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Perovskites are bringing revolutionization in a various fields due to their exceptional properties and crystalline structure. Most specifically, halide perovskites (HPs), lead-free halide perovskites (LFHPs), and halide perovskite quantum dots (HPs QDs) are becoming hotspots due to their unique optoelectronic properties, low cost, and simple processing. HPs QDs, in particular, have excellent photovoltaic and optoelectronic applications because of their tunable emission, high photoluminescence quantum yield (PLQY), effective charge separation, and low cost. However, practical applications of the HPs QDs family have some limitations such as degradation, instability, and deep trap states within the bandgap, structural inflexibility, scalability, inconsistent reproducibility, and environmental concerns, which can be covered by encapsulating HPs QDs into porous materials like metal-organic frameworks (MOFs) or covalent-organic frameworks (COFs) that offer protection, prevention of aggregation, tunable optical properties, flexibility in structure, enhanced biocompatibility, improved stability under harsh conditions, consistency in production quality, and efficient charge separation. These advantages of MOFs-COFs help HPs QDs harness their full potential for various applications. This review mainly consists of three parts. The first portion discusses the perovskites, halide perovskites, lead-free perovskites, and halide perovskite quantum dots. In the second portion, we explore MOFs and COFs. In the third portion, particular emphasis is given to a thorough evaluation of the development of HPs QDs@MOFs-COFs based materials for comprehensive investigations for next-generation materials intended for diverse technological applications, such as CO2 conversion, pollutant degradation, hydrogen generation, batteries, gas sensing, and solar cells. Finally, this review will open a new gateway for the synthesis of perovskite-based quantum dots.
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Molybdenum trioxide (MoO3) is an attractive semiconductor. Thus, bandgap engineering toward photoelectronic applications is appealing yet not well studied. Here, we report the incorporation of sulfur atoms into MoO3, using sulfur powder as a source of sulfur, via a self-developed hydrothermal synthesis approach. The formation of Mo-S bonds in the MoO3 material with the synergistic effect of sulfur doping and oxygen vacancies (designated as S-MoO3-x) is confirmed using Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The bandgap is tuned from 2.68 eV to 2.57 eV upon sulfur doping, as confirmed by UV-VIS DRS spectra. Some MoS2 phase is identified with sulfur doping by referring to the photoluminescence (PL) spectra and electrochemical impedance spectroscopy (EIS), allowing significantly improved charge carrier separation and electron transfer efficiency. Therefore, the as-prepared S-MoO3-x delivers a sensitive photocurrent response and splendid cycling stability. This study on the synergistic effect of sulfur doping and oxygen vacancies provides key insights into the impact of doping strategies on MoO3 performance, paving new pathways for its optimization and development in relevant fields.
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In this paper, undoped and copper-doped ZnO nanoparticles (NPs) were successfully synthesized using a gliding arc discharge (GAD) plasma technique, which is a sustainable, cost-effective, and scalable method. This method offers several advantages over traditional synthesis methods. The synthesized NPs were characterized by various techniques to understand their physicochemical properties. XRD analysis confirmed the presence of characteristic peaks of pure ZnO, while doped samples exhibited additional peaks corresponding to CuO crystal planes, indicating the successful incorporation of Cu into the lattice. As obvious, bare ZnO showed absorption peak at 378 nm corresponding to the band gap of 3.21 eV. The band gap of Cu-doped samples increased systematically, i.e., 3.35 eV for 2% Cu, 3.47 eV for 4% Cu, and 3.66 eV for 6% Cu. SEM images revealed aggregation and increase in particle size with the increasing in Cu concentration. EDAX analysis revealed a decrease in the weight percentage of oxygen and zinc with the increase in Cu concentration, suggesting structural changes within the lattice. Furthermore, the antibacterial activity against Gram-positive and Gram-negative bacteria, antioxidant activity, and photocatalytic activity against three different organic dyes such as Brilliant Cresyl Blue (BCB), Methylene Blue (MB), and Congo Red (CR) was studied. It is found that the photocatalytic activity of ZnO NPs varies with Cu concentration, leading to a decrease in its performance. The antibacterial activity of the NPs was also assessed, with undoped ZnO NPs showing dose-dependent effects against bacteria, while the Cu-doped ZnO NPs exhibited decreased efficacy. Interestingly, Cu doping significantly enhanced the antioxidant activity of the NPs compared to the undoped ZnO.
