Catalytic combustion of gas from biomass gasification over supported palladium catalysts

Pd/Al₂O₃, Pd/Ce/Al₂O₃, Pd/Mn/Al₂O₃ and Pd/La/Al₂O₃ catalysts were prepared by the impregnation method and characterized by BET and XRD analysis. The performance of catalysts for CO, H₂ and CH₄ combustion were explored in a fixed bed reactor. The results show that doping of La, Ce or Mn to catalyst can lead to the decrease of specific surface area and pore volume. And the doping of Ce can obviously improve the catalytic activity and thermal stability, while the doping of La don't improve catalytic activity, but enhance the thermal stability of catalysts under high-temperature calcinations. The doping of transition metal Mn leads to an enhancement of the combustion activity, whereas can accelerate the transition of γ-Al₂O₃ to α-Al₂O₃. It is also found that the ignition sequence of CO and H₂ varies for different catalysts, but all catalysts show similar activity for CO and H₂ combustion that can quickly conduct at low temperature, and the combustion characteristic temperature of them is far below that of CH₄.