Elaboration and characterization of ruthenium nano-oxides for the oxygen evolution reaction in a Proton Exchange Membrane Water Electrolyzer supplied by a solar profile
Résumé
Highly crystalline rutile-like structure ruthenium oxide material was synthesized from the hydrolysis method. A heat-treatment procedure was effective to recover catalyst powders free from organic carbon species which could be resulted in the traces of ethanol as solvent. Voltammetry (CV and LSV) and electrochemical impedance spectroscopy (EIS) were used to determine the capacitance and the kinetic parameters of the RuO2 anodes for the oxygen evolution reaction (OER). The utilization of this catalyst as anode in a single cell PEM electrolyzer has shown high activity toward pure H2 and O2 gases production. Exchange current density and Tafel slope of 3.3 10−8 A cm−2 and 51 mV dec−1, respectively determined at 60 °C, showed that the H2O oxidation to O2 was limited by intermediate species formation step. During the durability tests in a 25 cm2 single PEM water electrolyzer (PEMWE) supplied by a solar power profile, the area resistance was raised in the 300–345 mΩ cm2 range and an efficiency loss of 330 μV h−1 was measured from 1.85 V at 1 A cm−2 and 80 °C.