A recent paper by Abu Tarboush and Husein [1] discusses the catalytic activity of NiO nanopartides obtained from different precursors/sources and questions the catalytic activity of commercial NiO nanoparticles reported previously [2-4]. In this communication we would like to reiterate the salient features of our work [2-4] that have been overlooked in the article of reference [1]. Also we point out some misinterpretation of TG/DTA data and possible flaws in experimental procedure described [1]. Based on the TG/DTA data provided [1] we have found that in situ prepared NiO species are catalytically less active than the commercially available NiO nanoparticles under discussion. Few recommendations are suggested that may enable the authors to study in depth the catalytic role of NiO nanoparticles for post-adsorption asphaltenes oxidation. (C) 2013 Elsevier B.V. All rights reserved.