1992 Fiscal Year Final Research Report Summary
ELECTROCATALYTIC PROPERTIES OF METALS
| Project/Area Number |
03650642
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業物理化学・複合材料
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| Research Institution | CHIBA UNIVERSITY |
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Principal Investigator |
HORI Yoshio Chiba University, Faculty of Engineering, Department of Applied Chemistry, Professor, 工学部, 教授 (20114324)
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| Co-Investigator(Kenkyū-buntansha) |
KOGA Osamu Chiba University, Faculty of Engineering, Department of Applied Chemistry, Lectu, 工学部, 講師 (60110293)
ENYO Michio Hokkaido University, Catalysis Research Center, Professor, 触媒研究センター, 教授 (10001710)
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| Project Period (FY) |
1991 – 1992
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| Keywords | Electrochemical reduction / Carbon dioxide / Metal / Electrocatalysis / Electrode modification / Adatoms / Copper |
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| Research Abstract |
Electrochemical reduction of carbon dioxide in aqueous media yields various kinds of products, the distribution of which depends greatly upon metal electrodes. Metal electrodes are thus divided into four groups in accordance with the product selectivity in CO_2 reduction. (1)Copper electrode exclusively yields hydrocarbons, such as methane and ethylene, and alcohols. (HC metal) (2) Gold, silver, zinc and palladium give CO from CO_2. (CO metals) (3)Formic acid is produced at tin, lead, mercury and cadmium electrodes. (FA metals) (4)Nickel, iron and platinum can hardly reduce carbon dioxide and only hydrogen is evolved as a result of water reduction. The present investigators previously revealed that hydrocarbon formation at copper electrode proceeds with intermediate formation of adsorbed carbon monoxide. Thus metal electrodes which are active in CO_2 reduction may be classified into CO metals and FA metals.
The present work has been carried out in order to reveal the origin of the product selectivity in CO_2 reduction. We studied electroreduction of CO_2 at electrodes modified with other metal adatoms by in-situ electrodeposition. We obtained conclusions that metal adatoms have an order of electrocatalytic activity in CO production. The order may be Au> Ag> Cu> Zn>> Sn> Cd> Pb. Electrocatalytic activity of adatoms is also greatly affected by the properties of substrate metals.
Copper has a unique property that this metal exclusively yields hydrocarbons and alcohols. The present research work has revealed that adatom copper does not show electrocatalytic property of hydrocarbon formation and multilayer copper deposition is required for effective reduction of CO_2 to hydrocarbons.
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