Indian Journal of Chemistry

Sect. A: Inorganic, Bio-inorganic, Physical, Theoretical & Analytical

http://www.niscair.res.in; http://nopr.niscair.res.in

CODEN: ICACEC; ISSN: 0376-4710 (Print), 0975-0975 (Online)

 

 

 

 

 

VOLUME 52A

NUMBER 5

MAY 2013

 

CONTENTS

 

 

585

 

Nitrogen doped honeycomb-like carbon as a highly efficient catalyst support for Pt-Ru nanoparticles and their electrocatalytic oxidation of methanol

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Yunsong Zhang*, Weiguo Liu, Li Zhang &
Maojun Zhao
*

 

 

 

Nitrogen-doped honeycomb-like porous carbon is prepared by two-step carbonization of poly(ionic liquids) polymers and used as Pt-Ru NPs support. The Pt-Ru/NHPCs composite catalysts exhibit high electrocatalytic activity for methanol oxidation.

 

Fig

 

 

593

 

Sol-gel derived nanostructured niobium pentoxide thin films for electrochromic applications

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Amita Verma* & P K Singh

 

 

 

Coexistence of nanorod-like structures and round shaped polycrystalline grains contribute to the enhanced electrochemical and electrochromic activities in Nb2O5 thin films.

 

 

IJOC_Fig.2.tif

 

 

599

 

Role of Ru(III) as an inhibitor in oxidation of
lactose by [Cu(bipy)2]2+ in alkaline medium: Spectrophotometric and kinetic studies

 

 

 

 

 

 

 

 

Ashok Kumar Singh*, Manjula Singh,
Jaya Srivastava & Shahla Rahmani

 

 

 

Kinetics of oxidation of lactose by [Cu(bipy)2]2+ in alkaline medium with Ru(III) as inhibitor has been studied at 40 C spectrophotometrically. The reaction path with the rate determining step has been proposed.

 

GA.tif

 

 

Notes

 

608

 

Liquid phase preparation of catalysts used in slurry reactors to synthesize dimethyl ether from syngas: Effect of heat treatment temperature

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Zhihua Gao, Lihua Yin, Qin Jia & Wei Huang*

 

 

 

CuZnAl slurry catalysts are prepared by a complete liquid phase technology. The structure and performance of the catalysts are strongly influenced by the heat treatment temperature.

 

 

 

 

 

614

 

One-pot sonochemical synthesis of CdS-reduced graphene oxide composite and its application for photocatalytic degradation of methylene blue

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sandeep Gawande & Sanjay R Thakare*

 

 

 

In the CdS-RGO composite, the reduced graphene oxide nanosheets are densely decorated by the CdS nanoparticles. The composite exhibits enhanced photocatalytic activity for methylene blue degradation with a maximum removal rate of 96% under visible light.

 

 

 

 

619

 

Encapsulation of ibuprofen over mesoporous nanocrystalline hollow silica cuboids

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N Venkatathri*, M Nookaraju, A Rajini &
I A K Reddy

 

 

 

Ibuprofen encapsulation studies show that hollow nano silica cuboids store much more ibuprofen molecules than Si-MCM-41.

 

 

IC 3410 _GA.tif

 

 

 

 

Molecular interactions in binary liquid mixtures of
n-alkanes with higher alkanol: Ultrasonic, volumetric and viscometric studies

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Aravind R Mahajan* & Sunil R Mirgane

 

 

 

The large positive VmE values and negative deviations in viscosity are attributed to breaking up of the three-dimensional
H-bonded network of octan-2-ol due to the addition of solute, which is not compensated by the weak interactions between unlike molecules.

 

 

 

 

 

Authors for correspondence are indicated by (*)

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 585-592

 

 

Nitrogen doped honeycomb-like carbon as a highly efficient catalyst support for Pt-Ru nanoparticles and their electrocatalytic oxidation of methanol

Yunsong Zhanga, *, Weiguo Liub, Li Zhanga & Maojun Zhaoa, *

aCollege of Life and Science, Sichuan Agricultural University, Yaan, 625014, PR China

Email: yaanyunsong@yahoo.com.cn (YSZ); zmjun01@yahoo.com.cn (MJZ)

bAgronomy College, Sichuan Agricultural University , Wenjiang 611130, PR China

Received 6 December 2012; revised and accepted 12 April 2013

Nitrogen-doped honeycomb-like porous carbons (NHPCs) are synthesized by two-step carbonization of nitrogen containing poly(ionic liquids) polymers using silica sphere as template. Characterization data reveal that the NHPCs possess not only well developed three-dimensionally interconnected porosity, large specific surface area and pore volume, but also good electrical conductivity and excellent mechanical stability. The catalyst prepared by loading Pt-Ru nanoparticles onto NHPCs has been evaluated for methanol oxidation reaction and shows superior activity and stability in comparison with typical commercial Pt-Ru/C electrocatalyst, indicating that NHPC is a highly efficient anode catalyst support for methanol electrooxidation.

