Striking enhanced effect of PrF3 particles on Ti3C2 MXene for hydrogen storage properties of MgH2

The enhanced effect of metal catalysts is crucial to achieve advanced performance of hydrogen storage system. Rational design of catalysts with superior catalytic activity is significant to regulate the re-/hydrogenation kinetics of MgH2. Herein, Ti3C2-supported praseodymium(III) fluoride (PrF3) nanoparticles (PrF3/Ti3C2) composite was prepared by hydrothermal method, which exhibited superior catalytic activity toward hydrogen storage of MgH2. The onset temperature of dehydrogenation was reduced to 180 °C after adding 5 wt% PrF3/Ti3C2, corresponding to a reduction of 107 °C compared with pristine MgH2. About 7.0 wt% hydrogen was rapidly desorbed within 3 min at 260 °C and 6.6 wt% hydrogen was absorbed within 36 s at 200 °C for MgH2-5 wt% PrF3/Ti3C2. Moreover, MgH2-5 wt% PrF3/Ti3C2 exhibited an excellent capacity retention of 92.5% even after 10 cycles. Experimental results reveal that the electron transfer among Ti-species (Ti0, Ti2+, and Ti3+) occurred due to the striking enhanced effect of PrF3 on Ti3C2 MXene during the reaction process, and the synergistic action between Ti-species and PrF3 are responsible for the markedly enhanced hydrogen storage properties of MgH2. This study is helpful to the design and optimization of hydrogen storage materials for mobile application.