Application of TiO2-based photocatalysts to cementitious materials is the subject of many researches in the last two decades, and is mainly aimed at achieving two goals: the depolluting action due to the oxidation of NOx present in the atmosphere to NO3- and the self-cleaning effect of the photocatalytic cement surface. Regarding depollution, NOx emission reduction is a focus of environmental regulations. As for self-cleaning property, it tackles the problem of the preservation of the original appearance of the surface of the building, mainly of the architectural concretes over time. This technology is required mainly in dense and polluted areas – large cities for example.
The current TiO2-based photocatalyst is not efficient enough to tackle and compensate for its limited activity in real conditions – continuous refresh of the polluted air entering in contact with the photocatalytic surface and variable environmental conditions (sunlight intensity over year and over latitude).
The novel technology includes photocatalytic compositions, comprising a photocatalyst, and a graphenic material, as well as uses of the photocatalytic compositions / substrates (paint, plaster, cementitious composition, gypsum, hydraulic binder, etc.) particularly for reducing pollution in air or water. The preparation of the photocatalyst is a simple one-step process not requiring high-temperature heating or addition of toxic surfactants. The new photocatalyst shows up to 40% enhancement in photodegradation of a model organic target (Rhodamine B) and is 50-70% more efficient in reducing NOx than current photocatalysts. The catalysts maintains its photodegradation activity over at least several years.
- High and efficient photocatalytic action, based on titanium dioxide and a graphenic materials
- Catalyst is made by industrial scalable methods
- Low-cost starting commercial reagents
- Small amount of graphenic material needed to achieve the enhanced performance, lowering the TiO2 content, and, consequently, the cost of concrete
- Catalyst is suitable for environmentally friendly remediation with no progressive release of toxic compounds
Applications and Opportunities
- Photocatalysis in cementitious material for outdoor structures and buildings
- Smart photoactive surfaces for environmental remediation