Hydrogen Incorporation and Storage in Well-Defined Nanocrystals of Anatase Titanium Dioxide

Hydrogen incorporation into well-defined nanocrystals of anatase titanium dioxide (TiO2) has been investigated by a combination of experimental studies and density functional theory (DFT) calculations. The hydrogenation of TiO2 nanocrystals was determined at 450 degrees C with an initial hydrogen pressure of 7.0 MP, and storage capacities of 1.0 wt % and 1.4 wt % were achieved for nanocrystals with predominant (001) and (101) surface terminations, respectively. X-ray diffraction and Raman spectroscopy measurements indicate that the TiO2 crystal structure is very well preserved during the hydrogenation. DFT calculations show that hydrogen occupies the interstitial sites between titanium-oxygen octahedra and the energy barrier for hydrogen incorporation through the anatase (101) surface is lower than that through (001).