Titania-based photocatalysts functionalized on stainless steel and its photocatalytic antibacterial activity

Abstract

Owing to the potential environmental applications, photocatalytic reactions occurring on the surface of photoirradiated titanium(IV) oxide (TiO2) have garnered a wide interest. One of the many usage of TiO2 as a photocatalyst is in inhibiting bacterial growth. TiO2 is generally coated onto the surface of a substrate material and the material’s photocatalytic antibacterial activity is then investigated. In the present study, TiO2-based photocatalysts were coated on the surface of stainless steels by using an automatic film applicator (AFA), which is able produce a uniform coating with controllable thickness and high resistivity. By using this method, it is also possible to directly use TiO2 powder, instead of using other TiO2 source that requires crystallization process afterwards. The TiO2 photocatalysts were firstly prepared by preparing the mixture of the coating process, which consisted of anatase TiO2 powder, polyvinyl alcohol as the binder, ammonium citrate tribasic as the stabilizer and distilled water, where different compositions of TiO2 were used. After the coating process by AFA, the samples then underwent heating process at 200 °C. The prepared photocatalysts were characterized by field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, ultra violet-visible (UV-Vis) spectroscopy and grazing incidence X-ray diffraction (GI-XRD). The FESEM images clearly showed agglomerated TiO2 particles on the surface of the stainless steel, while EDX results further confirmed the presence of TiO2. The photocatalytic antibacterial activity of the synthesized TiO2 photocatalysts on stainless steels were then tested out by using Escherichia Coli (E.Coli) in agar plates at 37 °C for 24 h.