Добірка наукової літератури з теми "Mixed (NI)MoW catalysts"

Two trimetallic sulfurs, MoWNiS and MoWSNi, were synthesized to be used as a catalyst in hydrodesulfurization reactions. The mixed oxide mesoporous nanostructured MoO3-WO3 with an Mo:W atomic ratio of 1:1 was used as the precursor. The first catalyst was prepared by impregnating nickel in the oxide precursor and then subsequent sulfiding with an H2S/H2 mix at 400 °C for 2 hours. The second catalyst was prepared by sulfiding the precursor and then impregnating the nickel, and finally reducing the material with a H2/N2 at 350 °C. In both catalysts the Mo:W:Ni atomic ratio was maintained at 1:1:0.5. The materials obtained were characterized by physical adsorption of nitrogen, X-ray diffraction, scanning electron microscopy, transmission electron microscopy. Furthermore, the materials obtained were evaluated by a dibenzothiophene hydrodesulfuration reaction. The diffraction patterns show that both materials are polycrystalline and mainly of MoS2 and WS2 phases.

A surfactant-assisted co-precipitation method was used to prepare the catalysts Co,Ni,Pd/CaO, Co,Ni,Pd/Ca0.97La3+0.03O, Co,Ni,Pd/Ca0.93La3+0.07O, and Co,Ni,Pd/Ca0.85La3+0.15O (1% each of Co, Ni, and Pd). La2O3 doping effect on the activity and stability of Co,Ni,Pd/CaO catalysts was investigated in dry reforming of methane. Catalysts were characterized by several techniques (X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray Fluorescence (XRF), Fourier Transform Infra Red (FTIR), Temperature Programmed Desorption H2 (H2-TPR), Transmission electron microscopes (TEM), and Temperature Gravimetric Analysis (TGA)) and were tested in a fixed-bed reactor at 900 °C and (Gas Hourly Specific Velocity (GHSV) = 15000 mL.gcat−1.h−1, atmospheric pressure). Adding La2O3 had little effect on the morphology of the Co,Ni,Pd/CaO catalyst. However, it played a crucial role in enhancing the catalyst’s reducibility and CO2 adsorption at high temperatures, as indicated by the activity and stability of the Co,Ni,Pd/CaO catalyst. The carbon deposition on utilized catalysts after 5 hours at 900 °C was examined using TEM and thermal gravimetric analysis (TGA) techniques. Compared to Co,Ni,Pd/CaO catalysts across the entire temperature range, the tri-metallic Co,Ni,Pd/Ca0.85La3+0.15O catalyst with a lanthanum promoter demonstrated a greater conversion of CH4 (84%) and CO2 (92 %) at a 1:1 CH4:CO2 ratio. The selectivity of H2/CO reduced in the following order: Co,Ni,Pd/Ca0.85La3+0.15O > Co,Ni,Pd/Ca0.93La3+0.07O > Co,Ni,Pd/Ca0.97La3+0.03O > Co,Ni,Pd/CaO. Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Flame spray pyrolysis was used to produce nanosized Ni-based catalysts starting from different mixed oxides. LaNiO3 and CeNiO3 were used as base materials and the formulation was varied by mixing them or incorporating variable amounts of ZrO2 or SrO during the synthesis. The catalysts were tested for the steam reforming of glycerol. One of the key problems for this application is the resistance to deactivation by sintering and coking, which may be increased by (1) improving Ni dispersion through the production of a Ni-La or Ni-Ce mixed oxide precursor, and then reduced; (2) using an oxide as ZrO2, which established a strong interaction with Ni and possesses high thermal resistance; (3) decreasing the surface acidity of ZrO2 through a basic promoter/support, such as La2O3; and (4) adding a promoter/support with very high oxygen mobility such as CeO2. A further key feature is the use of a high temperature synthesis, such as flame spray pyrolysis, to improve the overall thermal resistance of the oxides. These strategies proved effective to obtain active and stable catalysts at least for 20 h on stream with very limited coke formation.

Catalytic wet air oxidation of Basic Yellow 11 (BY11), a basic dye, was studied in a batch reactor. Layered double hydroxides with the hydrotalcite-like structure containing nickel or iron cations have been prepared by coprecipitation and subsequently calcined leading to Ni- and Fe-doped mixed oxides, respectively. Compared with the results in the wet air oxidation of BY11, these catalysts showed high activity for total organic carbon (TOC), toxicity and dye removal at 120 °C and 50 bars after 120 min. It has been demonstrated that the activity depended strongly on the presence of catalyst. The results show that catalysts containing nickel provide a higher extent of oxidation of the dye whereas the reaction carried out with the iron catalyst is faster. The Ni and Fe dispersion determined from the TPR results was higher for the catalysts with a lower Ni or Fe content and decreased for higher Ni or Fe contents. On the basis of activity and selectivity, the Ni containing catalyst with the medium (3%) Ni content was found to be the best catalyst. Finally, a relationship between metal content of the catalyst and reaction rate has been established.

