Steam Reforming of Dimethyl Ether over Coupled ZSM-5 and Cu-Zn-Based Catalysts

Dimethyl ether (DME) steam reforming (SR) is one possible source of hydrogen for fuel cells. The synergistic effect of catalyst coupling for the DME SR process and the coupling of reaction-heat transfer was studied. A DME hydrolysis catalyst comprising ZSM-5 (Si/Al = 25) and a series of methanol steam reforming catalysts (a series of Cu-Zn-based catalysts and a commercial Cu-Zn-Al catalyst) were used for DME SR. The evaluation of catalytic activity was conducted in a fixed-bed reactor. The catalysts were characterized by scanning electron microscopy, X-ray diffraction, and N2 adsorption. The activity and selectivity were influenced by the catalyst composition and copper content, and also the content of Al and Zr. A Cu:Zn molar ratio of 60:30 together with Al and Zr gave the best dispersion of Cu crystals and the highest low-temperature catalytic activity, with a DME conversion of 72% at 260 °C and a space velocity of 4 922 ml/(g·h).