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ELECTROCATALYTIC PROPERTIES OF METALS

金属的电催化性能

基本信息

批准号：
03650642
负责人：
HORI Yoshio
金额：
$ 1.22万
依托单位：
CHIBA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

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.

二氧化碳在水介质中的电化学还原产物种类繁多，其分布在很大程度上取决于金属电极。因此，根据CO_2还原产物的选择性，将金属电极分为四组。(1)铜电极只能产生甲烷、乙烯等碳氢化合物和醇。(2)金、银、锌和钯从CO_2中生成CO。(CO金属)(3)甲酸在锡、铅、汞和镉电极上生成。(FA金属)(4)镍、铁和铂几乎不能减少二氧化碳，水减少后只放出氢气。目前的研究人员先前发现，铜电极上的烃形成是通过吸附的一氧化碳的中间形成进行的。因此，具有CO_2还原活性的金属电极可分为CO金属和FA金属。本工作旨在揭示CO_2还原产物选择性的来源。我们用原位电沉积的方法研究了CO_2在其他金属吸附原子修饰电极上的电还原。得出金属吸附原子在CO生成过程中具有一定的电催化活性的结论。顺序可以是Au&gt；Ag&gt；铜&gt；锌&gt；&gt；锡&gt；镉&gt；铅。基金属的性质也很大程度上影响了吸附原子的电催化活性。铜有一种独特的性质，这种金属只能产生碳氢化合物和醇。研究表明，吸附原子铜不具有电催化成烃性能，需要多层铜沉积才能有效地将二氧化碳还原为碳氢化合物。