The Open Catalysis Journal

2008, 1 : 11-16
Published online 2008 December 15. DOI: 10.2174/1876214X00801010011
Publisher ID: TOCATJ-1-11

Investigation of Transition Metal Oxide Catalysts for Diesel PM Removal Under Plasma Discharge Conditions

Shin Yamamoto , Shuiliang Yao , Satoshi Kodama , Chieko Mine and Yuichi Fujioka
Chemical Research Group, Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Kizugawa-shi, Kyoto 619-0292, Japan.

ABSTRACT

Seven different transition metal oxides (TiO2, ZnO, V2O5, Fe2O3, Co3O4, MnO2, and CuO) have been investigated for oxidation of diesel particulate matter (PM) under plasma discharge conditions. The experiments were carried out by measuring PM oxidation rates over each catalyst using a batch-type dielectric barrier discharge reactor. It was found that TiO2, ZnO, V2O5, and Fe2O3 can promote PM oxidation, among which Fe2O3 is a most desirable catalyst for PM oxidative removal as PM oxidation rate promoted by Fe2O3 is highest under plasma discharge conditions. The mechanism of PM catalytic oxidation over the metal oxides has been suggested to follow the redox catalytic cycles from the correlation of the catalytic oxidation rates with the formation enthalpies per oxygen atom of the catalysts. O atoms generated by plasma discharges may play an important role in promoting the re-oxidation of the catalysts. The highest catalytic activity for the PM oxidation with Fe2O3 has been suggested to be due to the balance between the reduction rate and the reoxidation rate within the redox catalytic cycles.

Keywords:

Transition metal oxide, catalytic oxidation, dielectric barrier discharge.