Rational approach to synthesis low-cost BiVO4–ZnO complex inorganic pigment for energy efficient buildings

Bismuth vanadate (BiVO4) gathered great attraction as a yellow inorganic pigment which could replace the conventional chrome and cadmium yellow. However, its high cost over other yellow pigment restricted its usage. Therefore, there is a huge demand is existing to develop cost-effective BiVO4 inorganic pigment without compromising its optical properties. In this work, we demonstrate an effective strategy to develop low-cost BiVO4 complex pigments. Nano particles of BiVO4 decoration on white pigment are achieved by the citrate-gel method. An appreciable decrease in BiVO4 content (75%) has been observed. The reduction in the BiVO4 have shown a remarkable impact on the economic viability of the new complex pigment. The developed complex inorganic pigment exhibited excellent greenish-yellow colour (a* = −6.28, b* = 76.45), which is similar to pure BiVO4. An exceptional near infrared reflectance has been recorded, which is estimated as high as 90%. High reflective coatings of developed complex pigment displayed significant response for temperature shielding experiment, could achieve reduction of 8.4 °C in the interior temperature, compared to the commercially available yellow coating. Moreover, the present work demonstrates that developed complex pigment could be a potential replacement for BiVO4 yellow pigment.