Study of ruthenium oxide catalyst for electrocatalytic performance in oxygen evolution

The RuO2 anode catalyst for water electrolysis was prepared by a pyrolysis process in a nitrate melt at 300 °C and then calcined at different temperature from 350 to 550 °C. The physio-chemical properties of RuO2 catalysts were examined by XRD, FE-SEM, CV, EIS, BET, etc. The impedance results in oxygen evolution region clearly show that the electrocatalytic activity of RuO2 material decreases with the increase of calcining temperature. The resistance of catalyst layer (Rf), however, decreases with increase of calcining temperature. Thus, optimum calcining conditions are found at 350 °C, where the total polarization reaches a minimum in higher current density (>200 mA cm−2). Furthermore, the RuO2 anode also displays better stability at higher current density (1.1 A cm−2) in the PEM based electrolysers.

At low current densities the uncalcined material exhibits the best catalytic properties with the lowest total overpotential for OER. The potential then increases with increasing calcining temperature. At high current densities, above 200 mA cm2, the potential of OER for uncalcined sample exceeds that of samples prepared at 350 and 450 °C and with a very steep rise of the slope of the curve. These results show that the catalytic properties of the material are governing the potential for OER at low current densities, whereas the ohmic resistance of the catalyst layer (Rf) determines the potential for OER at high current densities. This means that an optimum is found at 350 °C where the total anodic potential in the high current densities range of 0.2–1 A cm2 is lowest. Figure optionsDownload as PowerPoint slide