Optimizing TiO₂ Anatase Crystal Thin Film Growth for Photocatalysis
Gabriella Belén Chávez
Department of Chemistry & Biochemistry
Faculty Supervisor: Andrew Ichimura
Titanium dioxide (TiO₂) is a stable semiconductor widely used in photocatalysis and solar energy applications. The anatase phase, with a 3.2 eV band gap, generates electron–hole pairs under UV light that produce reactive oxygen species (ROS) for pollutant degradation and antimicrobial activity. Photocatalytic performance depends on crystal facet exposure: the (101) facet is more stable, while the (001) facet is more reactive. Hydrothermal synthesis with HF can stabilize the (001) facet, increasing its surface area, and [001]-oriented films improve charge transport. However, controlling facet orientation during synthesis remains a challenge. This study examines the effect of synthesis solution pH and TiF₄ concentration on crystal orientation, grain size, and photocatalytic activity of anatase TiO₂ films. Results indicate that lower pH and higher TiF₄ concentrations promote larger crystal grain formation, highlighting the importance of solution conditions in optimizing material performance.