Synthesis and characterization of CeO2-TiO2-Pr6O11 solid solutions for environmentally benign nontoxic red pigments

New inorganic pigments Ce1-(x+y)TixPryO2 (x ranges from 0.05 to 0.195 and y ranges from 0.005 to 0.15) based on CeO2-TiO2-Pr6O11 solid solutions have been synthesized by solid-state route with a goal of preparing environmentally secure red colorants. Characterizations using XRD, UV-vis spectroscopy and CIE 1976 color coordinates assessment reveals the formation of pigments displaying colors ranging from brick red to dark brown. The coloring mechanism is based on the introduction of additional electronic level of energy in the cerianite forbidden band from the unpaired 4f electron of lanthanide ion.