Hydrogen production by steam reforming of ethanol over mesoporous Ni-Al2O3-ZrO2 xerogel catalysts (denoted as XNiAZ) with different nickel content (X, wt%) was studied. A single-step epoxide-driven sol-gel method was employed for the preparation of the catalysts. The effect of nickel content of XNiAZ catalysts on their physicochemical properties and catalytic activities was investigated. All the XNiAZ catalysts exhibited a well-developed mesoporous structure and they dominantly showed an amorphous NiO-Al2O3-ZrO2 composite phase, leading to high dispersion of NiO. Nickel surface area and reducibility of XNiAZ catalysts showed volcano-shaped trends with respect to nickel content. Nickel surface area of XNiAZ catalysts played a key role in determining the catalytic performance in the steam reforming of ethanol; an optimal nickel content was required for maximum production of hydrogen. Among the catalysts tested, 15NiAZ catalyst with the highest nickel surface area exhibited the best catalytic performance in the steam reforming of ethanol. In addition, 15NiAZ catalyst showed high and stable hydrogen yields under different total feed rate, demonstrating its potential applicability in large-scale hydrogen production. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.