Computational catalysis on interface models
The central role of heterogeneous catalysts in society motivates us to invest considerable efforts in the study and development of systems with enhanced activity and selectivity. Pt alloys are used for various reactions, and are in particular promising for the preferential oxidation of CO in the presence of H2 (PROX). The rate accelerating effect of Pt alloys (PtSn, PtCo, PtCe, etc.) has previously been attributed to ligand effects, thus electronic modification of Pt. This interpretation has, however, recently been questioned as alloy segregation has been observed during CO oxidation. To elucidate the segregation hypothesis, and catalysis at the metaloxide/Pt interface, different interface systems will be investigated. The thermodynamic feasibility of constructed interface models will be assessed with ab initio thermodynamics. Furthermore, first-principles microkinetic modeling will be applied to compare the rate of CO oxidation at the metaloxide/Pt interface and a bare Pt surface. The possible co-catalytic role of the metaloxide rim should be manifested in an enhanced activity at low temperatures since the bare metal surfaces suffer there from CO poisoning. The present work would elucidates the long standing debate concerning the role of in situ formed metaloxides in Pt alloys for oxidation reactions and furthermore would highlight the effects of interfaces in heterogeneous catalysis.