Hydrogen storage investigation of fixed bed of nano-crystalline Mg-Ni-Cr mixed oxides

Nano-crystalline mixed oxides containing magnesium, nickel and chromium (MNCM)
have been synthesized as an adsorbent using coprecipitation method and showed its reversible
hydrogen storage capacity at ambient conditions using fixed bed. XRD and ICP-MS analyses
ensured the adsorbent’s phase and homogeneity. The microstructure of mixed oxide has been
investigated using FESEM and BET and TEM technique respectively. The adsorbent consisted of
mesoporous surface with a surface area of 254-370 m2gm-1 and SAED pattern showed that the
adsorbents are poly-crystalline. The mixed oxides exhibited a 3.2 wt% H2 storage capacity and
release 57% of adsorbed H2. Adsorption enthalpy (ΔH) and entropy (ΔS) change of -27.58 kJ/mol
and -70.21 J/mol.K are indicating favorable thermodynamics for reversible hydrogen storage
material.