Carbon-based TiO2-x heterostructure nanocomposites for enhanced photocatalytic degradation of dye molecules

Application of brown titanium dioxide (TiO_2-x) and its modified composite forms in the photocatalytic decomposition of organic pollutants in the environment is a promising way to provide solutions for environmental redemption. Herein, we report the synthesis of effective and stable TiO_2-x nanoparticles with g-C₃N₄, RGO, and multiwalled carbon nanotubes (CNTs) using a simple hydrothermal method. Among all the as-synthesized samples, excellent photocatalytic degradation activity was observed for RGO-TiO_2-x nanocomposite with high rate constants of 0.075 min^?1_, 0.083 min^?1 and 0.093 min^?1 for methylene blue, rhodamine-B, and rosebengal dyes under UV–Visible light irradiation, respectively. The altered bandgap (1.8 eV) and the large surface area of RGO-TiO_2-x nanocomposite impacts on both absorption of visible light and efficiency of photogenerated charge electron (e^?)/hole (h⁺) pair separation. This resulted in enhanced photocatalytic property of carbon-based TiO_2-x nanocomposites. A systematic study on the influence of different carbon nanostructures on the photocatalytic activity of brown TiO_2-x is carried out.     

Adsorption of anionic dye on eco-friendly synthesised reduced graphene oxide anchored with lanthanum aluminate: Isotherms,kinetics and statistical error analysis

In the present study we made an effort to deploy eco-friendly synthesized reduced graphene oxide/Lanthanum Alluminate nanocomposites (RGO-LaAlO₃) and Lanthanum Alluminate (LaAlO₃) as adsorbents to remove dye from the synthetic media. XRD, SEM, BET surface area and EDX have been used to characterize the above-mentioned adsorbents. The impacts of different factors like adsorbent dosage, the concentration of adsorbate and PH on adsorption were studied. The best fit linear and nonlinear equations for the adsorption isotherms and kinetic models had been examined. The sum of the normalized errors and the coefficient of determination were used to determine the best fit model. The experimental data were more aptly fitted for nonlinear forms of isotherms and kinetic equations. Pseudo-second-order and Freundlich isotherm model fits the equilibrium data satisfactorily. Methyl orange (MO) has been used as model dye pollutant and maximum adsorption capacity was found to be 469.7 and 702.2 mg g^?1 for LaAlO₃ and RGO-LaAlO₃, respectively.     

Silver nanoparticles anchored TiO2 nanotubes prepared using saponin extract as heterogeneous and recyclable catalysts for reduction of dyes

In the present study, we made an effort to synthesize silver nanoparticles anchored onto TiO₂ nanotubes using saponin extracted from Simarouba glauca oil seed meal. Obtained silver anchored TiO₂ nanotubes (Ag-TiO₂) were characterized using spectroscopic, microscopic and X‐ray diffraction techniques and used as catalysts for reduction of nitrophenol (NP), Methylene blue (MB), Methyl orange (MO) and Congo red (CR). The reduction reactions were carried out in aqueous medium in presence of NaBH₄ at room temperature. Progress of the catalytic reaction was observed by decolorization of the dye solution and monitored by recording UV–Vis spectra. It was observed that Ag-TiO₂ nanotubes emerged as an effective catalyst in reducing the dyes in the time range of 2–7 min with pseudo first-order kinetics and also effective in the simultaneous reduction of all dyes in 12 min. In addition, the catalyst showed a good recovery yield with unaffected catalytic efficiency up to ten cycles.     

Storage studies of tomato and bell pepper using eco‐friendly films

Tomato (Lycopersicon esculentum) and bell pepper (Capsicum annuum), packaged in cartons (approximately 0.35 kg per box) covered with either eco‐friendly chitosan film or synthetic petroleum‐based low‐density polyethylene (LDPE) film, were stored at room temperature (27 ± 1 °C) and 65 ± 3% relative humidity (RH). Fruits were withdrawn periodically and changes in physico‐chemical, instrumental and sensory characteristics were analysed. During storage, oxygen levels showed only marginal changes, while CO₂ levels showed a gradual increase, especially so in LDPE film‐covered cartons. The fresh weight loss, colour, firmness, formation of defective spots and shrivelling showed greater changes for unpackaged fruits as well as for those in LDPE film‐covered cartons, in comparison with fruits stored in chitosan film‐covered cartons, which retained many of the desirable attributes. Principle component analysis of data from sensory or instrumental sensory analyses indicated segregation of samples stored under different conditions with respect to both desirable and undesirable attributes. The fruits showed greater deterioration, including the loss of characteristic bell pepper odour, when packaged in cartons covered with LDPE films, while those packaged in chitosan film retained more of the desirable quality attributes for a longer period. Copyright © 2006 Society of Chemical Industry     

