Ternary Ni–Al–Fe catalysts for ethanol steam reforming

Abstract

Ternary mixed oxides prepared from takovite/reevesite Ni₃Al_1−xFe_x precursors were tested in ethanol steam reforming for hydrogen production. The influence of the trivalent cation (Al³⁺ or Fe³⁺) on phase composition and derived catalytic performance of the resulting oxides was studied. The physico-chemical properties of the hydrotalcite-like precursors and related oxides were characterized by ICP, XRD, TGA-DSC, Raman, H₂-TPR, and TEM analyses. Compared to pure binary systems (Ni₃Al and Ni₃Fe), the ternary systems showed the best performance in ethanol reforming, leading to high and stable hydrogen selectivity of up to ca. 70% in 100 h reaction tests. The increase in activity can be attributed to a cooperative effect between aluminum and iron, favoring ethanol dehydrogenation as the primary step, followed by acetaldehyde reforming and/or cracking, reverse water gas shift, and methanation, and concomitantly limiting the dehydration route to ethylene.