In this work, highly fluorescent green-emitting N-doped carbon dots (N-CDs) were derived from pulp-free lemon juice extract, as a green precursor, through a one-pot carbonization at 180 ^oC for 3 to 5 h. The newly fabricated N-CDs were thoroughly characterized using different imaging and analytical techniques, including Scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Fluorescence spectroscopy, X-ray diffraction analysis (XRD), and Ultraviolet-visible (UV-Vis) spectroscopy. The preliminary evaluation showed that N-CDs synthesized at 180 ºC for 3 and 5 hours emit bright green light under UV or blue light irradiation with a quantum yield of 16.33% and 21.80%, respectively. The fluorescence spectroscopic profiles revealed that as-developed N-CDs exhibit excitation-independent photoluminescence (PL) emission at 365 nm. FTIR profile reveals the functional group entities with evident peaks in 3190 cm⁻¹, 1660 cm⁻¹, 1580 cm⁻¹, 1405 cm⁻¹, 1365 cm⁻¹, 1190 cm⁻¹, and 1060 cm⁻¹ regions, among others that correspond to the presence of N-H, C-H, C=O and C=N, C=C, C-H, COOH, C-O-C, and C-O. SEM unveils uniform and well-crystalline morphology of N-CDs.

In the present research, a chemical co-precipitation approach has been used to approach the synthesis, characterization, and photocatalytic applicability of Ni-doped α-Fe₂O₃ (hematite) nanoparticles. Biosynthesized iron oxide nanoparticles (IONPs) were successfully synthesized using a non-toxic leaf extract of the Azadirachta indica (AI) plant (neem) as a reducing and stabilizing agent. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman spectroscopy, FT-IR spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, and vibrating sample magnetometer (VSM) have all been used to examine the synthesized materials. All of the produced NPs contain only the nanocrystalline hematite phase, according to XRD measurements. The morphology studies of the Ni-doping hematite nanoparticles, as demonstrated by TEM and SEM. The phase purity and phonon modes of the prepared nanoparticles are confirmed by Raman spectroscopy. The UV-Vis absorption tests show also that value of the band gap increases together with the reduction in particle size, going from 2.26 eV for chemical α-Fe₂O₃ to 2.5 eV for green Ni-doped α-Fe₂O₃ nanoparticles. Additionally, it was clear from the magnetic characteristics that all of the samples behaved ferromagnetically at ambient temperatures. On the other side, malachite green (MG) dye was used as a surrogate industrial wastewater dye in order to study the photocatalytic efficiency of Ni-doped α-Fe₂O₃ particles. The pure/green Ni-doped α-Fe₂O₃ NPs showed that after 70 minutes of exposure, 92% of the MG had become discolored.

This study explores the synthesis, properties, and applications of chitosan-encapsulated silver sulphide (Ag2S) quantum dots (QDs) for biological applications. The investigation focuses on the fluctuations in the physico-chemical characteristics of chitosan Ag2S QDs, which can be carefully studied due to their environmental activity. X-ray diffraction (XRD) measurements reveal that chitosan-coated Ag2S QDs exhibit higher-intensity peaks. The XRD analysis reports a range of crystallite sizes, with a minimum size of 8 nm and a maximum size of 12 nm. Fourier-transform infrared (FTIR) spectroscopy confirms the presence of chitosan through the detection of functional group peaks. High-resolution transmission electron microscopy (HRTEM) studies indicate that the size of the artificial quantum dots is 6 nm. Energy-dispersive X-ray spectroscopy (EDX) verifies the composition of chitosan-encapsulated Ag2S QDs. Moreover, the chitosan Ag2S quantum dots demonstrate exceptional photocatalytic activity, as evidenced by the degradation of 92% of methylene blue dye within one hour. This research provides valuable insights into the synthesis, properties, and potential applications of chitosan-encapsulated Ag2S quantum dots in diverse fields.

