Hydrogen uptake (H-uptake) is studied in ball milled Mg-B-electrochemically synthesized reduced graphene oxide (erGO) nanocomposites at PH2 ≈ 15 bar, ~ 320 °C. B/C (weight ratio): 0, ~ 0.09, ~ 0.36, ~ 0.90 are synthesized maintaining erGO≈10wt %. B occupies octahedral interstices within Mg unit cell—revealed by electron density maps. Persistent charge donations from Mg and B to C appear as Mg-C (~ 283.2 eV), B-C (~ 283.3–283.9 eV) interactions in C-1s core X-ray photoelectron spectroscopy (XPS) at all B/C. At B/C > 0.09, charge reception by B from Mg yields Mg-B interaction. This net charge acceptor role of B renders it electron-rich and does not alter Mg unit cell size significantly. Despite charge donation to both C and B, the Mg charge is <  + 2, resulting in long incubation times (> 5 h) at B/C > 0.09. At B/C≈0.09 the minimal Mg-B interaction renders B a charge donor, resulting in Mg-B repulsion and Mg unit cell expansion. Mg-C peak shift to lower binding energies (C-1s XPS), decreases incubation time to ~ 2.25 h and enhances H-uptake kinetics. Various atomic interactions influence the reduction of incubation time in H-uptake and increase its kinetics in the order: (Mg → C; B → C)B/C≈0.09, B: donor > (Mg → C)B/C=0 > (ternary Mg → B → C)B/C>0.09, B: acceptor.

Mg-reduced graphene oxide (rGO), Mg-Ni and Mg-Ni-rGO nanocomposites were synthesized by ball milling. They were subsequently hydrogenated at PH2 ≈ 15 bar, ~320 ℃. Isothermal (~320 ℃) and non-isothermal (room...

Depleting fossil fuels and greenhouse emissions render hydrogen (H) a promising alternative for powering automobiles. MgH2 with its promising H‐weight capacity ≈7.6 wt% can be used for this purpose. However, it exhibits long incubation times with no significant H‐release during the early stages. The present Mg–B–reduced graphene oxide (rGO) nanocomposites can reduce such incubation time drastically. Herein, Mg, rGO, and elemental B as a light weight catalyst at various proportions (viz. B/C (from rGO) weight ratios of 0, 0.09, 0.22, 0.36, and 0.90) are used to synthesize Mg–B–rGO nanocomposites by ball milling. They are eventually subjected to hydrogen uptake at ≈320 °C and PH2 ≈ 15 bar followed by H‐release in vacuum. The nanocomposite with B/C ≈ 0.22 exhibits remarkably negligible incubation time (≈43 s) vis‐à‐vis ≈11 min by B/C = 0. This B/C ≈ 0.22 nanocomposite experiences charge (electron) transfer from Mg and B to C, located external to MgH2 unit cell. This causes Mg←H→B “Tug‐of‐war” within MgH2 unit cell, containing B in its interstitials (due to ball milling) and shrinking it. This leads to “structural catalysis” of H‐release, understood by X‐ray photoelectron, valence band, Raman spectra, and novel electron density maps. These novel materials can alleviate the need for activation cycles for their application.

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