Catalytic effects of TiF₃ on hydrogen spillover on Pt/carbon for hydrogen storage

Recent studies have shown that using the hydrogen spillover phenomena is a promising approach for developing new materials for hydrogen storage at ambient temperature. However, the rates need to be improved. Significant catalytic effects on both spillover (i.e., adsorption) and reverse spillover (i.e., desorption) on Pt-doped carbon by TiF₃ were found. By doping 2 wt%TiF₃ on the Pt-doped Maxsorb (a superactivated carbon), both adsorption and desorption rates were significantly increased while the storage capacity decreased only slightly due to decreased surface areas. The effect of the heat treatment temperature (473 K vs 673 K) of the doped TiF₃ on its catalytic effects was also studied. XPS analyses showed that C-F bonds were formed upon heat treatment and that the amount of C-F bonds increased with the heat treatment temperature. The catalytic effects also increased with the heat treatment temperature, indicating that the catalytic mechanism possibly involved the formation of C-F bonds on the carbon edge sites. In addition, the issue of proper sample preparation of Pt/carbon was briefly addressed; missteps in metal doping and consequently poor metal dispersion will result in significantly diminished spillover enhancements (Stadie et al.).