Light-weight materials such as graphene have attracted a great interest for hydrogen storage applications. In this study, a metal-on graphene nanocomposite was synthesized for hydrogen storage for on-board applications. The graphene used as support was obtained from precursor graphite oxide, which was synthesized using the Improved Tours method and later reduced by L-Ascorbic acid and ammonia. The precursor graphite flakes used in the synthesis of graphite oxide were 100 mu m in size. The XRD patterns depicted a low angle shift in GO, 11.3 degrees from graphite 30 degrees proved successful oxidation of graphite. The FTIR and Raman band showed L-Ascorbic reduced the GO better than ammonia through the observed decrease on the functional bands after reduction. The elemental analysis carried out using XRF showed the successful loading of Ca on the graphene matrix and TEM images also confirmed this. The hydrogen storage capacity of the nanocomposite was tested using TGA and TPD equipped with Mass Spectrometer. The Ca/graphene nanocomposite reduced by ammonia exhibited a large hydrogen storage uptake at 4.98 wt. % compared to L-Ascorbic acid.