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

Titanium dioxide (TiO2) 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, TiO2 can utilize only ultraviolet (UV) light, which accounts for only 5% of sunlight. To improve photocatalytic efficiency, graphene/TiO2 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 TiO2 into cement mortar. The selfcleaning 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/TiO2 nanocomposites expresses high photocatalytic effectiveness on both RhB and NO. In addition, the regeneration of graphene/TiO2 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/TiO2-coated cement mortar is a potential candidate for effective building self-cleaning and air purification through the use of solar irradiation. (c) 2020 Elsevier Ltd. All rights reserved.