Brilliant IR Reflecting Yellow Colorants in Rare Earth Double Molybdate Substituted BiVO4 Solid Solutions for Energy Saving Applications

Brilliant IR reflecting yellow colorants are developed in rare earth double molybdate substituted BiVO4 solid solutions. Li(0.10)RE(0.10)Ei(0.8)Mo(0.2)V(0.8)O(4) (RE = La, Pr, Sm, Gd, Tb, Dy, Y, Yb and Lu) pigments are prepared by a conventional solid-state reaction route and their optical, structural and morphological properties are analyzed. X-ray diffraction analysis confirms the tetragonal scheelite phase formation in the series. These pigments have a strong optical absorption in the UV-blue light wavelength region. CIE LAB color analysis shows that different hues of yellow shades are obtained in these solid solutions. The color characteristics are comparable to commercial BiVO4 pigment. Incorporation of double rare earth molybdates of La, Gd, Tb, Y and Lu into BiVO4 results in nontoxic IR reflecting cool pigments. The applicability of the developed pigment was tested on a concrete cement surface as well as on a metal panel. These pigments are composed of less toxic elements that make them favorable for energy saving surface coating formulations for buildings and automotives.