NOPR Collection:

Hydrothermal synthesis and characterization of lanthanide oxalates: In situ oxalate formation from tartaric acid in presence of KI

2016-07-20T04:14:31Z

Title: Hydrothermal synthesis and characterization of lanthanide oxalates: In situ oxalate formation from tartaric acid in presence of KI Authors: Athar, Muhammad; Qureshi, Ashfaq Mahmood; Li, Guanghua; Shi, Zhan; Feng, Shouhua Abstract: Two new three-dimensional lanthanide oxalates [Pr₂(C₂O₄)₃(H₂O)₄]·2H₂O (1) and [Nd₂(C₂O₄)₃(H₂O)₄]·2H₂O (2) and a two-dimensional oxalate [Pr₂(C₂O₄)₃(H₂O)₆]·3H₂O (3) have been prepared by hydrothermal process and characterized by single crystal X-ray analysis. Compound (1) crystallizes in monoclinic crystal system with P2₁/c space group whereas (2) crystallizes in triclinic crystal system with Pī space group. Although Pr and Nd are twin lanthanides, they have produced different crystal structures under the same reaction conditions. Compound (3) is produced by the in situ hydrothermal degradation of tartaric acid to oxalate ions in presence of KI. In this reaction, the iodide anion instead of metal cation, acts as the reducing agent during the degradation of tartaric acid to oxalate. Thermogravimetric, elemental analysis and IR studies have also been carried out for these compounds. Page(s): 708-713

Study of sulphonic acid functionalization of Vulcan XC-72 carbon black support of Pt/Vulcan XC-72 catalyst for methanol electrooxidation

2016-07-20T04:13:26Z

Title: Study of sulphonic acid functionalization of Vulcan XC-72 carbon black support of Pt/Vulcan XC-72 catalyst for methanol electrooxidation Authors: Chandravathanam, Sundar; Kavitha, B; Viswanathan, Balasubramanian; Thangam, Y Yesu Abstract: Sulphonic acid groups have been grafted onto the surface of Vulcan XC-72 carbon of the Pt/Vulcan XC-72 catalyst to improve platinum utilization in methanol electrooxidation studies. The sulphonic acid modification has been carried out by reacting the Pt/Vulcan XC-72 catalyst with formaldehyde and sodium sulfite. The resultant sulphonated catalysts are characterized by X-ray diffraction, Fourier transform infrared spectroscopy and cyclic voltammetry. FT-IR spectra confirm the incorporation of the sulphonic acid group on the carbon black support of the catalyst. XRD shows better dispersion of the Pt nanoparticles upon sulphonic acid modification. The electrochemical measurement using cyclic voltammetry shows enhanced activity for methanol electrooxidation for the sulphonic acid modified catalyst as compared to the unmodified one. Page(s): 704-707

In situ bismuth film modified carbon fiber microelectrode for nanomolar detection of cadmium and lead

2016-07-20T04:12:26Z

Title: In situ bismuth film modified carbon fiber microelectrode for nanomolar detection of cadmium and lead Authors: Anandhakumar, S; Mathiyarasu, J; Phani, K L N Abstract: In situ bismuth film modified carbon fiber microelectrode is reported for sensitive detection of Cd(II) and Pb(II) in 0.1 M acetate buffer solution of pH 4.5. As compared to the unmodified electrode, in situ bismuth modification improves the detection limit at nanomolar level for individual as well as simultaneous detection of Cd(II) and Pb(II).Electroanalysis carried out using square wave anodic stripping voltammetry shows linear response over the 50-500 nM range. The minimum detection limits are not affected for the individual and simultaneous metal detection. Using the standard addition method, cadmium and lead have been detected in tap water samples successfully. Page(s): 699-703

A global model to predict density of non-aqueous binary solvent mixtures at various temperatures

2016-07-20T04:14:25Z

Title: A global model to predict density of non-aqueous binary solvent mixtures at various temperatures Authors: Jouyban, Abolghasem; Maljaei, Seyed Hamed; Khoubnasabjafari, Maryam; Fathi-Azarbayjani, Anahita Abstract: The combined form of the Jouyban-Acree model and the calculated Abraham solute parameters has been used to predict the density of binary solvent mixtures at various temperatures. The proposed model has been trained using 290 binary solvent systems at different temperatures (278.15 to 353.15 K) and concentration ranges. The results are discussed in terms of mean relative deviations (MRDs) between computed and experimental densities as an accuracy criterion. The MRD of the proposed model is 1.2 ± 1.9 %, indicating that the proposed model, together with the calculated Abraham parameters, is accureate to reproduce the concentration and temperature dependence of density values of binary solvent mixtures. Page(s): 695-698