Zhongshan Yuan

Methane Combustion over Pd/Al2O3 Catalyst: Effects of Chlorine Ions and Water on Catalytic Activity

Abstract The influences of residual chlorine ions and water on the performance of a Pd/Al2O3 catalyst in methane combustion have been studied. The results show that the catalyst containing Cl− exhibits a relatively low activity, and the addition of water to the reaction system accelerates the deactivation process. The catalyst has been characterized by N2 adsorption, X-ray fluorescence, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetry (TG). The results show that the presence of Cl− appears to strongly inhibit the total oxidation of methane and hinder the dispersion of Pd on Al2O3. The formation of Pd(OH)2 during the reaction is the most likely reason for the inhibition effect of water, which is confirmed by FT-IR and TG analysis. The regeneration of the Pd/Al2O3 catalyst can be achieved by purging in nitrogen at 550 °C.

Study of methane autothermal reforming catalyst

The effects of Ce-ZrOx, Ce-LaOx, Ce-SmOx and Ce-GdOx additions to Rh/Al2O3 catalysts on methane autothermal re-forming were investigated. Activity tests showed that the addition of Ce-ZrOx could significantly reduce the concentration of CO in reformats. When Ce/Zr atomic ratio was 1:1, Ce0.5Zr0.5O2 solid solution with high thermal stability was obtained, which could effectively improve the catalytic performance effectively. The additives of alkaline-earth metals (Mg, K and Ca) on the catalytic properties were also studied. The results of experiments showed that the addition of MgO to Rh/Ce0.5Zr0.5O2/Al2O3 improved the stable performance and the carbon resistance of the catalyst. The optimized catalyst was 0.1%Rh/2.0%MgO/40%Ce0.5Zr0.5O2/Al2O3, which showed a highly stable performance for methane autothermal reforming.