Synthesis of high near infrared reflection wurtzite structure green pigments using Co-doped ZnO by combustion method

A high near-infrared reflective green pigment with a low cobalt content, Zn_0.96Co_0.04O, was prepared by solution combustion synthesis. The pigment was characterized by XRD, SEM, TG-DSC, UV–vis and CIE L*a*b*C*h* colorimetric. The resulting green pigment showed that the chromaticity performance is better. The doping Co did not affect the main crystalline structure, all samples were retained ZnO wurtzite structure. The better green hue is a* = ?15.35 and achieved a near-infrared reflectivity up to 40%, when CoO content was x?=?0.04, combustion agent was glycine, calcination temperature was 1000?°C. The synthesized pigments have a better thermal stability, chemical stability and a small amount of cobalt oxide (2.8?wt%), and the preparation process is simple. Therefore, the green pigment of ZnO wurtzite structure has great potential in serving as cool pigments for building coatings.