This study provides a detailed investigation into the orbital interactions at the LaVO4@g-C3N4 (LACN) interface, highlighting their significant influence on the electronic structure, charge transfer dynamics, and catalytic activity during oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). A series of nanocomposites with different LaVO4 to g-C3N4 ratios were synthesized and characterized using different techniques. Natural Bond Orbital (NBO) analysis was employed to investigate the electronic interactions, revealing prominent charge transfer at intermediates (La-OH and La-OOH sites) during the reactions. These donor-acceptor transitions and electron delocalization effects are interpreted as qualitative descriptors of site preference and charge-transfer trends, correlating with enhanced catalytic performance through intermediate stabilization. The optimized nanocomposite (LaVO4/g-C3N4 in a 5:1 ratio) demonstrated the best catalytic activity, with an onset potential of 1.40V for OER and -0.22V for HER, accompanied by low overpotentials of 300mV vs RHE and 186mV vs RHE at 10mA/cm2, respectively. Electrochemical impedance spectroscopy (EIS) confirmed reduced charge transfer resistance and enhanced conductivity, consistent with the strong orbital interactions identified through NBO analysis. The synergistic interplay between LaVO4 and g-C3N4 facilitated efficient electron transport, leading to superior catalytic kinetics. These findings highlight the role of electronic structure modulation via orbital interactions for understanding and optimizing the electrocatalytic performance of the materials.

In this study, we demonstrate that the optimized incorporation of Cr into Mn-Fe containing mixed oxides effectively tailors the redox activity of the Mn and Fe centers for enhanced alkaline water splitting. This incorporation of Cr is precisely achieved through a facile controlled co-precipitation route yielding compositionally tuned Cr-Mn-Fe mixed oxides. The structural characteristics of the synthesized materials were verified via XRD, FTIR, and Raman spectroscopy. XRD analysis revealed that the synthesized materials are primarily composed of rhombohedral alpha-Fe2O3, while additional weak reflections in Cr-containing samples suggest the possible presence of Cr2O3 related secondary phases. Morphological evolution from dense agglomerated grains (F1N) to porous nanostructures (F4N) enhances electroactive surface exposure, while XPS confirms mixed-valence states of Fe2+/Fe3+, Mn2+/Mn3+, and Cr3+, facilitating synergistic redox coupling. Electrochemical evaluations in 1.0 m KOH reveal that the optimized F3N catalyst exhibits improved bifunctional activity, requiring remarkably low overpotentials of 0.28 V for the oxygen evolution reaction (OER) and 0.23 V for the hydrogen evolution reaction (HER) at 10 mA/cm2. The corresponding Tafel slopes of 37.64 mV/dec (OER) and 35.00 mV/dec (HER) indicate accelerated charge-transfer kinetics. Furthermore, the F4N catalyst also demonstrates improved long-term durability, retaining 90.87% of its catalytic current density under continuous operation.

This study explores the electrocatalytic behaviour of MoS2@WO3 nanocomposites towards potential electrochemical energy storage (EES) and oxygen evolution reaction (OER) in alkaline medium. The global transition towards sustainable and renewable energy devices imposes effective EES technologies, among which supercapatteries display high power density, energy density, and good cycling stability. This work highlights the promising attributes of the MoS2@WO3 (2:1) nanocomposite, which was subjected to thorough electrochemical evaluation in 1 M KOH electrolyte. It achieved a remarkable specific capacitance of 1058.35F g- 1 at 1 A g- 1. It also attained the maximum energy density of 26.88 Wh kg- 1 and power density of 1590.43 W kg- 1 at 2 A g- 1 and 10 A g- 1, respectively. A supercapattery device, MoS2@WO3 (2:1)||AC, demonstrated an impressive capacity and energy density of 606.60 mA h g- 1, 715.21 W h kg- 1 at 2 A g- 1. It also delivered a high power density of 6374.13 W kg- 1 at 5 A g- 1. Additionally, the study emphasizes the significance of MoS2@WO3 (2:1) as a promising OER electrocatalyst, demonstrating outstanding current densities of 10 mA cm- 2, 50 mA cm- 2 and 100 mA cm- 2 at low overpotentials of 272.6 mV, 329.7 mV and 358.8 mV vs RHE, respectively. Comprehensive characterization of the charge-transfer dynamics underpinning these enhanced performances was carried out, which delivers insights into the material composition and architecture that contribute to its efficiency. The findings underscore the potential of MoS2@WO3 nanocomposites for future applications in energy storage and conversion technologies towards more sustainable energy solutions.

