Abstract
Ruthenium oxide catalysts were prepared by a sol–gel technique and calcined at different temperatures e.g., 400 °C, 500 °C and 600 °C. The catalysts performance for the oxygen evolution reaction was studied using cyclic voltammetry and their performance in a high temperature proton exchange membrane water electrolyser (PEMWE) examined. Physio-chemical characterization was carried out to study the thermal stability, oxygen-metal bond formation, crystallinity phase and crystallite size, particle size and elemental analysis by TGA, FTIR, XRD, TEM and EDX respectively. The electrolyte used for electrochemical characterisation was 1.0 M H3PO4 and 0.5 M H2SO4. Additionally, the effect of calcination and electrolyte temperature on oxygen evolution reaction of RuO2 catalysts was studied and the apparent activation energy was determined using chronoamperometry. The prepared RuO2 were tested as anode catalyst in PEMWE in the temperature range of 120–150 °C using phosphoric acid doped polybenzimidazole membrane electrolyte. The physio-chemical and electrochemical characterization results indicate that RuO2 calcined at 500 °C gave the best performance with a current density of 0.875 A cm−2 at 1.8 V in a PEMWE operated at 150 °C.
•RuO2 prepared by a sol–gel technique and calcined at different temperatures.•RuO2 showed higher OER activity with increase in H3PO4 electrolyte temperature.•PEMWE operated at 150 °C with H3PO4 doped PBI electrolyte and RuO2 anode catalyst.•RuO2 calcined at 500 °C gave highest current density 0.875 A cm−2 at 1.8 V in PEMWE.