Hydrogen storage properties of a destabilized MgH2eSn system with TiF3 addition

Abstract

The MgH2eSn system is considered a promising reactive metal composite for hydrogen storage. Several ratios of MgH2eSn (2:1, 3:1 and 4:1) destabilized system were investigated experimentally using a ball milling method. Based on the temperature-programme desorption results, the onset dehydrogenation temperature of the MgH2eSn composite was consisted of two steps in the range of 235e250 C and 325 e340 C. TiF3 catalyst was introduced to enhance the desorption temperature of the MgH2eSn (4:1) system. The onset dehydrogenation temperature of the 4MgH2eSn-10 wt% TiF3 composite was reduced to approximately 100 C and 205 C compared to the MgH2eSn (4:1) and the as-milled MgH2. The Kissinger analysis established that the apparent activation energy for the first stage of the 4MgH2eSn composite was reduced from 149.0 kJ/mol to 114.0 kJ/mol after adding 10 wt% TiF3. However, the addition of TiF3 did not result in improvement of the absorption process. The improvement of the dehydrogenation properties of the MgH2eSn composite with the addition of TiF3 was due to the formation of Ticontaining and F-containing species. These species played a catalytic role in improving the dehydrogenation properties of the MgH2eSn system.