NOPR Collection:

Electrochemical characterization of LaNi₅ hydride electrode

Sat, 01 Jul 2000 00:00:00 GMT

Title: Electrochemical characterization of LaNi₅ hydride electrode Authors: Babu, R S Achyuthlal; Viswanathan, B; Srinivasamurthy, S Abstract: Galvanostatic, cyclic voltammetric and linear polarization characteristics of LaNi₅electrode with respect to cycling are presented. Variation in voltammetric charge-discharge current and potential values observed during cycling are discussed. Cyclic voltammetric redox currents are correlated with respective steps in P-C isotherms of LaNi₅ – H₂ system. The stepwise reactions taking place at the LaNi₅ electrode like in normal gaseous mode of hydrogenation is established.Values of the exchange current density of LaNi₅ electrode increases during cycling. Evolved gas analysis establishes the electrochemical hydrogen storage. Evolution of hydrogen from b-hydride phase takes place at room temperature, while from a-phase, hydrogen evolves at higher temperatures. Microscopic analysis indicates that microcracks in LaNi₅ electrodes appear due to electrochemical cycling. Page(s): 690-696

Preparation of Fe³⁺ -doped TiO₂ nanoparticles and their photocatalytic activities

Sat, 01 Jul 2000 00:00:00 GMT

Title: Preparation of Fe³⁺ -doped TiO₂ nanoparticles and their photocatalytic activities Authors: Chen, Hui; Jin, Xinglong; SU, Bitao; Fang, Yanjun; Zhu, Kun; Yang, Ruiqiang Abstract: Taking ferric nitrate as the precursor, Fe³⁺ -doped TiO₂ nanoparticles have been prepared through the acid-catalyzed sol-gel method. The characteristics of obtained Fe³⁺ -doped TiO₂ nanoparticles have been studied by XRD and TEM techniques. Illuminated with 450w high press mercury lamp (HPML) and natural sun light (NSL), photocatalytic oxidation of Acridine Orange (AO) has been investigated in the presence of the Fe³⁺-doped TiO₂ nanoparticles whose photocatalytic activities have been evaluated. It is found that photocatalytic reactions obey first-order kinetics. TiO₂ doped with 0.10% Fe³⁺ shows higher photoactivity. In the presence of 0.10% Fe³⁺-doped TiO₂ nanoparticles, decolorization rate and degradation rate of AO are up to 92.32%, 97.00% respectively with HPML illumination and up to 95.50%, 97.75% respectively with NSL illumination. Fe3+-doped TiO₂ nanoparticlcs provide a new approach for improving the photocatalytic efficiency of TiO₂. Page(s): 685-689

B-Z oscillator with fr uctose and tartaric acid as organic substrates

Sat, 01 Jul 2000 00:00:00 GMT

Title: B-Z oscillator with fr uctose and tartaric acid as organic substrates Authors: Rastogi, R P; Husain, M M; Das, Prem Chand Mukul Abstract: Experimental studies on fructose (F) + tartaric acid (TA) + Ce⁴⁺ + BrO₃^- + H₂SO₄ system are reported by keeping either of the two organic substrates at a fixed concentration and varying the concentration of the other. An attempt has been made to investigate the oscillatory behaviour and the mechanism of the reaction. The change in [Br₂] during the course of reaction has been monitored spectrophotometrically while [Br^-] has been estimated electrometrically. Effect of addition of fructose and BrO₃^-after the cessation of oscillation has also been investigated. The results confirm the earlier conclusion that the oscillations are non[Br^-] controlled. Page(s): 679-684

Analysis of crude oil for its trace metals content

Sat, 01 Jul 2000 00:00:00 GMT

Title: Analysis of crude oil for its trace metals content Authors: Tamrakar, P K; Pitre, K S Abstract: Electroanalytical techniques viz. DCP, DPP and DPASV have been developed for the determination of trace metals in crude oil sample. The analysis is done after ashing the sample, the reagents 0.1 M(NH₄)₂ tartrate , 0.05M EDTA and 0. 1M NH₄Cl have been separately used , for trace metal determination. The res ults indicate the presence of Ni²⁺, V⁵⁺, Zn²⁺, Fe³⁺, Pb²⁺ and Cr⁶⁺ metal ions in the sample. The method of standard addition has been used for quantitative analysis of trace metals in the sample. The proposed electroanalytical techniques are found to be highly useful for a qualitative and quantitative analyses of the crude oil sample for its trace metals content. The voltammetric results have been compared with those obtained using atomic absorption spectroscopic method and are found to be in good agreement. Page(s): 779-783

NOPR Collection:

Electrochemical characterization of LaNi5 hydride electrode

Preparation of Fe3+ -doped TiO2 nanoparticles and their photocatalytic activities

B-Z oscillator with fr uctose and tartaric acid as organic substrates

Analysis of crude oil for its trace metals content

Electrochemical characterization of LaNi₅ hydride electrode

Preparation of Fe³⁺ -doped TiO₂ nanoparticles and their photocatalytic activities