Study on the DC supply and charging effect on the growth of carbon nanotubes and their electrochemical properties

Journal of Materials Science: Materials in Electronics - Preparation of chirality-defined few-walled CNT (FWCNT) is one of the major challenges in the carbon nanotube (CNT) fields. In the last two...     

Reduced graphene oxide wrapped sulfur nanocomposite as cathode material for lithium sulfur battery

Sulfur has been investigated as an active electrode material for secondary batteries due to theoretically specific capacity compared to the lithium-ion battery. In the present study, reduced graphene oxide (RGO) sheets wrapped Sulfur nanocomposite (S-RGO) synthesized by hydrothermal method and confirmed the wrapping of RGO sheets on Sulfur nanoparticles by various analytical techniques. The synthesized S-RGO nanocomposite demonstrated improved interaction of sulfur nanoparticles with RGO which is confirmed through XPS analysis. The synthesized S-RGO resulted in significantly improved reversible specific capacity and higher rate capability (823 mAh/g at 0.1C, 400 mAh/g at 1C) with 77 wt% of sulfur loading amount on the cathode of the Li–S battery. Therefore, the present study opens up new insights into sustainable development in the field of Li–S battery energy storage applications.     

One-pot supercritical water synthesis of Bi2MoO6-RGO 2D heterostructure as anodes for Li-ion batteries

Two dimensional (2D) materials stacked with Van der waals bonding to obtain a heterostructure have always generated tailored physical and chemical properties. In this paper, the development and application of single-phase 2D Bi₂MoO₆-reduced graphene oxide (BMO-RGO) heterostructure by one-pot supercritical water (SCW) method is reported for the first time. The as-synthesized nanocomposite of BMO-RGO with single-phase orthorhombic crystal structure is confirmed by XRD. The 2D nanoflake morphology was observed under transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Fourier transform infrared spectroscopy is performed to confirm the presence of BMO-RGO, RGO, and other functional groups, respectively. The specific capacities obtained through charge-discharge measurements from BMO and BMO-RGO heterostructure nanocomposites are compared and the optimization of RGO wt% is established. After 50 cycles, the capacity retention is around 202 mA h g^?1 for BMO with 24 wt% RGO (BMO-24RGO) nanocomposite. This value is higher in comparison to pure BMO nanoflakes which have a capacity retention of 25 mA h g^?1. These results show the influence of RGO content on the performance of electrochemical measurements when compared to pure BMO and BMO-24RGO electrodes. One-pot SCW synthesis is found to be a reliable method for the synthesis of BMO-RGO nanocomposite.     

Identification and characterization of the n‐6 fatty acid‐producing Mucor rouxii native isolate CFR‐G15

In zygomycetes fungi, many Mucor spp. have been known to produce γ‐linolenic acid (GLA) in their biomass. Among 250 soil samples screened, 20 Mucor isolates showed GLA in their mycelial mass under normal cultivation conditions. Sudan Black B was used for screening their qualitative oleaginesity. Among the representative isolates, Mucor sp. CFR‐G15, when grown in a fat‐producing medium, showed a maximum lipid content of 30 ± 1.32% in its mycelia and 14.42 ± 0.74% GLA. By using gene‐specific primers, the 18S rRNA gene and the Δ⁶ DES gene were amplified by PCR technique. The nucleotide sequences of the 18S rRNA and Δ⁶ DES genes exhibited >98% homology with M. rouxii ATCC 24905 (accession nos. AF117923 and AF296076, respectively), suggesting taxonomic identity. The native isolate M. rouxii CFR‐G15 reported in this study was found to be promising for the development of an economical process in the industrial production of GLA.