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Green technology is gaining importance nowadays, it has become very important to synthesize various nanoparticles. This review mainly focuses on the phytosynthesis of silver nanoparticles (AgNPs) and shows their catalytic applications in the field of wastewater treatment. Plant-assisted synthesis of AgNPs has been documented by numerous studies. Plant-mediated synthesis has many advantages over conventional methods and is discussed comprehensively in this review. This critical review aims to help researchers to better understand and follow this rapid, cost-effective, and eco-friendly research area. Dye effluents in water bodies become a major environmental issue worldwide. This paper also offers a thorough understanding of the synthetic dyes such as Rhodamine B, Methylene Blue, Crystal violet, Methyl Orange, and Amido black 10B used in the textile industry, with a focus on the popular methods to degrade them from industrial wastewater, especially, chemical degradation, and photocatalytic dye degradation using silver nanoparticles and other Ag-systems. Additionally, the plausible mechanism involved in chemical and photocatalytic degradation was also provided. There are several review articles on all these topics, but such an in-depth study has not been investigated so far in the concerned research literature. [ABSTRACT FROM AUTHOR]

A novel class of nanomaterials known as carbon quantum dots (CQDs) has drawn significant attention because of numerous benefits, particularly its small size (between 1 and 10 nm) and great water solubility, fluorescence, ease of synthesis, and low toxicity among others. There are still many crucial questions that need to be answered, such as how to prepare high-quality CQDs with an appropriate yield using a simpler and easier approach. Most of the articles reviewed have discussed the production of CQDs intended for applications in imaging and sensing. Nevertheless, there is a scarcity of research focusing on producing undecorated and doped CQDs. In this review paper, the various methods for synthesizing CQDs by using various carbon sources have been summarized. Additionally, In this paper, we discuss the primary characterization techniques and the applications of CQDs in various fields. The fundamental objective of this paper is to analyze various synthesis methods used over different periods to address the challenges that one might encounter during the synthesis of CQDs. [ABSTRACT FROM AUTHOR]

Plant parts have unfathomable potential in the synthesis of nanoparticles. The current study was designed for the photosynthesis of silver nanoparticles (NC-AgNPs) using bark extract of N. cadamba. Different analytical methods were used to characterize the synthesized nanoparticles. HR-TEM analysis identifies the formation of multi-shaped NC-AgNPs like spherical, quasi-spherical, rod-shaped, trigonal, square, pentagonal, and hexagonal with a size range of 18-91 nm. The crystallize size of NC-AgNPs was found to be 27.6 nm. The catalytic effectiveness of NC-AgNPs in degrading Crystal violet (CV) dye is remarkable. Important parameters such as the effect of catalyst dose and pH were investigated. Dose-dependentantioxidant activity of NC-AgNPs was determined by using 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay. Low-cost synthesis and eco-friendly reagents were the salient features that made NC-AgNPs more attractive toward catalytic and antioxidant activities. N. cadamba bark was used the first time as a green source for the synthesis of silver nanoparticles. The synthesis of different shapes of nanoparticles in one-step synthesis. The study of NC-AgNPs for their catalytic and antioxidant activities is reported for the first time. [ABSTRACT FROM AUTHOR]

Advanced corrosion protection methods include covering stainless steel surfaces with conductive polymer-based coatings. Polypyrrole and polypyrrole composites of tungstate of different concentrations were deposited on stainless steel-304 using cyclic voltammetry and their elemental analysis was verified by EDX analysis. EIS and potentiodynamic polarization analysis show that the corrosion protection efficiency (CPE) of polypyrrole composites is higher than polypyrrole coating. The reduction in corrosion rate due to the inhibitory action of tungstate through the physical barrier and anodic protection mechanism was validated by greater Rct and lower Icorr values of polypyrrole composites. In the composites, with increasing the concentration of tungstate in polypyrrole from 5% to 15%, CPE also increases, as polypyrrole composites are more able to shift the corrosion potential of stainless steels towards the passive zone and form a new nonporous passive oxide film on the surface. With a 15% concentration coating, the highest CPE of 93% and the lowest corrosion rate of 130 mmpy were obtained, indicating that the entire stainless steel active surface area is completely absorbed and that no active sites exit for adsorption at this concentration. The synthesized polypyrrole composites with a 15% concentration offer excellent corrosion protection prospects. [ABSTRACT FROM AUTHOR]

