Enhanced mechanical and photocatalytic performance of cement mortar reinforced by nano-TiO2 hydrosol-coated sand

This study investigated the impact of natural sand supported nano-TiO 2 hydrosol (TiO 2 @Sand) on the mechanical and photocatalytic performance of cement mortar and the underlying mechanisms. The incorporation of TiO 2 @Sand in cement mortar (TiO 2 was 0.6 wt% of cement) improved 28-day compressive strength by 67% compared with the one without nano-TiO 2 . Various beneficial changes towards improved mechanical strength were also observed in TiO 2 @Sand cement mortar: reduced total porosity by 35%, densified interfacial transition zone (ITZ) microstructure, enhanced modulus of ITZ by 54%, reduced ITZ thickness by 40% and improved dispersion of TiO 2 . The degradation efficiency of Rhodamine B and NO by TiO 2 @Sand reinforced mortar was 40% and 25% higher than cement matrix with conventionally dispersed nano-TiO 2 powder, respectively. The significantly enhanced photocatalytic activity of the TiO 2 @Sand mortar was attributed to the expanded light absorption range, the reduced recombination of electron-hole pairs of TiO 2 @Sand, and the better dispersion of nano-TiO 2 in cement matrix. These results demonstrated the promising potential of using TiO 2 @Sand in cement mortar to deliver significant enhancement of both mechanical strength and photocatalytic activity.