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

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 NixMg1-xO solid solution contributes its unique property. This paper describes the interplay between Ni and NixMg1-xO to explore the roles of Ni-0 and Ni2+ in hydrogen production from bio-ethanol steam reforming. With a non-equilibrium synthetic method, the ratio of metallic Ni-0 to Ni2+ in Ni/NixMg1-xO system could be altered with same Ni loading. The catalytic performance of Ni/NixMg1-xO is dependent on the surface area of metallic Ni-0 and the surface concentration of Ni2+ sites. Ni/NixMg1-xO with balanced Ni-0 to Ni2+ sites could achieve H-2 production rate of 11.5 L.h(-1).g(cat)(-1) from renewable bio-ethanol at 400 degrees C. The results from in-situ diffuse reflectance infrared Fourier transform spectroscopy suggest that geometrically adjacent Ni-0 nanoparticles facilitate the oxidation of alpha-C in ethanol and electron-deficient Ni2+ sites promote the dehydrogenation of methyl group, further increasing H-2 selectivity and suppressing the formation of CH4.