Development, microstructural characterization, and photocatalytic evaluation of TiO2-modified rendering mortars

Abstract

The growing demand for sustainable construction materials has spurred research into cement-based composites that can contribute to environmental remediation. In this context, photocatalytic materials containing titanium dioxide (TiO?) have attracted considerable attention due to their ability to degrade organic pollutants under ultraviolet radiation. This study aimed to develop and evaluate TiO?-modified rendering mortars with enhanced photocatalytic performance for potential application in building facades and surface coatings. Mortar mixtures were produced with 0%, 2%, 6%, and 10% TiO?, expressed as a percentage of cement mass. The materials were characterized through ultraviolet–visible (UV–Vis) spectroscopy, scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS), and X-ray diffraction (XRD). Photocatalytic activity was assessed using methylene blue degradation tests under UV irradiation. The results demonstrated that TiO? incorporation influenced the methylene blue removal behavior of the mortars under UV irradiation. Among the TiO?-modified formulations, the mortar containing 10 wt.% TiO? exhibited the highest overall removal efficiency. Because no adsorption–desorption equilibrium was established before irradiation, the measured dye removal represents the combined effects of adsorption and photocatalytic degradation. Microstructural analyses confirmed the presence and distribution of TiO? particles within the cementitious matrix and indicated changes associated with increasing nanoparticle content. Although higher TiO? additions enhanced photocatalytic performance, they also reduced the workability of the fresh mortars. Overall, the findings demonstrate the potential of TiO?-modified rendering mortars as multifunctional construction materials capable of combining conventional protective functions with photocatalytic properties for environmental remediation applications.