催化学报 ›› 2018, Vol. 39 ›› Issue (9): 1484-1492.DOI: 10.1016/S1872-2067(18)63118-3

• 论文 • 上一篇    下一篇

Gd0.2Ce0.8O1.9纳米颗粒对固体氧化物电解池La0.6Sr0.4Co0.2Fe0.8O3-δ阳极析氧反应的影响

关放a,b,c, 张小敏a,b, 宋月锋a,b,c, 周莹杰a,b, 汪国雄a,b, 包信和a,b   

  1. a 中国科学院大连化学物理研究所, 催化基础国家重点实验室, 辽宁大连 116023;
    b 中国科学院大连化学物理研究所, 洁净能源国家实验室(筹), 辽宁大连 116023;
    c 中国科学院大学, 北京 100049
  • 收稿日期:2018-05-29 修回日期:2018-06-06 出版日期:2018-09-18 发布日期:2018-07-19
  • 通讯作者: 汪国雄, 包信和
  • 基金资助:

    国家重点研发计划(2017YFA0700102);国家自然科学基金(21703237,21573222,91545202);大连化学物理研究所DMTO项目(DICPDMTO201702);中国科学院先导专项(XDB17020200);中国科学院青年创新促进会(2015145).

Effect of Gd0.2Ce0.8O1.9 nanoparticles on the oxygen evolution reaction of La0.6Sr0.4Co0.2Fe0.8O3-δ anode in solid oxide electrolysis cell

Fang Guana,b,c, Xiaomin Zhanga,b, Yuefeng Songa,b,c, Yingjie Zhoua,b, Guoxiong Wanga,b, Xinhe Baoa,b   

  1. a State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    b Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    c University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-05-29 Revised:2018-06-06 Online:2018-09-18 Published:2018-07-19
  • Contact: 10.1016/S1872-2067(18)63118-3
  • Supported by:

    This work was supported by the National Key R&D Program of China (2017YFA0700102), the National Natural Science Foundation of China (21703237, 21573222, 91545202), Dalian Institute of Chemical Physics (DICP DMTO201702), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17020200) and CAS Youth Innovation Promotion (2015145).

摘要:

化石燃料的使用排放了大量CO2,对气候和环境造成了日益严重的危害.固体氧化物电解池(SOEC)能够利用可再生能源产生的电能将CO2高效转化成CO,降低CO2排放的同时,又能减少化石燃料的使用,近年来受到研究者的广泛关注.相比于低温液相CO2电还原,SOEC高的运行温度保证了其较高的反应速率,即较高的电流密度.典型的SOEC单电池由多孔阴极、致密电解质和多孔阳极以三明治的方式组装而成.CO2分子在阴极得到两个电子解离成CO和一个O2-;生成的O2-通过致密电解质传导至阳极,在阳极失去四个电子发生析氧反应(OER)生成一个O2.相比于两电子的阴极反应,阳极四电子的析氧反应更难进行,可能是整个电极过程的速控步,因此开发高性能的阳极材料有望显著提高SOEC的CO2电还原性能.
La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)因具有较高的混合离子-电子导电性而被用作SOEC阳极材料,但受LSCF-气体两相界面的限制,其OER性能较低.研究表明,LSCF-掺杂的CeO2-气体所构成的三相界面相比于LSCF-气体两相界面具有更高的电化学反应活性,即OER反应更易在三相界面进行.因此,本文将Gd0.2Ce0.8O1.9(GDC)纳米颗粒浸渍到SOEC LSCF阳极来提高其OER活性,考察了纳米颗粒浸渍量(3,5,10和20 wt%)对SOEC电化学性能的影响.结果表明,SOEC的电化学性能随浸渍量的增加而逐渐升高,当GDC纳米颗粒浸渍量为10wt%时(10GDC/LSCF),SOEC的电化学性能达到最高,在800℃和1.6V的电流密度为0.555A cm-2,是LSCF阳极SOEC性能的1.32倍.继续增加浸渍量到20wt%,电化学性能反而开始下降.电化学阻抗谱测试结果表明,GDC纳米颗粒的加入减小了SOEC的极化电阻.对应的弛豫时间分布函数解析结果表明10GDC/LSCF阳极上的OER由四个基元反应构成.电镜和O2-程序升温脱附结果表明,GDC纳米颗粒的加入显著增加了10GDC/LSCF阳极三相界面和表面氧空位的数量以及体相氧的流动性,从而促进了OER四个基元反应的反应速率,降低了这几个过程的极化电阻,因而降低了OER反应的极化电阻,提高了SOEC电还原CO2的电化学性能.

关键词: Gd0.2Ce0.8O1.9纳米颗粒, La0.6Sr0.4Co0.2Fe0.8O3-δ阳极, 析氧反应, 三相界面, 固体氧化物电解池

Abstract:

La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) anodes were infiltrated by Gd0.2Ce0.8O1.9 (GDC) nanoparticles to improve the oxygen evolution reaction (OER) performance of solid oxide electrolysis cells (SOECs) in CO2 electroreduction. The effect of GDC loading was investigated, and 10 wt% GDC nanoparticle infiltration of the LSCF (10GDC/LSCF) anode results in the highest OER performance. Electrochemical impedance spectra measurements indicate that the infiltration by GDC nanoparticles greatly decreases the polarization resistance of the SOECs with the 10GDC/LSCF anodes. The following distribution of relaxation time analysis suggests that four individual electrode processes are involved in the OER and that all of them are accelerated on the 10GDC/LSCF anode. Three phase boundaries, surface oxygen vacancies, and bulk oxygen mobility increased, based on scanning electron microscopy and temperature-programmed desorption of O2 characterizations, and contributed to the enhancement of the four electrode processes of the OER and electrochemical performance of SOECs.

Key words: Gd0.2Ce0.8O1.9nanoparticles, La0.6Sr0.4Co0.2Fe0.8O3-δ anode, Oxygen evolution reaction, Three phase boundaries, Solid oxide electrolysis cell