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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]

The various metal‐doped Silicalite‐1 (M−S1, M=Mg, Al, Fe and In) supports were prepared by hydrothermal synthesis method, then were used to disperse the PtSn species through impregnation. The resulting solids were further characterized through XRD, N2 adsorption/desorption isotherms, XPS, H2‐TPR, NH3‐TPD, Raman spectroscopy and TG techniques to investigate the structural property before and after propane dehydrogenation reaction. The results exhibited that the introduction of various metal dopants had profound effects on pore structure, reducibility, acidity and surface content of Pt which was directly related to the activation of propane. And the surface content of Pt acted as the dominant role for converting propane. As a consequence, the maximum initial conversion of propane was obtained over Fe‐modified PtSn/Fe−S1 sample, but it deactivated fast as well because of the coke deposition. [ABSTRACT FROM AUTHOR]

The preparation of the binary metal NiCe-based catalysts involved a 2-step protocol, the ceria was first coated on SiO 2 which was then utilized to disperse Ni nanoparticles. Various techniques including N 2 adsorption/desorption, ICP-OES, XRD, HRTEM, XPS, H 2 -chemisorption, H 2 -TPR, NH 3 -TPD, and TG etc. were performed to study the microstructure, redox, acid property and deactivation. The results revealed that CeO 2 and metallic Ni were well dispersed on the support surface, the synergistic effect between the two metal species was conserved well. The content of CeO 2 had considerable effects on redox and metallic properties rather than the acidic property. The dispersion of metallic Ni played a dominant role in promoting the catalytic activity. The levulinic acid conversion attained 84.0 % with a γ-valerolactone selectivity of 98.8 % on Ni/SiO 2 @2CeO 2 sample with the highest dispersion of 9.8 %. The amorphous CeO 2 suppressed the sintering of metallic Ni nanoparticles and improved the coke resistance, leading to better catalytic activity within 20 h time on stream. [Display omitted] • Synergistical effect of bimetallic NiCe promotes the production of GVL. • A 2-step preparation procedure modified the surface property and dispersion. • The content of ceria on SiO 2 affects the particle size of Ni0. • Coke resistance was improved for the Ni/SiO 2 @CeO 2 catalyst. [ABSTRACT FROM AUTHOR]

• 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]

NiZrAl layered double hydroxides (LDH) precursors were synthesized by co-precipitation and homogeneous precipitation processes. The introduction of hydrothermal treatment into crystallization showed its significant influences on structure of LDH as well as mixed-metal oxides after thermal decomposition. The characterization results showed that the catalysts prepared by hydrothermal synthesis involved bigger pore diameter of ca. 13.5 nm and wider pore size distribution of 2–60 nm, and hydrothermal treatment was helpful to enhance the reduction of NiO species weakly interacted with support and to enhance the interaction among the metal oxides. Although the Ni dispersion, the surface area as well as the ability of anti-sintering were evidently improved, the ability of coke resistance decreased by 2 times for samples prepared by co-precipitation and by nearly 10 times for the ones prepared by homogeneous precipitation due to the enlarged pores. The maximum value of conversion to gaseous products (96.5%) and minimum deposited coke (36 m gc /g cat.) were achieved on NiZrAl-u sample. • Better LDH crystalline structure was formed with hydrothermal synthesis. • Pore width and its distribution were acutely affected by hydrothermal treatment. • Reducibility was improved for the hydrothermal treated catalyst. • Sample prepared by hydrothermal method had better Ni dispersion and surface area. [ABSTRACT FROM AUTHOR]