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Antibacterianos , Antioxidantes , Cobre , Óxido de Zinc , Óxido de Zinc/química , Cobre/química , Antibacterianos/farmacología , Antibacterianos/química , Antioxidantes/química , Catálisis , Nanopartículas del Metal/química , Nanopartículas/químicaRESUMEN
Nile blue (NB) dye is a highly toxic substance that when discharged into sewage presents a significant risk to the environment and human health. Carbon-based nanomaterials, such as graphene oxide (GO), reduced graphene oxide (rGO), and their nanocomposites, offer considerable potential for eliminating hazardous pollutants from aqueous systems. In this study, we have successfully fabricated bare GO and rGO, and then, the rGO was decorated with silver (Ag) nanoparticles to develop the Ag-rGO composite. The as-prepared materials were characterized by various techniques, such as UV-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopies, X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and scanning electron microscopy (SEM) to elucidate their structure, morphology, and chemical composition. The pollutant removal performance of the as-prepared materials was evaluated through a batch approach under the effect of various experimental variables for removal of NB dye from wastewater. As obvious, the Ag-rGO composite revealed exceptional performance for NB dye removal from wastewater, with a maximum removal percentage of 94% within 60 min, which is remarkably higher than those of the rGO (i.e., 59%) and GO (i.e., 22%), under the same experimental conditions. The adsorption data was analyzed with thermodynamics, isotherms, and kinetics models to better understand the physicochemical mechanisms driving the effective removal of the NB dye. The results reveal that Ag-rGO nanocomposite exhibit excellent adsorption ability as well as favorable thermodynamic and kinetic parameters for NB dye removal. It was also found that the presence of light enhanced the adsorptive removal of NB while using Ag-rGO as an adsorbent. The present study noted significant reusability of the Ag-rGO nanocomposite, likely due to minimal Ag leaching and/or the robust stability of the Ag-rGO. It is suggested that Ag-rGO-based hybrid materials could serve as promising candidates for efficiently adsorbing and catalytically removing various toxic pollutants from wastewater.
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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.
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Herein, we present a novel approach for the synthesis of ZnO nanoparticles (ZnO NPs) using a non-thermal plasma source generated by the gliding arc discharge-air system. The effect of discharge time on the physical and optical properties, as well as the photocatalytic performance of the as-fabricated ZnO NPs, was investigated. The characterization techniques revealed that the as-synthesized ZnO exhibit hexagonal Wurtzite structure, with a wide energy gap and peak intensities of UV-vis absorption with longer discharge times. A decrease in particle size from 29 to 25 nm was also observed with increasing discharge time, while all samples were thermally stable between 25 and 700 °C. The photocatalytic performance of the ZnO NPs was evaluated by degrading Congo Red (CR) dye with a concentration of 20 ppm under sunlight at a dose of 1 mg/mL. The as-synthesized ZnO NPs revealed exceptional photocatalytic performance by degrading ~ 97% of CR dye after irradiation for 150 min. This work presents an easy and simple method for synthesizing NPs in a short time and pave the way for other potential ideas on the application of plasma gliding arc discharge.
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Óxido de Zinc , Óxido de Zinc/química , Catálisis , Nanopartículas/química , Tamaño de la Partícula , Nanopartículas del Metal/químicaRESUMEN
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.
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Modern industries rapid expansion has heightened energy needs and accelerated fossil fuel depletion, contributing to global warming. Additionally, organic pollutants present substantial risks to aquatic ecosystems due to their stability, insolubility, and non-biodegradability. Scientists are currently researching high-performance materials to address these issues. LaFeO3 nanosheets (LFO-NS) were synthesized in this study using a solvothermal method with polyvinylpyrrolidone (PVP) as a soft template. The LFO-NS demonstrate superior performance, large surface area and charge separation than that of LaFeO3 nanoparticles (LFO-NP). The LFO-NS performance is further upgraded by incorporating ZIF-67. Our results confirmed the ZIF-67/LFO-NS nanocomposite have superior performances than pure LFO-NP and ZIF-67. The integration of ZIF-67 has enhanced the charge separation and promote the surface area of LFO-NSwhich was confirmed by various characterization techniques including TEM, HRTEM, DRS, EDX, XRD, FS, XPS, FT-IR, BET, PL, and RAMAN. The 5ZIF-67/LFO-NS sample showed significant activities for CO2 conversion, malachite green degradation, and antibiotics (cefazolin, oxacillin, and vancomycin) degradation. Furthermore, stability tests have confirmed that our optimal sample very active and stable. Furthermore, based on scavenger experiments and the photocatalytic degradation pathways, it has been established that H+ and â¢O2- are vital in the decomposition of MG and antibiotics. Our research work will open new gateways to prepare MOFs-Perovskites nanocatalysts for exceptional CO2 conversion, organic pollutants and antibiotics degradation.
