 min, resulting in an 80.5 % yield of nanocellulose. Scanning electron microscopy showed the nanocellulose's needle like morphology, while transmission electron microscopy indicated an average particle size ranging from 50 to 60 nm. Fourier transform infrared spectroscopy confirmed the purity of the nanocellulose by indicating the removal of non-cellulosic components. X-ray diffraction analysis showed a crystallinity index (Crl) of 72.22 %, representing a 67.5 % increase compared to the Crl raw date waste. Dynamic light scattering showed a hydrodynamic diameter of approximately 100 nm. Thermal stability performed using thermogravimetric analysis indicated a high initial degradation temperature (Tonset) of 233 °C, while differential scanning calorimetry confirmed the absence of melting transitions up to 250 °C, underscoring the material's exceptional thermal stability. This study highlights the robust capability of [Bmim]HSO4 to produce high quality nanocellulose from lignocellulose-derived cellulose, broadening its application beyond the previously reported use with microcrystalline cellulose to produce nanocellulose.

This study investigates the structural and thermal properties of cerium-doped soda–lime glasses. A series of glasses with varying CeO2 concentrations (0.6–15 wt.

Supercapacitors are required to store energy from renewable resources to ensure a pollutant-free environment. To further encourage its study, researchers are interested in introducing green methods to produce electrode materials. Green synthesis is an innovative and emerging field because plant extracts are the best substitute for toxic chemicals. They are considered eco-friendly and cost-effective. In this work, two plant extracts, orange juice (ORJ) and lemon juice (LMJ), are used to synthesize the Sr0.8Ce0.2Fe0.8Co0.2O3 perovskite using the auto-combustion method. The electrochemical performance of Sr0.8Ce0.2Fe0.8Co0.2O3 made from LMJ and ORJ is compared to check their effectiveness. LMJ proved to be a better reducing agent than ORJ with a higher specific capacity of 300 C/g (544 F/g) at 1 A/g current density due to increased oxygen vacancies and surface area. These findings show that green-synthesized perovskites can be utilized in high-performance hybrid supercapacitor devices.

Cellulose fiber-based polymer composites are lightweight, eco-friendly, and inexpensive, attributes that make them potential candidates to be used in the automotive, packaging and aerospace industry. Their major drawback is low strength, mainly due to hydrophilic nature of fibers and poor interfacial bonding between fibers and polymers. This work aims to improve strength of cellulose fiber-reinforced unsaturated polyester (UPE) composites by functionalization of fibers and incorporation of small quantities of graphene nanofillers. Functionalized cellulose fibers (FCF) were produced by treating fibers with maleated high oleic sunflower oil (MHOSO) to improve dispersion of fibers in the UPE. Graphene fillers (Graphene oxide [GO], thermally reduced graphene oxide [TRGO], and thermally reduced graphene flakes [TRGF]) were mixed at a concentration of 0.1, 0.2, and 0.5 wt.% in the pure UPE and also in 3 wt.% FCF/UPE composites by three roll mill followed by mechanical stirring to produce single filler and hybrid composites, respectively. The tensile testing results showed that in the case of 0.2 wt.% GO/UPE composite, the tensile strength increased by 48% compared to pure UPE (from similar to 23 to similar to 34 MPa). Hybrid composites with 0.1 wt.% GO and 3 wt.% fibers exhibited similar to 30% higher strength compared to unhybrid FCF/UPE composites. The incorporation of graphene fillers resulted in rough fractured surfaces due to good interfacial bonding of graphene fillers with the matrix as examined by scanning electron microscope (SEM). TGA analysis revealed that all graphene fillers increased degradation temperature of the UPE from 445 degrees C to 470 degrees C. The addition of GO to the FCF/UPE hybrid composites increased their tensile strength, whereas the incorporation of TRGO and TRGF did not enhance the composite strength but improved their thermal properties. Graphene fillers' content higher than 0.1 wt.% in hybrid composites increased viscosity of resin, which leads to more porosity and filler agglomeration, resulting in reduced tensile strength.

