Ruthenium dioxide is an important electrode material for applications in electrocatalysis and power sources. High surface areas are achieved in hydrous RuO2 precipitates and in mixed ruthenium oxide−titanium oxide, (Ru−Ti)Ox, aerogels (in which nanoscale domains are networked to form a highly porous structure). The electrochemical properties of (Ru−Ti)Ox aerogels, RuO2, and hydrous RuO2 are examined by direct pressing of sub-milligram quantities of the solid onto the surface of a conductive carbon/wax composite. Voltammetric measurements in acidic electrolyte confirm a pseudocapacitive response for all the RuOx-based materials. Despite an improvement in BET surface area, as compared with other RuO2 materials, the (Ru−Ti)Ox aerogel displays a low specific capacitance, which correlates to the high degree of crystallinity of the aerogel. Nanocrystallites of rutile RuO2, formed during thermal treatment of the sol−gel Ru/Ti precursors, deleteriously affect the specific capacitance of the material; however, all...