Catalytic properties of Ag promoted ZnO/Al2O3 catalysts for hydrogen production by steam reforming of ethanol

Abstract Ag promoted ZnO/Al 2 O 3 catalysts were prepared by using the incipient wetness impregnation method. The catalytic properties of steam reforming reaction for hydrogen production on the prepared catalysts were evaluated with H 2 O:C 2 H 5 OH molar ratios of 3:1 at 450 °C and atmospheric pressure. Ag promoted ZnO/Al 2 O 3 catalysts show higher SRE catalytic activity than ZnO/Al 2 O 3 catalysts. H 2 and CH 3 CHO are the major products on Ag promoted catalysts, and C 2 H 4 is also produced probably due to acid sites on Al 2 O 3 . SRE mechanism on Ag promoted ZnO/Al 2 O 3 catalysts, which contains C–C scission, is different from that on ZnO/Al 2 O 3 catalysts. A method based on thermogravimetry (TG), differential scanning calorimetry (DSC) and mass spectrometry (MS) was used to analysis the coking behavior on catalyst surface. The surfaces of Ag promoted ZnO/Al 2 O 3 catalysts show two different types of coking, and suffer higher coke deposition during the steam reforming reaction.