Pervious concrete (PC) has been widely employed in parking areas, residential streets, walkways, etc. because it allows water to run through it at a rapid pace, thus reducing runoff from a site and allowing groundwater recharge. The major hindrance in utilizing PC for various applications is its lower compressive strength than conventional concrete. This work employed fillers such as chopped glass fibers (GFs), glass fiber mats, and graphene oxide (GO) to increase the compressive strength of PC without compromising its capability to drain water. The PC samples prepared by incorporating 0.375″ gravels exhibited maximum compressive strength (5.01 MPa) while the PC sample comprised of 6 mm sized chopped GF demonstrated ~1.7 times higher compressive strength than that prepared with GF mats. Furthermore, GO loading of 0.036 wt.% in PC improved the compressive strength by two times compared to the neat PC sample without altering the flow rate of the PC.

In this study, the role of a transition metal complex in improving hydrolysis efficiency during nanocellulose production was analysed. Cellulose nanocrystals (CNCs) were extracted from date seeds by incorporating a copper metal complex during HCl hydrolysis. In contrast to traditional HCl hydrolysis at moderate conditions, which yielded only microcrystalline cellulose (MCC), this approach resulted in the extraction of CNCs with a 10 % improved yield compared to MCC. Morphological analysis using scanning electron microscopy revealed semispherical shaped particles, while transmission electron microscopy showed CNCs with a particle size ranging from 70 to 80 nm. Dynamic light scattering analysis indicated a significant reduction in average particle size from 900 nm to 121 nm, highlighting the remarkable efficiency of using the copper metal complex in combination with HCl to improve yield and particle size. Energy dispersive X-ray spectroscopy analysis confirmed the purity of the CNCs, with no residual copper detected. Thermal analysis demonstrated the high stability of the CNCs, with an initial decomposition temperature (Tonset) of 274.02 degrees C and an activation energy (Ea) of 219.90 kJ/ mol. X-ray diffraction analysis revealed that the CNCs exhibited high degree of crystallinity (Crl=72.03 %). Disseminating these research findings will significantly impact the CNCs production industry, facilitating improved yields and the production of nano-sized fibers through the utilization of transition metal complexes alongside hydrolysis solvents.

A multiphase composite system AgCo3O4/FeMn-O was synthesized using an easy and low-cost solution combustion method for supercapacitor application. The multiphase composite system consisting of Co3O4, alpha-MnO2, and Mn5O8 was identified by X-ray diffraction analysis. The phases were observed as settled on each other in the form of large spherical and hair-like formations in morphological images obtained from scanning electron microscopy. UV-VIS spectroscopy supported the results of variation of band gap energies of Co3O4, alpha-MnO2, and Mn5O8 due to Ag and Fe. Based on Raman spectroscopy, characteristic modes of Co3O4, alpha-MnO2, and Mn5O8 were observed. In electrochemical analysis, the cyclic voltammetry (CV) confirmed the intercalation typepseudocapacitive nature of the prepared composites. Galvanostatic charge-discharge (GCD) analysis showed the highest specific capacitance of 904 F/g obtained from one of the composites at 1 A/g current density. The supercapacitor device was fabricated and showed remarkable cyclic stability of 89 % even after 5000 GCD cycles along with 11.5 Wh/kg energy density and 522 W/kg power density. The good electrochemical performance was attributed to the multiple redox reactions occurred in the bulk of electrode material. Hence, the solution combustion method provides an easy and cost-effective approach to synthesize metal-oxide composites for super- capacitor applications.

Growing demand for chemically resistant, thermally stable, and anti-icing coatings has intensified interest in boron nitride (BN)-based materials and surface coatings. In this study, BN coatings were developed on mild steel (MS) via chemical vapour deposition (CVD) at 1200 °C for 15, 30, and 60 min, and their structural, surface, and water-repellent characteristics were evaluated. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy confirmed the successful formation of BN, while water contact angle measurements indicated high hydrophobicity, demonstrating excellent barrier properties. Scanning electron microscopy (SEM) revealed morphological evolution from flower- and needle-like BN structures in the sample placed in the CVD furnace for 15 min to dense, coral-like, and tubular networks in the samples placed for 30 and 60 min. These findings highlight that BN coatings, particularly the one obtained after 30 min of deposition, have a high hydrophobic character following the Cassie–Baxter model and can be used for corrosion resistance and anti-icing on MS, making them ideal for industrial applications requiring long-lasting protection.

