Role of transition metal oxides in metal dusting: Density functional study

摘要

Density function theory was applied to study the mechanisms and energetics of two major metal dusting processes represented by Boudouard and steam-carbon reactions on the FeO(100) surface. Cluster models were utilized to represent the surface. The chosen cluster model was validated by examining CO adsorption binding energies on clusters of various sizes. We show that the lattice relaxation has a relatively small effect on the adsorption. The reaction process involving direct abstraction of O from the surface bq CO was excluded from consideration of the overall dusting processes due to unfavorable energetics. Minimum energy path calculations were carried our to investigate the reaction mechanisms. It was found that both the Boudouard and steam-carbon reactions are thermochemically and kinetically, unfavorable on transition metal oxide surfaces. Detailed insight into the reaction mechanisms was obtained by following the reaction trajectories and analyzing the electron population distribution along the reaction paths. This study elucidates the empirical observation that metal oxide can often minimize metal dusting. [References: 37]