Nickel-lanthanum composite oxides, LaNiO(x), were used for steam reforming of ethanol (SRE). The composite oxides (with 3:1, 1:1, 1:3 M ratios, assigned as 3La-1Ni, 1La-1Ni, and 1La-3Ni, respectively) were prepared by co-precipitation-oxidation (PO) and assisted with ultrasonic irradiation (240 W). Meanwhile, the as-prepared 1La-1Ni sample was further calcined at 300 and 700 degrees C for 2 h (assigned as C300 and C700). All samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and temperature programmed reduction (TPR). Catalytic activities towards the SRE reaction were tested from 300 to 450 degrees C in a fixed-bed reactor. The study focused on deriving optimized composition of composites and compared the effect on the reduction pretreatment under 200 degrees C [assigned with (H)]. The results indicated that the ethanol conversion reached completion around 325 degrees C for the 1La-1Ni(H) sample while it required 400 degrees C for the 1La-1Ni sample with a minor CO distribution for both samples under an H(2)O/EtOH molar ratio of 13 and 22,000 h(-1) GHSV. The yield of hydrogen (Y(H2)) approached 5.2 around 375 degrees C for the 1La-1Ni(H) sample. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.