Gas-phase reaction of CeVO5+ cluster ions with C2H4: the reactivity of cluster bonded peroxides

Abstract

Cerium–vanadium oxide cluster cations CeVO₅⁺ were generated by laser ablation, mass-selected using a quadrupole mass filter, thermalized through collisions with helium atoms, and then reacted with ethene molecules in a linear ion trap reactor. The cluster reactions have been characterized by time-of-flight mass spectrometry and density functional theory calculations. The CeVO₅⁺ cluster has a closed-shell electronic structure and contains a peroxide (O₂²⁻) unit. The cluster bonded O₂²⁻ species is reactive enough to oxidize a C₂H₄ molecule to generate C₂H₄O₂ that can be an acetic acid molecule. Atomic oxygen radicals (O⁻˙), superoxide radicals (O₂⁻˙), and peroxides are the three common reactive oxygen species. The reactivity of cluster bonded O⁻˙ and O₂⁻˙ radicals has been widely studied while the O₂²⁻ species were generally thought to be much less reactive or inert toward small molecules under thermal collision conditions. This work is among the first to report the reactivity of the peroxide unit on transition metal oxide clusters with hydrocarbon molecules, to the best of our knowledge.