Hydrogenation of 1,3-Butadiene on Single Crystal Surfaces

There have been correspondingly few papers describing this reaction on single crystal surfaces of metals. ° Four concern the reaction on various surfaces of platinum, but their value is unfortunately somewhat limited two of them used both Pt(lOO) and Pt(lll), but TOFs were given at quite different temperatures with another pair it is only possible to compare results on Pt(l 10). While activation energies (43 10 kJ mol ) and order of reaction where determined were broadly comparable (Table 8.4), values of TOF sometimes showed a marked variation between different surfaces, and it is not possible to define a unique hierarchy of activity. Most disappointingly there is little information on product selectivi-ties apart from Siot (Table 8.4) in one publication only partial information was 

TABLE 8.4. Kinetic Parameters for the Hydrogenation of 1,3-Bntadiene on Varions Single Crystal Faces of Platinnm, and on Platinnm Foil 

Note (i) Differences in TOF at 300 K may be partly due to use of different pressures of reactants. 

On Pd(100)(l X 1) precoated with either hydrogen or deuterium atoms, temperature-programming showed that butadiene was hydrogenated with 100% selectivity to butenes. The Pd(l 10) face was almost ten times more active than the (111) face at 300 species intermediate in the hydrogenation have been examined on the (110) surface.  

Work with bimetallic single crystal surfaces will be mentioned in Section 

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