Development of heterogeneous metal catalysts with superior activity and high selectivity towards the semi-hydrogenation of alkynes is of significant industrial importance. Bimetallic Pd-Ru nanocomposites were synthesized over the entire composition range using a capping-agent assisted solution-based approach. The as-prepared nanocomposites demonstrated excellent catalytic activity towards the hydrogenation of a wide range of olefinic substrates and exceptional selectivity towards styrene in a phenylacetylene semi-hydrogenation reaction under mild conditions. In addition, hydrogen sorption studies were performed on the as-prepared bimetallic Pd-Ru nanomaterials, where an increase in the incorporation of Ru atoms into the bimetallic structure resulted in a decrease in the hydrogen storage capacity of the resulting material. Comprehensive structural characterization and insights obtained from the hydrogen sorption studies revealed that the presence of weakly bound hydrogen atoms in the hydride phase of the bimetallic species contributes to its excellent selectivity in hydrogenation reactions.