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Gas sensors are crucial in environmental monitoring, industrial safety, and medical diagnostics. Due to the rising demand for precise and reliable gas detection, there is a rising demand for cutting-edge gas sensors that possess exceptional sensitivity, selectivity, and stability. Due to their tunable electrical properties, high-density surface-active sites, and significant surface-to-volume ratio, nanomaterials have been extensively investigated in this regard. The traditional gas sensors utilize homogeneous material for sensing where the adsorbed surface oxygen species play a vital role in their sensing activity. However, their performance for selective gas sensing is still unsatisfactory because the employed high temperature leads to the poor stability. The heterostructures nanomaterials can easily tune sensing performance and their different energy band structures, work functions, charge carrier concentration and polarity, and interfacial band alignments can be precisely designed for high-performance selective gas sensing at low temperature. In this review article, we discuss in detail the fundamentals of semiconductor gas sensing along with their mechanisms. Further, we highlight the existed challenges in semiconductor gas sensing. In addition, we review the recent advancements in semiconductor gas sensor design for applications from different perspective. Finally, the conclusion and future perspectives for improvement of the gas sensing performance are discussed.
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Nanomaterials (NMs) have garnered significant attention in recent decades due to their versatile applications in a wide range of fields. Thanks to their tiny size, enhanced surface modifications, impressive volume-to-surface area ratio, magnetic properties, and customized optical dispersion. NMs experienced an incredible upsurge in biomedical applications including diagnostics, therapeutics, and drug delivery. This minireview will focus on notable examples of NMs that tackle important issues, demonstrating various aspects such as their design, synthesis, morphology, classification, and use in cutting-edge applications. Furthermore, we have classified and outlined the distinctive characteristics of the advanced NMs as nanoscale particles and hybrid NMs. Meanwhile, we emphasize the incredible potential of metal-organic frameworks (MOFs), a highly versatile group of NMs. These MOFs have gained recognition as promising candidates for a wide range of bio-applications, including bioimaging, biosensing, antiviral therapy, anticancer therapy, nanomedicines, theranostics, immunotherapy, photodynamic therapy, photothermal therapy, gene therapy, and drug delivery. Although advanced NMs have shown great potential in the biomedical field, their use in clinical applications is still limited by issues such as stability, cytotoxicity, biocompatibility, and health concerns. This review article provides a thorough analysis offering valuable insights for researchers investigating to explore new design, development, and expansion opportunities. Remarkably, we ponder the prospects of NMs and nanocomposites in conjunction with current technology.
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In the context of growing arsenic (As) contamination in the world, there is an urgent need for an effective treatment approach to remove As from the environment. Industrial wastewater is one of the primary sources of As contamination, which poses significant risks to both microorganisms and human health, as the presence of As can disrupt the vital processes and synthesis of crucial macromolecules in living organisms. The global apprehension regarding As presence in aquatic environments persists as a key environmental issue. This review summarizes the recent advances and progress in the design, strategy, and synthesis method of various manganese-based adsorbent materials for As removal. Occurrence, removal, oxidation mechanism of As(III), As adsorption on manganese oxide (MnOx)-based materials, and influence of co-existing solutes are also discussed. Furthermore, the existing knowledge gaps of MnOx-based adsorbent materials and future research directions are proposed. This review provides a reference for the application of MnOx-based adsorbent materials to As removal.
