Novel modeling and optimization framework for Navy Blue adsorption onto eco-friendly magnetic geopolymer composite.

The disproportionate potency of dyes in textile wastewater is a global concern that needs to be contended. The present study comprehensively investigates the adsorption of Navy-Blue dye (NB) onto bentonite clay based geopolymer/Fe3O4 nanocomposite (GFC) using novel statistical and machine learning frameworks in the following steps; (1) synthesis and characterization of GFC, (2) experimental testing and modelling of NB adsorption onto GFC following Box-Behnken design and three response surface prediction models namely stepwise regression analysis (SRA), Support vector regression (SVR) and Kriging (KR), (3) parametric, sensitivity, thermodynamic and kinetic analysis of pH, GFC dose and contact time on adsorption performance, and (4) finding global parametric solution of the process using Latin Hypercube, Sobol and Taguchi orthogonal array sampling and combining SRA-SVR-KR predictions with novel hybrid simulated annealing (SA)-desirability function (DF) approach. Under the given testing range, parametric/sensitivity analysis revealed the critical role of pH over others accounting ∼37% relative effect and primarily derived the NB adsorption. The statistical evaluation of models revealed that all models could be utilized for elucidating and predicting the NB removal using GFC, however, SVR accuracy was better among others for this particular work, as the overall computed root mean squared error was only 0.55 while the error frequency counts remained <1 for 90% predictions. GFC showed 86.29% NB removal for the given experimental matrix which can be elevated to 96.25% under optimum conditions. The NB adsorption was found to be physical, spontaneous, favorable and obeyed pseudo-2nd order kinetics. The results demonstrate the suitability of GFC as the promising cost-effective and efficient alternative for the decolourization of urban and drinking water streams and elucidate the potential of machine learning models for accurate prediction & elevation of adsorption processes with less experimentation in water purification applications.

Structure and Magnetic Properties of Melilite-Type Compounds RE2Be2GeO7 (RE = Pr, Nd, Gd-Yb) with Rare-Earth Ions on Shastry-Sutherland Lattice.

Rare-earth (RE)-based frustrated magnets, such as typical systems of combining strong spin-orbit coupling (SOC), geometric frustration, and anisotropic exchange interaction, can give rise to diverse exotic magnetic ground states such as quantum spin liquid. The discovery of new RE-based frustrated materials is crucial for exploring the exotic magnetic phases. Herein, we report the synthesis, structure, and magnetic properties of a family of melilite-type RE2Be2GeO7 (RE = Pr, Nd, and Gd-Yb) compounds crystallized in a tetragonal P4̅21m structure, where magnetic RE3+ ions lay out on the Shastry-Sutherland lattice (SSL) within the ab plane and are well separated by nonmagnetic [GeBe2O7]6- polyhedrons along the c-axis. Temperature (T)-dependent susceptibilities χ(T) and isothermal magnetization M(H) measurements reveal that most RE2Be2GeO7 compounds except RE = Tb show no magnetic ordering down to 2 K despite the dominant antiferromagnetic (AFM) interactions, where Tb2Be2GeO7 undergoes AFM transition with Néel temperature TN ∼ 2.5 K and field-induced spin flop behaviors (T < TN). In addition, the calculated magnetic entropy change ΔSm from the isothermal M(H) curves reveals viable magnetocaloric effect for RE2Be2GeO7 (RE = Gd and Dy) in liquid helium temperature regimes; Gd2Be2GeO7 shows the maximum ΔSm up to 54.8 J K-1 kg-1 at ΔH = 7 T and Dy2Be2GeO7 has the largest value ΔSm = 16.1 J K-1 kg-1 at ΔH = 2 T in this family. More excitingly, the rich diversity of RE ions in this family enables an archetype for exploring exotic quantum magnetic phenomena with large variability of spin located on the SSL lattice.

Elucidating the performance of hexamethylene tetra-amine interlinked bimetallic NiCo-MOF for efficient electrochemical hydrogen and oxygen evolution.

