Sol–Gel Combustion‐Derived CoCuMnOx Spinels as Pigment for Spectrally Selective Paints

Abstract

In this work, sol–gel combustion synthesis of spinel CoCuMnOx was reported. X‐ray diffraction (XRD) and Fourier transformation infrared spectroscopy (FTIR) techniques were used to study the reaction processes. The as‐synthesized spinel CoCuMnOx was further characterized by XRD, X‐ray photoelectron spectroscopy, and field‐emission scanning electron microscopy. The CoCuMnOx powders with a deep black hue were then used as solar energy‐absorbing additive to make a novel kind of spectrally selective paint coatings. The solar absorptance (αs) and the thermal emittance (ɛT) of the coatings were determined from the corresponding diffuse reflectance spectra in the 0.3–20 μm range. The optimum selective sample exhibited values of αs=0.928 and ɛ100=0.198. Besides ideal optical properties, the coatings also show excellent long‐term stability, which is confirmed by results of accelerated tests established by IEA‐SHC Task X, indicating that they could be a good alternative to the materials present today in the market.