Harnessing the Potential of Photocatalytic Coatings: Enhancing Sustainability and Durability in Building Facades

TiO2-based coatings for application on the surfaces of mortars in building facades advances global climate change initiatives for a more sustainable built environment and the potential correlation between de-pollution and self-cleaning properties.

FREMONT, CA: Urban air pollution and global warming pose significant threats to environmental equilibrium in the present era. Cities grapple with poor air quality, characterized by the release of pollutants such as nitrogen oxides (NOx), sulfur oxides (SOx), Volatile Organic Compounds (VOCs), and organic particulate matter like soot. The impact of global warming extends beyond the natural environment, affecting communities, human health, and related infrastructure.

Adaptation to climate change is crucial for building sustainability, even in retrofit interventions. Within this context, photocatalysis emerges as a potential strategy to combat current environmental and climate challenges by transforming or eliminating hazardous greenhouse gases from the atmosphere. Titanium dioxide (TiO2) is a suitable alternative for converting mineral and organic compounds, thereby supporting climate change actions.

Utilizing TiO2 in Mortars for Building Facades: There are two primary approaches to incorporating TiO2 into mortars for building facades: adding it to the mixture proportion or as a surface coating. The efficiency of photocatalytic activity is influenced by both the method of TiO2 incorporation and the characteristics of the substrate itself. Adding the photocatalyst to the mixture enhances the long-term stability of mortars in terms of surface-mechanical properties. While mortars with intermixed TiO2 exhibit lower photocatalytic activity than those with TiO2-based thin surface layers, the former can still deliver acceptable results, although not always optimal. Incorporating TiO2 into mortar mixtures may not fully exploit the potential of the active material since only the nanoparticles on the outer face of the layer can be activated with UV light. Conversely, thin TiO2-based coatings optimize the photocatalytic activity more efficiently.