Les raffineurs doivent faire face au renforcement des exigences environnementales relatives à la teneur en soufre des carburants ainsi qu'à l'utilisation de pétrole brut plus lourd pour la production de carburants à l'aide de procédés catalytiques d'hydrotraitement. Une des approches pour améliorer l'activité catalytique est le développement de sulfures trimétalliques NiMoW. Sur des catalyseurs supportés sur alumine, l'utilisation de précurseurs mixtes, les hétéropolyacides (HPA) de Keggin H4SiMo1W11O40 et H4SiMo3W9O40, s'est avérée plus favorable à la formation d'une phase MoWS mixte hautement active que le mélange de deux précurseurs monométalliques H4SiMo12O40 et H4SiW12O40. Dans cette étude, un nouveau protocole pour la synthèse de précurseurs mixtes H4SiMonW12-nO40 avec n = 6 et 9 a été développé. Ces nouveaux composés ont été caractérisés par spectroscopie IR et Raman, ainsi que par DRX sur monocristal. Des catalyseurs d'hydrotraitement massiques et supportés ont été synthétisés à partir de cette série d’HPA. Concernant les catalyseurs non promus supportés sur alumine, l'influence du rapport atomique Mo/(Mo+W) sur la composition de la phase active a été étudié ainsi que son effet sur l'activité catalytique dans des réactions d'hydrotraitement de composés modèles (hydrodésulfuration du dibenzothiophène et hydrogénation du naphtalène). Il a été observé par HAADF que pour un rapport atomique Mo/(Mo+W) égal à 0,25 et 0,5, la structure de la phase active après sulfuration en phase gaz est une structure core-shell. Une augmentation de la teneur en molybdène jusqu'à un ratio Mo/(Mo+W) de 0,75 conduit à une structure désordonnée de la phase active, correspondant à une diminution de l'activité catalytique. En revanche, pour les catalyseurs obtenus à partir d'un mélange des HPA monométalliques, la phase active s’est avérée principalement constituée de cristallites monométalliques MoS et WS, quel que soit le rapport atomique Mo/(Mo+W), avec une activité inférieure à celle des catalyseurs préparés à partir de HPA mixtes.L'influence du rapport atomique Mo/(Mo+W) pour les systèmes promus au nickel, après sulfuration en phase liquide afin de se rapprocher au maximum des conditions industrielles, a également été étudiée. L'introduction de Ni n'empêche pas la formation de la phase active mixte MoWS, ce qui a été confirmé par HAADF et EXAFS. De plus, l’effet d’inhibition dû à la présence de composés azotés dans la charge à hydrotraiter a été analysé. Il a été observé que les catalyseurs NiMoW/Al2O3 riches en tungstène sont plus résistants à la présence des composés azotés et que le choix de la composition du catalyseur doit être adapté selon la composition de la charge traitée.La dissolution par acide du support alumine a permis d'obtenir à partir d'échantillons sulfurés MonW12-n/Al2O3 des catalyseurs massiques MoWS avec une concentration en phase active supérieure à 90%. Des analyses par ToF-SIMS et EXAFS ont montré que la phase MoWS2 mixte est présente à la fois dans les catalyseurs synthétisés à partir des HPA mixtes et dans les échantillons obtenus à partir du mélange de deux HPA. Cependant, la concentration en sulfures mixtes dans le premier cas est beaucoup plus élevée, du fait que des cristallites mixtes étaient déjà présentes dans le solide supporté, alors que dans le cas du mélange des deux HPA, une phase mixte se forme à la suite du frittage des particules lors de la re-sulfuration. La concentration élevée en sulfures mixtes a permis d’obtenir une activité plus élevée des catalyseurs dans des réactions modèles.Enfin, le remplacement de l'alumine par une silice mésostructurée a permis d'augmenter l'activité des catalyseurs MoW non promus. Cependant, les valeurs similaires du degré de sulfuration, de la dispersion ainsi que des résultats des tests catalytiques entre les catalyseurs obtenus à partir des deux types de précurseurs semblent indiquer que la formation de phase mixte MoWS ne se produit pas sur ce type de support
