Surface Chemistry of TiO2: Hydrophilic or Hydrophobic

Surface Chemistry of TiO₂: Hydrophilic or Hydrophobic

Liangliang Huang,^a* Luzheng Zhang,^b Adri C. T. van Duin,^c Xiaohua Lu,^d and Keith E. Gubbins^a

a. Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, 27695, USA

b. Illinois State Geological Survey, 615 East Peabody Drive, Champaign, IL 61820, USA

c. Department of Mechanical and Nuclear Engineering, Penn State University, Pennsylvania, 16801, USA

d. College of Chemistry and Chemical Engineering, Nanjing University of Technology, Nanjing, Jiangsu, China

Titanium dioxide (TiO₂) is considered to be a good candidate in solving or easing the environmental challenges and energy crisis. The performance of TiO₂ materials in environment and energy applications strongly depends on complex factors of materials, such as surface geometry, surface chemistry and activity, hydrostatic and thermal stability. Here we report a theoretical effort in understanding the surface chemistry of TiO2 material. By Density Functional Theory (DFT) calculation and reactive Molecular Dynamics simulation, we study the interactions of H₂O and NH₃ with TiO₂, and discuss the mechanism of controlling the hydrophilic and hydrophobic surface chemistry by hydroxyl and amino groups, respectively.