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Catalysis Letters

, Volume 141, Issue 3, pp 445–451 | Cite as

Study of the Catalytic Activity–Semiconductive Properties Relationship For BaTiO3 and PbTiO3 Perovskites, Catalysts for Methane Combustion

  • Ionel Popescu
  • Ioan Săndulescu
  • Ákos Rédey
  • Ioan-Cezar Marcu
Article

Abstract

The electrical conductivity of barium and lead perovskites used as catalysts for the total oxidation of methane, has been measured under nitrogen, methane–nitrogen mixture, air and methane–air mixture (reaction mixture) at the catalytic reaction temperature. The two compounds appeared to be p-type semiconductors under air with positive holes as the main charge carriers but became n-type when contacted with methane–nitrogen mixture. Their conductivities differ by 1.5 orders of magnitude as n-type semiconductors and by three orders of magnitude when being p-type semiconductors. These results explained the difference in the catalytic activity encountered on the two solids. The alkane activation was proposed to be related in both cases to the p-type semiconducting properties of the solids, likely through hydrogen abstraction by a surface O species, forming a CH 3 radical. The overall reaction mechanism on both perovskites can be assimilated to a Mars and van Krevelen mechanism.

Graphical Abstract

The electrical conductivity of barium and lead perovskites, catalysts for methane total oxidation, has been studied under different gaseous atmospheres at the reaction temperature and a reaction mechanism has been proposed.

Keywords

Electrical conductivity Ba–Ti perovskite Pb–Ti perovskite Catalytic total oxidation Methane 

Notes

Acknowledgments

The authors are grateful to Dr. Éva Makó from the University of Pannonia for her XRD expertise and for unit cell parameters calculation. The Romanian National Authority for Scientific Research (ANCS) is acknowledged for the financial support of this work under the contract PN II nr. 105/15.09.2008.

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Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Ionel Popescu
    • 1
  • Ioan Săndulescu
    • 1
  • Ákos Rédey
    • 2
  • Ioan-Cezar Marcu
    • 1
  1. 1.Department of Chemical Technology and Catalysis, Faculty of ChemistryUniversity of BucharestBucharestRomania
  2. 2.Department of Environmental Engineering and Chemical Technology, Faculty of EngineeringUniversity of PannoniaVeszprémHungary

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