Ruthenium Oxide-Based Microelectrochemical Devices: Electrochemical Behavior of the Oxide Formed by Reduction of RuO4(2-).

摘要

Properties of macroscopic electrodes and arrays of closely spaced (1.2 micro M) Au microelectrodes (approx. 2 micro M wide x 50 micro M long x 0.1 micro M high) coated with the oxide (RuOx) derived from reduction of RuO42- in 1 M NaOH are reported. XPS data show RuOx consists of a mixture of Ru oxidation states with significant amounts of RuIV. RuOx exhibits a well-defined cyclic voltammetric wave centered at Eredox = 0.0 vs. SSCE in pH 7.0 solution. The position, shape and area of the wave are insensitive to electrolyte composition, e.q. buffered solutions of LiCl, NaCl, CaCl2, (NH4)Cl, Na(ClO4) Na(OAc), Na(OTs), or Na(phosphate). A pH dependence of 71 mV/pH unit from pH = 2 to pH = 14 is found for the position of this wave. UV-vis spectroelectrochemistry shows four broad absorption bands in reduced RuOx. Oxidation increases absorbance across the entire visible spectrum, but the data suggest that only a fraction of the RuOx is electroactive. (mjm)