Characterisation of ruthenium catalysts and determination of their surfaces by electrochemical oxidation and reduction Original Research Article

Methods of electrochemical voltammetry and potential step method were tested both for a characterisation and the surface determination of ruthenium black, ruthenium and bi-metallic Ru–Sn catalysts on Al2O3 and sol–gel SiO2 supports. It was demonstrated that transforming ruthenium to its oxide is necessary for acquiring reproducible and correct results. It was found that compared to the BET determination, the above mentioned electrochemical methods also produce exact results when RuO2 black is used. Voltammetric curves of ruthenium dioxide deposited on supports showed that these oxides have rather different redox properties in comparison with RuO2 black. Consequently, this phenomenon brought about a decrease in the absolute accuracy of the electrochemical methods used for the determination of ruthenium surface on carriers, since it was not possible to exactly verify the value of the specific redox charge using any other independent method. Nevertheless, the tested electrochemical methods are possible to be utilised at least for the determination of relative surface area values of a supported ruthenium.