Photocatalytic zinc oxide thin films obtained by surfactant assisted spray pyrolysis deposition

- ZnO thin films were deposited by surfactant assisted SPD.
- All films could degrade methylorange under VIS radiation.
- Surfactant concentrations above CMC are recommended.
- VIS-efficiency up to 20% was obtained using SDS in the deposition of ZnO film.

Zinc oxide thin films were obtained by spray pyrolysis deposition using three surfactants with linear C12 tails as soft templating agents: anionic sodium dodecylsulfate (SDS), cationic dodecyltrimethylammonium bromide (DTAB) and nonionic dodecanol (DD). The influence of the surfactants' type and concentration (above and below critical micelle concentration in the precursor system) on the thin film formation was investigated and was correlated with their photocatalytic efficiency in methylorange removal, under visible and UV iradiation. The surfactants influence both the nucleation and growth stages, mainly through the Zn-surfactant interactions at the droplet border and/or on the micelles. In situ doping with Na+ (in SDS) improves the removal efficiency up to 19.88% under VIS irradiation, while the highest removal efficiencies in ZnO thin films obtained using DTAB and DD are 16.27% and 15.44%, respectively. Under UV irradiation the highest efficiencies are 45.28% (SDS), 51.59% (DTAB) and 49.43% (DD).