Bimetallic metal-organic frameworks (MOFs) play a significant role in the electrocatalysis of water due to their large surface area and availability of increased numbers of pores. For the inaugural time, we examine the effectiveness of a hexamethylene tetra-amine (HMT)-induced 3D NiCo-MOF-based nanostructure as a potent bifunctional electrocatalyst with superior performance for overall water splitting in alkaline environments. The structural, morphological, and electrochemical properties of the as-synthesized bifunctional catalyst were examined thoroughly before analyzing its behavior towards electrochemical water splitting. The HMT-based NiCo-MOF demonstrated small overpotential values of 274 mV and 330 mV in reaching a maximum current density of 30 mA cm-2 for hydrogen and oxygen evolution mechanisms, respectively. The Tafel parameter also showed favorable HER/OER reaction kinetics, with slopes of 78 mV dec-1 and 86 mV dec-1 determined during the electrochemical evaluation. Remarkably, the NiCo-HMT electrode exhibited a double-layer capacitance of 4 mF cm-2 for hydrogen evolution and 23 mF cm-2 for oxygen evolution, while maintaining remarkable stability even after continuous operation for 20 hours. This research offers a valuable blueprint for implementing a cost-effective and durable MOF-based bifunctional catalytic system that has proven to be effective for complete water splitting. Decomposition of water under higher current densities is crucial for effective long-term generation and commercial consumption of hydrogen.

Magnesium Magic: State-of-the-Art Nanocrystalline Materials Paving the Way for Hydrogen Storage.

Hydrogen has been regarded as a promising alternative to traditional fossil fuels, presenting itself as a viable and environmentally friendly energy choice. The design and fabrication of highly efficient hydrogen storage materials is crucial to the wide utilization of hydrogen-based technologies. Magnesium-based nanocrystalline materials have received significant interest in the field of hydrogen storage due to their remarkable hydrogen storage capabilities and release efficiency. This review emphasizes on the most useful techniques including vapor deposition, sol-gel synthesis, electrochemical deposition, magnetron sputtering, and template-assisted approaches used for the fabrication of Magnesium-based nanocrystalline hydrogen storage materials (Mg-NHSMs), stressing their advantages, limitations, and recent advancements. These cutting-edge techniques demonstrate their significance in offering useful insights into the performance of Mg-NHSMs. Further, this review describes various applications of Mg-NHSMs. In addition, this review highlights the conclusion and future perspectives on the improvement of magnesium based nanocrystalline materials for efficient hydrogen storage.

Tailoring NiCoCu layered double hydroxide with Ag-citrate/polyaniline/functionalized SWCNTs nanocomposites for supercapacitor applications.

Supercapacitors have substantially altered the landscape of sophisticated energy storage devices with their exceptional power density along with prolonged cyclic stability. On the contrary, their energy density remains low, requiring research to compete with conventional battery storage devices. This study addresses the disparities between energy and power densities in energy storage technologies by exploring the integration of layered double hydroxides (LDH) and highly conductive materials to develop an innovative energy storage system. Four electrodes were fabricated via a hydrothermal process using NiCoCu LDH, Ag-citrate, PANI, and f-SWCNTs. The optimal electrode demonstrated exceptional electrochemical properties; at 0.5 A g-1, it possessed specific capacitances of 807 F g-1, twice as high as those of the pure sample. The constructed asymmetric supercapacitor device attained energy densities of 62.15 W h kg-1 and 22.44 W h kg-1, corresponding to power densities of 1275 W kg-1 and 11 900 W kg-1, respectively. Furthermore, it maintained 100% cyclic stability and a coulombic efficiency of 95% for 4000 charge-discharge cycles. The concept of a supercapacitor of the hybrid grade was reinforced by power law investigations, which unveiled b-values in the interval of 0.5 to 1. This research emphasizes the considerable potential of supercapacitor-grade NiCoCu LDH/Ag-citrate-PANI-f-SWCNTs nanocomposites for superior rate performance, robust cycle stability, and enhanced energy storage capacity.

Enhancing supercapacitor performance of Ni-Co-Mn metal-organic frameworks by compositing it with polyaniline and reduced graphene oxide.

