This paper describes investigations (a) on the efficacy of Ti layer as a barrier against the intermixing of Pd and Mg in Pd/Ti/Mg films and (b) the hydrogen storage characteristics of the tri-layered films and the related bulk composites. The Mg film was prepared by resistive evaporation while the Pd and Ti films were deposited by e-beam evaporation. The analysis by Rutherford backscattering spectrometry (RBS) and glancing-incidence X-ray diffraction (GI-XRD) of the Pd/Ti/Mg/Si(substrate) films annealed in vacuum in 348-573 K temperature range revealed that Ti effectively prevents the intermixing of Pd and Mg up to similar to 523 K. However, mixing across Pd/Ti, Ti/Mg and Mg/Si interfaces commences around 523 K that progresses with the temperature of annealing though Pd-Mg phases are not formed even at 573 K. The as-deposited Pd/Ti/Mg films are hydrogenated to similar to 7 wt % (62 at%) at 323 similar to 423 K at 0.15 MPa hydrogen pressure and dehydrogenated completely at similar to 473 K. The extent of (de)hydrogenation of the films was determined non-destructively by the H-1(F-19,alpha gamma)O-16 nuclear reaction. The powder composites derived from the films, on the other hand, reversibly stored similar to 2.2 wt% hydrogen up to 18 cycles in 323-473 K temperature range. The superior cyclic stability is attributed to the inhibition of mixing between Pd and Mg and, as a result, the formation of Pd-Mg inter-metallics by titanium. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.