Field ionization effect on hydrogen adsorption over TiO_2-coated activated carbon

摘要

Behaviors of hydrogen adsorption over TiO_2-coated activated carbon under various electric potentials were studied. TiO_2 particles were introduced onto carbon via the hydrolysis of TiCl_4 in acid solution. The results showed that the hydrogen adsorption first increased and then decreased with the increase of electric field. The improved storage was due to a stronger interaction between charged carbon surface and polarized hydrogen molecule caused by field induced polarization of TiO_2 coating. When the electric field was sufficient to cause considerable ionization of hydrogen, the decrease of hydrogen adsorption occurred. The electricity detected at 3000 V was a sign of ionization of hydrogen. The DFT calculations showed a much stronger binding between TiO_2-doped coronene and hydrogen molecule under an electric field, which is consistent with our experimental observations.