Hydrogen release: In-situ calorimetry studies of NaBH4+2MgH2 doped by ZrF4

• Published in: International journal of hydrogen energy Vol. 46; no. 1; pp. 922 - 929
• Main Authors: Xi, Senliang, Wang, Xiaojun, Tome, Kudzaishe Caren, Zhang, Tonghuan, Han, Zongying, Gao, Meng, Zhou, Shixue, Yu, Hao
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2021
• Subjects: Hydrogen desorption kinetics; Hydrogen storage; In-situ calorimetry technology; NaBH4+2MgH2; ZrF4; Hydrogen desorption kinetics; Hydrogen storage; In-situ calorimetry technology; NaBH4+2MgH2; ZrF4
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.09.237

In this work, NaBH4+2MgH2 doped by ZrF4 was prepared by the ball-milling method. The structure and the morphology of different systems were characterized by X-ray diffraction and scanning electron microscopy. The thermodynamic properties of hydrogen release were determined by temperature-programmed desorption and differential scanning calorimetry. Hydrogen desorption kinetic properties and hydrogen content were investigated by pressure composition isothermal method. The main objective of this work was to study the relationship between the heat of hydrogen release and the quantity of hydrogen released by In-situ calorimetry measurement. The NaBH4+2MgH2+0.1ZrF4 can release about 7.4 wt.% H2 by two steps. Firstly, the heat of hydrogen release of the first and the second steps were lower by 480.82 J·g−1 and 430.8 J·g−1 than that of NaBH4+2MgH2, respectively. And the dehydrogenation enthalpy of NaBH4+2MgH2 went from −243.81 kJ·mol−1 to −191.2 kJ·mol−1. Secondly, the addition of ZrF4 can improve the hydrogen release kinetic property of NaBH4+2MgH2, which can release 5 wt.% H2 in 2.5 h at 385 °C under 0.01 MPa hydrogen pressure. Therefore, NaBH4+2MgH2+0.1ZrF4 will be a potential candidate as a fuel cell hydrogen supply system. [Display omitted] •The addition of ZrF4 can decrease the thermodynamic stability of NaBH4+2MgH2.•In-situ calorimetry studies of NaBH4+2MgH2+0.1ZrF4.•High hydrogen desorption kinetic performance of NaBH4+2MgH2+0.1ZrF4.