Refiners have to face the strengthening of environmental requirements for the sulfur content in fuels together the use of heavier crude oil for producing market fuels using hydrotreatment catalytic processes. One of the approaches to improve catalytic activity is the development of bulk and supported ternary NiMoW sulfide catalysts following the recent introduction of industrial mixed bulk NiMoW catalysts NEBULA and Celestia. Previously, for supported alumina catalysts, the use of mixed precursors, H4SiMo1W11O40 and H4SiMo3W9O40 Keggin heteropyacids, has shown a better positive effect on the formation of a highly active mixed MoWS phase than the use of two corresponding monometallic H4SiMo12O40 and H4SiMo12O40 precursors. In this study, a new protocol for the synthesis of mixed Keggin-type H4SiMonW12-nO40 precursors with n = 6 and 9 has been developed. The new compounds were characterized by IR and Raman spectroscopy, as well as single-crystal XRD. Bulk and supported hydrotreating catalysts based on the whole series of H4SiMonW12-nO40 HPAs were synthesized. The influence of the atomic Mo/(Mo+W) ratio on the composition and structure of the active phase and its effect on the catalytic activity of unpromoted alumina supported catalysts in model hydrotreating reactions (hydrodesulfurization of dibenzothiophene and hydrogenation of naphthalene) were studied in detail. It was found that for an atomic Mo/(Mo+W) ratio equal to 0.25 and 0.5, the structure of the active phase under gas-phase sulfidation conditions is a core-shell structure, according to HAADF. A further increase in the molybdenum content up to 0.75 leads to disordering of the active phase structure, which has a negative effect on the catalytic activity. In contrast, for the catalysts obtained from a mixture of monometallic H4SiMo12O40 and H4SiMo12O40 HPAs, the active phase consisted mainly of monometallic MoS2 and WS2 crystallites, regardless of the atomic Mo/(Mo+W) ratio, as a result of which the catalysts showed lower activity compared to the samples prepared from mixed HPAs.The study of the influence of atomic Mo/(Mo+W) ratio for Ni-promoted systems, under the liquid-phase sulfidation in order to be as close as possible to industrial conditions, is also reported. It was shown that the introduction of Ni does not prevent the formation of a mixed MoWS active phase, which was confirmed by HAADF and EXAFS. Moreover, testing in the presence of a nitrogen-containing component made it possible to further study the inhibition on catalytic reactions. It was found that tungsten-rich NiMoW/Al2O3 catalysts are more resistant to the action of nitrogen-containing compounds indicating that the choice of the catalyst composition should be adapted to the composition of the processed feedstock.The use of acid (HF) etching of the alumina support made it possible to obtain from sulfided MonW12-n/Al2O3 samples bulk MoWS catalysts with an active phase concentration of more than 90%. ToF-SIMS and EXAFS showed that the mixed MoWS2 phase is present both in the catalysts synthesized from the mixed HPAs and in the samples obtained from the mixture of two HPAs. However, the concentration of mixed sulfides in the first case is much higher, due to the fact that mixed crystallites have already been formed, whereas in the case of a mixture of two HPAs, a mixed phase is formed as a result of the sintering of particles during re-sulfidation. The high concentration of mixed sulfides made it possible to provide a higher activity of catalysts in model reactions.Replacing alumina with mesostructured silica made it possible to increase the activity of unpromoted MoW catalysts. At the same time, similar values of the degree of sulfidation and dispersion, as well as the results of catalytic tests, seem to indicate that the formation of mixed MoWS2 phase does not occur on this type of supports, which requires additional research to be confirmed

Le développement de catalyseurs HDS plus efficaces est un enjeu majeur pour répondre aux exigences environnementales concernant la teneur en soufre dans les carburants. L'une des approches pour améliorer l'activité catalytique est le développement de catalyseurs ternaires NiMoW. Cette étude se concentre sur la synthèse et la caractérisation de catalyseurs (Ni)MoW préparés à partir hétéropolyacides (HPA) mixtes SiMo1W11 et SiMo3W9 de structure de Keggin. Les catalyseurs basés sur les HPAs monométalliques SiMo12 et SiW12 et leurs mélanges ont été préparés et étudiés. Les solides ont été caractérisés par spectroscopie Raman, SPX et MET. Les propriétés catalytiques ont été évaluées dans des réactions d’HDS, d'HYD et d'HDN. Les propriétés physico-chimiques et l'activité catalytique dépendent de la nature des précurseurs initiaux. La genèse de la phase active des catalyseurs a été étudiée lors de la sulfuration in-situ sous H2S/H2 par SAX au synchrotron SOLEIL. La