Synthesis and coloration of highly dispersive SiO2/BiVO4 hybrid pigments with low cost and high NIR reflectance

Highly dispersed SiO2/BiVO4 hybrid pigments with a spherical structure and high near-infrared (NIR) reflectance have been successfully fabricated by a facile sol-gel method followed by calcination. The dispersed and uniformly spherical particles of the hybrid pigments were caused by the support provided by SiO2 microspheres, and their color was adjusted via the band-gap energy, which was changed with the incorporation of SiO2 microspheres. The SiO2/BiVO4-3 hybrid pigment presented higher yellow hues (b* = 91.42) and more dispersed spherical particles than other as-prepared hybrid pigments and commercially available BiVO4-based yellow pigment. This strategy could save 72 wt% resource of BiVO4 while yielding the same amount of yellow pigment with high color performance. Therefore, the prepared hybrid pigments not only dramatically decreased the cost of expensive pigments, but also saved scarce resources and reduced environmental pollution. In addition, the SiO2/BiVO4-3 hybrid pigment also presented high NIR reflective performance, which demonstrated that it would be a favorable candidate for colorful NIR reflective pigments with wide applications in heat insulation.