This study aims to green synthesize and full characterize CdO nanoparticles by means of an environmentally friendly synthesis using Crocus sativus in its reaction with cadmium ions. The CdO nanoparticles were characterized and their purity was confirmed by XRD and UV.-Vis. spectroscopy. Moreover, scanning electron microscopy (SEM) showed that the prepared cadmium oxide nanoparticles were polymorphic. Furthermore, cadmium oxide nanoparticles were cast in the gas storage (H ₂) study. The hydrogen storage results prove that the maximum H ₂ uptake was equal to 2.85 Wt.%H ₂ at a pressure of 69 bar at 77 K with ∆H=0.62607 KJ/mol H ₂ and ∆S=3.35697 J/mol H ₂. K. Moreover, the thermodynamic studies under four different temperatures proves that the maximum H ₂ uptake could be recorded at a pressure limit of 69-86.2 bar.