Co metal nanoparticles incorporated three-dimensional mesoporous graphene nanohybrids for electrochemical hydrogen storage

Co metal nanoparticle incorporated graphene nanohybrids were successfully synthesized via a simple decomposition reaction of the metal precursor, dicobalt octacarbonyl (Co₂(CO)₈), in the presence of the mesoporous graphene (MG) for enhanced hydrogen storage performance. As a host material, MG, which has a three-dimensional interconnected pore structure (S_BET of 860 m² g⁻¹, pore size of 6.3 nm), can provide a facile diffusion pathway to electroactive species, along with an appropriate pore size for immobilizing Co metal nanoparticles. According to the XRD and TEM analyses, after hybridization, the cubic phased Co metal nanoparticles were homogeneously dispersed and stabilized on the surface of the host MG with sizes of 5.3 nm. According to the measurement of the electrochemical hydrogen storage, the discharge capacity of the obtained sample exhibited 250 mAh g⁻¹ with good cyclic stability, caused by the synergetic effect of the MG and Co metal nanoparticles.