Studies On CuO/Ce_1-xZr_xO₂-Al₂O₃ Catalysts For CO Preferential Oxidation In Rich Hydrogen

Fuel cell is one of the most prespective techonologies to solve the problems of energy security, air pollution and greenhouse gas emission. Proton exchange membrane fuel cells (PEMFC) become the up-to-date fuel cells, for its merits (the rapid response, the low operating temperature, and so on), and especially attract people's attention, for its application in the moving energy aspect in the future. The preferential oxidation of CO in excess H2 is a promising method which can reduce the concentration of CO in H2 to less than 100ppm. Because of its favorable catalytic activity for preferential oxidation CO, the non-noble metal catalysts CuO-CeO₂ become the hot field in recent years.The CuO/CexZr1-xO₂-Al₂O₃ catalyst prepared by the co-precipitation impregnation method were studied in this paper. Some preparation conditions such as the Al₂O₃, ZrO₂ content in the carrier, the loading capacity of CuO and the different preparation method of carrier were investigated.It was revealed that CuO/CeO₂ catalyst can show higher activity at 95-175℃and CuO content can improve the dispersion of CuO on the support. Incorporating Al₂O₃ increased the dispersion of CexZr1?xO₂, but did not change their main structures and did not weaken their redox properties. The catalyst which prepared by the aluminium nitrate exhibited a good activity and selectivity. But they exhibited a bad tolerant towards H2O and CO₂. The CuO/CeO₂-Al₂O₃ catalyst prepared by the active Al₂O₃ method exhibited a good tolerance towards H2O and CO₂; doping zirconium into CuO-CeO₂ enhanced the selectivity of catalyst, increased surface area of catalysts and ameliorate of pore structure, and exhibited a good tolerance towards H2O and CO₂. But the amount of ZrO₂ should be appropriate, because the interaction between CuO and CeO₂ decreased as the amount of Zr4+ doped in CexZr1?xO₂-Al₂O₃(20%) increased, so the enhancement of CO oxidation became weaker as the amount of Zr4+ increased above 0.1 (1 ? x >0.1).The experimental results indicate that the composition of CuO/CexZr1-xO₂-Al₂O₃ catalyst which is favorable to catalytic activity for preferential oxidation CO: the catalyst with 20wt% Al₂O₃ and 0.1 ZrO₂ in the carrier, and 7wt% CuO capacity shows excellent catalysis performance, and exhibites a best tolerance towards H2O and CO₂.