Nano-crystalline RuxSn1 − xO2 powder catalysts for oxygen evolution reaction in proton exchange membrane water electrolysers

Nano-crystalline powders of Ru_xSn_1 − xO₂ (1.0 ≥ x ≥ 0.2) were prepared as high performance electrocatalysts for oxygen evolution in polymer electrolyte membrane water electrolysers (PEMWE). A modified Adams fusion method was developed to produce these oxides. The Ru_xSn_1 − xO₂ powder catalysts were investigated with XRD, SEM, TEM, CV, and EIS. XRD showed a nano-crystalline rutile structure results over the whole composition range. The particle sizes determined by TEM were between 5 and 20 nm. With an increase in the Sn content in Ru_xSn_1 − xO₂ (x-value was decreased), the catalytic performance increased initially and then decreased dramatically. The catalyst Ru_0.6Sn_0.4O₂ demonstrated the best performance in general, which may be due to its smaller particle size and greater ratio of outer active surface area. Repetitive cyclic voltammograms demonstrated that the Ru_0.6Sn_0.4O₂ catalyst had better stability than pure RuO₂. Both the mass normalized current density and chronocoulometry at 1.4 V indicated that Ru_0.6Sn_0.4O₂ and RuO₂ had better performance at 70 °C than at 25 °C.