Metal/Covalent Organic Framework Encapsulated Lead-Free Halide Perovskite Hybrid Nanocatalysts: Multifunctional Applications, Design, Recent Trends, Challenges, and Prospects.

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.

MoO3 with the Synergistic Effect of Sulfur Doping and Oxygen Vacancies: The Influence of S Doping on the Structure, Morphology, and Optoelectronic Properties.

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.

Multifunctional assessment of copper-doped ZnO nanoparticles synthesized via gliding arc discharge plasma technique: antioxidant, antibacterial, and photocatalytic performance.

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.

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.

Effective Removal of Nile Blue Dye from Wastewater using Silver-Decorated Reduced Graphene Oxide.

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.

Rapid synthesis of ZnO nanoparticles via gliding arc discharge: unveiling the impact of discharge time on particle properties and photocatalytic performance.

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.

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.

Preparation of visible-light active MOFs-Perovskites (ZIF-67/LaFeO3) nanocatalysts for exceptional CO2 conversion, organic pollutants and antibiotics degradation.

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 •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.

Designing State-of-the-Art Gas Sensors: From Fundamentals to Applications.

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.

A critical review on metal-organic frameworks (MOFs) based nanomaterials for biomedical applications: Designing, recent trends, challenges, and prospects.

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.

Application of manganese oxide-based materials for arsenic removal: A review.

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.

Design and Fabrication of Biomass Derived Black Carbon Modified g-C3N4/FeIn2S4 Heterojunction as Highly Efficient Photocatalyst for Wastewater Treatment.

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 (•OH) and superoxide radicals (•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.

Manipulation of Electron Spins with Oxygen Vacancy on Amorphous/Crystalline Composite-Type Catalyst.

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.

Synthesis of Metal-Organic Framework-Based ZIF-8@ZIF-67 Nanocomposites for Antibiotic Decomposition and Antibacterial Activities.

Toxic antibiotic effluents and antibiotic-resistant bacteria constitute a threat to global health. So, scientists are investigating high-performance materials for antibiotic decomposition and antibacterial activities. In this novel research work, we have successfully designed ZIF-8@ZIF-67 nanocomposites via sol-gel and solvothermal approaches. The ZIF-8@ZIF-67 nanocomposite is characterized by various techniques that exhibit superior surface area enhancement, charge separation, and high light absorption performance. Yet, ZIF-8 has high adsorption rates and active sites, while ZIF-67 has larger pore volume and efficient adsorption and reaction capabilities, demonstrating that the ZIF-8@ZIF-67 nanocomposite outperforms pristine ZIF-8 and ZIF-67. Compared with pristine ZIF-8 and ZIF-67, the most active 6ZIF-67@ZIF-8 nanocomposite showed higher decomposition efficacy for ciprofloxacin (65%), levofloxacin (54%), and ofloxacin (48%). Scavenger experiments confirmed that •OH, •O2-, and h+ are the most active species for the decomposition of ciprofloxacin (CIP), levofloxacin (LF), and ofloxacin (OFX), respectively. In addition, the 6ZIF-67/ZIF-8 nanocomposite suggested its potential applications in Escherichia coli for growth inhibition zone, antibacterial activity, and decreased viability. Moreover, the stability test and decomposition pathway of CIP, LF, and OFX were also proposed. Finally, our study aims to enhance the efficiency and stability of ZIF-8@ZIF-67 nanocomposite and potentially enable its applications in antibiotic decomposition, antibacterial activities, and environmental remediation.