A series of Ni(5)Ti(x)Zr(5-x)O(15) ( x = 0, 1, 2.5, 4, and 5) catalysts was prepared by a one-step sol-gel method for use in hydrogen production by auto-thermal reforming of ethanol. The effect of the Ti:Zr ratio on the crystalline structure, electronic property, and catalytic performance of Ni(5)Ti(x)Zr(5-x)O(15) was investigated. The coexistence of titanium and zirconium favorably served to form metallic nickel ( Ni(0)) species, and the reducibility of nickel oxide species was closely related to the catalytic performance of Ni(5)Ti(x)Zr(5-x)O(15) catalysts. The hydrogen selectivity over Ni(5)Ti(x)Zr(5-x)O(15) catalysts showed a volcano-shaped curve with respect to titanium substitution. Along with the reducibility, the water-activation ability of ZrO(2) was an important factor affecting the catalytic performance. Among the catalysts tested, Ni(5)Ti(x)Zr(5-x)O(15) showed the best catalytic performance. (C) 2008 Elsevier Ltd. All rights reserved.