In this study, a high-entropy oxide (CaCu3Ti3.85Mn0.05Sn0.1O12) was synthesized via a semi-wet route, playing a crucial role in advancing multifunctional electrocatalysis. Pre- and post-XPS analyses revealed synergistic interactions among the multi-cation species, while Raman spectroscopy indicated enhanced crystallinity and atomic stabilization. HR-TEM/SEM/EDS and elemental mapping confirmed a homogeneous composition, characterized by densely agglomerated clusters intertwined with thread-like crystalline structures that promote redox transitions and facilitate active-oxygen participation. The HEO electrode exhibited a high specific capacitance of 681.3 F g-1 at 1 A g-1, along with an energy density of 17.5 Wh kg-1 and a power density of 214.2 W kg-1 at the same current density. Furthermore, the material demonstrated outstanding bifunctional electrocatalytic performance in water splitting, achieving a low overpotential of 130 mV vs. RHE at 10 mA cm-2 with a Tafel slope of 83.3 mV dec-1 for the OER, and 201 mV vs. RHE with a Tafel slope of 185.7 mV dec-1 for the HER. Detailed investigations of charge-transfer dynamics provided insight into the structure-performance relationship, supported by thermodynamic and kinetic analyses to determine the activation enthalpy and reaction order. Overall, the study highlights the immense promise of HEOs for integrated energy-storage and conversion applications, contributing to the development of sustainable energy technologies.

Thiospinels are sulfur-containing transition metal materials that have exceptional electrochemical competence, making them practical for widespread electrochemical applications. In this study, we successfully synthesized NiCo2S4, reduced graphene oxide (rGO), and their nanocomposite, NiCo2S4@rGO (in ratios 3:1, 1:1 and 1:3), at low temperatures. We comprehensively characterized the synthesised materials using advanced physicochemical techniques, viz. Powder X-ray Diffraction (PXRD), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM)-Energy Dispersive X-ray Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Selected Area Electron Diffraction (SAED) and BrunauerEmmett-Teller (BET). The electrochemical performance of these materials is rigorously evaluated in a threeelectrode cell setup using 1 M aqueous KOH electrolyte. The NiCo2S4@rGO (3:1) nanocomposite significantly outperforms its components, achieving an impressive specific capacitance of 1063.25F.g- 1 at 2 A.g- 1, along with an energy density of 26.73 Wh.kg- 1 and a power density of 425.59 W.kg- 1 at the same current density. Even at a high current density of 5 A.g- 1, it maintains an energy density of 13.03 Wh.kg- 1 and a power density of 970.58 W.kg- 1. Moreover, we observe a Tafel slope of 113.4 mV.dec-1 derived from the LSV experiment for the 3:1 nanocomposite. It requires a low overpotential of 288.5 mV vs RHE to achieve a current density of 50 mA.cm- 2, confirming its potential as a superior Oxygen Evolution Reaction (OER) electrocatalyst. The enhanced electrochemical activity of the NiCo2S4@rGO (3:1) nanocomposite results from the synergistic effects of combining pristine NiCo2S4 with rGO. This makes the NiCo2S4@rGO (3:1) nanocomposite an outstanding candidate for EES applications and OER electrocatalysis.

High-entropy oxide (CaCu 3 Ti 3.85 Mn 0.05 Sn 0.1 O 12 ) was synthesized via a semi-wet route as a electrocatalyst for supercapattery and water electrolysis.

