Enhancement of photocatalytic activities with nanosized polystyrene spheres patterned titanium dioxide films for water purification

For environmental applications, such as water and air purification utilizing photocatalysts, we synthesized patterned titanium dioxide (TiO₂) thin films using polystyrene (PS) spheres. This was primarily done to enhance the surface area and photocatalytic activities. TiO₂ thin films were deposited on silicon wafers attached to variously sized PS spheres via the spin coating method and were annealed at 600^◦C. The processing step involved patterning and coating a TiO₂ sol–gel. The photocatalytic performance was analyzed using an UV–visible spectrophotometer. Within 20 min, a high catalytic efficiency (98% removal) with a 20-time faster decomposition rate of the malachite green (MG) solution than that of the nonpatterned TiO₂ was obtained from the patterned TiO₂ with 400 nm sized PS due to the large surface area. In addition, the phenol in the water removed as much as 50% within 2 h with the same photocatalyst, which was expected to be one of the strong candidates to be applied to the next generation of photocatalysts for water purification.