Lessons Learned from Surface Science

Here we follow the elegant analysis presented by Barteau as it discusses some of the critical factors that control the activity and selectivity of metal oxides. In addition, it illustrates how the surface structure and properties can be controlled even under reducing UHV conditions in order to impart specific reactivity. 

The surface structure and properties can be modulated in order to establish specific surface ensembles active for carrying out a range of different oxygenate and hydrocarbon coupling reactions. However, by specifically controlling 

3) the redox properties of a well-defined oxide surface 

Barteauwas able to demonstrate for well-defined Ti02 and ZnO surfaces the activity and selectivity for C2 oxygenate (carboxylates and aldehydes) and hydrocarbon (alkynes) coupling reactions over these model metal oxide surfaces under UHV conditions that is typically only seen in organometallic systems in solution. 

Aldol condensation, on the other hand, is favorably carried out over basic oxygen sites on the Ti02 smface and does not appear to require coordinatively unsaturated Ti sites. The reaction is thought to proceed initially by the proton abstraction at the carbonyl carbon from the aldehyde reagent molecule by a basic oxygen site on the surface 

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