Durable Cu composite catalyst for hydrogen production by high temperature methanol steam reforming

• Activity and durability of Cu/ZnO/ZrO2/Y2O3/In2O3 coprecipitated on ZrO2 have been tested.
• The composite catalyst containing only 3 wt.% Cu is active and stable at 400 °C.
• The deactivation rate empirically relates to the cube of the activity.
• The lifetime of the 3 wt.% Cu catalyst is as long as 53 × 102 h at 400 °C.
• The Cu surface activity increases with a decrease in the Cu particle size.

Durable catalysts are necessitated for the high temperature methanol steam reforming in compact hydrogen processors. The high durability at 400 °C can be obtained with a composite Cu catalyst where a small amount of Cu–ZnO–ZrO2–Y2O3–In2O3 is coprecipitated on a zirconia support. The lifetime of the composite catalyst containing 3 wt.% Cu is estimated to be as long as 53 × 102 h at 400 °C to produce the full conversion at a contact time of 250 g h m−3. The deactivation rate empirically relates to the cube of the activity. The gradual deactivation is caused by the gradual reduction of the Cu surface amount and also by the reduction of the surface activity which is believed to decrease with an increase in the Cu particle size. The interaction between the thin layer of the coprecipitate and the support surface probably suppresses the aggregation of the coprecipitate leading to Cu sintering.