A LaNi1-xZnxO3-delta perovskite structured oxide catalyst is prepared with a one-step citrate complex method and applied as the precursor of the catalyst in ethanol steam reforming (ESR) reaction. The Zn substitution makes the perovskite-oxide difficult to be reduced due to the strong bond of La-O-Zn, which favors the formation of small Ni particle size thus moderates the sintering of nickel. The doping of Zn also effectively suppresses coking in the reaction. The spillover of oxygen and the electron donation effect of Zn species to the surface of metallic nickel is confirmed with an XPS technique. The doping amount shows an optimum value and a LaNi0.85Zn0.15O3-delta sample exhibits the highest H-2 product yield and best stability at 700 degrees C. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.