刘进轩

个人信息Personal Information

教授

博士生导师

硕士生导师

主要任职:大连理工大学莱斯特国际学院副院长

性别:男

毕业院校:波鸿大学

学位:博士

所在单位:化工学院

学科:应用化学. 精细化工

办公地点:大连理工大学西部校区精细化工国家重点实验室E段521

联系方式:+86-411-84986487

电子邮箱:jinxuan.liu@dlut.edu.cn

扫描关注

论文成果

当前位置: 中文主页 >> 科学研究 >> 论文成果

Direct Observation of Structural Evolution of Metal Chalcogenide in Electrocatalytic Water Oxidation

点击次数:

论文类型:期刊论文

发表时间:2018-12-01

发表刊物:ACS NANO

收录刊物:SCIE、Scopus

卷号:12

期号:12

页面范围:12369-12379

ISSN号:1936-0851

关键字:in situ TEM; water oxidation; cobalt chalcogenide; structural evolution; XPS

摘要:As one of the most remarkable oxygen evolution reaction (OER) electrocatalysts, metal chalcogenides have been intensively reported during the past few decades because of their high OER activities. It has been reported that electron-chemical conversion of metal OER chalcogenides into oxides/hydroxides would take place after the OER. However, the transition mechanism of such unstable structures, as well as the real active sites and catalytic activity during the OER for these electrocatalysts, has not been understood yet; therefore a direct observation for the electrocatalytic water oxidation process, especially at nano or even angstrom scale, is urgently needed. In this research, by employing advanced Cs-corrected transmission electron microscopy (TEM), a step by step oxidational evolution of amorphous electrocatalyst CoSx into crystallized CoOOH in the OER has been in situ captured: irreversible conversion of CoSx to crystallized CoOOH is initiated on the surface of the electrocatalysts with a morphology change via Co(OH)(2) intermediate during the OER measurement, where CoOOH is confirmed as the real active species. Besides, this transition process has also been confirmed by multiple applications of X-ray photoelectron spectroscopy (XPS), in situ Fourier-transform infrared spectroscopy (FTIR), and other ex situ technologies. Moreover, on the basis of this discovery, a high-efficiency electrocatalyst of a nitrogen-doped graphene foam (NGF) coated by CoSx has been explored through a thorough structure transformation of CoOOH. We believe this in situ and in-depth observation of structural evolution in the OER measurement can provide insights into the fundamental understanding of the mechanism for the OER catalysts, thus enabling the more rational design of low-cost and high-efficient electrocatalysts for water splitting.