Nanostructured black moly surfaces for solar thermal absorbers by wet chemical etching

Abstract

Black Moly (MoO3) coatings obtained by a facile sustainable wet chemical etching method has been investigated to understand the effect of etchant time on the prepared coatings. The effect of the time of etching on the structural, morphological and optical properties of black moly coatings have been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy. The XRD spectrum of the prepared coatings showed only peaks from the Molybdenum substrate indicating amorphous coatings. But when annealed at 500˚C, it showed crystallisation to MoO2. In this work, we developed a nanostructured coating, black moly, with a high solar absorptance of over 81%. These results suggest that black moly coatings made from refractory metal oxides can be used for solar thermal absorbers.