Environmental-friendly yellow pigments based on Zr doped Y4MoO9

A novel class of environmental-friendly yellow inorganic pigments with the general formula Y4−xZrxMoO9+δ (x = 0, 0.2, 0.4, 0.6 and 0.8) have been successfully synthesized by a conventional solid-state reaction route at 1400 °C for 6 h in air atmosphere and characterized by XRD, XPS, EDS, SEM, UV–vis-NIR diffuse reflectance spectroscopy and CIE 1976 L*a*b* color scales. The results show that the greenish yellow color of obtained pigments is strongly dependent on the sample composition. When x is about 0.2, the value of color lightness L* and yellow hue b* of Y4−xZrxMoO9+δ is up to 93.1 and 57.5, respectively. Furthermore, the band gaps of the resultant pigments vary from 2.43 to 2.68 due to O2p-Mo4d charge transitions and phase conversion, and the average NIR reflectance is about 90%. It is likely that the synthesized pigments could be interesting alternatives to toxic yellow pigments.