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 MgH 2. Herein, Ti 3 C 2 -supported praseodymium(III) fluoride (PrF 3) nanoparticles (PrF 3 /Ti 3 C 2) composite was prepared by hydrothermal method, which exhibited superior catalytic activity toward hydrogen storage of MgH 2. The onset temperature of dehydrogenation was reduced to 180 °C after adding 5 wt% PrF 3 /Ti 3 C 2 , corresponding to a reduction of 107 °C compared with pristine MgH 2. 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 MgH 2 -5 wt% PrF 3 /Ti 3 C 2. Moreover, MgH 2 -5 wt% PrF 3 /Ti 3 C 2 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 PrF 3 on Ti 3 C 2 MXene during the reaction process, and the synergistic action between Ti-species and PrF 3 are responsible for the markedly enhanced hydrogen storage properties of MgH 2. This study is helpful to the design and optimization of hydrogen storage materials for mobile application. • Ti 3 C 2 supported PrF 3 nanoparticles composite is prepared by hydrothermal method. • The addition of PrF 3 /Ti 3 C 2 improves the re-/dehydrogenation kinetics of MgH 2. • The onset dehydrogenation temperature is reduced by 107 °C compared with pure MgH 2. • Ti-species and PrF 3 contributes to excellent hydrogen storage properties of MgH 2. [ABSTRACT FROM AUTHOR]