This paper describes the design of Ni/SiO 2 catalysts obtained from a phyllosilicate precursor that possess high activity and stability for bioethanol steam reforming to sustainably produce hydrogen. Sintering of metal particles and carbon deposition are two major issues of nickel-based catalysts for reforming processes, particularly at high temperatures; strong metal−support interaction could be a possible solution. We have successfully synthesized Ni-containing phyllosilicates by an ammonia evaporation method. Temperature programmed reduction results indicate that the metal− support interaction of Ni/SiO 2 catalyst prepared by ammonia evaporation method (Ni/SiO 2P ) is stronger due to the unique layered structure compared to that prepared by conventional impregnation (Ni/SiO 2I ). With the phyllosilicate precursor nickel particles highly disperse on the surface, remaining OH groups in the unreduced phyllosilicates promote nickel dispersion and carbon elimination. We also show that high dispersion of Ni and strong metal−support interaction of Ni/SiO 2P significantly promote ethanol conversion and H 2 production in ethanol steam reforming. Ni/SiO 2P produces less carbon deposition compared to Ni/SiO 2I ; for the latter, a surface layer of Ni 3 C formed during the deactivation.

This paper describes an investigation regarding the influence of Ni precursors on catalytic performances of Ni/ Al 2 O 3 catalysts in glycerol steam reforming. A series of Ni/ Al 2 O 3 is synthesized using four different precursors, nickel nitrate, nickel chloride, nickel acetate, and nickel acetylacetonate. Characterization results based on N 2 adsorption− desorption, X-ray diffraction, H 2 temperature-programmed reduction, H 2 chemisorption, transmission electron microscopy, and thermogravimetric analysis show that reduction degrees of nickel, nickel dispersion, and particle sizes of Ni/ Al 2 O 3 catalysts are closely dependent on the anion size and nature of the nickel precursors. Ni/Al 2 O 3 prepared by nickel acetate possesses the moderate Ni reduction degree, high Ni dispersion, and small nickel particle size, which possesses the highest H 2 yield. Reaction parameters are also examined, and 550 °C and a steam-to-carbon ratio of 3 are optimized. Moreover, coke deposition, mainly graphite species, leads to the deactivation of Ni/Al 2 O 3 catalysts in glycerol steam reforming. Nickel chloridederived Ni/Al 2 O 3 catalysts suffer from severe coke deposition and low reaction activity due to large Ni particle size, low Ni dispersion, and residual chloride.

This paper describes the sorption of carbon dioxide for enhanced steam reforming of ethanol to produce hydrogen via Ni-CaO-Al 2 O 3 multifunctional catalysts derived from hydrotalcite-like compounds (HTlcs). The catalysts were characterized by N 2 adsorption-desorption, X-ray powder diffraction (XRD), transmission electron microscopy (TEM), H 2 temperature-programmed reduction (H 2 -TPR) and thermogravimetric analysis (TGA) and tested in sorption enhanced steam reforming of ethanol (SESRE), in which products were monitored by an online mass spectrometer (MS). The Ni-CaO-Al 2 O 3 catalysts possess uniform distribution of Ni, Ca and Al, contributing significantly to the excellent CO 2 adsorbent capacity and reforming activity in SESRE. We have also examined the effect of Ca/Al ratios on Ni dispersion, CaO particle size, and catalytic reactivity; a Ca/Al of 3.0 was optimized. The Ni-CaO-Al 2 O 3 catalysts outperform the conventional mixture of CaO adsorbents and Ni/Al 2 O 3 catalysts for SESRE. CH 3 CH 2 OH + 3H 2 O 4 2CO 2 + 6H 2 , DH r,298 K ¼ 173 kJ mol À1 (1) CO + H 2 O 4 CO 2 + H 2 , DH r,298 K ¼ À41 kJ mol À1 (2) CaO (S) + CO 2 4 CaCO 3(S) , DH r,298 K ¼ À178 kJ mol À1 (3)

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