Plant extract mediated nanoparticles have gained enormous attention for their green and rational approach and developed as an alternative to conventional chemical and physical methods. Here, the less exploited Jatropha integerrima flower extract is used in the synthesis of silver nanoparticles. The as-prepared nanoparticles exhibit a strong surface plasma resonance around 420 nm. Several spectroscopic techniques confirmed the formation of silver nanoparticles with an average size of 32.07 nm, stabilized by functional groups. The catalytic activity of synthesized nanoparticles for Rhodamine B dye degradation in the presence of sodium borohydride was investigated. The results showed that the 100 µL catalyst dose degraded the alkaline solution of dye up to 98%, with a high rate constant of 1.2110 min−1. In addition, the nanoparticles were tested for antioxidant activity using the 2,2-dipehnyl-1-picrylhydrazyl free radical assay. The calculated IC50 value for synthesized nanoparticles was 33.63 ± 0.53 µg/mL. Thus, the as-prepared nanoparticles are excellent candidates for catalytic and antioxidant activities compared to other materials used so far. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) are esteemed as an intriguing technological for advanced energy storage in the impending era, owing to their intrinsic safety attributes and their unique features such as quick charging, good permeability, extended life-cycle, high power density (P d), thermal durability, and large specific surface area (SSA). Besides these properties, commercial SCs have certain drawbacks, such as low energy density, sustainability, environmental footprint, and energy at low cost. To improve the efficacy of SCs, CQDs (Carbon Quantum Dots) are a novel family of 0-D carbon nanoparticles, with a dimension of <10 nm, a new and emerging precursor to developing electrode nanomaterial for energy storage devices. Here's a review, we summarized the various types of green-source derived CQDs precursors, (plant parts, agro-waste, waste materials, micro-organisms, etc.) to synthesize electrode constituents for SCs, different methods of synthesis, and properties. This analysis explains a detailed outlook of various types of hybrid materials and their effect on the performance of SCs, alongside their captivating utilizes in the area of SCs. A systematic examination of important variables like electrode material, electrolyte, pore size, potential range, and temperature that influence the mechanisms of the SCs is also included in this extensive review. • Synthesis of green sources-based carbon quantum dots as electrode material in supercapacitor. • Preparation of CQDs composites to improve the electrochemical properties of supercapacitors. • Key factors affecting the performance of supercapacitors. [ABSTRACT FROM AUTHOR]

The Pb2+ doped ZnAl 2 O 4 ceramic with different concentrations (0–2 mol %) has been prepared via the fast citrate sol-gel technique. Crystalline size of prepared samples was found in the range of 26–32 nm using XRD data. The X-ray pattern revealed that all samples are polycrystalline in nature with cubic phase and Fd͞3 m space group. The preferred orientation and structure parameter of spinel ZnAl 2 O 4 has been tailored significantly after doping Pb2+ ions. The FTIR technique was used to identify the characteristic functional group of the prepared spinel structure. The optical band gap of Zn 1-x Pb x Al 2 O 4 (0 ≤ x ≤ 2 mol %) ceramic powder was found to increase from 3.65 eV to 4.36 eV with an increase in Pb2+ content. The prominent emission was observed in the violet-blue region (387 nm) after exciting the sample at 270 nm. The impedance data has been analyzed to explore the dielectric constant (k), dissipation loss factor (DF), and ac conductivity. The observed violet-blue emission and improved dielectric behavior endorse the potential applications of Zn 1-x Pb x Al 2 O 4 (0 ≤ x ≤ 2 mol %) ceramic powder in UV sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • RGO and CNT-doped-based MOFs with diamond-like structure were fabricated. • The band gap was 2.62 eV at 474 nm for RGO@MIL-53 and 2.33 eV at 531 nm for CNT@MIL-53. • The photocatalytic degradation efficiency against AB10 dye is 88.15% for RGO@MIL-53 and 98.42% for CNT@MIL-53. • DPPH assay showed EC50 at 183.89 with 77.81 % inhabitation for RGO@MIL-53 and 153.59 with 92% for CNT@MIL-53. This research examines the antioxidant and photocatalytic capabilities of diamond-shaped RGO and CNT-doped Fe-based Metal-Organic Frameworks (MOFs), utilizing MIL-53 as the structural framework. A solvothermal method was used for the synthesis of diamond-shaped RGO and CNT-doped MOFs. MOFs structural properties were characterized using FTIR, Raman spectroscopy, FE-SEM, XPS, and p-XRD methods. UV–visible spectroscopy was utilized to analyze the photocatalytic performance and band gap measured as 2.62 eV at 474 nm for RGO-doped MOF and 2.33 eV at 531 nm for CNT-doped MOFs. Amido black 10B (AB10) dye was used to assess the sample's photocatalytic efficacy in the presence and absence of H 2 O 2. After 40 min of sunshine exposure, the RGO-doped MOFs-H 2 O 2 combination revealed 88.15 % photocatalytic degradation capability, while the CNT-doped MOFs demonstrated 98.42 %. To determine the antioxidant activity of the material, a DPPH test was performed. At 400 μg/ml, RGO-doped MOFs showed an EC50 value of 183.89 and 77.81 % inhibition, while CNT-doped MOFs showed 153.59 and 92 % inhibition. [ABSTRACT FROM AUTHOR]

