Catalytic effect of vanadium, iron and lead oxides on the oxidation of moderator graphite

Abstract

The catalytic effect of the oxides V₂O₅, Fe₂O₃ and PbO on the air oxidation of graphite has been investigated. Graphite surfaces were contaminated with the oxides by soaking in standard solutions of the metal ions. The oxidation reaction was monitored kinetically, by differential thermal oxidation, and chemically, using X-ray photoelectron spectroscopy. The results showed that PbO and V₂O₅ were active catalysts, increasing the rate by up to 16 times at 450 °C, in the case of V₂O₅. By contrast, the catalytic activity of Fe₂O₃ was low. A mechanism is proposed to explain the catalytic activity of PbO and V₂O₅ based on the interaction of metal orbitals with the π-system of graphite.