Sol-gel based simonkolleite nanopetals with SnO2 nanoparticles in graphite-like amorphous carbon as an efficient and reusable photocatalyst

We report a new sol-gel nanocomposite (STC) having simonkolleite nanopetals (SC) and quasi-spherical tin oxide (SO) nanoparticles embedded in graphite-like amorphous carbon (C) as an efficient and reusable photocatalyst for the degradation of rhodamine 6G dye under UV (254 nm) illumination. The STC was synthesized using vacuum curing (450 degrees C) of precursor gel derived from a sol (Zn : Sn, 2 : 1) in 2-methoxyethanol with acetylacetone. The presence of tetragonal SO well decorated on rhombohedral SC forming nanoheterostructures in the carbon matrix was identified by X-ray diffraction, micro-Raman and X-ray photoelectron spectroscopy and electron microscopes (field emission scanning electron and transmission electron) studies. Carbon content and thermal weight loss behaviour in STC were studied by carbon determinator and thermogravimetry. The nanocomposite showed high photocatalytic activity (10(-5) M dye solution degraded completely in 32 min). Reusability test of the photocatalyst exhibited about 95% of dye degradation after five successive recycles. In addition to accelerating photo-induced charge carrier separation and electron transport in the nanoheterostructures as revealed from electrochemical impedance spectroscopy response of the UV-exposed nanocomposite, an active role of the carbon at an optimum content (similar to 18%) was found for generating high BET specific surface area (similar to 143 m(2) g(-1)). This simple synthesis strategy could open a new avenue to the development of sol-gel nanocomposites as efficient and reusable photocatalysts from various simonkolleite-based metal oxide semiconductors embedded in graphite-like amorphous carbon

Fabrication and characterization of sol-gel-based coatings on quartz glass to obtain antireflective effect at 1054 nm for optics of high power Nd:phosphate glass laser

In order to obtain higher laser-induced damage threshold (LIDT) and lower loss of laser radiation, the incident radiation must have an insignificant absorbance and high anti-reflectance. In this work, a single-layer porous SiO2-based anti-reflective (AR) coating for the optics of Nd:phosphate laser system has been developed on quartz glass optics adopting sol-gel dip coating technique, following quarter wavelength optical design. As measured by spectroscopic ellipsometer, the refractive index (RI) of the coated layer is found to be similar to 1.2. A maximum transmittance of similar to 99% in single-layer-coated quartz glass has been achieved at 1054 nm. In addition, the non-quarter wavelength-based double layer with an optical design (glass/ 0.7153 M / 1.134 L / air) and triple-layer AR coating with an optical design (glass / 0.28 H / 1.65 M / 1.03 L / air, where H, M and L indicate one-quarter wave thick layers of high, medium and low RI materials) have been fabricated. The deposition of M and H layers has been made from mixed metal oxide precursor sols of zirconia-silica, while L has been made from silica precursor sol to obtain porous silica coating. A maximum transmittance of about 98.1 and 97.6% was found at 1054 nm in double- and triple-layer AR-coated samples, respectively. The LIDT values have been measured on the AR coatings. Based upon the number of layers in the AR coatings, the LIDT values varied in the range of 8.7-2.4 J cm(-2) starting from single to double to triple layer. The AR coatings developed by sol-gel dip coating technique could find application in Nd:phosphate high power laser system

Effect of Ga doping on Microstructural, Optical and Photocatalytic Properties of Nanostructured Zinc Oxide Thin Films

Ga doped nanostructured zinc oxide thin films (thickness, 160-170 nm) on pure silica glass substrate were prepared from zinc acetate based precursor solutions by varying Ga doping level (0 to 6%). The presence of nanocrystalline hexagonal ZnO was confirmed by X-ray diffraction study whereas the field emission scanning and transmission electron microscopic analyses evidenced the existence of quasi-spherical ZnO with a decreased trend in crystallite/particle size vis-à-vis an enhancement of direct band gap energy of the films on increasing the doping level. Root means square (RMS) film surface roughness was determined by atomic force microscope and found maximum RMS roughness value in 1% doped film. Photoluminescence (PL) emission spectral study revealed the formation of various intrinsic/extrinsic defects along with the presence of characteristics band edge emission of ZnO at ~ 385 nm (UVPL). However, a lowest relative intensity of the UVPL emission was found in 1% doped film (G1ZO), indicating an appreciable decrease in the recombination rate of photogenerated charge carriers in the semiconductor. The photocatalytic activity of the films towards degradation of rhodamine 6G dye was performed under UV (254 nm) and obtained the maximum value of dye degradation rate constant (considering first order reaction kinetics) in 1% doped film (G1ZO). On increasing doping level, the trend in change of defect concentration (oxygen vacancies) as analyzed by Raman spectral study was found identical with the dye photodegradation activity of the films. The G1ZO film would expect to decompose micro-organisms even under exposure of visible light

Indium Oxide Based Nanomaterials: Fabrication Strategies, Properties, Applications, Challenges and Future Prospect

Nanostructured metal oxide semiconductors (MOS) in the form of thin film or bulk attract significant interest of materials researchers in both basic and applied sciences. Among these important MOSs, indium oxide (IO) is a valuable one due to its novel properties and wide range of applications in diversified fields. IO based nanostructured thin films possess excellent visible transparency, metal-like electrical conductivity and infrared reflectance properties. This chapter mainly highlights the synthesis strategies of IO based bulk nanomaterials with variable morphologies starting from spherical nanoparticles to nano-rods, nano-wires, nano-needles, nanopencils, nanopushpins etc. In addition, thin film deposition and periodic 1-dimensional (1D)/2-dimensional (2D) surface texturing techniques of IO based nanostructured thin films vis-à-vis their functional properties and applications have been discussed. The chapter covers a state-of-the-art survey on the fabrication strategies and recent advancement in the properties of IO based nanomaterials with their different areas of applications. Finally, the challenges and future prospect of IO based nanomaterials have been discussed briefly

