Ni/ZrO2 catalysts in ethanol steam reforming: Inhibition of coke formation by CaO-doping

• CaO addition to the support was effective in inhibiting coke formation.
• The effects of CaO-doping on Ni/ZrO2 catalysts were evaluated.
• The addition of CaO increased the NiO fraction reducible at lower temperatures.
• Ca2+ replaced the Zr4+ cation and generated oxygen vacancies.
• A strong decrease of the Lewis acidity of the support was detected.

In this work the performance of CaO-doped Ni/ZrO2 catalysts in ethanol steam reforming was studied. The addition of CaO did not affect the morphology or the crystalline structure of the support. On the contrary, Ni reducibility markedly increased. Moreover, the Lewis acidity of zirconia gradually decreased as the CaO content increased, thus inhibiting coke deposition and improving the carbon balance. The addition of a basic oxide helps to prevent some of the side reactions responsible for coke formation and deposition, that can gradually deactivate the catalyst.

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