Materials Chemistry

This work investigated the effect of polystyrene on the corrosive behaviour of hydrochloric (HCl) and tetraoxo sulphate VI (H2SO4) acids on mild steel using weight loss technique. Cold rolled mild steel sample with chemical composition C: 0.21%, Mn: 0.593%, Si: 0.044, S: 0.032% and Fe: 98.4% was used. Five different concentrations of the polystyrene were used in 200ml solution of the acids. The corosion rate and inhibition efficiencies of polystyrene as a corrosion inhibitor were determined at different concentrations in HCl and H2SO4 as it was varied from 1 ml to 5 ml. It was observed that corrosion of the mild steel reduced as the concentration of polystyrene increased but decreased with increase in time. From the work also, one can deduce that polystyrene is a good inhibitor going by its efficiencies in HCl and H2SO4 with up to about 90% efficiency for HCl and 84% efficiency for H2SO4. It was therefore concluded that introduction of polystyrene into acidic medium where mild steel...

High strength cements can be synthesised by alkali activation of  materials rich in Al2O3 and SiO2. In this study, amorphous aluminosilicate polymers produced by sodium silicate activation of metakaolinite were studied, with particular reference to chemical optimisation of the compressive strength according to the relative
concentrations of Si, Al and Na in the polymer. The sodium silicate was manufactured from silica fume and sodium hydroxide. The compressive strengths of polymers with Si :Al molar ratios of 1.0–3.0 and Na :Al molar ratios of 0.5–2.0 were considered. The polymers were cured at 75 uC for 24 h and their compressive strengths measured after aging for 7 days. The strength was found to depend systematically on the relative amounts of Si, Al and Na, with the maximum being 64 ¡ 3 MPa for an Si :Al : Na molar ratio of 2.5 : 1 : 1.3. X-Ray diffraction/scattering data indicate qualitatively that the bonding network in the amorphous aluminosilicate
alters systematically with composition.

Transparent conducting ZnO:F was deposited as thin films on soda lime glass substrates by atmospheric pressure chemical vapor deposition (CVD) deposition at substrate temperatures of 480–500 °C. The precursors diethylzinc, tetramethylethylenediamine and benzoyl fluoride were dissolved in xylene. The solution was nebulized ultrasonically and then flash vaporized by a carrier gas of nitrogen preheated to 150 °C. Ethanol was vaporized separately, and these vapors were then mixed to form a homogeneous vapor mixture. Good reproducibility was achieved using this new CVD method. Uniform thicknesses were obtained by moving the heated glass substrates through the deposition zone. The best electrical and optical properties were obtained when the precursor solution was aged for more than a week before use. The films were polycrystalline and highly oriented with the c-axis perpendicular to the substrate. The electrical resistivity of the films was as low as 5 × 10−4 Ωcm. The mobility was about ...

Straightforward synthetic routes to the preparation of transition metal phosphides or their chalcogenide analogues are highly desired due to their widespread applications, including catalysis. We report a facile and simple route for the preparation of a pure phase nickel phosphide (Ni 2 P) and phase transformations in the nickel sulfide (NiS) system through a solvent-less synthetic protocol. Decomposition of different sulfur-based complexes (dithiocarbamate, xanthate, and dithiophosphonate) of nickel(II) was investigated in the presence and absence of triphenylphosphine (TPP). The optimization of reaction parameters (nature of precursor, ratio of TPP, temperature, and time) indicated that phosphorus-and sulfur-containing inorganic dithiophosphonate complexes and TPP (1:1 mole ratio) produced pure nickel phosphide, whereas different phases of nickel sulfide were obtained from dithiocarbamate and xanthate precursors in the presence or absence of TPP. A plausible explanation of the sulfide or phosphide phase formation is suggested, and the performance of Ni 2 P was investigated as an electrocatalyst for supercapacitance and overall water-splitting reactions. The performance of Ni 2 P with the surface free of any capping agents is not well explored, as common synthetic methods are solution-based routes; therefore, the electrocatalytic performance was also compared with metal phosphides, prepared by other routes. The highest specific capacitance of 367 F/g was observed at 1 A/g, and the maximum energy and power density of Ni 2 P were calculated to be 17.9 Wh/kg and 6951 W/kg, respectively. The prepared nickel phosphide required overpotentials of 174 and 316 mV along with Tafel slopes of 115 and 95 mV/dec to achieve a current density of 10 mA/cm 2 for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), respectively.

Novel electronic materials play an ever-increasing role in technological applications. They cover a rather broad spectrum of materials that exhibit exotic transport and magnetic properties. These include superconductors, narrow band gap semiconductors, electronically active polymers, colossal magneto resistive systems, nanoscale electronic materials, and Fullerenes, to name a few. Understanding the interplay between strong electronic correlations and structural properties of these materials is important. In this communication, we report the growth and preliminary characterization of single crystal Cerium based intermetallic compounds that are known to show superconductivity at Tc = 2.3K.