CeO2-supported Pt/Ni catalyst for the renewable and clean H2 production via ethanol steam reforming

The steam reforming of biomass-derived ethanol is a promising method for hydrogen production. It needs the development of efficient catalysts, especially when the reaction is carried out at temperature lower than 600 °C. The performances of a bimetallic sample, based on Pt (3 wt.%) and Ni (10 wt.%) and supported on CeO2 were investigated, in terms of activity, selectivity and stability. Very interesting results were obtained in the range 250–600 °C, even with a stoichiometric water/ethanol molar ratio: the ethanol was completely converted at T ≥ 300 °C, with a products distribution extremely close to the equilibrium calculations. Moreover, the selectivity towards the desired compounds was very high, and as a consequence, the sample showed a very low coke selectivity (<1%) and a high stability, that was further improved with higher amount of water in the feed stream. The analysis of the products distribution as a function of contact time (3–600 ms) and temperature (340–480 °C) and the temperature programmed desorption (TPD) experiments, were used to hypothesize the possible reactions involved, in order to develop a mathematical model, able to simulate the kinetic behaviour of the low temperature-ethanol steam reforming over Pt/Ni/CeO2. Finally, a possible Pt/Ni/CeO2 catalyzed reaction pathway at 370 °C, was formulated, that includes the following steps: ethanol adsorption followed by dehydrogenation to acetaldehyde; intermediate decomposition and reforming to CH4, CO, H2 and CO2; CO-WGS and CO2 methanation reaction.

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► Pt/Ni/CeO2 showed promising performance at low temperature.
► The products distribution was close to the equilibrium.
► Few carbon depositions could occur, but not linked to the active sites.
► The water promotes the gasification reactions.
► The reaction pathway includes 6 reactions.