transformation du W dans les catalyseurs basés sur les précurseurs moléculaires mixtes, présentant une proximité nanométrique Mo-W, est plus rapide que celle observée dans le cas des catalyseurs préparés à partir du mélange de deux HPAs et conduit à la sulfuration simultanée des métaux et à la formation de la phase mixte MoWS2. La présence de feuillets mixtes (Ni)MoxW1-xS2 lorsque des HPA mixtes ont été utilisés a été mise en évidence par EXAFS et HAADF. La substitution d'un ou trois atomes de tungstène par du molybdène dans le cas des HPAs mixtes a entraîné une augmentation significative des activités en HDS et en HYD, par rapport à celles obtenues pour les catalyseurs préparés à partir du mélange de HPAs
Developing highly active HDS catalysts has been one of the most challenging and important subjects because of strengthening of environmental requirements for the sulfur content in fuels. One of the approaches to improve catalytic activity is the development of ternary NiMoW catalysts. This investigation focuses on the synthesis and characterization of (Ni)MoW catalysts prepared by using mixed SiMo1W11 and SiMo3W9 heteropolyacids (HPA) with Keggin structure. For comparison purposes, catalysts based on monometallic SiMo12 and SiW12 HPAs and their mixtures were also prepared and studied. The samples were characterized by Raman spectroscopy, X-ray Photoelectron Spectroscopy, HRTEM. The catalytic properties were evaluated in HDS, HYD and HDN reactions. The physical-chemical properties and catalytic activity depends on the nature of the initial precursors. Genesis of the active phase was studied during in situ H2S/H2 sulfidation of the catalysts by X-ray absorption at SOLEIL Synchrotron. It was found that W transformation from mixed molecular precursors with a Mo-W nanoscale proximity is faster than from mixture of two HPAs resulting in simultaneously sulfidation of metals and the formation of mixed MoWS2 phase. The presence of mixed (Ni)MoxW1-xS2 slabs when mixed HPAs were used for preparation of the catalyst was evidenced by EXAFS and High angle annular dark field scanning transmission electron microscopy. Substitution of one or three tungsten atoms by molybdenum ones in the case of mixed HPAs resulted in a significant increase in HDS as well as in HYD activity, compared to those obtained for catalysts prepared from mixture of monometallic HPAs

Le développement de catalyseurs HDS plus efficaces est un enjeu majeur pour répondre aux exigences environnementales concernant la teneur en soufre dans les carburants. L'une des approches pour améliorer l'activité catalytique est le développement de catalyseurs ternaires NiMoW. Cette étude se concentre sur la synthèse et la caractérisation de catalyseurs (Ni)MoW préparés à partir hétéropolyacides (HPA) mixtes SiMo1W11 et SiMo3W9 de structure de Keggin. Les catalyseurs basés sur les HPAs monométalliques SiMo12 et SiW12 et leurs mélanges ont été préparés et étudiés. Les solides ont été caractérisés par spectroscopie Raman, SPX et MET. Les propriétés catalytiques ont été évaluées dans des réactions d’HDS, d'HYD et d'HDN. Les propriétés physico-chimiques et l'activité catalytique dépendent de la nature des précurseurs initiaux. La genèse de la phase active des catalyseurs a été étudiée lors de la sulfuration in-situ sous H2S/H2 par SAX au synchrotron SOLEIL. La transformation du W dans les catalyseurs basés sur les précurseurs moléculaires mixtes, présentant une proximité nanométrique Mo-W, est plus rapide que celle observée dans le cas des catalyseurs préparés à partir du mélange de deux HPAs et conduit à la sulfuration simultanée des métaux et à la formation de la phase mixte MoWS2. La présence de feuillets mixtes (Ni)MoxW1-xS2 lorsque des HPA mixtes ont été utilisés a été mise en évidence par EXAFS et HAADF. La substitution d'un ou trois atomes de tungstène par du molybdène dans le cas des HPAs mixtes a entraîné une augmentation significative des activités en HDS et en HYD, par rapport à celles obtenues pour les catalyseurs préparés à partir du mélange de HPAs
