Effects of iron-phosphate coating on Ru dissolution in the PtRu thin-film electrodes

The effects of FePO₄ nanoscale coating on PtRu thin films were investigated on the block of Ru crossover. Ru dissolution was examined by the accelerated-potential cycles between 0.4 and 1.05 V. The results showed that Ru dissolution from FePO₄-coated PtRu surface was inevitable due to the direct contact between the PtRu surface and aqueous electrolyte. However, the FePO₄ coating layer on PtRu thin-film electrodes effectively retained the dissolved Ru species, thus preventing the dissolved Ru species from diffusing into the electrolyte. Moreover, the retained Ru species within the FePO₄-coating layer were redeposited onto the PtRu surface during the cycling in the fresh electrolyte.