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

Nano-crystalline powders of RuxSn1 − 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 RuxSn1 − 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 RuxSn1 − xO2 (x-value was decreased), the catalytic performance increased initially and then decreased dramatically. The catalyst Ru0.6Sn0.4O2 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 Ru0.6Sn0.4O2 catalyst had better stability than pure RuO2. Both the mass normalized current density and chronocoulometry at 1.4 V indicated that Ru0.6Sn0.4O2 and RuO2 had better performance at 70 °C than at 25 °C.