Synthesis, Characterization and Photocatalytic Behavior of SiO2 @nitrized-TiO2 Nanocomposites Obtained by a Straightforward Novel Approach

We report on the facile synthesis of SiO2 @nitrized-TiO2 nanocomposite (NST) by calcination of TiO2 xerogel with OctaAmmonium POSS® (N-POSS; POSS=polyhedral oligomeric silsesquioxanes). The as-obtained nanoporous mixed oxide is constituted by uniformly distributed SiO2 and nitrized-TiO2 , where the silica component is present in an amorphous state and TiO2 in an anatase/rutile mixed phase (92.1 % vs. 7.9 %, respectively) with very small anatase crystallites (3.7 nm). The TiO2 lattice is nitrized both at interstitial and substitutional positions. NST features a negatively charged surface with a remarkable surface area (406 m2  g-1 ), endowed with special adsorption capabilities towards cationic dyes. Its photocatalytic behavior was tested by following the degradation of standard aqueous methylene blue and methyl orange solutions under UV and visible light irradiation, according to ISO 10678:2010. For comparison, analogous investigations were carried out on a silica-free N-TiO2 , obtained by using NH4 Cl as nitrogen source.

Novel N,Cl-doped deep eutectic solvents-based carbon dots as a selective fluorescent probe for determination of morphine in food

In the present study, new N,Cl co-doped carbon dots (N,Cl-CDs) based on deep eutectic solvent (DES) were fabricated by a facile hydrothermal process. This fluorescent probe exhibited a good quantum yield of 14% and was applied for the sensitive and selective quantification of morphine in foods. In addition, the influence of solution pH, interaction time, system temperature, interfering substances and analogues on the determination was also investigated. Under the optimized conditions, the luminescence intensity of carbon dots increased linearly with the addition of morphine in the concentration range of (0.15–280.25) μg mL⁻¹ (R² > 0.9969) and the limit of detection (LOD) of 46.5 ng mL⁻¹. Based on these results, it is suggested that N,Cl-CDs is a promising fluorescent probe for sensitive and selective quantification of morphine in foods.

A schematic illustrating the synthesis and morphine detection of N,Cl-CDs.

Application of highly efficient and reusable H3PW12O40/Fe3O4@SiO2-Pr-Pi nanocatalyst for preparation of dihydro-2-oxypyrrole derivatives

In this study, a novel heterogeneous catalyst (H3PW12O40/Fe3O4@SiO2-Pr-Pi) was prepared via immobilization of H3PW12O40 on the surface of piperidine modified magnetic nanoparticles (Fe3O4@SiO2-Pr-Pi). The synthesis of dihydro-2-oxypyrrole derivatives was carried out by the reaction of substituted aniline, formaldehyde, and dimethyl acetylenedicarboxylate, promoted by H3PW12O40/Fe3O4@SiO2-Pr-Pi in EtOH. The formation of resultant catalyst was confirmed by FTIR spectroscopy, FE-SEM, EDX, VSM, and TGA techniques. The magnetically separable and environmentally friendly nanostructured catalyst remained quite stable during reaction conditions and was reused for at least five recycle runs.

Highly Efficient Visible-Light-Induced Photocatalytic Hydrogen Production via Water Splitting using FeCl3 -Based Ionic Liquids as Homogeneous Photocatalysts

