The Role of Non-Reactive Binding Sites in the AlVO4 + +CO/AlVO3 + +N2 O Catalytic Cycle.

The mechanisms involved in catalytic oxidation of CO by N2 O promoted by the AlVO3 + and AlVO4 + ions are evaluated using temperature-dependent rate constants and statistical modeling. Reactions were studied from 300-600 K using a selected ion flow tube (SIFT) apparatus, and the data compared to statistical modeling of proposed mechanisms previously identified by density functional theory (DFT) calculations. Reduction of N2 O by AlVO3 + was found to take place only by complexation to the Al site; however, attack on the V site also occurred and led to stable association complexes, reducing the overall efficiency of the reaction. As the AlVO3 + (N2 O) complex resulted from approach on the V site, it did not block the reactive Al site and was observed to further react with N2 O to form AlVO4 + (N2 O). The oxidation of CO by AlVO4 + was found to proceed solely by activation on the Al-O site; however, isomerization of complexes formed with CO initially complexed to the V site were found to add to the reactivity, especially at lower temperatures.