Herein, we report a novel method for the electrochemical deposition of TiO2 on Al substrate through the formation of peroxotitanium complex without any post heat treatment process. The alkaline treated titanium precursors were used as an electrolyte and TiO2 was deposited onto aluminium substrate by both cathodic reduction and electrophoretic deposition through the formation of peroxotitanium complex. The electrodeposition process was optimized by varying the pH, concentration of the electrolyte, deposition voltage, time and area of the electrode respectively. The optimized condition to obtain a maximum yield is as follows: voltage (4.5 V), time (2.5 h), pH (5) and area of the electrode 3 × 3 cm2. The deposits were then characterized using various material characterization techniques such as high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy respectively. The morphological analysis showed the deposition of nanocrystalline TiO2 with irregular morphology on Al substrate. The AFM revealed a non-uniform deposition of TiO2 with high surface roughness (average roughness: 44.60 nm). The XRD pattern and Raman spectrum confirmed the presence of anatase phase of TiO2. The obtained TiO2 were then subjected to photoelectrochemical studies by coating over an ITO electrode. The nanocrystalline TiO2 showed excellent photocurrent response which could be due to the short hole retrieval and fast electron transport across the electrode-electrolyte interface. The proposed method can be promising towards the industrial application for the extraction and recovery of TiO2 from the mineral ore residues and spent mining waste.

We designed a simple coumarin-hydrazone-based Schiff base fluorescent probe, namely 7-(diethylamino)-N'-(2,4-dihydroxybenzylidene)-2-oxo-2H-chromene-3-carbohydrazide (L), which was successfully synthesized and utilized for selective detection of Al3+ ion via fluorescence ‘turn-on’ method. The Probe L could detect Al3+ by a sharp increment in fluorescence intensity (∼15 times) in a semi-aqueous DMSO medium. The detection limit of L towards Al3+ was calculated to be 50 nM, and the former undergoes a 1:1 stoichiometry binding with a higher binding constant of ∼ 2.14 × 104 M−1. Probe L detects Al3+ by the well-known chelation-enhanced fluorescence (CHEF) mechanism and inhibits C = N isomerization by fluorescence time-resolved measurement. Experimental results from FT-IR, NMR, and ESI mass spectrometry confirm the interaction mechanism between probe L and Al3+ ions, further supported by DFT calculations. In addition, the probe L fabricated paper strips could detect Al3+ in the naked eye under UV light.

Developing efficient electrode materials for detecting 4-nitrochlorobenzene (4-NCB) is highly desirable for living organisms and environmental safety. Herein, we designed a hierarchical 1D-2D nanostructure of zinc oxide nanorods@copper tin sulfide nanoflowers (ZnO-NRs@CTS-NFs) by a facile hydrothermal synthesis route for electrochemical detection of 4-NCB. The ZnO-NRs@CTS-NFs modified glassy carbon electrode (GCE) exhibits excellent electrocatalytic performance for 4-NCB, much higher than that of bare GCE, ZnO-NRs/GCE, and CTS-NFs/GCE. Such a desirable electrocatalytic performance is attributed to the large surface area, rich active sites, fast electron transfer through local pn junctions of CTS NFs on ZnO NRs, and the synergistic effect of the as-prepared ZnO-NRs@CTS-NFs nanocomposite. Under optimum conditions, the fabricated ZnO-NRs@CTS-NFs/GCE provides a trace-level detection limit with a wide detection range and high sensitivity. Besides, the fabricated electrochemical sensor displays good selectivity and reproducibility for 4-NCB detection. The practical application of the ZnO-NRs@CTS-NFs modified GCE exhibits satisfactory results in determining 4-NCB in river water, pond water, and industrial wastewater. These results demonstrate that the as-prepared ZnO-NRs@CTS-NFs nanostructures might be one of the most promising electrode materials for 4-NCB detection.

Morphological and compositional stabilities of pristine and metal-oxide-supported gold/gold-gallia nanostructures were determined at elevated temperatures (800 °C) for the first time. Emphasis was on the size and shape dependence of the transitional melting temperatures, from which conclusions were drawn predominantly from monitoring in-situ changes to plasmonic properties of the nanostructures. The morphological, crystalline, optical and elemental analyses supported and revealed new insights into temperature-driven morphological transformations. The experimentally-derived melting temperature of pristine nanostructures was corroborated using theoretical melting models, with the best results for the liquid skin melting model. The shape deformations and thermal expansion of pristine nanostructures were precluded by reinforcement of the plasmonic Au nanostructures with a matrix material of gallium oxide, which gave markedly different results in terms of enhancing thermal stability at temperatures where the pristine nanostructures were completely vaporized. The interfacial energies were likely the reason for the enhanced stability against shape transitions and/or melting, wherein it was found that the formative steps of gallia were insufficient to achieve these effects and that complete phase formation was necessary for stabilization. The insights concerning the reasons for the enhancements, the supportive role of the metal oxide matrix, the plasmonic stabilities of the Au nanoparticles, the shape dependence of the melting transitions and the crystalline stabilities of the composites in this report will help in predictive composite design for high-temperature applications such as sensing, catalysis, energy storage and design of compatible optical communication devices.