• Novel NCs were synthesized using rGO and ACT NPs using the hydrothermal method. • NCs show Photocatalytic activity against MB dye both in UV and Sunlight. • Shows 99 % corrosion inhibition efficiency in 1.0 N H 2 SO 4 at 10 ppm. • ZOI was tested against E. coli and S. aureus bacteria strains. • Contributes to the advancement of nanotechnology and Materials Science. Reduced graphene oxide@Al 2 O 3 -CuO-TiO 2 (ACT) based nanocomposites (NCs) were combined by regulated hydrothermal technique to create novel rGO@metal oxides-based NCs. The resultant NCs showed excellent photocatalytic, antibacterial, anticorrosive, and magnetic characteristics. The use of FTIR, TEM, UV-visible, X-ray diffraction, and SEM aids the structural examination of NCs. The synergistic pairing of ACT NPs with rGO exhibits enhanced photocatalytic, magnetic, anticorrosive, and antibacterial characteristics. The NCs exhibited paramagnetic character (χ = 0.140) and increased induced current with applied magnetic field. The photocatalytic properties of NCs were examined for decomposing methylene blue dye in UV and Sunlight. 94.7 % and 70.5 % dye degradation was observed under UV and Sunlight after 335 and 110 min. of exposure, respectively. The Zone of Inhibition was examined against S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria and was found comparable with standard antibiotics (Ampicillin) against S. aureus bacterial strain. The NCs show 99 % corrosion inhibition efficiency at a low concentration (10 ppm). The potential applications of ACT@rGO NCs in environmental rehabilitation, the medical field, anticorrosive coatings, and impure water purification, contribute toward the development of advanced nanomaterials-based devices. The synergistic combination of rGO and ACT NPs shows improved magnetic, antimicrobial activity, anticorrosion, and photocatalytic properties. NCs exhibited paramagnetic character (χ = 0.140) and increased induced current with applied magnetic field. The photocatalytic properties of NCs were investigated for decomposing methylene blue dye both in UV and Sunlight. 94.7 % and 70.5 % dye degradation were observed under UV and Sunlight after 335 and 110 min. of exposure, respectively. Zone of Inhibition against S. aureus and E. coli bacteria were determined at different NCs concentrations and was found comparable with standard antibiotics (Ampicillin) against S. aureus bacterial strain. The NCs show 99 % corrosion inhibition efficiency at a very low concentration (10 ppm). The developed ACT@rGO NCs hold potential applications for water purification, biomedical devices, anticorrosive coatings, and environmental remediation, which will help in advancing nanotechnology, and materials science. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Iron shaped MOFs with diamond like structure were fabricated. • The band gap was 3.0 eV at 434 nm. • The photocatalytic degradation efficiency against CV dye is 97.98%. • DPPH assay showed EC50 at 179.79 with 76.68 % Inhabitation. This study investigates the antioxidant and photo-catalytic activities of diamond-shaped iron-based Metal-Organic Framework (MOFs) using MIL-53 as the chosen framework. The synthesis of diamond-shaped MIL-53(Fe) MOFs is presented using the solvothermal method. The structural properties of the sample were determined using FTIR, FESEM-EDX, and powder XRD methods. UV–visible Spectroscopy was used to investigate the band gap, which was 3.09 eV at 401 nm, and also employed to assess the photo-catalytic performance of the MOFs under simulated sunlight irradiation. Crystal violet (CV) dye was used to test the photo-catalytic efficacy of the sample with H 2 O 2, and compared to the absence of H 2 O 2 , the Iron-based MIL-53-H 2 O 2 system demonstrated improved photo-catalytic degradation performance, attaining a clearance rate of 97.98 % for CV after 100 min of exposure to sun radiation. The antioxidant activity of the sample was analyzed by using a DPPH assay. It showed EC50 at 179.7 and 76.68 % inhibition at 400 μg/ml. [ABSTRACT FROM AUTHOR]

Using the sol-gel method, we have synthesized nanocrystalline Yb3+: SiO 2 /In 2 O 3 ceramic nanopowder. XRD pattern shows the cubic phase of In 2 O 3 that is perfectly evolved at 300°C. The In 2 O 3 nanoparticles of ∼10–15 nm size were formed, and their W-H plots demonstrated the microstrain owing to the structural imperfections. In FTIR, a fingerprint region was observed near 577 cm−1, corresponding to the In-O bond. SEM images have determined the irregular surface morphology and formation of grain boundaries in prepared ceramic powder. X-ray photoelectron spectroscopy established the 3+ oxidation state of ytterbium and confirmed the oxide phases of SiO 2 and In 2 O 3. Absorption bands were observed in UV-Vis spectra at 250, 320, and 895 nm corresponding to the SiO 2 host, In 2 O 3 nanoparticles, and dopant ions. To investigate the emission corresponding to Yb3+, the In 2 O 3 consequences were explored on structural parameters and infrared emission of Yb3+: SiO 2 where In 2 O 3 acted as the sensitize. The NIR luminescence was efficiently boosted by increasing the In 2 O 3 content. The energy transfer from In 2 O 3 to Yb3+ ions takes place effectively, and thus, UV photons are converted to NIR in the 980–1060 nm region for Si-solar cell substitutes. Moreover, the broad luminescence from UV-to-NIR would be employable in photonic appliances, particularly fiber lasers and 3D displays. [Display omitted] • The effect of annealing has been discussed first time on Yb3+: SiO 2 /In 2 O 3 ceramic nanopowder. • XPS confirms the impurity free SiO 2 & In 2 O 3 compound in prepared ceramic powder. • NIR emission at 893 & 1020 nm is reported for solar cell applications. • Effect of annealing, the role of sensitizer, and dopant conc are discussed on optical behavior. [ABSTRACT FROM AUTHOR]