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• MNi/CNTs with controlled metal distribution was successfully synthesized. • The secondary metal M had profound effects on reducibility and surface property. • CoNi/CNTs showed the best abilities in anti-sintering and coke resistance. • Hydrogen was more selective over CoNi/CNTs by promoting water gas shift reaction. The bimetallic MNi/CNTs (M Co, Cu and Fe) catalysts with controlled metal distribution were prepared by a two-step impregnation method. The catalysts were characterized by N 2 adsorption/desorption, XRD, XPS, TPR, HAADF-STEM, TEM and TG to study the porous structure, changes in crystalline phases during the reaction, surface chemical state, reducibility, the element distribution, sintering of metal particles and the deposited coke for the calcined and/or spent catalysts. The results showed that the Ni oxide was successfully introduced into the cave and the other one was dispersed on the external wall of CNTs. The addition of the secondary metals had significant influences on the reducibility, resulting in the quite different surface properties which was directly linked to the products distribution in glycerol reforming reaction. The sample CoNi/CNTs performed better in both anti-sintering and coke resistance, and over which the product was more selective to hydrogen by enhancing the water gas shift reaction. [ABSTRACT FROM AUTHOR]

A series of NiCe x Al (x = 0.1, 0.3, 0.5, 0.7 and 0.9) mixed metal oxides catalysts was synthesized through decomposing the corresponding layered double hydroxides (LDH) precursors, and then characterized by TG, XRD, N 2 adsorption/desorption, XPS, H 2 -TPR, H 2 -TPD etc. techniques. The results showed that the introduction of Ce could efficiently restrict the agglomeration of Ni species. The generated Ni–Ce–O solid solution could create the oxygen vacancies and enhance the oxygen mobility which further improved the properties of active sites including Ni dispersion and surface area, and suppressed coke deposition. The Ni2+ species was reduced by Ce3+ under the reaction conditions to give the metallic Ni as active sites in catalyzing steam reforming of glycerol for the production of hydrogen. The best catalytic performance was obtained over the sample NiCe 0.7 Al which exhibited the better Ni dispersion and larger surface, and lower quantity of deposited coke by establishing the correlations. The reaction was more selective to hydrogen thanks to the enhancement of water gas shift reaction and suppression of CO methanation reaction. Image 1 • Impurity co-existed in Ce contained NiAl layered double hydroxides precursors. • Ce could stabilize the Ni species but restrict the reduction of Ni2+ by hydrogen. • Ce3+ reduced the Ni2+ into the active metallic Ni under the reaction conditions. • Ce/Al ratio had important influences on Ni properties. • Coke deposition was suppressed by introducing Ce into the catalyst. [ABSTRACT FROM AUTHOR]