Improving hydrogen sorption kinetics of MgH2 by mechanical milling with TiF3

MgH2 + TiF3 system was mechanically prepared and investigated with regard to hydrogen absorption/desorption performance. It was found that the sorption kinetics of MgH2 can be markedly improved by mechanical milling with 4 mol% TiF3, in particular at reduced operation temperatures. Even at a moderate temperature range (313–373 K), the hydrogen absorption can be largely completed within about 25 s. On the desorption aspect, the catalytic enhancement arising upon adding TiF3 allows the sample to desorb near 5 wt.% hydrogen within 600 s at 573 K. Furthermore, such enhancement in kinetics was observed to persist in the absorption/desorption cycles. Preliminary XRD examination was also performed to understand the observed catalytic effect of TiF3 additive.