The primary global source of water pollution is textile dyes. Highly stable organic dyes are produced by these industries that are released untreated into nearby ponds, lakes and rivers. This paper is devoted to synthesis of nickle doped anatase phase of TiO₂ nanoparticles (Ni-ATD NPs) by encapsulating plant Tinospora cordifolia (TC) through microwave assisted method for degradation of malachite green (MG) dye. The synthesized NPs were calcinated at 400 ^oC temperature to achieve the anatase phase. The synthesized Ni-ATD NPs were analysed with different characterization methods. X-ray diffraction (XRD) and Raman analysis confirmed the crystalline nature for Ni-ATD NPs with a tetragonal structure having crystallite size of 11 nm. Scanning electron microscope (SEM) determined the spherical surface morphology for synthesized NPs. The absorption peaks of Ni-ATD NPs were originated from 360 to 370 nm from UV-Visible spectroscopy in which the bandgap was found to be 3.45 eV. The photocatalytic activity for MG dye was evaluated under ultra-violet (UV) light using Ni-ATD NPs for 90 minutes which exhibited the degradation up to 100 %.

Magnetic nanoparticles (MNPs) are receiving increasing attention from individual scientists and research companies as promising materials for biomedical applications. MNPs can be synthesized by many different methods. Before proceeding to the synthesis process, the cost of using it and the practicality of the synthesis conditions are well investigated. Especially in their use in the biomedical field, features such as not containing toxic substances, high biocompatibility, and low particle size are desired. However, the use of magnetic nanoparticles in biomedical applications is limited due to various difficulties such as particle agglomeration and oxidation of magnetic cores of MNPs. To overcome these challenges, MNPs can be coated with various natural and synthetic polymers to alter their morphological structure, magnetic character, biocompatibility, and especially surface functional groups. Therefore, this review focuses on the synthesis of MNPs by different methods and the effects of these synthesis methods on magnetic properties and size, their modifications with natural and synthetic polymers, and the use of these polymer-coated MNPs in biomedical fields such as targeted drug release, enzyme immobilization, biosensors, tissue engineering, magnetic imaging, and hyperthermia. The review article also provides examples of advanced biomedical applications of polymer-coated MNPs and perspectives for future research to promote polymer-coated MNPs. To this end, we aim to highlight knowledge gaps that can guide future research to improve the performance of MNPs for different applications.

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Reducing CO₂ net emissions is one of the most pressing goals in tackling the current global warming emergency. Therefore, the development of carbon recycling strategies has resulted in the application of heterogeneous catalysts toward the electro/photocatalysis reduction of CO₂ into hydrocarbons with potential reusability. Their morphology is among the properties that affect the performance and selectivity of catalysts towards this reaction. Nanostructuring methods offer popular strategies for catalytic applications since they allow an increase in the area/volume ratio and versatile control over surface physicochemical properties. In this review, we summarize studies that report the use of versatile synthesis techniques for obtaining nanostructured metallic and semiconductor materials with application in the electro/photocatalytic reduction of CO_2. Enhancing mechanisms to the catalytic CO₂ reduction yield, such as improved charge carrier separation efficiency, defect engineering, active site concentration, and localized plasmonic behavior, are described in conjunction with the control over the morphologies of the nanostructured platforms. Special attention is given to ZnO and silicon-based matrices as candidates for developing abundant and non-toxic catalytic materials. Therefore, this work represents a guide to the efforts made to design electro/photocatalytic systems that can contribute significantly to this field.

Plastics have become one of the most concerning pollutants today. They are non-biodegradable and potentially carcinogenic and lead to the generation of microplastics categorised as an emerging pollutant. Microplastics are plastic particles smaller than 5 microns in size. They are reported in various parts of the biosphere including human blood and tissues of various organs. Industrial and domestic effluents are two major contributing sources of microplastics in the ecosystem. A large volume of microplastics escape from the filtration processes of wastewater treatment plants (WWTP). This review studies the various removal methods for these pollutants in large-scale as well as lab-scale models and the present state of art facilities available to deal with it.

Functional coatings provide durability to the bulk material and add other value-added properties which enhance the surface's mechanical, electrical, optical, and many other properties. The functional response of these coatings stems from the ambiance, which can be made to sense in response to a sharp change in the temperature, pH, moisture, active ions, or mechanical stresses. Recently, many efforts have been made to impart multi-functionality within a single coating, i.e., to achieve hydrophobicity and antifouling characteristics, which can be achieved by combining an appropriate coating material with a geometric nanopattern. Such coatings are poised to shape the future of the transport, healthcare, and energy sectors, including marine, aeronautics, automobile, petrochemical, biomedical, electrical and electronic industries. This perspective sheds light on the design specifications and requirements to fabricate functional coatings and critically discusses the fabrication methods, working principles, and case studies to survey various applications with a particular focus on anti-corrosion and self-cleaning applications.