Correlations between shape and near infrared reflective properties of nano/micro-yttria.

Yttria nanorods, nanoflakes and microshperes have been prepared via solvothermal and homogeneous precipitation methods followed by further calcining treatment, without any catalysts, templates, or substrates, in which yttrium nitrate was used as the yttrium source, sodium hydroxide and urea as the precipitators. The results show that the reflectivity of nano-yttria has significant correlations with its nanostructures. In contrast, Y2O3 microshperes possess about 90% reflectivity in the NIR region, which can be applied in energy saving and military camouflage etc.