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 %.

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.

The contemporary era's top environmental problems include the lack of energy, recycling of waste resources, and water pollution. Due to the speedy growth of modern industrialization, the utilization of non-renewable sources has increased rapidly, which has caused many serious environmental and energy issues. In photocatalysis, as a proficient candidate, g-C₃N₄ (metal-free polymeric photocatalyst) has gained much attention due to its auspicious properties and excellent photocatalytic performance. But, regrettably, the quick recombination of photoinduced charge carriers, feeble redox ability, and inadequate visible light absorption are some major drawbacks of g-C₃N₄ that hamper its photocatalytic ability. Henceforth, these significant limitations can be solved by incorporating modification strategies. Among all modification techniques, the amalgamation of g-C₃N₄ with two or more photocatalytic semiconducting materials via heterojunction formation is more advantageous. In this review, we have discussed various modification strategies, including conventional, Z-scheme and S-scheme heterojunctions. S-scheme heterojunction is consideredan efficient and profitable charge transferal pathway due to the excellent departure and transferal of photoexcited charge carriers with outstanding redox ability. Consequently, the current review is focused on various photocatalytic applications of S-scheme-based g-C₃N₄ photocatalysts in pollutant degradation, H₂ production, and CO₂ reduction.

The research of energy-storage systems has been encouraged in the last ten years by the rapid development of portable electronic gadgets. Hybrid-ion capacitors are a novel kind of capacitor-battery hybrid energy storage device that has earned a lot of interest because of their high power density while maintaining energy density and a long lifecycle. Mostly, lithium-based energy storage technology is now being studied for use in electric grid storage. But the price increment and intermittent availability of lithium reserves make lithium-based commercialization unstable. Therefore, sodium-based technologies have been proposed as potential substitutes for lithium-based technologies. Sodium-ion capacitors (SICs) are acknowledged as potential innovative energy storage technologies which have lower standard electrode potentials and lower costs than lithium-ion capacitors. However, the large radius of the sodium ion also contributes to unfavorable reaction kinetics, low energy density, and brief lifespan of SICs. Recently, transition metal oxide (TMO)-based candidates have been considered potential due to the large theoretical capacity, environmental friendliness, and low cost for SICs. This brief study summarizes current advancements in research of TMOs and sodium-based TMOs as electrode candidates for SIC applications. Also, we have covered in detail the state of the exploration and upcoming prospects of TMOs for SICs.

Rapid tooling using additive manufacturing, or 3D printing, is an emerging manufacturing technology that has the potential to revolutionize the production of complex parts using only a computer and a design program. Lightweight structures with excellent dimensional precision and lower cost for customizable geometries are possible with these printed parts. In recent years, inherent constraints of polymers, metals, and ceramics have pushed researchers toward superior alternative composite materials to boost mechanical and other critical features; current 3D printing research follows this route from neat to composite materials. The characteristics, performance, and future uses of composite materials produced using additive manufacturing methods are discussed in this review. In addition, to discuss the state of the art in additive manufacturing, this article also fabricated many technologies, including robotics, machine learning, organ-on-a-chip, and 4D bioprinting.

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.