Catalyst action

The choice of catalyst is influenced by considerations of tolerance of contaminants in the gas flows. A pure Pt catalyst works well for extremely pure hydrogen feed, but even small amounts of CO in the H2 fuel will deteriorate 

Molecular level modelling of the catalyst reactions are made in the manner described in section 3.1.4. Such quantum chemical modelling can also be performed for CO adsorbing to the Pt or Pt-Ru catalyst surface at the negative electrode, where a number of reactions may take place in addition to (3.15), describing the competition between splitting of hydrogen molecules and the conversion of CO and any water present to CO2 and protons. 

The reaction (3.74) would remove CO, but quantum calculations find it energetically unfavourable (cf., e.g., the calculation with just two Pt catalyst atoms performed by Narayanasamy and Anderson, 2003). However, Liu and Norskov (2001) were able to prove that although unfavourable at either Pt or Ru surfaces, the combined presence of Pt and Ru allows OH to attach to Ru faster than to Pt, while the presence of Ru reduces the binding of CO to Pt sites and thus furthers the second reaction in (3.73), even though CO is not willing to adsorb to Ru itself. 

Macroscopic modelling of the catalyst electrode-electrolyte interface behaviour is made by use of the Butler-Volmer equations (3.25), and this model is then incorporated into the gas flow and ion diffusion models described in sections 3.5.2 and 3.5.3. 

The loading of catalyst particles influences cost, and values have been decreased over time, with the lowest ones about 14 pg/cm achieved by using a 

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In an alternative mode of catalyst action, a disubstituted ketene 66 initially suffers a nucleophilic attack of 64, leading to zwitterionic enolate 71 (Fig. 38). 

Bazaki, H Negative Catalyst Action of SrC03 on AP Composite Propellants, In-House Research Report 2005, Asahi Kasei Chemicals, 2005. 

In the two-layer model of a catalytic coating, soot particles oxidize when found within the field of catalyst action . This is modeled with a parameter... 

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