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Understanding and optimizing the sensitization of anatase titanium dioxide surface with hematite clusters.

Kati AsikainenMatti AlataloMarko HuttulaBernardo BarbielliniAssa Aravindh Sasikala Devi
Published in: Journal of physics. Condensed matter : an Institute of Physics journal (2024)
The presence of hematite (Fe 2 O 3 ) clusters at low coverage on titanium dioxide (TiO 2 ) surface has been observed to enhance photocatalytic activity, while excess loading of hematite is detrimental. We conduct a comprehensive density functional theory study of Fe 2 O 3 clusters adsorbed on the anatase TiO 2 (101) surface to investigate the effect of Fe 2 O 3 on TiO 2 . Our study shows that TiO 2 exhibits improved photocatalytic properties with hematite clusters at low coverage, as evidenced by a systematic study conducted by increasing the number of cluster adsorbates. The adsorption of the clusters generates impurity states in the band gap improving light absorption and consequently affecting the charge transfer dynamics. Furthermore, the presence of hematite clusters enhances the activity of TiO 2 in the hydrogen evolution reaction. The Fe valence mixing present in some clusters leads to a significant increase in H 2 evolution rate compared with the fixed +3 valence of Fe in hematite. We also investigate the effect of oxygen defects and find extensive modifications in the electronic properties and local magnetism of the TiO 2 -Fe 2 O 3 system, demonstrating the wide-ranging effect of oxygen defects in the combined system.
Keyphrases
  • visible light
  • quantum dots
  • density functional theory
  • molecular dynamics
  • healthcare
  • affordable care act
  • gold nanoparticles