Application of porous anodic alumina monolith catalyst in steam reforming of dimethyl ether: Cu/γ-Al2O3/Al catalyst degradation behaviors and catalytic activity improvement by pre-competition impregnation method

A novel plate type anodic alumina supported Cu composite catalyst was developed to catalyze dimethyl ether steam reforming (DME SR) for hydrogen production. The degradation behaviors of the Cu/γ-Al2O3/Al catalyst during DME SR were systematically studied. It is demonstrated that the catalyst was subjected to deactivation above 350 °C mainly due to the copper sintering. The selectivity of by-product CO is found to be very sensitive to the copper grain size. The aggregation of copper resulting in bigger copper grains will favor the reverse water gas shift reaction (r-WGS), which can be an efficient indicator to monitor the catalyst sintering process. A novel pre-competitive impregnation method was used to improve the composite catalyst. The catalystʹs BET surface was significantly increased and the metal dispersion was improved via this method. The catalyst exhibited high activity and stability in DME SR even above 375 °C. A mechanism of this competitive impregnation was also proposed.