Keywords: Catalysts, Carbon, Porous carbons, Electrocatalysts, Catalyst supports, Electrooxidation,
Methanol oxidation

 

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 593-598

 

 

Sol-gel derived nanostructured niobium pentoxide thin films

for electrochromic applications

Amita Verma* & P K Singh

Physics of Energy Harvesting Division, CSIR-National Physical Laboratory,

Dr K S Krishnan Road, New Delhi 110 012, India

Email: amitaverma75@gmail.com

Received 30 October 2012; revised and accepted 17 April 2013

Nb2O5 thin films have been prepared using diethanolamine stabilized precursor sol and annealed at 500 C. The optical, electrochemical, structural and morphological properties of Nb2O5 thin film are described. The X-ray diffraction study shows the formation of hexagonal crystal structure in the film. The presence of Nb-O linkage has been confirmed from the FT-IR data. The coexistence of nanorod-like structures and round shaped polycrystalline grains has contributed to an enhanced electrochemical activity in the film. The Li ion storage capacity of the film is ~ 9.0 mC cm-2 at a sweep rate of 20 mV s-1 for a single layer coating. The optical modulation, coloration efficiency, and coloration/bleaching times of the film are 30.6% (at 550 nm), 25 cm2 C-1 (at 550 nm) and 171 s/6 s, respectively. The appreciably high coloration efficiency and fast switching kinetics shows the potential utility of these films in electrochromic windows.

Keywords: Nanomaterials, Nanocrystals, Niobium oxide, Oxides, Thin films, Sol-gel process, Spin coating,
Electrochromism

 

 

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 599-607

 

 

Role of Ru(III) as an inhibitor in oxidation of lactose by [Cu(bipy)2]2+ in
alkaline medium: Spectrophotometric and kinetic studies

 

Ashok Kumar Singh*, Manjula Singh, Jaya Srivastava & Shahla Rahmani

Department of Chemistry, University of Allahabad, Allahabad 211 002, India
Email: ashokeks@rediffmail.com/ ashok_au2@yahoo.co.in

Received 21 September 2012; revised and accepted 17 April 2013

Kinetics of oxidation of lactose by [Cu(bipy)2]2+ in alkaline medium using Ru(III) as an inhibitor has been studied spectrophotometrically at 40 C. The studies show that the rate of the reaction is zero order with respect to [Cu(bipy)2]2+ and first order with respect to [lactose]. The order of reaction is found to be two at low concentrations of OH (from 1.48105 to 3.47105 M) and less than two at its high concentrations (from 4.27105 to 6.31105 M). There is a substantial decrease in the pseudo-zero order rate constant with increase in the concentration of Ru(III) chloride, indicating the role of Ru(III) chloride as an inhibitor. Decrease in the rate with increase in dielectric constant of the medium is observed, while ionic strength of the medium and bipyridyl concentration has no influence on the rate. Based on kinetic data and spectrophotometric evidences, a suitable mechanism is proposed for the studied reaction.

Keywords: Kinetics, Reaction mechanisms, Oxidations, Copper-bipyridyl complex, Ruthenium, Lactose

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 608-613

 

 

Liquid phase preparation of catalysts used in slurry reactors to synthesize
dimethyl ether from syngas: Effect of heat treatment temperature

Zhihua Gao, Lihua Yin, Qin Jia & Wei Huang*

Key Laboratory of Coal Science and Technology of Ministry of Education and Shanxi Province,
Taiyuan University of Technology, Taiyuan 030024, Shanxi, China

Email: huangwei@tyut.edu.cn

Received 18 January 2013; revised and accepted 15 April 2013

The CuZnAl slurry catalysts have been prepared by a complete liquid phase technology and characterized by X-ray diffraction, H2 temperature-programmed reduction and temperature-programmed desorption of ammonia. The activity of the catalysts for direct synthesis of DME from syngas is evaluated in a slurry reactor. The structure and performance of the catalysts under different heat treatment temperatures are investigated. The results indicate that the phase of copper species, reducibility of catalysts and acid distribution are affected by the heat treatment temperature. Moreover, the catalyst heat treated at 513 K shows the smallest crystal size of Cu, good dispersion, more weak acidic sites and larger amount of stable Cu2O species. In the DME synthesis reaction, it is found that the effect of heat treatment temperature on the catalytic activity is depended strongly on the ratio of Cu0/Cu+ and the proportion of weak acid sites in the catalyst. The catalyst shows maximum activity at 513 K.