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The environmental deterioration caused by dye wastewater discharge has received considerable attention in recent decades. One of the most promising approaches to addressing the aforementioned environmental issue is the development of photocatalysts with high solar energy consumption efficiency for the treatment of dye-contaminated water. In this study, a novel low-cost π-π biomass-derived black carbon modified g-C3N4 coupled FeIn2S4 composite (i.e., FeInS/BC-CN) photocatalyst is successfully designed and fabricated that reveals significantly improved photocatalytic performance for the degradation of Eosin Yellow (EY) dye in aqueous solution. Under dark and subsequent visible light irradiation, the amount optimized composite reveals 99% removal performance for EY dye, almost three-fold compared to that of the pristine FeInS and BC-CN counterparts. Further, it is confirmed by means of the electron spin resonance spectrometry, quenching experiments, and density functional theory (DFT) calculations, that the hydroxyl radicals (â¢OH) and superoxide radicals (â¢O2 -) are the dominant oxidation species involved in the degradation process of EY dye. In addition, a systematic photocatalytic degradation route is proposed based on the resultant degradation intermediates detectedduring liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. This work provides an innovative idea for the development of advanced photocatalysts to mitigate water pollution.
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By substituting the oxygen evolution reaction (OER) with the anodic urea oxidation reaction (UOR), it not only reduces energy consumption for green hydrogen generation but also allows purification of urea-rich wastewater. Spin engineering of the d orbital and oxygen-containing adsorbates has been recognized as an effective pathway for enhancing the performance of electrocatalysts. In this work, we report the fabrication of a bifunctional electrocatalyst composed of amorphous RuO2-coated NiO ultrathin nanosheets (a-RuO2/NiO) with abundant amorphous/crystalline interfaces for hydrogen evolution reaction (HER) and UOR. Impressively, only 1.372 V of voltage is required to attain a current density of 10 mA cm-2 over a urea electrolyzer. The increased oxygen vacancies in a-RuO2/NiO by incorporation of amorphous RuO2 enhance the total magnetization and entail numerous spin-polarized electrons during the reaction, which speeds up the UOR reaction kinetics. The density functional theory study reveals that the amorphous/crystalline interfaces promote charge-carrier transfer, and the tailored d-band center endows the optimized adsorption of oxygen-generated intermediates. This kind of oxygen vacancy induced spin-polarized electrons toward boosting HER and UOR kinetics and provides a reliable reference for exploration of advanced electrocatalysts.
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Developing low-cost, high-efficiency and stable electrocatalysts for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is crucial but highly challenging. Density functional theory (DFT) calculations reveal that doping ruthenium (Ru) into catalysts can effectively optimize their electronic structure, hence leading to an optimal Gibbs free energy on the catalyst surface. Herein, an ultra-low Ru (about 2.34 wt%)-doped Ni3Se2 nanowire catalyst (i.e., Ru/Ni3Se2) supported on nickel foam has been fabricated by a hydrothermal reaction followed by a chemical etching process. The unique three-dimensional (3D) interconnected nanowires not only endow Ru and Ni3Se2 with uniform distribution and coupling, but also provide higher electrical conductivity, more active sites, an optimized electronic structure and favorable reaction kinetics. Therefore, the as-obtained Ru/Ni3Se2 catalyst exhibits excellent electrocatalytic performance, with low overpotentials of 24 and 211 mV to supply a current density value of 10 mA cm-2 towards the HER and OER in an alkaline environment, respectively. Notably, the as-fabricated Ru/Ni3Se2 catalyst only requires a low voltage of 1.476 V to derive a current density of 10 mA cm-2 in the constructed two-electrode alkaline electrolyzer and exhibits exceptionally high stability. This work will provide a novel strategy for the design and fabrication of low-cost and high-performance bifunctional electrocatalysts for hydrogen production by water electrolysis.
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This article describes a comprehensive Synthetic Aperture Radar (SAR) satellite based ships dataset for use in state of the art object detection algorithms. The dataset comprises 11,590 image tiles containing 27,885 ships examples. Each image tile has spatial dimensions of 512 × 512 pixels and is exported in JPEG format. The dataset contains a wide variety of inshore and offshore scenes under varying background settings and sea conditions to generate an all-inclusive understanding of the ship detection task in SAR satellite images. The dataset is generated using images from six different satellite sensors covering a wide range of electromagnetic spectrum including C, L and X band radar imaging frequencies. All the sensors have different resolutions and imaging modes. The dataset is randomly distributed into training, validation and test sets in the ratio of 70:20:10, respectively, for ease of comparison and bench-marking. The dataset was conceptualized, processed, labeled and verified at the Artificial Intelligence and Computer Vision (iVision) Lab at the Institute of Space Technology, Pakistan. To the best of our knowledge, this is the most diverse satellite based SAR ships dataset available in the public domain in terms of satellite sensors, radar imaging frequencies and background settings. The dataset can be used to train and optimize deep learning based object detection algorithms to develop generic models with high detection performance for any SAR sensor and background condition.