Fabrication and multifunctional properties of fluorine-free durable nickel stearate based superhydrophobic cotton fabric

A fluorine-free superhydrophobic cotton fabric based on nickel stearate with multifunctional properties has been fabricated by a two step simple solution process. The cotton fabric (aNS-CF) exhibits static water contact angle, similar to 160 degrees, and water shedding angle, < 10 degrees, due to in-situ formation of hierarchical (micro and nano) broccoli-like structures of nickel stearate. The superhydrophobic cotton fabric, having superoleophilic property, has been used for separation of a series of light/heavy oil-water mixtures, and similar to 99% separation efficiency has been achieved after 10 cycles of separation process and it has been found to be slightly reduced to similar to 98% after 50 cycles. Antifouling and self-cleaning performance of the fabric has been evaluated effectively using solid and liquid contaminants as well as some common food liquids. The coating exhibits significant mechanical and chemical robustness and laundering durability in harsh conditions. The coated fabric possesses antibacterial (gram-negative E. coli and gram-positive S. aureus) and antifungal (C. albicans) properties leading to similar to 99.99% reduction in microbial growth, which has been remarkably sustained after 50 cycles of washing, abrasion and separation of oil-water mixtures. The stable multifunctional properties of the fabric exhibits a great potential towards a huge domain of practical implementations in smart textiles. GRAPHICS]

Development of superhydrophobic coating from biowaste and natural wax

Nowadays, superhydrophobic coatings (SHCs) fabricated from eco-friendly and sustainable materials are high in demand as they do not contribute to additional carbon footprint. In the present work, biowaste eggshell powder and food grade natural beeswax based SHC with static water contact angle, SCA ti 156 degrees, and sliding angle, SA 150 degrees) and also prevents adherence of the liquids. The fabricated coating also exhibits significant stability towards handling. In addition, the SHC inhibits protein adsorption on its surface. Thus, the fabricated eco-friendly SHC can be used as a potential liquid anti-adhesive food packaging coating to prevent wastage of common drinks consumed in our daily life.Copyright (c) 2022 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Smart and Sustainable Developments in Materials, Manufacturing and Energy Engineerin

Fabrication and multifunctional properties of marigold-like nanostructured beta-Ni(OH)(2) coated cotton fabric

Oil spillage from petroleum industry and also the mixing of industrial wastewater into water bodies are some of the major ways of water pollution. Low cost, biodegradable and biocompatible materials are highly required for tackling the pollution problem without causing further indirect pollution. In this work, a superamphiphilic nanomarigold-like beta-Ni(OH)(2) based coating on commercial cotton fabric (bNH-CF) has been fabricated by a simple one pot hydrothermal process. The fabric is able to simultaneously separate oil and water from oil-water mixtures where the sample is pre-wetted by either oil or water. The coated fabric shows under-oil superhydrophobicity and underwater superoleophobicity. The sample is able to separate both light and heavy oils from oil-water mixtures, oil-alkaline/acidic/salt/hot water mixtures with similar to 99% separation efficiency. In addition, it shows an excellent reusability (up to 50 cycles) with superior mechanical and chemical durability under harsh conditions without affecting the nanomarigold-like structure of beta-Ni(OH)(2) that developed upon the cotton fabric. The presence of beta-Ni(OH)(2) coated fabric shows significant bacterial (E. coli and S. aureus) and fungal (C. albicans) reduction in contaminated water. Hence, the coated cotton fabric fabricated by cost effective process can be useful for hassle-free simultaneous separation of oil-water mixtures as well as removal/growth inhibition of microbes from wastewater. The coated fabric also shows significant electrical conductivity. On the other hand, hexadecyltrimethoxysilane modified beta-Ni(OH)(2) coated fabric (bNHS-CF) shows excellent in-air superhydrophobicity, self-cleaning and anti-staining properties.Thus, the versatility of coated fabric can broaden the domain of practical applications as antimicrobial and superwetting multifunctional textiles. GRAPHICS]

Green synthesis of hierarchically structured Ag-Cu2O on cotton fabric with sustained antimicrobial activity and on-demand oil-water separation ability

Film deposition/modification of cotton fabric surface is an effective way to impart multiple functionalities towards a broad range of applications. In this work, we demonstrate a facile approach for the green fabrication of hierarchical hollow structures of Ag-Cu2O on cotton fabric (ACN). The effect of key parameters such as time, temperature, precursor concentrations, and type of substrates upon the formation of a unique mud-dauber wasp nest-like structure has been studied and also the formation mechanism of the structure has been proposed. The fabric shows underwater superoleophobicity owing to the presence of hierarchical surface structures and after modification with hexadecyltrimethoxysilane (ACNS), it also shows superhydrophobicity. By virtue of switchable super-wettability, the fabric has been used for on-demand separation of light oil-water and heavy oil-water mixtures with similar to 99% separation efficiency and superior reusability. In addition, the coated fabric, ACNS exhibits an excellent self-cleaning ability towards solid and liquid contaminants. Moreover, the coated fabric, ACN shows antimicrobial activity towards bacteria E. coli and S. aureus and fungi C. albicans with 100% microbial reduction efficiency. The superhydrophobic cotton fabric (ACNS) has been employed to enhance the longevity of antimicrobial activity by hindering the uninhibited release of copper and silver ions. As a result, an efficient and sustainable antimicrobial activity up to 90 days has been achieved. This modification strategy could be useful for advancing research in the field of surface science