Developing highly active HDS catalysts has been one of the most challenging and important subjects because of strengthening of environmental requirements for the sulfur content in fuels. One of the approaches to improve catalytic activity is the development of ternary NiMoW catalysts. This investigation focuses on the synthesis and characterization of (Ni)MoW catalysts prepared by using mixed SiMo1W11 and SiMo3W9 heteropolyacids (HPA) with Keggin structure. For comparison purposes, catalysts based on monometallic SiMo12 and SiW12 HPAs and their mixtures were also prepared and studied. The samples were characterized by Raman spectroscopy, X-ray Photoelectron Spectroscopy, HRTEM. The catalytic properties were evaluated in HDS, HYD and HDN reactions. The physical-chemical properties and catalytic activity depends on the nature of the initial precursors. Genesis of the active phase was studied during in situ H2S/H2 sulfidation of the catalysts by X-ray absorption at SOLEIL Synchrotron. It was found that W transformation from mixed molecular precursors with a Mo-W nanoscale proximity is faster than from mixture of two HPAs resulting in simultaneously sulfidation of metals and the formation of mixed MoWS2 phase. The presence of mixed (Ni)MoxW1-xS2 slabs when mixed HPAs were used for preparation of the catalyst was evidenced by EXAFS and High angle annular dark field scanning transmission electron microscopy. Substitution of one or three tungsten atoms by molybdenum ones in the case of mixed HPAs resulted in a significant increase in HDS as well as in HYD activity, compared to those obtained for catalysts prepared from mixture of monometallic HPAs

This work of thesis is focused on the synthesis, characterization and testing of Ni-based catalysts supported on the ZrO2, Ce34Zr66O2, Ce33Zr63Pr4O2 mixed oxides to conduct the reactions of carbon dioxide methanation and steam reforming of methane at low temperature. The catalysts are prepared employing the water-in-oil synthetic technique through the incipient wetness impregnation and bulk methods to evaluate the differences resulting from their performance in a fixed-bed plant. The different supports are compared as well to investigate the effect of the Ce and Pr addition on the oxygen storage capacity of the catalysts and the consequent yields and conversions of methane. The testing of a Ni-impregnated catalyst synthetized at the ICPEES-CNRs of Strasbourg with similar conditions as the ones employed in the laboratory of Bologna constitutes a further comparison to analyze in this work. Several characterization techniques are employed to correlate the structural properties of the samples to their performance in the plant. The comparisons show the bulk-synthetized-samples to achieve higher methane yields with respect to the incipient wetness impregnated ones even though they are significantly subjected to the sintering phenomena that can cause a severe loss of activity. The methane conversion as well shows consistently higher values if the reaction is performed with the bulk-synthetized catalysts, in particular an increasing trend is individuated corresponding to a progressively enhanced oxygen storage capacity that permits to overcome the carbon formation on the catalytic sites. Eventually, the interaction between the support and the active phase is thought to represent the fundamental parameter to consider to achieve higher activities in both of the reactions together with the specific selectivity towards the products.

碩士
國立臺灣科技大學
化學工程系
104
Hydrogen is a possible choice for future energy supplies. Hydrogen mainly comes from the steam reforming of methane (SRM), which contains a high ratio of H/C = 4. Industrial SRM operating temperature is around 700~900℃, but high temperature increase energy consumption and process stability. Therefore, the SRM at mid-temperatures (400–600°C) is examined in this study. A series of La2O3-ZrO2-CeO2-mixed oxide is studied as the support for Ni catalysts. Increase in CeO2 content results in increased activity and stability at ≦500℃. The prepared Ni/LZC, with La:Zr:Ce = 1:1:1 (mole), catalysts readily catalyzed SRM and can reach equilibrium conversion starting from 400°C at WHSV = 2 h-1. The best-performed Ni/LZC provides high H2 yield of around 4 and low CO selectivity of less than 5% and the catalyst shows no activity loss during SRM at 500°C for 24 hours. TGA demonstrate that carbon deposition is significantly suppressed on this catalyst. Moreover, XRD results show Ni particle size of around 10 nm when Ni content is as high as 40% and no particle agglomeration is observed after 24-h reaction test at 500°C. EXAFS analyses show a coordination number of Ni metal of around 6, which shows high Ni metal dispersion probably by enhance the interactions between Ni and the support.

