Photocatalytic property of cement mortars coated with graphene/TiO2 nanocomposites synthesized via sol–gel assisted electrospray method

Titanium dioxide (TiO 2 ) photocatalyst coatings on cement material surfaces of buildings or structures that require high mechanical integrity, such as tunnel walls and pedestrian roads, can directly utilize solar energy for self-cleaning surfaces and removing air pollutants in the environment. However, TiO 2 can utilize only ultraviolet (UV) light, which accounts for only 5% of sunlight. To improve photocatalytic efficiency, graphene/TiO 2 nanocomposites are prepared by a sol-gel assisted electrospray method and characterized by various instrumental analysis methods. Photocatalytic cement mortars are prepared by incorporating the as-prepared nanocomposites and commercial TiO 2 into cement mortar. The self-cleaning and air purifying properties of the cement mortars are evaluated by the discoloration of rhodamine B (RhB) and the removal of nitric oxide (NO). As desired, cement mortar coated with graphene/TiO 2 nanocomposites expresses high photocatalytic effectiveness on both RhB and NO. In addition, the regeneration of graphene/TiO 2 nanocomposite photocatalysts has also been studied. The results show that the photocatalytic activity can be effectively regenerated by UV irradiation, with good repeatability and stability. Therefore, graphene/TiO 2 -coated cement mortar is a potential candidate for effective building self-cleaning and air purification through the use of solar irradiation .