Study On The Modification Of CuO-ZnO-ZrO₂ Catalyst And Their Catalytic Properties For The Steam Reforming Of Methanol

In this paper, CuO-ZnO-ZrO₂ and CuO-ZnO-ZrO₂-RE₂O3 catalysts were prepared by co-precipitable method. The catalytic performances for steam reforming of methanol reaction(SRM) were investigated and the structure and surface performances of the CuO-ZnO-ZrO₂-Y₂O₃ catalyst were characterized by XRD> TPR, BET, TPD, TG-DTA, UV, TEM and IR techniques .In comparison to CuO-ZnO-ZrO₂ catalyst, the activity of CuO-ZnO-ZrO₂-Y₂O₃ catalyst for SRM is higher. The methanol conversion and H₂ yield varied with Y₂O₃ contents in CuO-ZnO-ZrO₂-Y₂O₃ catalyst. Among a series of CuO-ZnO-ZrO₂-Y₂O₃ containing different amounts of Y₂O₃, the catalytic activity is highest when CuO-ZnO-ZrO₂-Y₂O₃ catalyst contain 5mol% Y₂O₃. The results of XRD indicate that the addition of Y₂O₃ result in CuO and ZnO crystallites smaller and improve copper dispersion, meanwhile, interaction between CuO and ZnO strengthen.The influences of preparation parameters (precipitation temperature, precipitator, precipitate way, calcined temperature, liquid velocity, reduction gases and H₂o:Me0H molar ratio) on the catalytic activity of CuO-ZnO-ZrO₂-Y₂O₃ catalyst were investigated. The catalytic activity of CuO-ZnO-ZrO₂-Y₂O₃ catalyst were best when the precipitator is (NH₄)₂CO₃, precipitation temperature is the room temperature, calcined temperature is 350℃, reduce gas is N₂+H₂ and H₂O:MeOH molar ratio is 1.3:1.The results of BET and TEM indicate that the addition of Y₂O₃ in CuO-ZnO-ZrO₂ catalyst result in CuO crystallite sizes decrease and the interactions between CuO and ZnO strengthen. The results of XRD indicate that the addition of Y₂O₃ makes crystallite degree of CuO-ZnO-ZrO₂ catalyst became poor. The results of H₂-TPD, CO-TPD and H₂-TPR show that the adding Y₂O₃ to CuO-ZnO-ZrO₂ catalyst can...