The Electroche:Rvhcal Syntheses And Characterizations Of Nickel Nanoparticles And Zinc-Nickel Nanoalloy On Composite Graphite Substrate
| dc.contributor.author | Tehrani, Ramin Mohammad Ali | |
| dc.date.accessioned | 2016-10-27T02:51:32Z | |
| dc.date.available | 2016-10-27T02:51:32Z | |
| dc.date.issued | 2009-10 | |
| dc.description.abstract | The nickel (Ni) nanocrystals with an average size of9.7 ± 2.3 nm were deposited onto composite graphite electrode from a plating solution of 5.0 mM NiCh.6H20 and 1.0 M NRtCI using scan rate of 6500 m V s -I. The initial potential -1.5 V vs. Ag/ AgCI, final potential-o.5 V and applied time 120 s were used for the whole deposition process. The variation of applied potentials and times has affected the characteristics of deposited Ni nanocrystals. It was found that the structural formation of Ni nanocrystals o!Jtained were almost hexagonal close-packed (hcp). The hcp nanocrystalline Ni modified composite graphite (hcp-nano Ni/CG) electrode was investigated for the catalytic oxidation of methanol in alkaline medium through the formation of NiOOH. A high anodic current was obtained at peak potential of +570 m V vs. Ag/ AgCI. Both the scan rate and the methanol concentration affected the oxidation of methanol. The results showed that catalytic activity had increased with decreasing Ni particle size. Thus, the modified electrode was the most efficient catalyst in the oxidation of methanol. The single phase gamma Zinc-Nickel alloy (y-Zn3Ni) nanocrystal was deposited on composite graphite electrode at a scan rate of 10,000 mvs-1 • The average particles size obtained was 11.8 ± 3.1 nm. The TEM analysis indicated that co-deposition applied potential, i.e. nucleation overpotential, scan rate, and co-deposition time were critical on crystals sizing and Ni content in the matrix. Cyclic voltammetry and analysis of XRD have also indicated that single phase (y-phase) alloy was, indeed, obtained at the scan rate used. The results also revealed that 19.0 wt. % Ni nanoparticles were, unifonnly, dispersed in the phase compositions of the alloy coating. The y-Zn3Ni nanoalloy modified CG (nano-y-Zn3Ni/CG) was employed for detection of uric acid (UA) by voltammetry techniques. This non-enzymatic modified electrode had an excellent response and specificity to the electrocatalytic oxidation of UA in 0.2 M phosphate buffer (PB) (pH 7.0) at +280 mV vs. Ag/AgCI as compared to an unmodified electrode at +360 mV. A limit of detection (SIN = 3) at 0.2 J!M and concentration linear range from 1 to 400 J.!M UA were obtained. The presence of ascorbic acid (AA) did not interfere in the measurement. The nano-y-Zn3Ni/CG was used for the detennination of UA in untreated human urine and serum samples with satisfactory results. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/2899 | |
| dc.subject | Chemical Sciences | en_US |
| dc.subject | Nickel nanocrystals | en_US |
| dc.title | The Electroche:Rvhcal Syntheses And Characterizations Of Nickel Nanoparticles And Zinc-Nickel Nanoalloy On Composite Graphite Substrate | en_US |
| dc.type | Thesis | en_US |
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