Compositional Effects of Ceria-supported Nickel–copper Catalyst on Its Reduction Behavior and Catalytic Performance for Ethanol Steam Reforming

Abstract

We investigated the effects of the Ni : Cu ratio and metal loading of a CeO₂-supported bimetallic Ni–Cu catalyst on its reduction behavior and catalytic performance during steam reforming of ethanol for H₂ production. Compared with monometallic Ni and Cu catalysts, both the NiO and CuO phases in the bimetallic catalysts were reduced at lower temperatures to form fine NiCu alloy crystallites. At a reaction temperature of 673 K, Ni/CeO₂ exhibited a higher H₂ yield than Cu/CeO₂ but also produced a large quantity of CH₄ and carbon deposits. The undesired byproducts were substantially inhibited by replacing a portion of the Ni with Cu. The highest H₂ yield and an excellent carbon inhibition were achieved when the content of each metal was 5 wt%. Notably, a physical mixture of Ni/CeO₂ and Cu/CeO₂, each with the same metal contents, exhibited a lower H₂ yield and heavy carbon deposition. This indicates that the higher reducibility and alloying in the bimetallic catalyst are key factors for synergistic improvements of the catalytic properties.