Self-cleaning and air purification performance of Portland cement paste with low dosages of nanodispersed TiO2 coatings

• Published in: Construction & building materials 2020-12, Vol.263, p.120558, Article 120558
• Main Authors: Wang, Zixiao, Gauvin, Florent, Feng, Pan, Brouwers, H.J.H., Yu, Qingliang
• Format: Article
• Language: English
• Subjects: Air purification performance; Portland cementitious materials; Self-cleaning coatings; Synthetic temperature; TiO2 hydrosol
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2020.120558

•The stable nanodispersed anatase TiO2 particles are synthesized in hydrosol form.•The TiO2 hydrosol-based coating presents a much better self-cleaning performance than that of P25 suspension.•The TiO2 hydrosol-based coating shows excellent air purification properties. The strong agglomeration potential and poor re-dispersibility of nano TiO2 particles in powder form seriously affect the depollution and self-cleaning performances. The nano TiO2 particles in hydrosol form can be stably dispersed in aqueous solution, but the synthetic temperature influences the crystal pattern, stability, and hydrodynamic diameter of nano TiO2 particles. In this study, a stable and nano dispersed anatase TiO2 hydrosol is synthesized by hydrolysis of titanium isopropoxide, and the effects of synthetic temperature on physicochemical properties and stability of TiO2 hydrosol are discussed. The photocatalytic and self-cleaning performances of synthetic TiO2 hydrosol coating are characterized by the colour change rate of Rhodamine B and NOx conversion UV irradiation. Compared with a commercial nano TiO2 powder (Degussa P-25), the TiO2 hydrosol coating with very low dosages shows better photocatalytic and self-cleaning performances under the same experimental conditions.