2020 Fiscal Year Research-status Report
Pioneering 3d transition-metals coordination polymers as novel electrocatalysts for metal-air batteries.
| Project/Area Number |
20K05689
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| Research Institution | Shibaura Institute of Technology |
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Principal Investigator |
ジェズニチカ イザベラ 芝浦工業大学, 工学部, 教授 (40565769)
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| Co-Investigator(Kenkyū-buntansha) |
堀 顕子 芝浦工業大学, 工学部, 教授 (90433713)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | oxygen evolution / oxygen reduction / electrocatalyst / coordination polymers / 3d transition metals / metal-air batteries |
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| Outline of Annual Research Achievements |
Research objectives planned for this year included synthesis and characterization of copper coordination polymers. Two coordination polymers (CPs), namely copper dithiooxamide Cu(dto), and a perfluorinated mononuclear complex with CuO4 core were synthesized. The complexes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET sorption studies. In the later stage, Cu(dto) was subject to electrochemical tests including cyclic voltammetry and linear sweep voltammetry in 1 M KOH solution, under either nitrogen or oxygen saturated conditions. The results show that CuO nanocomposite derived from Cu(dto) serve as efficient electrocatalyst for oxygen evolution reaction (OER) in alkaline solutions. The nanocomposite has an overpotential of 280 mV (at 1 mA/cm2) and a Tafel slope of 81 mV/dec in 1 M KOH solution. It has a seven-fold higher current than the benchmark IrO2/C catalyst, per metal loading. This work revealed a new method to produce an active nanocomposite catalyst for OER in alkaline media using a non-noble metal chelate polymer. The method can be applied to the synthesis of transition metal oxide nanoparticles used in the preparation of composite electrodes for water electrolyzers and can be used to derive cathode materials for aqueous-type metal-air batteries. In addition, the Cu(dto) was also investigated as catalyst in oxygen reduction reaction (ORR). The studies revealed formation of nanostructured Cu2O/C nanocomposite. The half-wave potential was around 0.72V vs. RHE, which is close to the value of the benchmark 40% Pt/C catalysts.
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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
Two research objectives, originally planned for the first year of the grant, have been successfully realized (Objective 1,3). This included synthesis and characterization of copper chelate polymers (CPs). Synthesized copper dithioxamide (Cu(dto)) CPs was fully characterized as electrocatalysts for OER and ORR in 1 M KOH solution. Electrocatalytic characterization of fluorinated mononuclear copper complexes are underway. Realization of Objective 2 has been partially fulfilled by taking Raman spectra of dithioxamide adsorbed on a copper electrode in alkaline solutions. Construction of differential electrochemical mass spectrometry (DEMS) has been abandoned due to truncated budget. Peer-reviewed research papers have been published and the work was presented at international and domestic conferences (Objective 4). In addition, synthesis of nickel chelate polymer and its characterizations have been proceeding ahead of the schedule.
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| Strategy for Future Research Activity |
In accord with the originally proposed plan, in the second year of the project, synthesis of nickel coordination polymers and their characterization will be executed. The Ni-CPs will be tested as ORR and OER electrocatalyst in alkaline solutions. Three types of nickel CPs are to be synthesized; Ni(dto), mono and dinuclear Ni CPs. In situ-Raman studies will be carried out to evaluate ORR reaction mechanism.
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| Causes of Carryover |
Due to reduced budget it was not possible to buy potentiostat, originally planned for the 1st year. In order to perform experiments, scheduled in 2020, the PI decided to buy a rotating disk electrode unit (RDE) (planned for the 2nd year) and lease a potentiostat. As a results, 1.107.000 yen of the budget was transferred to the 2nd year. With the carryover budget, and the budget allocated for the 2nd year, PI can now buy a potentiostat that was originally planned for the 1st year.
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