Effect of synthesis route of graphene on the hydrogen storage in Mg-Ni-rGO ternary system

The H uptake/release performance of Mg is studied by combining transition metal (Ni) and lightweight C-based (rGO) catalysts. Further, the effect of the synthesis route on the morphology and catalytic ability of rGO is understood by synthesizing it via electrochemical (erGO), chemical (crGO) and thermal (trGO) exfoliation. These rGOs (10 wt%) and 3 atom% of Ni were ball-milled with Mg and subjected to isothermal H uptake at 15 bar and 320 °C. The Mg 97 -Ni 03 -erGO nanocomposite shows the lowest incubation period of 2–3 h, whereas it is 8–9 h for Mg 97 -Ni 03 -trGO. Moreover, the Mg 97 -Ni 03 -erGO nanocomposite shows the lowest onset temperature of H release at 275 °C, which is 300 °C in the case of Mg 97 -Ni 03 -trGO. From the spectroscopic analysis, it is inferred that the presence of lower defects in erGO and higher C–C sp 2 domains facilitate enhanced Mg–C interaction during the H uptake/release. • The erGO, crGO, trGO were synthesized electrochemically, chemically, and thermally. • Mg 97 –Ni 03 -erGO results in the lowest incubation period of 2–3 h during H uptake. • Lowest onset temperature of H release (275 °C) by Mg 97 –Ni 03 -erGO and Mg 97 –Ni 03 -crGO. • Mg 97 –Ni 03 -trGO exhibits higher incubation of 8–9 h and onset temperature of 300 °C. • Lower defects and higher sp 2 carbon results enhanced kinetics in Mg 97 –Ni 03 -erGO.