Influence of different cone angles for hydrogen adsorption of cup-stacked carbon nanotube: A DFT study

• Published in: International journal of hydrogen energy 2024-01, Vol.50, p.1174-1188
• Main Authors: Xu, Zhitong, Sun, Mengying, Sui, Yinquan, Wang, Yongxin, Yan, Jinglu, Liu, Huanpeng
• Format: Article
• Language: English
• Subjects: Cup-stacked carbon nanotubes; Density functional theory; Hydrogen adsorption; Pt decoration
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2023.09.086

Many phenomena remain to be investigated regarding the micro adsorption kinetics of hydrogen storage in different carbon nanomaterials. The hydrogen adsorption behaviour on the wall surface of the conical graphene layers (CGL) of three kinds of different cup-stacked carbon nanotubes (CSCNTs) is investigated using density functional theory (DFT). Furthermore, Pt decoration of the CGL wall was also investigated. The hydrogen adsorption result of the Pt-CGL is examined through the charge transfer and electron density difference approach. The optimisation results show that as the cone angle increases, the hydrogen adsorption capacity on the outside of the CGL wall increases gradually. In contrast, the hydrogen adsorption capacity on the inside of the wall decreases as the cone angle increases. The adsorption energy (Eads) of intrinsic CGL can only reach 5 kJ/mol, and the Eads of defective CGL can reach 10 kJ/mol. In contrast, the Eads of Pt-CGL can reach more than 30 kJ/mol, indicating that the hydrogen adsorption capacity of the CGL can be effectively increased by the Pt atom decoration, which can meet the adsorption energy target of hydrogen storage material formulated by the United States Department of Energy (DOE). [Display omitted] •The hydrogen adsorption behaviour on the cup-stacked carbon nanotube wall surface was investigated.•The conical graphene layer wall has weak physical adsorption on hydrogen.•With the cone angle increase, the inside of the conical graphene layer wall adsorption capacity decreases.•The adsorption energy of the C–Pt–H2 unit can meet the United States Department of Energy targets.•The adsorption behaviour of the C–Pt–H2 unit belongs to Kubas coordination.