| Hydrogen is an efficient and clean energy, which can simultaneously solve the energy crisis and environmental pollution. In the last few decades, the rapid development of fuel cell technology broadens the application of hydrogen. However, in the traditional hydrogen production methods, fossil materials are used, which are non-renewable and discharge greenhouse gases. The steam reforming of bio-ethanol is one of the indirect biomass to hydrogen ways, which is a CO2-closed cycle (not to generate new CO2). Research and development of hydrogen production from ethanol is of great theoretical and practical significance. In this paper, the thermodynamics of steam reforming of ethanol (SRE), partial oxidation of ethanol (POE) and carbon dioxide reforming of ethanol (DRE) were studied; a series of nickel based catalysts were prepared by different methods, characterized by BET, TPR, XPS and XRD, and studied in the ethanol steam reforming.The thermodynamic results showed that for the direct decomposition of ethanol (DE), SRE, POE and DRE, high temperature favored H2 and CO formation, but unfavored CH4 and coke formation; the addition of inert component favored H2 production and coke elimination; high pressure unfavored H2 production and coke elimination. The optimal operating conditions were found for the supply of fuels to molten carbonate fuel cell (MCFC) and solid oxide fuel cell (SOFC). The noncatalytic reaction path was investigated through Density Function Theory (DFT) and thermodynamic analysis. The results showed that ethanol is first decomposed to methane and formaldehyde, and then formaldehyde is converted to H2 and CO. In SRE, the hydrogen partially comes from the water molecules, and water is also involved in the production of methane, formaldehyde and methanol.The SRE was studied over Ni metal catalyst. It is found that acid treatment increased the surface area and activity of the catalysts; high temperature promoted the formation of H2 and CO, but the yields of H2 and CO were still lower than the thermodynamic equilibrium values; the increase of H2O/C2H5OH molar ratio increased the yields of H2 and CO2; increasing LHSV decreased the yields of H2 and CO. The SRE was also investigated over a series of 10NixCu/MgO/γ-Al2O3 catalysts prepared by an impregnation method. 10Ni5Cu/MgO/γ-Al2O3 exhibited excellent catalytic performance. Ethanol conversion rate and the hydrogen yield were 100% and 71% over this catalyst, respectively. The increase of water-to-ethanol molar ratio increased the yield of hydrogen, but decreased the yields of methane and CO. The increase of LHSV decreased the yield of hydrogen.The adsorption of CO on the surface of Ni(111) was investigated through DFT. The results showed that CO was easy to be adsorbed in a bridge mode on the surface of Ni(111), and C–O bond was weakened. There were appreciable electron feedbacks from Ni d orbits. With the addition of Cu, Cu enriched on the surface of the catalyst and donated electron to Ni, which made the C–O bond strengthen and therefore the carbon formation was restrained. Methane formation, resulting from the hydrogenation of deposited carbon, was reduced.The SRE was also investigated over Ni metal oxide catalysts prepared by precipitation, citric acid complexing and urea combustion methods. The results showed that NiO-MgO catalyst gave the highest activity and hydrogen yield at low temperatures; the activity of the catalysts did not change significantly with LHSV below 20 ml·g-1·h-1.
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