Anatase-silica additive for self-cleaning materials based on cement

Introduction. The cost of anatase additives to concrete can be lowered by synthesizing it and applying it to a mineral substrate that is active against cement. In particular, the use of anatase in mineral powders such as silica shows promise. This paper describes the synthesis of anatase-silica photocatalysts with varying anatase to silica ratios and evaluates their performance in cement-based materials. Materials and methods. The photocatalytic additive was obtained by TiO2 deposition on the microsilica substrate using sol-gel technology. The physicochemical studies included X-ray phase analysis and electron scanning microscopy. To determine the self-cleaning, we used the rhodamine test. Results and discussion. An increase in the TiO2/SiO2 ratio increases the area covered with anatase and the height of the main anatase reflections in the X-ray phase analysis. But the increase in the anatase reflection intensity is not proportional to the change in the TiO2/SiO2 ratio with the same size of anatase crystallites. With an increase in TiO2 relative to SiO2, the self-cleaning efficiency increases and reaches the required level when the ratio of oxides in the additive is slightly less than 1:1. It means that 1 g of TiO2 is enough per specific surface area of the substrate 22 m2 to create an effective photocatalytic additive. Conclusion. The optimal TiO2/SiO2 ratio of 1:1 was revealed by varying the amount of anatase relative to the substrate in the range of TiO2/SiO2 ratios from 1:2 to 1:0.5. The results can be used in the production of technically and economically effective photocatalytic additives for self-cleaning materials based on cement.