Keywords: Catalysts, Liquid phase catalysts, Slurry catalyst, Dimethyl ether, Syngas

 

 

 

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 614-618

 

 

One-pot sonochemical synthesis of CdS-reduced graphene oxide composite
and its application for photocatalytic degradation of methylene blue

Sandeep Gawandea & Sanjay R Thakarea, b, *

aGovt. Institute of Science, Civil lines, Nagpur 440 001, Maharashtra, India

bNanotechnology lab, Department of Chemistry, Science College, Congress Nagar, Nagpur 440 012, Maharashtra, India

Email: sanjaythakare@yahoo.co.uk

Received 9 July 2012; revised and accepted 18 April 2013

A one-pot synthesis of CdS-reduced graphene oxide (RGO) composite via sonochemical reduction of graphite oxide and simultaneous CdS formation is reported. The composite is characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy and UV-vis absorption spectroscopy and its photocatalytic performance is evaluated for the degradation of methylene blue. Results show that in the composite the RGO nanosheets are densely decorated by CdS nanoparticles, displaying a good combination between RGO and CdS. The CdS-RGO composite exhibits enhanced photocatalytic performance for the dye degradation with a maximum removal rate of 96% under visible light irradiation due to increased light absorption intensity as well as the reduced electron-hole pair recombination in CdS.

Keywords: Sonochemical reduction, Photocatalysis, Graphene oxide, Reduced graphene oxide, Composites,
CdS-RGO composite, Methylene blue, Cadmium sulphide

 

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 619-623

 

 

Encapsulation of ibuprofen over mesoporous nanocrystalline
hollow silica cuboids

N Venkatathri*, M Nookaraju, A Rajini & I A K Reddy

Department of Chemistry, National Institute of Technology Warangal,
Warangal 506 004, Andhra Pradesh, India

Email: venkatathrin@yahoo.com

Received 29 March 2012; revised and accepted 17 April 2013

Nanocrystalline hollow nano silica cuboids and MCM-41 have been synthesized and characterized using small angle powder X-ray diffraction, scanning electron micrograph, transmission electron micrograph, thermogravimetry/differential thermal analysis, Fourier transfrom infrared spectroscopy, nitrogen adsorption-desorption and ibuprofen adsorption followed ultraviolet spectroscopic analysis. The results indicate that mesoporous silica nanohollow cuboids store much more guest molecules than conventional nanocrystaline mesoporous Si-MCM-41.

Keywords: Silica, Mesoporous nano hollow cuboids, Cuboids, Hollow cuboids, Ibuprofen, Mesoporous materials

 

 

 

Indian Journal of Chemistry

Vol. 52A, May 2013, pp. 624-629

 

 

Molecular interactions in binary liquid mixtures of n-alkanes with higher alkanol: Ultrasonic, volumetric and viscometric studies

Aravind R Mahajan* & Sunil R Mirgane

P G Department of Chemistry, J E S College, Jalna 431 203
Maharashtra, India

Email: marvind22@yahoo.co.in

Received 14 September 2012; revised and accepted 16 April 2013

From experimental values of densities, viscosities, and speeds of sound at 298.15 K of the binary mixtures of n-octane, n-decane, n-dodecane and n-tetradecane with octan-2-ol, excess molar volume (VmE), deviations in viscosity (Δη) and excess isentropic compressibility (ksE) have been calculated. The large positive VmE values and negative deviations in viscosity for binary mixtures are attributed to the breaking up of the three-dimensional H-bonded network of octan-2-ol due to the addition of solute, which is not compensated by the weak interactions between unlike molecules. The theoretical values of speed of sound and isentropic compressibility have also been estimated using the Prigogine-Flory-Patterson theory with the van der Waals potential energy model and shows good performance in predicting excess molar volumes of mixtures of -alkanes+octan-2-ol. Bloomfield-Dewan model and Jouyban-Acree model show good agreement between the estimated and experimental values for the studied binary systems.

Keywords: Solution chemistry, Excess volumes, viscosity, Binary mixtures, Octan-2-ol, Alkanes,
Prigogine-Flory-Patterson theory