Synthesis and characterization of NiTiO₃ yellow nano pigment with high solar radiation reflection efficiency

In this paper, we report on the facile synthesis method to obtain nickel titanate (NiTiO₃) nanoparticles through pyrolysis of polymeric precursor. The pyrolysis behaviors of the polymer precursors prepared via the in situ polymerization of metal salts and acrylic acid were analyzed by simultaneous thermogravimetric and differential scanning calorimetry. The structural and morphological characteristics of the products were studied by powder X-ray diffraction and transmission electron microscope. The results reveal that ilmenite NiTiO₃ nanoparticles with spherical-like shape are obtained through pyrolysis of Ni-Ti polyacrylate precursor at above 600°C. The mean particle size of NiTiO₃-600°C and NiTiO₃-800°C is about 30nm and 60nm, respectively. Ultraviolet-visible (UV-vis) near infrared (NIR) reflectance spectra study show that the NiTiO₃ nanoparticles have a high reflection peak of ~580nm, which is associated with the deep and brilliant yellow color of this pigment. The average reflectance of NiTiO₃-600°C and NiTiO₃-800°C in NIR range are 62.1% and 58.8%, respectively. We have observed brilliant yellow color and high UV-vis-NIR reflectance of NiTiO₃ nanoparticles. Moreover, these NiTiO₃ nanoparticles have great potential in serving as cool pigment for building coating.