@article { ISI:000226804000015, title = {Controlling the optical properties of lemongrass extract synthesized gold nanotriangles and potential application in infrared-absorbing optical coatings}, journal = {Chemistry of Materials}, volume = {17}, number = {3}, year = {2005}, month = {FEB}, pages = {566-572}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Anisotropic metal nanoparticles have distinct optical behavior when compared with their spherical counterparts. In this report, we demonstrate a simple method involving the reduction of aqueous gold ions by the extract of the lemongrass plant leading to the formation of gold nanotriangles with interesting absorption in the near-infrared (NIR) region of the electromagnetic spectrum. We show that, by simple variation of the experimental conditions, it is possible to vary the size of the gold nanotriangles and, thus, to tune the absorbance of flat gold nanoparticles in the NIR region. The NIR absorption of the gold nanotriangles is expected to be of application in hyperthermia of cancer cells and in IR-absorbing optical coatings. We show that the lemongrass extract synthesized gold nanotriangles can be easily cast in the form of films on glass substrates and that these films are highly efficient in absorbing IR radiation for potential architectural applications.

}, issn = {0897-4756}, doi = {10.1021/cm048292g}, author = {Shankar, S. S. and Rai, A. and Ahmad, Absar and Sastry, M.} } @article {18}, title = {Role of halide ions and temperature on the morphology of biologically synthesized gold nanotriangles}, journal = {Langmuir}, volume = {22}, number = {2}, year = {2006}, month = {JAN}, pages = {736-741}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{In this paper, we demonstrate the effect of halide ions on the formation of biogenically prepared gold nanotriangles using the leaf extract of lemongrass (Cymbopogonflextiosus) plant. We have also studied the effect of halide ions on the morphology of biogenic nanotriangles. It has been shown that iodide ions have a greater propensity to transform flat gold nanotriangles into circular disklike structures as compared to other halide ions. The study also suggests that the presence of Cl- ions during the synthesis promotes the growth of nanotriangles, whereas the presence of I- ions distorts the nanotriangle morphology and induces the formation of aggregated spherical nanoparticles. The change in the morphology of gold nanotriangles has been explained in terms of the ability of the halide ions to stabilize or inhibit the formation of (I 11) faces to form [

}, keywords = {DME steam reforming, fuel cells, Hydrogen, Mixed oxides, supported Ga2O3, XPS}, issn = {1520-6106}, doi = {10.1021/la052055q}, author = {Rai, A. and Singh, A. and Ahmad, Absar and Sastry, M.} } @article { ISI:000241996500012, title = {Vapour phase methylation of phenol over nanocrystalline ZnFe(2-x)A1(x)O(4) (x=0, 0.25, 0.5, 0.75 and 1.0) ferrospinel system}, journal = {Indian Journal of Chemical Technology}, volume = {13}, number = {5}, year = {2006}, month = {SEP}, pages = {493-498}, publisher = {NATL INST SCIENCE COMMUNICATION}, type = {Article}, address = {DR K S KRISHNAN MARG, NEW DELHI 110 012, INDIA}, abstract = {

The alkylation ofphenol with methanol was carried out over ZnFe2-xAlxO4 (x = 0, 0.25, 0.5, 0.75 and 1.0) type spinel systems in a Fixed bed, down flow reactor. The influence of Surface acidity, cation distribution in the spinel lattice and various reaction parameters are discussed. A maximum yield of 70.9 and 22.9\% with selectivity of 73.5 and 23.3\% was obtained for 2,6-xylenol and o-cresol respectively, giving a total ortho selectivity of: 96.8\% over ZnFeAlO4 at 350 degrees C, methanol to phenol molar ratio of 5 and WHSV of 0.6 h(-1). Catalyst characterization was made by XRD, Mossbauer spectroscopy, ammonia desorption and BET surface area measurements. Mossbauer spectroscopy reveals isomorphic substitution or Fe 3 by smaller A 13, into the octahedral sites leading to lattice distortion, Unsymmetrical charge distribution and charge transfer from iron to oxygen making it more basic and proton attracting. This helps vertical adsorption ofphenol and formation of 2.6-xylenol. It has been concluded that catalyst acidity plays major role in the reaction as compared to surface area.

}, keywords = {consecutive methylation, ferrospinels, vertical and horizontal adsorption}, issn = {0971-457X}, author = {Reddy, Vanga S. and RadheShyam, A. and Dwivedi, Reena and Rai, A. and Anilkumar, Mettu and Chumbhale, Vilas R. and Aswar, A. S. and Prasad, R.} }