INSITU PHOTOACOUSTIC-SPECTROSCOPY OF MIXED-OXIDE ELECTROCATALYSTS

The chlorine evolution reaction was studied comparatively at Ru/Ti, Ir/Ti, and (Ir + Ru)/Ti mixed oxides by a combination of electrochemical and in situ photoacoustic techniques with ex situ Rutherford backscattering measurements. The oxide layers were generated in situ by electrochemical oxidation of near-surface implanted titanium alloys. Rutherford backscattering allowed an estimate of the actual surface concentration of the electrocatalytically active sites. In situ photoacoustic spectroscopy, together with Tafel slope measurements, provided a means to probe the electronic structure of mixed oxides. For the three systems, a transition from a semiconducting to a metallic layer was observed for a similar critical surface concentration of noble metal in the mixed oxides. © 1990, The Electrochemical Society, Inc. All rights reserved.