Effect of calcination temperature on catalytic performance of Pd-Cu/attapulgite clay catalyst for CO oxidation at room temperature

Using attapulgite clay(APT) as the support, the catalysts Pd-Cu/APT were prepared by wet impregnation method. The effect of calcination temperature on the catalytic performance for CO oxidation at room temperature was investigated in a fixed-bed continuous flow reactor. Structure and property of the catalysts were characterized by N₂-physisorption, XRD, TG, FT-IR and H₂-TPR. The results showed that as the calcination temperature increased, structure and texture of the catalysts changed due to the desorption of water in the support. Cu species changed from Cu(OH)Cl to CuO gradually, while interactions between highly dispersed Pd and Cu species increased firstly and then decreased. The catalyst calcined at 300 ℃ possessed the highest surface area, dispersed Cu(OH)Cl, and strong interaction between Pd and Cu species, which significantly improved the reducibility of the catalyst. At the reaction conditions of CO 0.5%, GHSV 6 000 h^-1, water content 3.3% and room temperature, the catalyst was able to maintain its activity for CO complete oxidation more than 800 min. Calcination temperatures higher or lower than 300 ℃ caused the lower catalytic activity.