In the present study, three different structures with preferentially exposed crystal faces were supported on commercial carbon black by the polyol method (nanoparticles (NP/C), nanobars (NB/C) and nanorods (NR/C)). The electrocatalysts were characterized by XRD, TEM, TGA and cyclic voltammetry at three different ethanol concentrations. Considerable differences were found in terms of catalytic electroactivity. At all ethanol concentrations, the trend observed for the ethanol oxidation peak potential was preserved as follows: NB/C < NP/C< NR/C < commercial Pd/C. This result indicates that, from a thermodynamics point of view, the NB/C catalyst enclosed by Pd(100) facets presented the highest activity with respect to ethanol electro-oxidation among all of the catalysts studied.

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The activity of Ni/Al 2 O 3 -La 2 O 3 catalysts prepared by sol-gel process for hydrogen production using ethanol steam reforming was studied. The effect of Ni and La loading in the reaction activity and hydrogen selectivity was analyzed. The catalytic measurements were performed on a fixed-bed microreactor for a 6 h period; within this time, the catalysts showed partial deactivation. The catalyst containing 12 wt % La showed the highest yield to H 2 , but it also presented the highest deactivation. The other catalysts with the same Ni loading showed a decrease in H 2 yield over time. The increase of Ni loading from 5 to 10 wt % caused an increase in H 2 and CO yields in all La containing catalysts. The catalyst supported on sol-gel synthesized alumina showed the highest activity after 6 h on stream. This catalyst showed the lowest deactivation from all the systems that were studied. Polymeric and graphitic carbon were identified by DTA analysis of the spent catalysts. TGA analysis showed that the total coke deposited after reaction followed the trend: Ni/Al > Ni/12La ≈ Ni/8La > Ni/5La. However, less graphitic coke was identified on the catalysts as the lantana loading increased in the supports. Additionally, TEM results indicate that the radius of the graphite tubes decreased as the concentration of La in the support increased. A slight increase of H 2 and CO 2 yields was obtained when the water to ethanol mole ratio increased from 3 to 6. Higher deactivation was observed when more steam was fed to the reaction, even when lower carbon contents were determined by DTA-TGA analysis.

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