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Exploring highly efficient hydrogen evolution reaction (HER) electrocatalysts for large-scale water electrolysis in the full potential of hydrogen (pH) range is highly desirable, but it remains a significant challenge. Herein, a simple pathway is proposed to synthesize a hybrid electrocatalyst by decorating small metallic platinum (Pt) nanosheets on a large nickel telluride nanosheet (termed as PtNs /NiTe-Ns). The as-prepared PtNs /NiTe-Ns catalyst only requires overpotentials of 72, 162, and 65 mV to reach a high current density of 200 mA cm-2 in alkaline, neutral and acidic conditions, respectively. Theoretical calculations reveal that the combination of metallic Pt and NiTe-Ns subtly modulates the electronic redistribution at their interface, improves the charge-transfer kinetics, and enhances the performance of Ni active sites. The synergy between the Pt site and activated Ni site near the interface in PtNs /NiTe-Ns promotes the sluggish water-dissociation kinetics and optimizes the subsequent oxyhydrogen/hydrogen intermediates (OH*/H*) adsorption, accelerating the HER process. Additionally, the superhydrophilicity and superaerophobicity of PtNs /NiTe-Ns facilitate the mass transfer process and ensure the rapid desorption of generated bubbles, significantly enhancing overall alkaline water/saline water/seawater electrolysis catalytic activity and stability.
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The rapid growth in population and industrialization has given rise to serious environmental issues, especially the water pollution. Photocatalysis with the assist of semiconductor photocatalysts has been considered as an advanced oxidation technique for degrading a variety of pollutants under solar irradiation. In this work, we have fabricated SnO2-TiO2 heterostructures with different ordered layers of SnO2 and TiO2 via the sol-gel dip-coating technique and utilized in photocatalysis for degradation of methyl blue dye under UV irradiation. The influence of the layer's position on SnO2 and TiO2 properties is investigated via the various techniques. The grazing incidence X-ray diffraction (GIXRD) analysis reveals that the as-prepared films exhibit pure anatase TiO2 and kesterite SnO2 phases. The 2SnO2/2TiO2 heterostructure exhibit the maximum crystallite size and smallest deviation from the ideal structure. Scanning electron microscopy cross-section images manifest good adhesion of the layers to each other and to the substrate. Fourier transform infrared spectroscopy reveals the characteristic vibration modes of SnO2 and TiO2 phases. UV-visible spectroscopy measurements indicate that all films exhibit high transparency (T = 80%) and the SnO2 film reveals a direct band gap of 3.6 eV, while the TiO2 film exhibits an indirect band gap of 2.9 eV. The optimal 2SnO2/2TiO2 heterostructure film revealed best photocatalytic degradation performance and the reaction rate constant for methylene blue solution under UV irradiation. This work will trigger the development of highly efficient heterostructure photocatalysts for environmental remediation.
