The catalytic properties of the M/Al2O3 (M = NiO, Au, NiO/Au) catalysts were investigated during the conversion of ethanol into C3+ hydrocarbons at 623 K. The NiO clusters with a size of 3.5 nm possess low selectivity (12.73%) and low turnover frequency (TOF) 0.051 s(-1). By decreasing the size of the Au particles from 15.1 to 5 nm, the TOF increased from 0.095 to 0.384 s(-1). The reaction with the 5-nm Au particles afforded C3+ hydrocarbons with a selectivity of 11.69%. Growing the Au particles by aggregating and/or forming the mixed NiO/Au particles resulted in an increased C3+ hydrocarbons selectivity, up to 34.19%. The peculiarities of the reaction mechanism are discussed, with the specific surface and electronic features of the prepared catalysts being considered. (c) 2012 Elsevier Inc. All rights reserved.