Catalytic effect of Ti2C MXene on the dehydrogenation of MgH2. (8th March 2019)

• Record Type: Journal Article
• Authors: Li, Jingxiao; Wang, Shun; Du, Yulei; Liao, Wenhe
• Is Part Of: International journal of hydrogen energy. Volume 44:Number 13(2019)
• Page Start: 6787
• Page End: 6794
• Publication Date: 2019-03-08
• Subjects: Ti2C MXene -- Dehydrogenation -- MgH2; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2019.01.189
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: In the present work, the Ti2 C MXene is prepared by selective etching Al layer from Ti2 AlC. The catalytic effect of Ti2 C MXene on the dehydrogenation of MgH2 is investigated. Compared with the pure MgH2, the onset desorption temperature, apparent activation energy ( E a ) and the overall enthalpy changes (△ H ) of dehydrogenation of MgH2 -5 wt%Ti2 C decreased by 37 °C, 36.5%, 11%, respectively. The catalytic mechanism of Ti2 C on the dehydrogenation of MgH2 is investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). It is suggested that the surface Ti atoms with multivalence serve as the intermediate for electrons shifting between H − and Mg 2+, which makes the dehydrogenation of MgH2 easier. In addition, the good hydrogen adsorption ability and thermal conductivity of Ti2 C MXene could also contribute to the improvement of thermodynamics of MgH2 . Highlights: Dehydrogenation of MgH2 can be improved by addition of Ti2 C MXene. The onset desorption temperature of MgH2 decreased by 37 K by adding Ti2 C. The activation energy of dehydrogenation of MgH2 decreased by adding Ti2 C. Catalytic effect is due to easier e − transfer induced by multivalence Ti atom.