Role of Fe Species of Ni-Based Catalysts for Efficient Low-Temperature Ethanol Steam Reforming

The suppression of methane and coke formation over Ni-based catalysts for low temperature ethanol steam reforming remains challenging. This paper describes the structural evolution of Fe-modified Ni/MgAl₂O₄ catalysts and the influence of iron species on methane and coke suppression for low temperature ethanol steam reforming. Ni-Fe alloy catalysts are gradually oxidized by water to generate Ni-rich alloy and γ-Fe₂O₃ species at steam-to-carbon ratio of 4. The electron transfer from iron to nickel within Ni-Fe alloy weakens the CO adsorption and effectively alleviates the CO/CO₂ methanation. The oxidation capacity of γ-Fe₂O₃ species promotes the transformation of ethoxy to acetate groups to avoid methane formation and the elimination of carbon deposits for anticoking. Ni10Fe10/MgAl₂O₄ shows a superior performance with a highest H₂ yield of 4.6 mol/mol ethanol at 400 °C for 15 h. This research could potentially provide instructions for the design of Ni-based catalysts for low-temperature ethanol steam reforming.