Study on near-infrared high reflectivity blue pigments based on 13X zeolite

Colored cooling materials play an important role in lowering the surface temperature of buildings and minimizing the reliance on air-conditioners. In this study, a novel cooling pigment was prepared via the solid-state reaction method, with 13X zeolite serving as the matrix and sulfur anions as the chromogenic groups, which exhibits a blue hue in the visible region and high reflectivity in the near-infrared (NIR) region. The samples were mainly characterized using X-ray diffraction (XRD), UV-vis-NIR spectrophotometry, thermogravimetric-differential scanning calorimeter (TG-DSC) and other analytical equipments. The results revealed that the content of sodium carbonate plays a key role in the spectral modulation of blue cooling pigment. With the content increase of sodium carbonate, the color of the product changed from dark blue to white gradually. When the mass ratio of Na 2 CO 3 /S was 1:1, the NIR reflectance of synthesized pigment reached 77%, which was approximately 25% higher than that of commercial. The cooling performance test shows that the prepared blue pigments could reduce the inner surface temperature of an Al plate by 5.7 °C compared to the commercial blue pigment. This study indicates that the 13X zeolite is a promising candidate for the preparation of NIR high reflectance pigments, which is of great significance for the development of colored cooling materials.