This study presents a strategic enrichment of graphitic carbon nitride (g-C3N4) through targeted doping with phosphorus (P), boron (B), and sulphur (S) to boost its electrocatalytic efficiency for water splitting and supercapacitor applications. The g-C3N4 matrix was synthesized via thermal polymerization of melamine, with dopants introduced in the solution phase. Comprehensive characterization techniques including FTIR, Raman spectroscopy, XPS, Rietveld refined XRD, SEM/EDX, and HRTEM reveal that doping induces profound vibrational, electronic, and structural transformations such as lattice expansion, defect generation, and the formation of hierarchical porosity. Among the dopants, phosphorus-doped carbon nitride (CNP) exhibits superior electrocatalytic activity, demanding overpotentials of only 250 mV and 223 mV (vs RHE) @10 mA/cm2 for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) respectively, alongside Tafel slopes of 76.9 mV/dec (OER) and 118.8 mV/dec (HER). Moreover, CNP again demonstrates outstanding capacitive properties, achieving a high specific capacitance of 420.06 F/g (at 20 mV/s), energy density of 28.58 Wh/kg, and power density of 2940.42 W/kg and predominating the capacitive charge storage mechanism. Furthermore, the order of the reaction with respect to OH- ions, underscores the pivotal role of surface-controlled processes in driving OER activity. The enhanced electrocatalytic active is further validated the rapid charge transfer characteristics of CNP using EIS technique (Rct approximate to 2.5 Omega). Collectively, these findings highlight phosphorus doping as a powerful strategy to tailor the morphological, structural, and electronic properties of g-C3N4, positioning it as a highly promising candidate for next-generation energy storage and conversion technologies.

Perovskite-type oxides having composition LaxSm0.8-xSr0.2NiO3 (0 <= x <= 0.6) were explored for their ability to act as facilitators for oxygen evolution reaction (OER) in alkaline media. Synthesis of the materials was conducted through a sol-gel procedure via malic acid. The materials underwent advanced physicochemical characterization utilizing techniques, namely transmission electron microscope (TEM), scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDS), inductively coupled plasma - mass spectrometry (ICP-MS) and X-ray diffraction (XRD). These analyses provided crucial details about the material's particle size, surface morphology/chemical composition and crystalline structure, opening up exciting possibilities for their diverse applications. From TEM analysis, the average particle size of the oxide materials has been estimated and found to be 5.9 nm for Sm0.8Sr0.2NiO3 and 4.8 nm for La0.6Sm0.2Sr0.2NiO3. The particle size of the oxide material decreases when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. Cyclic voltammetry and Tafel plot were observed for the electrochemical analysis in 1 M KOH (25 degrees C). An investigation on the anodic polarization of oxides revealed an increased electrocatalytic activity when La was partially substituted for Sm in Sm0.8Sr0.2NiO3. La0.6Sm0.2Sr0.2NiO3 was found to be most active at 800 mV with a current density, j = 184.1 mA/cm2. The Tafel experiment was conducted in 1M KOH at varying temperatures to determine thermodynamic properties like standard electrochemical energy of activation (Delta Hel degrees#$\Delta H_{{\mathrm{el}}}<^>{<^>\circ \# \ }$), standard enthalpy of activation (Delta H degrees#), and standard entropy of activation (Delta S degrees#).

This research explores the effect of optimizing molar ratios in a series of innovative nanocomposites to enhance their electrocatalytic performance for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline environments using molecular engineering of the two components. The study involved the synthesis of a novel nanocomposite consisting of carbon nitride (C3N4) and meso-Ni0.5Co2.5O4 using the simplest feasible route with systematic variations in their molar ratios. Comprehensive physicochemical characterization, including Rietveld refinement, provided detailed insights into the crystal structure, phase purity, morphology, and electronic properties. The electrochemical tests provide evidence in favor of the nanocomposite with a 1:2 molar ratio for its outstanding electrocatalytic activity, requiring only 253 mV (Vs RHE) overpotential for 10 mA/cm2 during OER and 198 mV (Vs RHE) for 10 mA/cm2 during HER in 1 M KOH at 25 degrees C. Thermodynamic and kinetic analyses were conducted to determine the enthalpy of activation and reaction order to substantiate the electrochemical performance. The results highlight the significance of precise molar ratio optimization in developing high-performance electrocatalysts. This investigation demonstrates superior catalytic activity and provides a comprehensive understanding of the thermodynamic and kinetic factors influencing electrocatalytic performance, laying the groundwork for more efficient hydrogen generation technologies.

