Improving hydrogen storage in Ni-doped carbon nanospheres

7 pages, 8 figures.-- Article in press.The effect of nickel distribution and content in Ni-doped carbon nanospheres on hydrogen storage capacity under conditions of moderate temperature and pressure was studied. It was found that the nickel distribution, obtained by using different doping techniques and conditions, has a noticeable influence on hydrogen storage capacity. The samples with the most homogeneous nickel distribution, obtained by pre-oxidising the carbon nanospheres, displayed the highest storage capacity. In addition, storage capacity is influenced by the amount of nickel. It was found a higher storage capacity in samples containing 5 wt.% of Ni. This is due to the greater interactions between the nickel and the support that produce a higher activation of the solid through a spillover effect.L.Z. acknowledges the support received from the CSIC I3P Programme co-financed by the European Social Fund. The authors would like to thank BIOGAS FUEL CELL (Project CENIT BAIP 2020) for their financial support.Peer reviewe