Investigations on the formation of RuO2/ZrO2-based electrocatalytic thin films by surface analysis techniques

Secondary ion mass spectrometry (SIMS) was used to follow the evolution of RuO2/ZrO2 film electrodes. The coating mixtures with compositions 20% Ru 80% Zr and 50% Ru + 50% Zr prepared on titanium supports from isopropanolic solutions of RuCl3 x 3H(2)O and ZrOCl2 x 8H(2)O precursors were heated to 200, 300, and 500 degrees C and analyzed by SIMS. Cl--concentration depth p rofiles as ion intensity versus sputtering time curves showed the hydrolyti c conversion of the ZrOCl2 precursor in the outer part of the film at low t emperature and noble metal content and a rather uniform distribution at ele vated temperatures. Zr+/Ru+ ion intensity ratios showed the relative enrich ment of ruthenium in the near surface region at 500 OC, while slight accumu lation of zirconia at the surface was evidenced for both compositions in ha rmony with the results of emission FTIR measurements. No reaction between t he oxide components or between coatings and support was identified in the s ystems investigated.