Tunable metal-oxide interaction with balanced Ni0/Ni2+ sites of NixMg1−xO for ethanol steam reforming.

[Display omitted] • The ratio of Ni0 to Ni2+ in Ni-MgO is tuned by a non-equilibrium synthetic method. • 11.5 L∙h−1∙g cat −1 H 2 is generated at 400 °C with balanced Ni° to Ni2+ sites. • Ni0 particles facilitate the oxidation of α-C in ethanol to acetate intermediate. • Ni2+ stabilized by Ni x Mg 1− x O promotes the dehydrogenation of methyl group. Steam reforming of bio-ethanol is one of the most promising methods to produce renewable hydrogen and reduce carbon footprint. Nickel and magnesium are two main elements in commercial steam reforming catalysts for which Ni x Mg 1− x O solid solution contributes its unique property. This paper describes the interplay between Ni and Ni x Mg 1− x O to explore the roles of Ni0 and Ni2+ in hydrogen production from bio-ethanol steam reforming. With a non-equilibrium synthetic method, the ratio of metallic Ni0 to Ni2+ in Ni/Ni x Mg 1− x O system could be altered with same Ni loading. The catalytic performance of Ni/Ni x Mg 1− x O is dependent on the surface area of metallic Ni0 and the surface concentration of Ni2+ sites. Ni/Ni x Mg 1− x O with balanced Ni0 to Ni2+ sites could achieve H 2 production rate of 11.5 L∙h−1∙g cat −1 from renewable bio-ethanol at 400 °C. The results from in-situ diffuse reflectance infrared Fourier transform spectroscopy suggest that geometrically adjacent Ni0 nanoparticles facilitate the oxidation of α-C in ethanol and electron-deficient Ni2+ sites promote the dehydrogenation of methyl group, further increasing H 2 selectivity and suppressing the formation of CH 4. [ABSTRACT FROM AUTHOR]