A Revisit to the Hydrogen Desorption/Absorption Behaviors of LiAlH4/LiBH4: Effects of Catalysts

Abstract

Abstract:The hydrogen desorption/absorption behaviors of LiAlH 4 /LiBH 4 with a focus on the effects of catalysts, namely TiCl 3 , TiO 2 , VCl 3 , and ZrCl 4 , were investigated using a thermal-volumetric apparatus. The hydrogen desorption was performed from room temperature to 300 °C with a heating rate of 2 °C min −1. The LiAlH 4 -LiBH 4 mixture with a molar ratio of 2:1 decomposed between 100 and 220 °C, and the hydrogen desorption capacity reached up to 6.6 wt %. Doping 1 mol % of a catalyst to the mixture resulted in the two-step decomposition and a decrease in the hydrogen desorption temperature. All the doped samples provided lower amountz of desorbed hydrogen than that obtained from the undoped one. No hydrogen absorption was observed under 8.5 MPa of hydrogen pressure and 300 °C for 6 h. Despite the fact each of the catalysts may affect the hydrogen storage behaviors of the mixture differently, none resulted in a change in the sample reversibility.

Enhanced hydrogen storage properties of LiAlH4 catalyzed by CoFe2O4 nanoparticles

“…Since Bogdanovic et al 17 conducted the seminal work in improving the hydrogen storage performance of NaAlH 4 by doping TiCl 3 , extensive efforts have been devoted to ameliorate the re/dehydrogenation properties of LiAlH 4 by adding various catalysts to lower its onset dehydrogenation temperature and increase its dehydrogenation kinetics. To date, the documented catalysts for LiAlH 4 can be classied as: (1) 18,20 (5) metal oxides [14][15][16]43,44 and (6) other compounds.…”

“…To date, the documented catalysts for LiAlH 4 can be classied as: (1) 18,20 (5) metal oxides [14][15][16]43,44 and (6) other compounds.…”

“…28,35,44,50 However, the rehydrogenation property was not ideal. From the practical applications perspective, solid-state materials (LiAlH 4 , NaAlH 4 , MgH 2 , etc.) do have the potential to outperform physical methods of storage (cryostorage or high-pressure technologies) through comprehensively considering the safety, environment friendless and cost, which has been reported in many review papers.…”

“…Upon heating, LiAlH 4 would gradually release hydrogen, according to the following three steps. 12 The rst reaction step (R1) occurs in the 150-175 C temperature range and releases 5.3 wt% hydrogen:…”

“…Thus, the dehydrogenation properties of LiAlH 4 are generally analyzed for the rst two decomposition reactions due to the high onset and decomposition temperatures, and the low desorbed hydrogen content of the reaction R3 from the practical applications perspective.…”