Supercapacitors have emerged as potent energy storage devices for the past few decades. Researchers are putting their best efforts into fabricating a device that offers high capacitance as well as high energy and power density by merging different classes of materials. In this pursuit, polyaniline (PANI) is considered a potential material for supercapacitor electrodes because it offers good conductivity, ease of processing, and the possibility of making composite with other materials. The drawback of PANI is the lack of stability that decreases because of the volumetric changes occurring during redox reactions. On the other hand, TiO2 is considered a good supercapacitor electrode material because it offers high chemical stability, non-toxicity, and low cost. However, the specific capacitance achieved from it is low due to its low conductivity. Herein, we report the TiO2/PANI composite by in-situ chemical oxidative polymerization method to enhance the performance of supercapacitor electrodes through a synergistic effect. An optimal addition of 5 wt.% TiO2 in PANI resulted in high specific capacity of 925 C/g at 1 A/g current density.

This study presents a novel method for nanocellulose production using [Bmim]Cl as a green solvent, with enhanced hydrolysis efficiency achieved through the addition of a transition metal complex as a catalyst. The redox capability of the transition metal complex to break the glycosidic bonds in cellulose is amplified by the addition of an oxidizing agent. This protocol represents the latest innovation in the field of nanocellulose production, resulting in improved yield and reduced particle size. Nanocellulose (NC) was extracted from date seeds using 1-butyl-3-methylimidazolium chloride [Bmim]Cl coupled with a transition metal complex comprising copper metal and pyridine as a ligand along with H2O2 as an oxidizing agent. Unlike conventional [Bmim]Cl hydrolysis, which typically yields only microcrystalline cellulose (MCC), this approach resulted in a 25% higher yield of NC than that of MCC. Dynamic light scattering analysis showed a substantial reduction in hydrodiameter from 1200 nm for MCC to 128.7 nm for NC, highlighting the remarkable efficiency of this process. Thermal analysis demonstrated the high stability of NC, which showed a T onset of 286 degrees C and an activation energy (E-a) of 220.41 kJ/mol. X-ray diffraction analysis indicated that NC possessed a high degree of crystallinity (C-rl = 70.28%). Furthermore, NC underwent modification with 3-aminopropyltriethoxysilane to replace free hydroxyl groups (-OH), making it redispersal and suitable for various applications. This modification was confirmed through Fourier transform infrared spectroscopy, which showed the presence of characteristic functional groups, and energy-dispersive X-ray spectroscopy, which verified the elemental composition. Zeta potential measurements revealed surface charge differences, with MCC at - 27.87 mV, NC at - 27.28 mV, and modified NC at - 44.72 mV, indicating improved colloidal stability after modification. These findings highlight the protocol's effectiveness and its potential impact on the NC production industry, offering improved yields and the production of nanosized fibers using green solvents.

Coating technology has been emerged as a recognized and cost-effective approach in regard to mitigating issues that are linked to corrosion. We employed in-house synthesized boron nitride nanosheets (BNNS-CVD) and commercially available nanosized boron nitride (BN-nano) as fillers in this study to fabricate composite coatings with enhanced thermal stability and corrosion resistance. These fillers were dispersed in polydimethylsiloxane (PDMS) resin to develop composite coatings. The Fourier-transform infrared spectroscopy (FTIR), UV-visible spectroscopy, field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), and electrochemical impedance spectroscopy (EIS) were employed to characterize the prepared composite coatings. The FTIR analysis revealed a prominent absorption band around 1350 cm(-1) that is indication of the distinctive BN in-plane bending vibrations characteristic of boron nitride (BN). The FESEM images simultaneously confirmed the sheet-like morphology of both BN-nano and BNNS-CVD, which both found to be uniformly dispersed in the PDMS matrix. The EIS revealed that the composite films based on BNNS-CVD exhibited superior corrosion resistance compared to those based on BN-nano when exposed to a 3.5 wt% NaCl solution. Further, TGA profiles indicated that the composite films maintained their structural integrity up to 200 degree celsius without degradation. Therefore, thermally stable and corrosion resistant coatings can be valuable for various new technology applications that involve corrosion issues.