The ionic liquid (IL) 1-octyl-3-methylimidazolium bromide/FeCl₃ [OMIM]Br/FeCl₃ was prepared with three molar ratios of [OMIM]Br/FeCl₃ (0.5 : 1, 1 : 1, and 2 : 1), and fully characterized through ¹ H and ¹³ C NMR, Fourier-transform IR, and Raman spectroscopic techniques. The optical properties of the prepared [OMIM]Br/FeCl₃ ILs were revealed via diffuse reflectance and photoluminescence spectra. The photocatalytic activity of [OMIM]Br/FeCl₃ ILs as homogenous photocatalysts were investigated towards hydrogen generation from methanol/water mixtures under visible light irradiation. The FeCl₃ -based IL with [OMIM]Br/FeCl₃ molar ratio of 1 : 1 exhibited the highest visible light photocatalytic activity with a hydrogen productivity of 243.2 mmol h^-1  g^-1 and a hydrogen purity of 95.5 %; such a high hydrogen yield and purity was reported for the first time. It was proposed that [OMIM] Br acted as an electron acceptor, which delayed the electron-hole pair recombination of FeCl₃ . Also, [OMIM] Br could capture the produced carbon dioxide that is released with hydrogen gas. Additionally, [OMIM] Br/FeCl₃ could be reused six times with nearly the same photocatalytic activity. These outstanding credits in terms of hydrogen generation rate and purity plus the economic feasibility, through several cycles of reuse, could certify such an IL as a promising photocatalyst for employment in water splitting. This paper suggests ways forward for research to develop the use of ILs as efficient and effective photocatalysts for hydrogen generation via water splitting.

Rapid preparation of terbium-doped titanium dioxide nanoparticles and their enhanced photocatalytic performance

Further applications of photocatalysis were limited by the high recombination probability of photo-induced electron-hole pairs in traditional titanium dioxide nanoparticles (TiO₂ NPs). Herein, we modified them with rare earth metal via a facile sol-gel method, using tetrabutyl titanate as a precursor and terbium (III) nitrate hexahydrate as terbium (Tb) source. The resulting samples with different Tb doping amounts (from 0 to 2%) have been characterized by X-ray diffraction, UV-visible diffuse reflectance spectroscopy, X-ray photo-electron spectroscopy and a scanning electron microscope. The photocatalytic performance of Tb-doped TiO₂ was evaluated by the degradation of methylene blue. The effects of Tb doping amount and initial pH value of solution were investigated in detail. The composite with Tb doping amount of 1.0 wt% showed the highest photocatalytic performance. It exhibited approximately three times enhancement in photocatalytic activity with a reaction rate constant of 0.2314 h^-1 when compared with that of commercial P25 (0.0827 h^-1). In addition, it presented low toxicity on zebrafishes with 96 h-LC₅₀ of 23.2 mg l^-1, and has been proved to be reusable for at least four cycles without significant loss of photocatalytic activity. A probable photocatalytic mechanism of Tb-doped TiO₂ was proposed according to the active species trapping experiments. The high photocatalytic performance, excellent reusability and low toxicity of Tb-doped TiO₂ indicated that it is a promising candidate material in the future treatment of dye wastewater.

New Developments in Material Preparation Using a Combination of Ionic Liquids and Microwave Irradiation

During recent years, synthetic methods combining microwaves and ionic liquids became accepted as a promising methodology for various materials preparations because of their high efficiency and low energy consumption. Ionic liquids with high polarity are heated rapidly, volumetrically and simultaneously under microwave irradiation. Hence, combination of microwave irradiation as a heating source with ionic liquids with various roles (e.g., solvent, additive, template or reactant) opened a completely new technique in the last twenty years for nanomaterials and polymers preparation for applications in various materials science fields including polymer science. This review summarizes recent developments of some common materials syntheses using microwave-assisted ionic liquid method with a focus on inorganic nanomaterials, polymers, carbon-derived composites and biomass-based composites. After that, the mechanisms involved in microwave-assisted ionic-liquid (MAIL) are discussed briefly. This review also highlights the role of ionic liquids in the reaction and crucial issues that should be addressed in future research involving this synthesis technique.

Acidic ionic liquids: an alternative to HF for {001} reactive facet controlled synthesis of anatase titania

A HF free method for the controlled synthesis of nanosized TiO₂ with a higher percentage of {001} reactive facets.

Ureas as safe carbonyl sources for the synthesis of carbamates with deep eutectic solvents (DESs) as efficient and recyclable solvent/catalyst systems

A simple, efficient and eco-friendly one-pot synthesis of primary, N-mono- and N-disubstituted carbamates is developed from ureas.