Bioglasses are used in applications related to bone rehabilitation and repair. The mechanical and bioactive properties of polysaccharides like alginate and agarose can be modulated or improved using bioglass nanoparticles. Further essential metal ions used as crosslinker have the potential to supplement cultured cells for better growth and proliferation. In this study, the alginate bioink is modulated for fabrication of tissue engineering scaffolds by extrusion-based 3D bioprinting using agarose, bioglass nanoparticles and combination of essential trace elements such as iron, zinc, and copper. Homogeneous bioink was obtained by in situ mixing and bioprinting of its components with twin screw extruder (TSE) based 3D bioprinting, and then distribution of metal ions was induced through post-printing diffusion of metal ions in the printed scaffolds. The mechanical and 3d bioprinting properties, microscopic structure, biocompatibility of the crosslinked alginate/agarose hydrogels were analyzed for different concentrations of bioglass. The adipose derived mesenchymal stem cells (ADMSC) and osteoblast cells (MC3T3) were used to evaluate this hydrogel's biological performances. The porosity of hydrogels significantly improves with the incorporation of the bioglass. More bioglass concentration results in improved mechanical (compressive, dynamic, and cyclic) and 3D bioprinting properties. Cell growth and extracellular matrix are also enhanced with bioglass concentration. For bioprinting of the bioinks, the advanced TSE head was attached to 3D bioprinter and in situ fabrication of cell encapsulated scaffold was obtained with optimized composition considering minimal effects on cell damage. Fabricated bioinks demonstrate a biocompatible and noncytotoxic scaffold for culturing MC3T3 and ADMSC, while bioglass controls the cellular behaviors such as cell growth and extracellular matrix formation.

Abstract Out of all the candidate plasmonic metals, copper has noteworthy optical characteristics and is also economically favourable for use. However, the stability of plasmonic copper nanomaterials against the loss of the plasmonic property is a setback. The present work is on the synthesis of oxidation-stable copper micro/nanoparticles (CuMps/NPs) at ambient conditions with chosen precursors, antioxidizing agents, polymeric capping agents and chelating ligands. The Surface Plasmon Response (SPR) response of the synthesized Cu structures and their morphological analyses are studied. The refined XRD data were subjected to a detailed structural investigation over fundamental aspects such as crystallite sizes, distortion and dislocation densities. We present herein micro/nanostructures of oxidation-stable plasmonic Cu. The validation of the aggregation and oxidation stabilities of the different synthesized samples make them a worthy choice for multiple plasmonic applications, along with showing the synthesis protocols as viable approaches for achieving such structures with a markedly increased shelf life.

In this report, photochemical synthesis of monodispersed gold (Au) and silver (Ag) nanoparticles (NPs) was reported using cholic acid functionalized star poly(DL-lactide) (CA-(PDLLA)) as a capping and reducing agent. CA-(PDLLA) was synthesized by ring-opening polymerization (ROP) of DL-lactide with a feed ratio of 1:120 (cholic acid: DL-lactide). The molecular weight of CA-(PDLLA) was measured by using the gel permeation chromatography (GPC) technique. The thermal properties of the polymer and its nanocomposite materials were studied by thermogravimetric analysis (TGA). The optical properties of Ag and Au NPs were studied by UV–visible absorption spectroscopy. Morphological studies and size of the polymer-nanocomposites were assessed by using field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) techniques. The percentage composition of Au and Ag present in the polymer-nanocomposites was calculated using energy-dispersive X-ray spectroscopic (EDX) analysis. Finally, the synthesized polymer-metal nanocomposites were used as heterogeneous catalysts for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as a model reaction and the apparent rate constant (kapp) values of CA-(PDLLA)-AuNPs and CA-(PDLLA)-AgNPs were found to be 5.76 × 10−4 s−1 and 19.7 × 10−4 s−1, respectively.

BackgroundPhotocatalysis is a green, environmentally friendly approach for converting organic contaminants into harmless byproducts. Especially, Bismuth oxyhalides (BiOX, where X = Cl, Br and I) have emerged as promising photocatalysts for wastewater treatment due to their layered-by-layered structure, strong chemical stability and nontoxicity in compare to other metal oxides, which makes the photocatalyst advantageous for photocatalytic application. MethodsThis review provides an overview of recent developments in the synthesis and application of BiOX-based porous photocatalysts for the removal of organic contaminants from wastewater. Firstly, morphology-controlled synthesis of BiOX in degradation of organic contaminants. Then, modulation of electronic structure through doping, facet engineering and surface engineering has been highlighted for better photocatalytic applications. Furthermore, fabrication of diverse heterojunctions and co-catalyst loading upon BiOX are introduced, which can vary photocatalytic activity towards the degradation of organic contaminants. Significant findingsFinally, this review ended on the future trend and prospects of BiOX for the creation of potential high-performance photocatalysts in the near future. The porous structure of BiOX improved photocatalytic activity, pollutant degradation efficiency, visible light response charge carrier separation, and stability. Overall, bismuth oxyhalide photocatalysts have a lot of potential for effective and long-term wastewater treatment, and their development represents an important step towards addressing the global water pollution crisis.

This paper presents the development of (002) textured Ti2AlN coated wear resistant tool utilizing reactive magnetron co - sputtering. The Ti2AlN coating was developed in two different Argon, Nitrogen ratios such as 64:3 and 64:4, the influence of these parameters was identified using crystallographic, microstructural, mechanical and tribological studies. Experimental studies were performed to compare the cutting force as well as the tool life of superimposed Ti2AlN tool with a commercial tool by turning titanium alloy (Ti-6Al-4V). Results from the experimental analysis revealed an 80–85 % increase in hardness, a 13–20 % decrease in wear rate and a 27 % increase in tool life for Ti2AlN coated cutting tool. According to chip morphology, there is a 12 % increase in shear angle, 43 % and 51 % decrease in friction angle and coefficient of friction respectively. The nanomechanical studies were performed which show a maximum hardness of 29.12 ± 5.4 GPa and minimum wear rate of 10.078 × 10−9 mm3/mN.m−1 for superimposed Ti2AlN.