Synthesis and Characterization of Calcium Copper Titanate (CaCu₃Ti₄O₁₂) Powder as a Brown-Coloured Inorganic Pigment with High Infra-Red Reflectance

Abstract

To mitigate the Urban Heat Island (UHI) effect there is a stringent need to develop non-toxic and low cost Infra-red (IR) reflective pigments. Therefore, in present work the Calcium Copper Titanate (CaCu3Ti4O12) abbreviated as CCTO was prepared at different temperatures 800 °C, 850 °C, 875 °C, 900 °C, 925 °C, and 950 °C. X-ray diffraction (XRD), diffuse reflectance measurement in the Ultra Violet (UV), Visible (Vis) (295 nm to 700 nm), and Near Infra-Red (NIR) region (700 nm to 2500 nm), optical band gap and colour were measured to establish its use as IR reflective pigment. The chemical stability and cooling performance were also investigated. The XRD investigations showed the single-phase CCTO with cubic symmetry can be obtained by the calcination of reactants at an optimum temperature of 925 °C. The Diffuse reflectance data, within the heat-producing NIR band (700 nm to 1100 nm) varied from 46.23% to 53.34%. The optical band gap was observed to vary from 3.30 eV to 2.03 eV. No significant color degradation was observed upon treatment with 10% H2SO4 and 10% HNO3. Cooling performance assessment showed a significant difference of ∼5 °C between coated and uncoated red brick surfaces.