Potential dependence of segregation and surface alloy formation of a Ru modified carbon supported Pt catalyst

Improvement of methanol electro-oxidation activity of PtRu/C and PtNiCr/C catalysts by anodic treatment

“…−1 value for the PtRu-900 catalyst, the current density of the PtRu-1.1V and PtRu-1.3V catalysts is 137% higher. This result confirms that, for high MOR activity, the Ru (hydrous) oxides are more beneficial than metallic Ru, as was suggested in recent publications [20][21][22][23][24][25][26][27][28]. Fig.…”

“…They claimed that the irreversible Ru (hydrous) oxides are harmful for MOR while the reversible ones are beneficial. Additionally, in other reports it was suggested that Ru hydrous oxide is more active for the MOR than metallic Ru, with both being far more active than RuO 2 (i.e., Ru hydrous oxide > Ru metal RuO 2 ) [21][22][23][24][25][26][27][28]. In this study, we apply an anodic treatment to powder versions of the PtRu/C and PtNiCr/C catalyst compositions examined previously in thin film form to verify the effect of an anodic treatment on MOR activity improvement, and also to better understand how anodic treatment can improve the MOR activity of the combinatorial libraries.…”

In situ Ru K-edge EXAFS of CO adsorption on a Ru modified Pt/C fuel cell catalyst

“…Preparation of the Ru modified Pt/C catalyst by the reaction of reduced 19.5 wt% Pt/C catalyst powder with a solution of ruthenocene in n-heptane was conducted, as has been described previously [4,5], to provide a coverage equivalent to 1.5 monolayers of Ru on the Pt surface. Briefly, the 19.5 wt% Pt/C catalyst powder was reduced by heating in H 2 at 200 °C for 3 hours and then exposed to the required amount of ruthenocene dissolved in n-heptane to yield a coverage of 0.75 monolayers of Ru based on the known dispersion (fraction of surface atoms) of the base Pt/C catalyst.…”

Effect of reduction conditions on electrocatalytic activity of a ternary PtNiCr/C catalyst for methanol electro-oxidation

“…In commercial PtRu catalysts, Ru exists as mixtures of Ru, Ru oxide, and Ru hydrous oxide, with the amount of metallic Ru in the commercial PtRu being less than 25% [29]. Among the various types of Ru, the activity for the MOR shows Ru hydrous oxide > Ru metal > Ru oxide [30][31][32][33][34][35][36][37]. Likewise, here the higher activity of PtNiCr-5t and PtNiCr-300 compared to the completely reduced samples processed at high temperatures suggests that the oxide/hydrous oxide forms of Ni and Cr yield higher MOR activity than their metallic forms.…”