Oxidative steam reforming of methanol over CuO/ZnO/CeO_2/ ZrO_2/Al_2O_3 catalysts

摘要

The composition (CuO/ZnO/Al_2O_3 = 30/60/10) of a commercial catalyst G66B was used as a reference for designing CuO/ZnO/CeO_2/ZrO_2/Al_2O_3 catalysts for the oxidative (or combined) steam reforming of methanol (OSRM). The effects of Al_2O_3, CeO_2 and ZrO_2 on the OSRM reaction were clearly identified. CeO_2, ZrO_2 and Al_2O_3 all promoted the dispersions of CuO and ZnO in CuO/ZnO/CeO_2/ZrO_2/Al_2O_3 catalysts. Aluminum oxide lowered the reducibility of the catalyst, and weakened the OSRM reaction. Cerium oxide increased the reducibility of the catalyst, but weakened the reaction. Zirconium oxide improved the reducibility of the catalyst, and promoted the reaction. A lower CuO/ZnO ratio of the catalyst was associated with greater promotion of ZrO_2. The critical CuO/ZnO ratio for the promotion of ZrO_2 was approximately 0.75-0.8. Introducing of ZrO_2 into CuO/ZnO/Al_2O_3 also improved the stability of the catalyst. Although Al_2O_3 inhibited the OSRM reaction, a certain amount of it was required to ensure the stability and the mechanical strength of the catalysts.