Metal-organic frameworks (MOFs) are one of the most sought-after materials in the domain of supercapacitors and can be tailored to accommodate diverse compositions, making them amenable to facile functionalization. However, their intrinsic specific capacitance as well as energy density is minimal, which hinders their usage for advanced energy storage applications. Therefore, herein, we have prepared six electrodes, i.e., Ni-Co-Mn MOFs, polyaniline (PANI), and reduced graphene oxide (rGO) along with their novel nanocomposites, i.e., C1, C2, and C3, comprising MOFs : PANI : rGO in a mass ratio of 100 : 1 : 0.5, 100 : 1 : 1, and 100 : 1 : 10, respectively. The polyaniline conducting polymer and rGO enabled efficient electron transport, enhanced charge storage processes, substantial surface area facilitating higher loading of active materials, promoting electrochemical reactions, and ultimately enhanced nanocomposite system performance. As a result, scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques confirmed the successful synthesis and revealed distinct morphological features of the materials. Following electrochemical testing, it was observed that composition C2 exhibited the highest performance, demonstrating a groundbreaking specific capacitance of 1007 F g-1 at 1 A g-1. The device showed a good energy density of 25.11 W h kg-1 and a power density of 860 W kg-1. Remarkably, the device demonstrated a capacity retention of 115% after 1500 cycles, which is a clear indication of the wettability factor, according to the literature. The power law indicated b-values in a range of 0.58-0.64, verifying the hybrid-type behavior of supercapacitors.

Advancements in Biomass-Derived Activated Carbon for Sustainable Hydrogen Storage: A Comprehensive Review.

The increasing global energy demand, which is being driven by population growth and urbanization, necessitates the exploration of sustainable energy sources. While traditional energy generation predominantly relies on fossil fuels, it also contributes to alarming CO2 emissions. Hydrogen has emerged as a promising alternative energy carrier with its zero-carbon emission profile. However, effective hydrogen storage remains a challenge. When exposed to hydrogen, conventional metallic vessels, once considered to be the primary hydrogen carriers, are prone to brittleness-induced cracking. This has spurred interest in alternative storage solutions, particularly porous materials like metal-organic frameworks and activated carbon (AC). Among these, biomass-derived AC stands out for its eco-friendly nature, cost-effectiveness, and optimal adsorption properties. This review offers a comprehensive overview of recent advancements in the synthesis, characterization, and hydrogen storage capabilities of AC. The unique benefits of biomass-derived sources are highlighted, as is the pivotal role of chemical and physical activation processes. Furthermore, we identify existing challenges and propose future research directions in AC-based hydrogen storage. This compilation aims to serve as a foundation for potential innovations in sustainable hydrogen storage solutions.

Polymer Matrix Nanocomposites with 1D Ceramic Nanofillers for Energy Storage Capacitor Applications.

Recent developments in various technologies, such as hybrid electric vehicles and pulsed power systems, have challenged researchers to discover affordable, compact, and super-functioning electric energy storage devices. Among the existing energy storage devices, polymer nanocomposite film capacitors are a preferred choice due to their high power density, fast charge and discharge speed, high operation voltage, and long service lifetime. In the past several years, they have been extensively researched worldwide, with 0D, 1D, and 2D nanofillers being incorporated into various polymer matrixes. However, 1D nanofillers appeared to be the most effective in producing large dipole moments, which leads to a considerably enhanced dielectric permittivity and energy density of the nanocomposite. As such, this Review focuses on recent advances in polymer matrix nanocomposites using various types of 1D nanofillers, i.e., linear, ferroelectric, paraelectric, and relaxor-ferroelectric for energy storage applications. Correspondingly, the latest developments in the nanocomposite dielectrics with highly oriented, surface-coated, and surface-decorated 1D nanofillers are presented. Special attention has been paid to identifying the underlying mechanisms of maximizing dielectric displacement, increasing dielectric breakdown strength, and enhancing the energy density. This Review also presents some suggestions for future research in low-loss, high energy storage devices.