Disclosed herein is an article having: a substrate and a RuO2 coating having nanoparticles of RuO2. Also disclosed herein is an article having: a substrate and a RuO2 coating. The coating is made by: immersing the substrate in a solution of RuO4 and a nonpolar solvent at a temperature that is below the temperature at which RuO4 decomposes to RuO2 and warming the substrate and solution to ambient temperature under ambient conditions to cause the formation of the coating.