Hydrothermally synthesized layered nanocomposite of MoS 2 and rGO (1 : 2.4) exhibited efficacious electrocatalytic behaviour towards supercapattery and OER due to the nanoarchitectural finesse of the material. The impact of MoS 2 : rGO ratio has also been discussed in detail.

The electrochemical properties of spinel oxide-spinel oxide composites [NiCo2O4-Mn1-xCrxCo2O4 (x = 0.2, 0.6, 0.8)] with regard to oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) have been investigated. Co-precipitation and sol–gel techniques were utilized to synthesize the materials. Fourier-transform infrared (FTIR) spectroscopy, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) were employed to analyse the physicochemical properties of the synthesized materials. Electrochemical examinations such as cyclic voltammetry (CV) and Tafel experiment were performed in 1 M KOH with and without methanol at 25 °C. The electrocatalytic performance of the materials was assessed via anodic polarization curves and NiCo2O4-Mn0.2Cr0.8Co2O4 was found to be most active towards the OER (j = 33.5 mAcm−2) and NiCo2O4-Mn0.8Cr0.2Co2O4 was found to be most active towards the MOR (j = 74.3 mAcm−2) at 750 mV. The electrodes’ durability was investigated using chronoamperometric studies and electrochemically active surface area (ECSA) evaluations using Electrochemical Impedance Spectroscopy (EIS) offered further understanding into the enhancement in electrocatalytic activity. From the EIS experiment, the roughness factor for NiCo2O4-Mn0.8Cr0.2Co2O4 and NiCo2O4-Mn0.2Cr0.8Co2O4 was calculated and found to be 6.48 22.48, respectively in 1 M KOH. Using chronoamperometry experiment, the retained current ( Δ H_el^∘# at 650 mV for OER and the nanocomposite NiCo2O4-Mn0.6Cr0.4Co2O4 demands only 45 kJ mol−1 of Δ H_el^∘# at 550 mV for MOR.

Rocks in arid to semi-arid regions all over the world have a naturally occurring coating called “rock varnish” or “desert varnish” on their surface. These lustrous, black-to-brown mesoscopic coatings on rocks have long piqued the interest of scholars from a wide range of disciplines. However, there are gaps in our understanding, particularly in relation to the formation of rock varnish. Rock varnish development is supported by competing evidence from the biotic and abiotic schools of thought. In the current investigation, we advance and support a previous polygenetic model by proposing that biotic and abiotic factors collaborate to form these microscopic coatings on the rock surfaces. Physicochemical evidences in this work points toward a new perspective, citing an initial abiotic triggering event followed by biotic processes.

CoFe2O4–La1−xSrxCoO3 (x = 0.2, 0.6, 0.8) composites have been synthesized using a two‐step, low‐temperature wet chemical approach that combines coprecipitation and sol–gel techniques. The composite materials have been physicochemically analyzed using Fourier‐transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscope. The electrocatalytic properties of the composite materials have been assessed in terms of their performance in oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) in alkaline medium. Cyclic voltammetry has been used for analyzing the redox behavior of the materials in 1 M KOH solution. The electrocatalytic activity of the materials has been assessed using anodic polarization curves on Ni substrate and the CoFe2O4–La0.2Sr0.8CoO3 film electrode demonstrates excellent activity, with current densities of 11.1 mA cm−2 for OER and 47.4 mA cm−2 for MOR at 650 mV. Also, the CoFe2O4–La0.2Sr0.8CoO3 film electrode has the maximum specific activity of 1.1 × 103 mA cm−2 g−1 at 650 mV toward OER. The electrodes’ stability has been assessed through chronoamperometric experiments and additional insight into the enhancement of electrocatalytic activity gained through the electrochemical surface area estimations using electrochemical impedance spectroscopy. From chronoamperometric experiment, it has been observed that the CoFe2O4–La0.2Sr0.8CoO3 film electrode attains stability within 114 s with a current density of 108.7 mA cm−2. Furthermore, the thermodynamic parameters, including the standard enthalpy of activation (ΔH°#), standard entropy of activation (ΔS°#), and standard electrochemical energy of activation (), have been estimated by anodic polarization curve recorded in KOH as well as KOH with CH3OH solutions at various temperatures.

