Abstract
Surface application of photocatalyst in cement-based materials could endow it with photocatalytic properties, however, the weak adhesion between photocatalyst coatings and the substrates may result in poor durability in outdoor environments. In this study, TiO2@SiO2 core-shell nanocomposites with different coating thicknesses were synthesized by varying the experiment parameters. The results indicate that SiO2 coatings accelerated the rhodamine B removal to a certain extent, owing to its high surface area; however, more SiO2 coatings decreased its photocatalytic efficiencies. The cement matrix treated with TiO2@SiO2 core-shell nanocomposites showed good photocatalytic efficiency and durability after harsh weathering processing. A reaction mechanism was revealed by the reaction of TiO2@SiO2 nanocomposites with Ca(OH)2.
Highlights
The application of TiO2 nanoparticles in cementitious materials has gained considerable interest and research, which could endow it with photocatalytic properties, such as self-cleaning [1], air-purifying [2], and antibacterial properties [3]
In order to investigate the photocatalytic properties of WC specimens, the rhodamine B (RhB) degradation rates of these specimens were first measured after the TiO2 @SiO2 nanocomposites were sprayed on the surface of the WC pastes
RhB degradation rates of WC 1 and WC 4 are the highest, and the tendency is different from the degradation rates of TiO2 @SiO2 nanocomposites. This probably because adsorption action is more effective on the RhB degradation after nanocomposites are applied on the surface of WC pastes
Summary
The application of TiO2 nanoparticles in cementitious materials has gained considerable interest and research, which could endow it with photocatalytic properties, such as self-cleaning [1], air-purifying [2], and antibacterial properties [3]. The obtained TiO2 -containing cement-based materials show accelerated cement hydration [8], lower porosity, improved mechanical properties [9], self-cleaning [10], air-purifying [11], and antibacterial properties [3]. Boule [12] studied TiO2 -containing cement-based materials prepared using different techniques, and the results show that the TiO2 -cement mixture has significantly less efficiency than TiO2 slurries for the degradation of 3-nitrobenzenesulfonic acid and 4-nitrotoluenesulfonic acid. This is attributed to the reduction in the active surface. A reaction mechanism was revealed by the reaction of TiO2 @SiO2 nanocomposites with Ca(OH)
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