A structured Cu-based/γ-Al2O3/Al plate-type catalyst for steam reforming of dimethyl ether: Self-activation behavior investigation and stability improvement

- A novel structured Cu-based anodic γ-Al2O3/Al catalyst was applied for DME SR.
- The self-reduction mechanism of fresh Cu/γ-Al2O3/Al catalyst was analyzed.
- The mechanism of Ni doping on the structure evolution of Cu/γ-Al2O3 was evaluated.
- The addition of nickel can improve the thermal stability of Cu-based catalyst.

A plate-type anodic alumina supported Cu composition catalyst was developed to investigate its catalytic performance in steam reforming of dimethyl ether (DME). It is found that the fresh Cu/γ-Al2O3/Al catalyst without H2 pre-reduction treatment exhibited the similar catalytic activity as the pre-reduced one. The XPS results show that Cu+ species exist in the surface of the fresh catalyst, which results in the self-activation reaction. However, the Cu/γ-Al2O3/Al catalyst showed a quick deactivation at 350 °C due to the sintering of copper. As an approach, a second component Ni was doped to the Cu-based catalyst, and a series of Cu/Ni/γ-Al2O3/Al catalysts with different Ni loadings were prepared by impregnation method. Furthermore, the effect of nickel loading and chemical state on the activity of catalyst was extensively investigated. The results show that the catalytic performance was related to both of the nickel loading and chemical state. The proper amount of nickel doping is helpful in improving the dispersion of copper species, and thus enhancing the catalytic activity. Finally, a 180 h stability evaluation was carried out and the results show that the optimized Cu/Ni/γ-Al2O3/Al catalyst has an excellent stability under critical conditions with 400 °C, and gives a 100% DME conversion, which demonstrated that the novel γ-Al2O3/Al monolith supported Cu and Ni composite catalyst was an excellent catalyst for steam reforming of dimethyl ether.

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