Rock varnish, a dark-coloured natural feature rich in manganese (Mn), iron (Fe), and clay minerals that forms on rock surfaces and subsurface rock fractures in extremely dry and cold environments, is believed to provide nutritional support to microbiota. Because varnish supports an extensive microbial community, this rock coating is considered a substrate for potential microbial life to thrive in extreme environments on Earth. Although research in the past decades have advanced understanding of the varnish microbiome, little is known about this microbial community in settings that are high altitude (lower oxygen), dry, and cold. We present here new morphological, chemical, and rock magnetic results of rock varnish from this environmental setting, the Ladakh, a potential analogue site for life in extreme environments. Our results include the presence of putative magnetofossils-in the form of nanochains present in the rock varnish layer. Further, the higher concentrations of oxidised Mn4+ and carboxylic acid functionality on the varnish surface revealed organic signatures. These collective results point towards the enriched concentration of magnetic minerals on the varnish layer that are possibly sourced through biotic forms. Consequently, the rock varnish can serve as an archive of ancient environmental records, as well as a potential geomaterial for astrobiological studies from the Martian analogue field location of Ladakh, which needs to be explored further for extensive biogeochemical studies.

Plant gums are useful excipient materials for preparation of different health care formulations. Gums are generally carbohydrates, which consist of long chain polysaccharides. Traditionally, plant gums have been utilized for preparation of different drug delivery systems. A. nilotica seed has nutritional and ethnobotanical values, which has been traditionally used as food and folk medicine. Thus, the purpose of this study was separation of A. nilotica seed endosperm and isolation of endospermic gum for exploration of their physicochemical properties. Result revealed that isolated endospermic gum was amorphous in nature based on SEM and XRD analysis. Elements C, K and Mg were found to be attached on gum surface in EDS analysis pH, tapped and true density were found to be closer in seed endosperm and their isolated gum. Hygroscopicity, water holding capacity, porability, swelling index, angle of repose and porosity were enhanced in isolated gum. Tensile strength and viscosity of isolated gum i.e., 60.93 mN.m-1-1 and 5-200 cP respectively, were increased as compared to seed endosperm i.e., 55.73 mN.m-1-1 and 4-100 cP respectively. Thus, isolated endospermic gum was found to be suitable in terms of physicochemical properties and may be used as plant based safe, non-toxic and eco-friendly excipient material in pharmaceutical applications.

CoFe2O4-LaCoO3 was synthesized employing a two-step, low-temperature wet chemical method involving co-precipitation and sol-gel techniques. The co-precipitation process was employed to prepare CoFe2O4, with pH regulation at 11 using NaOH solution. Subsequently, CoFe2O4-LaCoO3 was synthesized via sol-gel process. The synthesized materials were subjected to physicochemical analysis using Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The electrocatalytic properties of these materials were evaluated in terms of their performance towards oxygen evolution reaction (OER) and methanol oxidation reaction (MOR) in alkaline medium. The redox behaviour of the materials was characterized through cyclic voltammetry analysis in 1M KOH solution. The electrocatalytic activity of the materials, when assessed using anodic polarization curves revealed that CoFe2O4-LaCoO3 exhibited higher activity, with current densities of 1.6 mA cm(-2) for OER and 9.2 mA cm(-2) for MOR recorded at 650 mV. Further, the thermodynamic parameters like standard enthalpy of activation (Delta H-degrees#), standard entropy of activation (Delta S-degrees#) and standard electrochemical energy of activation (Delta H-el(degrees#)) were calculated by recording anodic polarization curve in KOH as well as KOH with CH3OH solutions at various temperatures. The findings presented in this study demonstrate the promising electrocatalytic performance of CoFe2O4-LaCoO3 film electrode for applications in OER and MOR under alkaline condition.