This work reports on the hydrogenation and dehydrogenation abilities of the Pd-Mg bimetal capped Ti nanoparticles (NPs) layer on Si substrate, which were prepared by the Radio Frequency magnetron sputtering system (RF sputtering). Samples were prepared by varying the deposition rate and annealing conditions, then characterized using the FE-SEM, XRD, and XPS to investigate the optimum material structure for better sensing performance. The fabricated devices show resistivity changing in the hydrogenation state and a complete reversible dehydrogenation at room temperature (RT = ∼ 25 °C). The fabricated device showed a detection range of 1,000–10,000 ppm and fast hydrogenation/dehydrogenation time of 3/3 s for 10,000 ppm (1 vol%) at RT along with good selectivity. This Pd-Mg bimetal capped Ti nanoparticles (Pd-Mg/TiNPs) layer on silicon (Si) substrate can be a potential sensing device for its application in low temperature environments where fast hydrogenation/dehydrogenation processes are required.