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Titanio , Rayos Ultravioleta , Titanio/química , Espectroscopía Infrarroja por Transformada de FourierRESUMEN
PURPOSE: In research people are often asked to fill out questionnaires about their health and functioning and some of the questions refer to serious health concerns. Typically, these concerns are not identified until the statistician analyses the data. An alternative is to use an individualized measure, the Patient Generated Index (PGI) where people are asked to self-nominate areas of concern which can then be dealt with in real-time. This study estimates the extent to which self-nominated areas of concern related to mood, anxiety and cognition predict the presence or occurrence of brain health outcomes such as depression, anxiety, psychological distress, or cognitive impairment among people aging with HIV at study entry and for successive assessments over 27 months. METHODS: The data comes from participants enrolled in the Positive Brain Health Now (+ BHN) cohort (n = 856). We analyzed the self-nominated areas that participants wrote on the PGI and classified them into seven sentiment groups according to the type of sentiment expressed: emotional, interpersonal, anxiety, depressogenic, somatic, cognitive and positive sentiments. Tokenization was used to convert qualitative data into quantifiable tokens. A longitudinal design was used to link these sentiment groups to the presence or emergence of brain health outcomes as assessed using standardized measures of these constructs: the Hospital Anxiety and Depression Scale (HADS), the Mental Health Index (MHI) of the RAND-36, the Communicating Cognitive Concerns Questionnaire (C3Q) and the Brief Cognitive Ability Measure (B-CAM). Logistic regressions were used to estimate the goodness of fit of each model using the c-statistic. RESULTS: Emotional sentiments predicted all of the brain health outcomes at all visits with adjusted odds ratios (OR) ranging from 1.61 to 2.00 and c-statistics > 0.73 (good to excellent prediction). Nominating an anxiety sentiment was specific to predicting anxiety and psychological distress (OR 1.65 & 1.52); nominating a cognitive concern was specific to predicting self-reported cognitive ability (OR 4.78). Positive sentiments were predictive of good cognitive function (OR 0.36) and protective of depressive symptoms (OR 0.55). CONCLUSIONS: This study indicates the value of using this semi-qualitative approach as an early-warning system in predicting brain health outcomes.
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Infecciones por VIH , VIH , Humanos , Estudios Prospectivos , Calidad de Vida/psicología , Ansiedad/diagnóstico , Encéfalo , Depresión/terapiaRESUMEN
Metal-organic frameworks (MOFs) show great promise for electrocatalysis owing to their tunable ligand structures. However, the poor stability of MOFs impedes their practical applications. Unlike the general pathway for engineering ligands, we report herein an innovative strategy for leveraging metal nodes to improve both the catalytic activity and the stability. Our electrolysis cell with a NiRh-MOF||NiRh-MOF configuration exhibited 10 mA cm-2 at an ultralow cell voltage of 0.06 V in alkaline seawater (with 0.3 M N2H4), outperforming its counterpart benchmark Pt/C||Pt/C cell (0.12 V). Impressively, the incorporation of Rh into a MOF secured a robust stability of over 60 h even when working in the seawater electrolyte. Experimental results and theoretical calculations revealed that Rh atoms serve as the active sites for hydrogen evolution while Ni nodes are responsible for the hydrazine oxidation during the hydrazine oxidation assisted seawater splitting. This work provides a paradigm for green hydrogen generation from seawater.
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This research work focuses on the isolation and thermo-chemical modification of cellulose and its application as an adsorbent for the removal of organic pollutants. The used cellulose was collected from a locally available plant (Olive Europa) commonly called Zaitoon. The stem branches of Zaitoon were collected and then kept in water for 40-45 days at room temperature to extract the cellulose fibers. These cellulose fibers were then kept in the Soxhlet apparatus for washing in n-hexane for 72 h. The purified cellulose was divided into three parts: one part was subjected to thermal activation (TAC), the second was modified chemically (CMC) with Benzyl Chloride, while the last one remained un-functionalized (UFC). All the three forms of cellulose were characterized via FTIR and SEM, then utilized for the removal of Titan Yellow (TY) dye from aqueous media via adsorption process by varying the contact time, temperature, concentration of dye and type, and dose of adsorbent. The adsorption efficiencies of all adsorbents were compared under different experimental variables. Thermally activated cellulose showed the best results for the removal of TY compared with other materials. The calculated removal percentage of TY was found to be 97.69, 94.83, 94.83, and 98% under equilibrium conditions of contact time, temperature, adsorbent dose, and TY concentration. Similarly, the uptake capacities of TAC under optimal experimental conditions were found to be 19.56, 18.96, 18.52, and 18.75 mg/g. Thermodynamic studies of TAC, CMC, and UFC showed that the values of ΔG are negative, while those of ΔH and ΔS are positive in all cases and at all temperatures. This indicates that the TY elimination process is endothermic and spontaneous with an entropy-driven nature. The obtained results indicate that the as-fabricated low-cost biomaterials can effectively remove dyes from wastewater through physicochemical interactions. The removal process was influenced by the nature of the adsorbent and the operating variables.