Effect of carbon monoxide on H2 dissociation and H diffusion on Fe(100) and Fe(110) surfaces

• Published in: Physica. B, Condensed matter Vol. 677; p. 415743
• Main Authors: Yang, Xinyue, Liang, Jingxuan, Li, Wenhao, Wei, Shikai, Ding, Huihui, Ji, Zhen, Wang, Jianing, Gao, Lei, Song, Weiyu, Zheng, Shuqi
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2024
• Subjects: Carbon monoxide; Density functional theory; Fe surface; Hydrogen diffusion; Fe surface; Hydrogen diffusion; Density functional theory; Carbon monoxide
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2024.415743

Hydrogen and hydrogen-injected natural gas have been vigorously developed. However, H2 can cause hydrogen embrittlement of pipeline steel during transportation. To investigate the mechanism of CO suppression of hydrogen embrittlement in pipeline steels, this work utilizes the first-principles method of density functional theory (DFT) to explore the impact of CO on H2 dissociation and H diffusion processes on Fe(100) and Fe(110) surfaces. Adsorption of CO reduces the charge density around Fe atoms, with the surface charge density of (110) reduced to a greater extent. The planar-average charge density shows that the change in charge density is primarily focused near the interface, where charge of the matrix Fe atom is partially transferred to C atom of CO molecule. An increase in the dissociation energy barrier shows that CO has an inhibitory effect on the dissociation of H2. In addition, CO can hinder H atom diffusion on the Fe surface. Among them, the hindrance of penetration from surface to interior of the bulk structure is the most obvious, and the strength of hindrance also depends on how close the CO is to the H atom. This study theoretically explains the inhibition mechanism of CO on hydrogen embrittlement of pipeline steel.