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The performance of different Ni/Ce 1Àx Zr x O 2 (ss) catalysts of varying composition (x ¼ 0, 0.12, 0.18 and 0.26) were investigated for hydrogen production by ethanol steam reforming (ESR). All catalysts were prepared by co-precipitation method and characterized for their surface area, pore volume, structure and morphology using different techniques (N 2 -BET, XRD and HRTEM). The Ce 4+ /Ce 3+ redox couple in ceriacontaining catalysts is known to be responsible for the OSC of these materials, so, the redox behaviors of these materials were investigated by EPR. Reaction parameters were optimized by varying steam to ethanol molar ratio (6, 8 and 10) in order to produce hydrogen with low carbon monoxide formation as low as possible. The minimum amounts of CO and carbon deposited are observed over Ni/CeZr-8 catalyst at 1 : 10 ethanol-water ratios. The obtained data are compared with data obtained from oxidative steam reforming of ethanol (OSRE) using hydrogen peroxide as an oxidant. The activity data indicated that hydrogen peroxide is an effective oxidant for OSRE over Ni/Ce 1Àx Zr x O 2 catalysts due to its ability to suppress CO formation and increase H 2 /CO ratio.

Summary The improvement of hydrogen concentration in the obtained syngas during methane dry reforming is strongly demanded. Additionally, enhancement of CO2 and CH4 conversions has been of high preference. In line with these aims, this research work studies the impact of incorporating lanthanum metal either as a catalytic promoter or as a cosupport, on the efficiency of the reforming process. Two percentages namely 2.5 and 5 wt% were added to a catalyst composed of Ni(10%)–Zr(90%). Thus, four catalytic composites for methane dry reforming were produced. The prepared composites were characterized using XRD, N2‐physisorption, HR‐TEM, TPR, and Raman spectrometer. The catalytic performance and H2/CO ratio were deteriorated as a result of using lanthanum as a promoter, when compared to the nonpromoted zirconia‐supported Ni catalyst. However, using La as a cosupport showed a strong positive effect on reactants' conversions, the resultant H2/CO ratio and H2 yield%. The most active catalyst in this work was Ni/5La‐ZrO2 catalyst; it showed 73% of hydrogen yield and syngas with H2/CO molar ratio of 1.61 which can be used as feed gas in the Fischer–Tropsch process for the production petroleum distillates.

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