Glycerol Adsorption on TiO₂ Surfaces: A Systematic Periodic DFT Study

Area of Science:

• Materials Science
• Surface Chemistry
• Computational Chemistry

Background:

• Glycerol conversion to valuable products is crucial due to its abundance from biodiesel production.
• Titanium dioxide (TiO2) is a widely investigated catalyst for such transformations.
• Understanding glycerol adsorption on different TiO2 facets is key to catalyst design.

Purpose of the Study:

• To systematically investigate glycerol adsorption on anatase (101), anatase (001), and rutile (110) TiO2 surfaces.
• To determine the adsorption energies and modes (molecular vs. dissociative) for each facet.
• To analyze the impact of surface structure and defects on glycerol adsorption.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Systematic study of glycerol adsorption on three distinct TiO2 crystal facets.
• Analysis of adsorption energies, modes, surface reconstructions, electronic structure, and charge transfer.

Main Results:

• Anatase (001) exhibited the highest reactivity, facilitating both molecular and dissociative adsorption with significant surface reconstruction.
• Rutile (110) also showed molecular and dissociative adsorption but was less reactive than anatase (001).
• Anatase (101) was the least reactive, with only molecular adsorption and weaker binding energies.
• Oxygen vacancies influenced adsorption states and energies.
• Glycerol adsorption primarily affected the band gap, with strong adsorption linked to substantial charge transfer.

Conclusions:

• The reactivity of TiO2 facets towards glycerol varies significantly, with anatase (001) being the most active.
• Adsorption mechanisms (molecular vs. dissociative) and surface interactions are dependent on the specific TiO2 crystal face.
• DFT provides valuable insights into glycerol-TiO2 interactions, guiding future catalyst development for glycerol valorization.