A Structured Cu-Based/γ-Al2O3/Al Multifunctional Catalyst for Steam Reforming of Dimethyl Ether: Investigation on in-Situ CO Reduction Strategy

A plate-type Cu/Ni/gamma-Al2O3/Al catalyst exhibited a good stability in steam reforming of dimethyl ether (DME SR); however, a high CO concentration (ca. 26%) was detected. As such, a multifunctional catalyst combined DME SR and high temperature water gas shift reaction (HT-WGSR) was developed in this work. It is found that the reaction temperature regions of Fe-based and Cu-based catalysts coupled perfectly, and thus resulted in an in situ CO reduction during DME SR process. Meanwhile, the CO reduction mechanism was proposed over the Fe-doped Cu-based multifunctional catalyst. Furthermore, the effects of iron loading on the physicochemical properties and performance of catalysts were extensively investigated. The results show that the proper amount of iron doping was helpful in improving the dispersion of Cu, and thus enhancing the catalytic performance and decreasing CO concentration. Finally, it is found that the optimized Cu/NiO/Fe3O4/gamma-Al2O3/Al multifunctional catalyst has excellent stability during a 200 h test, and gives a 100% DME conversion at 400 degrees C.