Li-storage and cycling properties of Sn–Sb-mixed oxides, (M1/2Sb1/2Sn)O4, M = In, Fe

The mixed oxide compounds, (M_1/2Sb_1/2Sn)O₄, M = In and Fe are prepared by the high-temperature solid-state reaction, at 800 °C for M = In and at 1,150 °C for M = Fe. High-energy ballmilling is used to reduce the particle size to nm-range. The compounds are characterized by X-ray diffraction, Rietveld refinement, scanning electron microscopy, and Brunauer–Emmett–Teller surface area methods. The Li-storage and cycling properties of the bare and ballmilled compounds are evaluated by galvanostatic cycling at ~0.15 C and in the voltage ranges 0.005–1.0 and 0.005–1.2 V vs. Li up to 50 (or 100) cycles and by cyclic voltammetry (CV) at room temperature. Effect of electrode heat treatment and carbon nanotube (CNT) addition is also studied. Initial reversible capacities in the range 425–550 mAh g^?1 are observed depending on the metal (M) upper cut-off voltage, CNT content and electrode heat treatment. Ballmilled (In_1/2Sb_1/2Sn)O₄ showed a stable capacity of 445 mAh g^-1 up to 30 cycles and 5 % capacity fading after 50 cycles. In all other cases, capacity fading is observed ranging from 9 to 60 %. The CV showed that the main cathodic and anodic peaks occur at 0.15–0.25 V and ~0.5 V vs. Li, respectively, for both M. The reaction mechanism involves alloying–de-alloying reactions of Sn and In with Li₃Sb or Fe acting as conducting matrix, and corroborated by the ex-situ X-ray diffraction data on (In_1/2Sb_1/2Sn)O₄.     

Synthesis and Characterization of Poly[N-Vinyl-2-Pyrrolidone-Polyethylene Glycol Diacrylate] Copolymeric Hydrogels for Drug Delivery

Abstract

Novel polymeric biodegradable and biocompatible copolymeric hydrogels based on N-vinyl-2-pyrrolidone (NVP) and polyethylene glycol diacrylate (PAC) were designed and synthesized. PAC macromonomer was synthesized by a modified procedure and characterized. Poly[N-vinyl-2-pyrrolidone-polyethylene glycol diacrylate] (Poly[NVP-PAC]) hydrogels were synthesized by varying the concentration of PAC. Azobisisobutyronitrile (AIBN) was used as the free radical initiator and N,N¹-methylene bis(acryl-amide) (BIS) was employed as the crosslinking agent. These hydrogels were characterized by various spectroscopic techniques. Fourier transform-infrared spectroscopy (FT-IR) confirms the formation of copolymer. Thermogravimetric analysis (TGA) curves obtained were continuous indicating the formation of copolymer. The glass transition temperature (T_g) of the copolymer was measured using differential scanning calorimetry (DSC). The equilibrium swelling measurements were carried out in simulated gastric and intestinal fluids (SGF & SIF). These swelling studies indicated that these gels had a higher sorption capacity in SIF when compared to that in SGF. 5-Fuorouracil (5-FU), an anti-cancer drug was entrapped in these hydrogels and the in-vitro release profiles were established in a sequential manner in SGF and SIF. About 50–56% of the drug entrapped was released in a period of 10 days.     

Synthesis and Enhanced Photocatalytic Activity of Visible-Light-Driven Co-Doped Bi2MoO6 Photocatalyst with Flower-Like Nanostructures

Russian Journal of Physical Chemistry A - Co-doped Bi2MoO6 photocatalyst has been synthesized by a simple and facile solvothermal method. It exhibits the flower-like microspheres composed of...     

Multimetallic Oxynitrides Nanoparticles for a New Generation of Photocatalysts

A versatile synthetic strategy for the preparation of multimetallic oxynitrides has been designed and here exemplarily discussed considering the preparation of nanoscaled zinc–gallium oxynitrides and zinc–gallium–indium oxynitrides, two important photocatalysts of new generation, which proved to be active in key energy related processes from pollutant decomposition to overall water splitting. The synthesis presented here allows the preparation of small nanoparticles (less than 20 nm in average diameter), well-defined in size and shape, yet highly crystalline and with the highest surface area reported so far (up to 80 m² g⁻¹). X-ray diffraction studies show that the final material is not a mixture of single oxides but a distinctive compound. The photocatalytic properties of the oxynitrides have been tested towards the decomposition of an organic dye (as a model reaction for the decomposition of air pollutants), showing better photocatalytic performances than the corresponding pure phases (reaction constant 0.22 h⁻¹), whereas almost no reaction was observed in absence of catalyst or in the dark. The photocatalysts have been also tested for H₂ evolution (semi-reaction of the water splitting process) with results comparable to the best literature values but leaving room for further improvement.     

Design,Synthesis, and Evaluation of Isoxazole-Thiadiazole Linked Carbazole Hybrids as Anticancer Agents

Russian Journal of General Chemistry - A series of isoxazole-thiadiazole linked carbazole derivatives 12a–12j are synthesized and their chemical structures confirmed by 1H and 13C NMR and...     

Synthesis of phenanthroimidazole-based four coordinate organoboron compounds

The synthesis of N,C-coordinated organoboron compounds (B1-B4) based on phenanthroimidazole described. All the compounds were characterized by various spectroscopic techniques. Single crystal X-ray diffraction analysis of the compounds B1 and B3 revealed that the vicinity around the boron atom adopts tetrahedral geometry. Except compound B4, other organoboron compounds (B1-B3) does not show solvatochromism. All our newly synthesized organoboron compounds exhibited moderate to good solution state quantum yields (0.07–0.88) and moderate solid state quantum yields.     

Selective Methylation of Phenol,Aniline and Catechol with Dimethyl Carbonate Over Calcined Mg-Al Hydrotalcites

Calcined Mg-Al hydrotalcites (Mg/Al=3) can be used as an efficient catalyst in the selective O-methylation of phenol and catechol and N-monomethylation of aniline employing dimethylcarbonate (DMC) as a methylating agent in vapor phase at 275°C.     

Phase Transition and Structural Investigations in 50.5, 50.6 and 50.7

Abstract

We report X-ray diffraction, density, ultrasonic velocity and refractive index studies in the N(p-n-pentyloxy benzylidene) p-n-alkylaniline compounds, viz. 50.5, 50.6 and 50.7. The nematic-smectic A (NA) transition is found to be weak first order in 50.6 while it is second order in 50.5 and 50.7. The salient features observed are cybotactic clusters in the nematic phase in all the compounds, molecular tilt which was inferred due to the end alkyl chains tilt causing orienta-tional disorder (smaller orientational order parameters ‘s’ than expected) in smectic A phase, smectic F phase and large tilt angle variation in smectic C phase in a small temperature range in 50.5. The observed results are discussed in the light of available data in other n0.m compounds.