碩士
國立中興大學
環境工程學系所
103
Take into consideration of today’s global energy crisis to investage the simultaneous recycling of waste plastic and generation of renewable energy in this study. The mixed gas is created by the gasification of waste plastic to produce the clean energy-hydrogen. The H2 production ability has been considerably increased by using Ni/SiO2 core-shell catalyst. SiO2 prepared by Stöber process was used as supports to prepare nickel core-shell catalyst. This study evaluated the effect of SiO2 core particles in various solvents (methanol, ethanol and isopropanol) on the morphological features and catalytic performances of Ni/SiO2 core-shell catalysts. Ni/SiO2 core-shell catalysts were prepared by the deposition-precipitation method and it was applied to generate hydrogen from the simulated mixed gas derived from the plastic waste gasification. Different synthesis parameters on the production of Ni/SiO2 core-shell catalyst were investigated to improve the bonding strength between the Ni active phase and SiO2 support, enhance dispersion of Ni/SiO2 and reduce the the grain size of active phase. The physico-chemical properties of the Ni/SiO2 core-shell catalysts were characterized by means of the FESEM, XRD, FTIR, TEM, H2-TPR, and BET method. Solvents resulted in different particle size of SiO2 support. Due to the difference in dielectric constants of solvents influenced the SiO2 nucleation process by changing the electrostatic repulsion and Van der Waals force of interaction between particles. The particle size of the prepared SiO2 support is in the order: SiO2-methanol < SiO2-ethanol < SiO2-isopropanol. Because of the bigger dielectric constant of methanol resulted in the smallest particle size and largest specific surface area of SiO2 particles which showed good dispersion of Ni/SiO2 core-shell catalyst and bonding between the Ni active phase and SiO2 support. Previous researches reported that the amount of steam is a key role in the catalystic gasification plastic waste. Further investigation of feed composition with different amounts (0, 0.34, 0.75 g-H2O/h) effected the hydrogen generation of Ni/SiO2-Methanol catalyst. However, Ni/SiO2- Methanol showed no hydrogen production at 600oC in the absence of steam. The Ni/SiO2-M catalyst can benefit by understanding an incresed H2 production rate at high steam content (0.75 g-H2O/h) because of the water gas shift reaction tending to form H2 from CO and H2O. Besides, steam reforming of methane occurs under a high steam content and at a high reaction temperature. The stability of Ni/SiO2 catalyst prepared with methanol a long term stability test carried out for 280 minutes with a steam content of 0.75 g-H2O/h at 800oC. The overall research confirmed that the Ni/SiO2 core-shell catalyst prepared with methanol has a strong bonding between the active phase and support due to the abundant formation of nickel phyllosilicates. Ni/SiO2- Methanol exhibited better stability during long term stability test. Experimental results of hydrogen production indicated that the highest catalytic activity is achieved by Ni/SiO2-Methanol catalyst, which is effective in catalytic H2 production from simulated mixed gas derived from the plastic waste gasification. The hydrogen production rate is 181 mmol/g-h at 800oC and steam content (0.75 g-H2O/h).

A series of well crystallized Ni-Co-Zn-Al LDHs materials has been prepared by the urea hydrolysis method as precursors of mixed oxide catalysts for the Ethanol Steam Reforming (ESR) reaction. The calcination of the layered precursors gives rise to high surface area mixed oxides, mainly a mixture of rock-salt phase (NiO), wurtzite phase (ZnO) and spinel phase. Both precursors and mixed oxides have been throughtfully characterized and the steam reforming of ethanol has been investigated over the calcined catalysts in flow reactor and in-situ FT-IR experiments. The data here reported provide evidence of the good catalytic activity of Co-Zn-Al and Co-Ni-Zn-Al catalysts prepared from hydrotalcite-like LHD precursors for ethanol steam reforming. At 823 K the most active Co/Ni catalyst containains a predominant spinel phase with composition near Zn0.58Ni0.42[Al0.44Co0.56]2O4 and small amounts of NiO and ZnO. On the other side, at 873 K the selectivity to hydrogen increases with cobalt content. In particular, the presence of cobalt increases selectivity to H2 and CO2 and decreases selectivity to methane in the low temperature range 720–870 K. The most selective catalyst is the Ni-free Co-Zn-Al mixed oxide essentially constituted by a single spinel type phase Zn0.55Co0.45[Al0.45Co0.55]2O4. Cobalt catalysts appear consequently to behave better than nickel based catalysts in this temperature range. The key feature for high selectivity to hydrogen is proposed to be associated to a stability of a relatively high oxidation state at the catalyst surface, the most relevant selectivity determining step being constituted by the evolution of surface acetate species. In fact, over oxidized catalyst surface the acetate species evolve producing carbon dioxide and hydrogen while over a more reduced surface they evolve giving rise to methane and COx. Water is supposed to have the main role of allowing surface sites to stay in an unreduced state at least in the temperature range 720–870 K.