Operando Fuel Cell Studies Hydrogen Oxidation in 100 ppm CO

Operando Fuel Cell Studies Hydrogen Oxidation in 100 ppm CO 

CO oxidation on both the Ru and the Pt simultaneously. This is a somewhat unexpected result, and one that needs further study. The apparent greater effectiveness of the small amount of Ru on the Pt surfaces in the PtRu Mix catalyst vs. the PtRu Alloy catalyst, as exhibited in Fig. 15, is consistent with the effect of Ru island size as noted above for methanol. Small Ru islands, such as those in the PtRu Mix catalyts, cause the BF mechanism to be more effective at lower overpotentials, whereas larger islands promote the ligand effects. Consequently, more OH can be provided by the smaller islands on the PtRu Mix, before the CO mobility finally goes into synchronous mode and poisons these sites. 

Alloy with the larger Ru islands, so much so as to weaken the Pt-CO bond and therefore decrease the CO coverage by H replacement at low potential. Recall that the PtRu Alloy has a much greater fraction of Ru in the cluster interior than P u Mix so we cannot completely rale out some effect of the interior Ru atoms, but as stated above this interior ligand effect appears to be much less effective. 

The PtRu results presented here and similar Ap XANES studies reported elsewhere reveal or at least confirm the following morphology-adsorbate relationships  

The XAS studies reported here and similar studies have also revealed new information on the behaviour of adsorbates namely the following  

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