An effective strategy of utilizing electrospinning techniques to fabricate MgCl2 catalyzed ammonia borane (AB) nanofibers with a tunable fiber diameter is reported. The synergistic effect obtained by combining nanofibers and metallic catalyst plays a crucial role in the decomposition of MgCl2-doped AB nanofibers, which leads to significant improvements in dehydrogenation kinetics and complete suppression of unwanted byproducts. The results of dehydrogenation show that MgCl2-doped AB nanofibers were able to release over 10.0 wt % pure H-2 below 100 degrees C with favorable kinetics, a significant advance over releases from bulk AB. Furthermore, the dehydrogenation of MgCl2-doped AB nanofibers gives a weak exothermic reaction, -3.84 kJ mol(-1) H-2, which is dramatically lower than that of neat AB (-21 kJ mol(-1) H-2), which suggests that the electrospun sample is potentially more feasible to reverse. The findings in this paper provide general guidelines and inspiration for the design and synthesis of novel nano-fibrous materials with controllable dimensions for hydrogen storage applications.