Efficient design and optimization of multifunctional N-F-TiO2/rGO films via orthogonal composite approach

An orthogonal composite approach is proposed to study the multielement synergistic modified TiO2 photocatalytic films. The relationship between different preparation factors and photocatalytic evaluation indexes including photo-degradation activities, antibacterial properties, light transmittance and hydrophilicity, is revealed by the correlation and difference analysis. The increase of F content improves the photocatalytic and antibacterial activities. While the increase of Fe content and calcination temperature are not conducive to the transmittance. Additionally, reduced graphene oxide (rGO) is beneficial to improve the antibacterial properties, but it is not conducive to the self-cleaning performance. The interaction between different factors cannot be ignored in the design of multifunctional TiO2 films from Pareto analysis. The optimal state shows that the glass coated with multifunctional F(9%)-N(1%)-TiO2/rGO(0.5%)-300 ℃ film exhibits the highest photo-degradation (59.8%) and antibacterial activities (87.1%) with superior transmittance (84.1%) and hydrophilicity (7.0°) under visible-light irradiation condition.