Lignin-containing nanocellulose (LNC) is a compelling alternative to traditional nanocellulose (NC), it offers enhanced yields and a reduction in the demand for toxic chemicals. This research involves the isolation of LNC from date palm waste using a green hydrolysis process and its subsequent characterization. The potential of using ionic liquids (ILs) as green solvents to isolate LNC has not yet been explored. Our findings suggest that 1-ethyl-3methylimidazolium chloride ([Emim]Cl) can hydrolyze partially delignified and unbleached lignocellulose, achieving LNC synthesis. The obtained LNC showed a higher yield than its NC counterpart and exhibited rodshaped fibers with nanoscale diameters and micrometer lengths, indicating a high aspect ratio. Dynamic Light Scattering (DLS) results indicate average particle sizes of 143.20 nm for NC and 282.30 nm for LNC, with a narrow particle size distribution conforming their monodisperse behavior. Thermogravimetric analysis and differential scanning calorimetry revealed high thermal stability (initial degradation temperature = 222.50 degrees C and glass transition temperature = 84.45 degrees C) of LNC. Moreover, the obtained LNC fibers were crystalline (crystallinity index = 52.76 %). Their activation energy (124.95 kJ/mol) was determined using the Coats-Redfern method by employing eight solid-state diffusion models. Overall, this study motivates the use of ILs as green solvents to produce lignocellulose derivatives that are suitable for various applications.

Natural deep eutectic solvent (NADES) composed of choline chloride and formic acid was used to fractionate date waste into lignin and cellulose streams. NADES treatment increased the cellulose content from 44 wt% in raw waste (RW) to 72 wt% in extracted cellulose fibers (CFs). Scanning electron microscopy revealed needle-like fibers, underlining the effectiveness of NADES treatment in removing non-cellulosic components. Additionally, the CFs exhibited improved thermal stability, with an initial decomposition temperature () of 265 °C. Kinetic analysis revealed a higher activation energy () of 100.90 kJ/mol for CFs than 63.10 kJ/mol for RW, indicating higher thermal stability due to enhanced cellulose content. Pyrolysis coupled with gas chromatography/mass spectroscopy analyses of CFs showed a lower release of nitrogen compounds and a higher content of hydrocarbons and cyclic ethers, all of which are beneficial for bio-oil production. Overall, the findings of this study will promote the use of NADES as an inexpensive, nontoxic, and recyclable solvent to advance the field of selective pyrolysis.

We report, for the first time, the thorough electrochemical characterization of zinc aluminate spinel. Four different stoichiometric composition of zinc aluminate (ZnAl1.5O3.25, ZnAl2O4, ZnAl2.87O5.30, and ZnAl4O7) were prepared by solution combustion method. The obtained powders after calcination at 1000 degrees C were characterized through scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDX) and x-ray diffraction to analyze the morphology, elemental composition and structure, respectively, of the zinc aluminate compositions. The electrodes were prepared by coating slurry of zinc aluminate, carbon black and polyvinylidene fluoride on nickel foam in a ratio of 8:1:1. The electrochemical characterization was carried out by cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS). ZnAl1.5O3.25 exhibited the highest specific capacity of 546 C/g at 1 mV/s and 336 C/g at 1 A/g, as appraised by CV and GCD analysis, respectively. EIS test revealed that ZnAl1.5O3.25 had the modest impedance value. The energy density value for ZnAl1.5O3.25 sample was 16.79 Wh/kg at 1 A/g with a power density of 179.9 W/kg. The as developed electrodes showed predominantly pseudo-capacitive charge storage mechanism.