Study on novel blue-purple high-NIR reflectance pigments and acrylic coatings based on Ca2Zn1-xMxSi2O7 (M = Mn and Ni)

The coating optimized with high near-infrared reflectance pigments can effectively reduce the energy consumption for heating and cooling in buildings, thereby alleviating the pressure on global energy consumption. Using a high-temperature solid-state method, blue-violet pigments with high near-infrared reflectance, Ca 2 Zn 1- x M x Si 2 O 7 (M = Mn, 0 ≤ x  ≤ 0.4 and Ni, 0 ≤ x  ≤ 0.2) solid solutions, were synthesized for the first time, with a maximum solar reflectance of 82.67%. Using XPS analysis, it was determined that the oxidation state of Ni in the pigment is +2, while Mn exists in mixed oxidation states of +2 and +3. UV-VIS-NIR spectroscopy analysis indicates that the blue-violet color of the pigment originates from the d-d transitions of the transition metal ions. As the doping concentration increases, the near-infrared reflectance of the pigment decreases. The DFT calculations have also confirmed that the color of pigments originates from transition metal ions. The as-synthesized pigments were incorporated into acrylic to create colored coatings. Improving the near-infrared solar reflectance of the acrylic coating. The excellent high near-infrared solar reflectance and coating property optimization make the synthesized pigment a potential energy-saving coating.