Nanostructured TiO2 Sensitized with MoS2 Nanoflowers for Enhanced Photodegradation Efficiency toward Methyl Orange.

Nanostructured titanium dioxide (TiO2) has a potential platform for the removal of organic contaminants, but it has some limitations. To overcome these limitations, we devised a promising strategy in the present work, the heterostructures of TiO2 sensitized by molybdenum disulfide (MoS2) nanoflowers synthesized by the mechanochemical route and utilized as an efficient photocatalyst for methyl orange (MO) degradation. The surface of TiO2 sensitized by MoS2 was comprehensively characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence spectroscopy (PL), Brunauer-Emmett-Teller (BET) surface area, and thermogravimetric analysis (TGA). From XRD results, the optimized MoS2-TiO2 (5.0 wt %) nanocomposite showcases the lowest crystallite size of 14.79 nm than pristine TiO2 (20 nm). The FT-IR and XPS analyses of the MoS2-TiO2 nanocomposite exhibit the strong interaction between MoS2 and TiO2. The photocatalytic results show that sensitization of TiO2 by MoS2 drastically enhanced the photocatalytic activity of pristine TiO2. According to the obtained results, the optimal amount of MoS2 loading was assumed to be 5.0 wt %, which exhibited a 21% increment of MO photodegradation efficiency compared to pristine TiO2 under UV-vis light. The outline of the overall study describes the superior photocatalytic performance of 5.0 wt % MoS2-TiO2 nanocomposite which is ascribed to the delayed recombination by efficient charge transfer, high surface area, and elevated surface oxygen vacancies. The context of the obtained results designates that the sensitization of TiO2 with MoS2 is a very efficient nanomaterial for photocatalytic applications.

Scraps to superior anodes for Li-ion batteries: Sustainable and scalable upgrading of waste rust.

The abundant iron rust of no value generated from industrial scraps presents environmental problem and burden. Chemical etching and related methods deployed to convert rust into α-Fe2O3 nanoparticles, however, have serious shortcomings namely higher chemical consumption and generation of secondary pollution. In an unprecedented illustration, herein the intercalation of ammonium bicarbonate (ABC) as a gaseous bubble template into bulky iron rust is described; formation of ammonium iron carbonate hydroxide hydrate and the reduction of particle size using a simple ball milling method followed by calcination is accomplished. The salient features of ABC, optimization of ratios (rust: ABC), and the ideal calcination temperature were optimized for attaining desirable properties of meso-α-Fe2O3 NPs. The electrode obtained at 500 °C delivered a superior reversible capacity of 1,055 mAh g-1 at 1 A g-1 over 100 cycles, which is comparable to the best performance reported for meso-α-Fe2O3 NPs. The superior electrochemical performance is ascribed to the porous nature of meso-α-Fe2O3 NPs maximizing the surface area, ensuring good charge transfer kinetics and enhanced pseudocapacitive contribution. Thus, we believe that the high-energy ball milling (HEBM) process represents a novel route for the scalable recycling of iron rust scraps for promoting the sustainable production of lithium-ion batteries.

Direct hydrothermal synthesis of amine-functionalized cubic hematite (C-Fe2O3) and sonochemical deposition of nanosized Au for its application as a visible-light photocatalyst.

Cubic-shaped hematite (C-Fe2O3) functionalized with amine groups was directly prepared via one-pot hydrothermal reaction of Fe3+ with 1,12-diaminododecane (DA-12) in aqueous solution (50% ethanol). Herein, DA-12 (as a Lewis acid) promoted the aggregation of α-FeOOH nanorods with Lewis base sites, leading to the rapid recrystallization and conversion into uniform C-Fe2O3. C-Fe2O3 was subsequently deposited with nanosized Au via sonochemical reduction of 1.0 wt% HAuCl4 (0.1-0.8 mL), hereafter referred to as Au-deposited C-Fe2O3 (C-Fe2O3@Au). X-ray diffraction patterns of C-Fe2O3@Au confirmed the hexagonal crystalline phases of hematite and crystalline Au (111) and showed a weak broad band attributed to the amorphous carbon of DA-12. C-Fe2O3@Au was tested as a visible-light photocatalyst towards the degradation of methylene blue (MB) dye. C-Fe2O3@Au (0.1-0.4 mL of 1.0 wt% HAuCl4) exhibited 6-8 times higher photocatalytic activity than the Au-free counterpart (C-Fe2O3). The enhanced photocatalysis was mainly attributed to the improved separation efficiency of photo-excited charge carriers, i.e., the facilitated transport of electrons from the conduction band to the lower lying Fermi level of Au. However, the photocatalytic activity of C-Fe2O3@Au (0.8 mL of 1.0 wt% HAuCl4) was decreased probably due to the reduction of active sites for MB adsorption by the high coverage of the Au layer. The combined hydrothermal and sonochemical methods provided the direct synthetic route to cubic-shaped hematite decorated with nanosized Au and surface amine functionality as a promising visible-light photocatalyst.