Effect of alkali amount on layered titanate as tunable solar reflective material

Abstract

In urban areas huge population play a pivotal role on environmental pollution, the roofs of buildings in these areas have a greater effect on the absorption of heat from the sun light which increases the greenhouse gases emission to the environment and finally causes global warming. To avoid such energy consumption, special coating materials are important to block radiations in the near-infrared, (NIR) spectrum. In the current work, an experimental study for the evaluation of this phenomenon about infrared-reflective materials has been made. A layered type Na2Ti3O7 (NTO) as a parent compound was used to produce Na2-xHx Ti3O7 type titanate (HTO) material by the exchange of Na+ for H+. Here x means the ion-exchanged Na+ for H+ in the titanate (Ti3O7)2- gallery. Depending on the Na+ amount in the titanate gallery, the NTO and the ion exchanged HTO materials showed the high and tunable solar reflective properties from 84 to 94% compared to high refractive index commercial rutile TiO2. The materials crystalline nature, structural, morphological and optical properties were investigated using XRD, FE-SEM, EDS and UV–Vis–NIR spectrophotometer. The results showed that the layered NTO and ion-exchanged HTO materials could be a suitable candidate for tuning solar heat reflectance in coating industries.