Catalytic hydrogen combustion for treatment of combustible gases from fuel cell processors

Catalytic combustion of H2 was carried out over combustion synthesized noble metal (Pd or Pt) ion-substituted CeO2 based catalysts using a feed stream that simulated exhaust gases from a fuel cell processor. The catalysts showed a high activity for H2-combustion and complete conversion was achieved below 200 °C over all the catalysts when O2 was used in a stoichiometric amount. With higher amounts of O2, the reaction rates increased and complete conversions were possible below 100 °C. The reaction was also carried out over Pd-impregnated CeO2. The conversions of H2 with stoichiometric amount of O2 were found to be higher over Pd-substituted compound. The mechanism of the reaction over noble metal-substituted compounds was proposed on the basis of X-ray photoelectron spectroscopy studies. The redox couples between Ce and metal ions were established and a dual site redox mechanism was proposed for the reaction.

Research highlights▶ Pd and Pt ion-substituted CeO2 catalysts were synthesized. Catalytic combustion of H2 was carried out over these catalysts. ▶ Complete conversion was achieved below 100 °C. The reaction mechanism was proposed on the basis of XPS studies. ▶ A dual site redox mechanism was proposed for the reaction.