2016 Fiscal Year Research-status Report
Development of a chemical synthesis technique to prepare Cu-Co NWs
| Project/Area Number |
16K04891
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| Research Institution | The University of Shiga Prefecture |
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Principal Investigator |
クヤウアマン ジョンレーマン 滋賀県立大学, 工学部, 特任准教授 (70727867)
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| Co-Investigator(Kenkyū-buntansha) |
松本 高利 東北大学, 多元物質科学研究所, 助教 (50343041)
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | Nanowires / Alcohol / Polyol / Cobalt / Copper / Co-Cu / Nanoparticles / Oleylamine |
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| Outline of Annual Research Achievements |
The synthesis of metallic Co and Cu were theoretically and experimentally examined. Alcohols with high boiling point such as ethylene glycol, 1-heptanol, 1-octanol and benzylalcohol were selected to synthesize irregularly shaped Co and Cu nanoparticles (NPs) from their salts.
The selection of metallic salts was an important factor to enhance the reducibility by alcohols. In this regard, salts with high pKa value such as metallic acetylacetonate and acetate eased the reduction of Co and Cu by the generation of highly reducing species in the alcoholic system. However, increasing the reduction potential of the system favored the formation of Co/Cu NPs. To obtain 1-D nanostructures, metallic salts with high and low pKa values were required in addition to other parameters such as surfactant concentration, reaction temperature and atmosphere.
Though the formation mechanism of Co-Cu nanostructures proceeded in several steps, the formation of oleylamine complexes and glycolates or hydroxides prior to the Cu-Co reduction was important. From the study to investigate the formation mechanism, Co compounds were detected (XRD and SEM-EDX) prior to Cu precipitation. This suggested that Co nucleus catalyzes the reduction of metal Cu through galvanic reaction in accordance with the difference in their redox potentials.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The progress of the experiments are a little slower than expected and the elucidation mechanism are not completed. The reason for the same are as follow:
a.Both elements are unstable under oxidizing atmospheres in the presence of Cl ions. Thus, the control over their composition was difficult.
b.Though Co facilitated the galvanic reaction for the formation of metal Cu, its incorporation into the metallic system was difficult. It was due to high affinity of Co to form complexes with amines.
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| Strategy for Future Research Activity |
Since we are able to synthesis Cu NWs in large quantities, coating the same with cobalt in the same batch by adding Co salts at later stages or depositing cobalt after collecting the Cu NWs can be considered as an alternative techniques to produce composition controlled Cu-Co nanostructures.
If CoCu NPs with different sizes and compositions are obtained; we will examine the catalytic and electrochemical properties of the same. Although, these particles were easily dispersed in organic solvents such as toluene, we plan to evaluate the dispersion in aqueous systems by using a ligand exchange technique where oleylamine is replaced by mercapto acid.
We will also continue to monitor the reaction to elucidate the formation mechanism of CuCo nanostructures.
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| Causes of Carryover |
We will continue with the experimental part of the project for optimizing composition and physical dimensions of CuCo nanostructures. For that, chemical reagents, glassware, disposable materials, equipment, etc. are required for the characterization and evaluation of properties.
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| Expenditure Plan for Carryover Budget |
The money will be used for experiments related to:
(1) The control of physical and chemical characteristics of obtained CoCu nanostructures (nanoparticles and nanowires) for obtaining enhanced electrical, magnetic and optical properties. (2) The application of the developed technique to prepare other functional materials such as Cu-Ag, Cu-Pd, etc. that could find applications in different engineering fields.
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