Surface functionalization-enhanced spillover effect on hydrogen storage of Ni–B nanoalloy-doped activated carbon

Surface functionalization-enhanced spillover effect on hydrogen storage behaviors of Ni–B nanoalloy-doped activated carbon is investigated in comparison to the 3D graphene-based material. It is discovered that the hydrogen storage capacity of the activated carbon increases from Ni–B nanoalloy-doping but much less than that of graphene. After surface functionalization, although the specific surface area and micropore volume of the doped activated carbon decrease significantly, a hydrogen storage capacity is still almost as same as that of the unfunctionalized larger surface one, while showing a large desorption hysteresis. We argue that the surface functionalization greatly enhances the spillover process on carbon based adsorbents, thus playing an essential role in hydrogen storage capacity improvement.

► H capacity of activated carbon increases from Ni–B much less than that of graphene.
► Surface functionalization leads to a large desorption hysteresis and high H capacity.
► We argue surface functionalization greatly enhances the spillover process.