Peroxo and superoxo anions: A DFT study on Fe/ZSM-5 zeolite

Metal peroxide species are the active sites in lots of solid-state and enzyme catalytic systems. With density functional calculations, the configurations of peroxide and superoxide anions in Fe/ZSM-5 zeolite were first resolved. The presence of superoxide anion was validated, which is less stabilized than the peroxide anion, especially at higher temperatures. It acts as the precursor to the active peroxide anion. Raman frequencies of these two species were analyzed considering O-18/O-16 isotope effects. The present results are in fine agreement with previous theoretical and experimental results. (c) 2007 Elsevier B.V. All rights reserved.