2015 Fiscal Year Annual Research Report
| Project/Area Number |
15F15766
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
山内 悠輔 国立研究開発法人物質・材料研究機構, 国際ナノアーキテクトニクス研究拠点, MANA主任研究者 (10455272)
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| Co-Investigator(Kenkyū-buntansha) |
WANG ZHONGLI 国立研究開発法人物質・材料研究機構, 国際ナノアーキテクトニクス研究拠点, 外国人特別研究員
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| Project Period (FY) |
2015-11-09 – 2018-03-31
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| Keywords | 多孔体 |
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| Outline of Annual Research Achievements |
A critical element in the pursuit of this quest is the discovery of efficient and cost-effective catalysts for use in electrochemical energy conversion processes such as oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and carbon dioxide reduction reaction (CO2RR). Various carbon-based materials feature unique advantages for designated catalysis due to their tunable molecular structures, abundance and strong tolerance to acid/alkaline environments. Very recent advances in low-dimensional carbon materials have shown their promising future in energy-related electrocatalytic reactions. The addition of certain transition metals (e.g., Fe, Co) to the metal-free, nitrogen-doped carbon frameworks results in a nonprecious metal catalyst system with improved ORR activity in acidic media. Strongly coupled inorganic/nanocarbon hybrid materials are demonstrated to improve the electrocatalytic activities and stability of inorganic metal oxides, hydroxides, sulfides, and metal-nitrogen complexes. Achieving comparable activity and durability of the non-precious metal catalysts with the state-of-the-art noble metals catalyst still remains a challenge. Our purpose is to developing new synthetic strategies of functional carbons to realize the controllability of structure and component. To promoting better applications of functional carbons in electrocatalysis, the mechanisms and relationships of structure-property in carbon catalysts will be investigated for ORR, HER, and CO2RR in this research.
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
(a)Write a review (Overview).
The recent progresses of nanostructured nonprecious metal catalysts for electrochemical reduction of carbon dioxide are summarized. These catalysts are classified into five categories, including metals, partial oxidized metals, metal oxides and sulfides, doped carbons, and organic frameworks. The focuses are placed on material synthesis, structure and component, catalytic performance, and reaction mechanism. Several important factors that affect the activity, such as particle size, interface strain, grain boundary, crystal facet, oxidation state, heteroatom configuration, and organic hybrid, are discussed in detail.
(b)Synthesize the hierarchical porous metal-carbon catalyst for CO2RR.
The electrodeposited polyaniline polymers are used as precursor for carbon fibers. By adjusting deposition conditions, a special nanostructure with hierarchical pores and high surface area has been obtained. Little metal is introduced in the carbon matrix to form functional composite carbon materials. The preliminary test has showed that this catalyst can catalyze CO2 reduction to produce formic acid.
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| Strategy for Future Research Activity |
Design and synthesis of highly active metal-containing carbon electrocatalysts. Although progress has been made in improving catalytic performance, metal-containing carbon materials still have markedly lower catalytic activity and stability than noble metal catalysts in most experimental systems. In future, novel strategies will be developed to tailor the catalytic activity of metal-containing carbons by varying the reaction conditions and element components. For the hybrid materials, suitable approaches can afford strong chemical attachment and electrical coupling between the electrocatalytic nanoparticles and nanocarbon, which would synergistically improve activity and durability. Besides the coupling effect, the introduction of heteroatoms in transition metal compounds will influence the catalytic activity of hybrid materials by tuning the d-band electronic structure of parent metals, in turn optimizing the bond strengths between metal and absorbed reactive intermediates. Except for that, we also design efficient structure to increase the density of catalytic active sites and the effective surface area. For the metal doped carbons such as Fe-N-C and Co-N-C, we will improve the activity and stability by varying transition metal type and loading, carbon support surface properties and nitrogen content, and heat treatment conditions and duration.
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