Abstract A simple and efficient route to decorate carbon nanotubes (CNTs) with nanocrystalline RuO2 has been developed. In this method, RuCl3.3H2O was oxidized into RuO2 by oxygen in supercritical diethyl amine, and the produced RuO2 deposited on CNTs, resulting in RuO2/CNT nanocomposites. The as-prepared composites were structurally and morphologically characterized by X-ray diffraction, X-ra…